Changes in Disc Status and Condylar Regeneration After Intracapsular Condylar Fractures in Rabbits

BACKGROUND

The treatment procedure for intracapsular condylar fractures (ICF) is still being debated. The temporomandibular joint (TMJ) disc is a key factor for treating ICF. The study aims to investigate the changes in TMJ disc status and condylar cartilage regeneration following ICF in a rabbit model, to assist in planning treatment.

METHODS

Adolescent and adult rabbits received surgery on the left TMJs: (1) ICF with anterior disc displacement, (2) ICF with the removal of the ICF segment and disc. The animals were euthanized immediately, and at 4, 8, and 12 weeks after surgery. Their left TMJs were collected for histological, SOX 9 immunohistochemical, and micro-CT analyses.

RESULTS

All 36 TMJs (100%) showed anterior disc displacement at 4, 8, and 12 weeks after surgery. Also, condylar cartilage regeneration was observed in all 36 joints. Notably, partial regeneration of condylar cartilage was noted at 4 weeks after removal of the disc and ICF fractured segment in both adolescent and adult groups.

CONCLUSION

Anterior displaced disc after ICF in adolescent and adult rabbits exhibited sustained disc displacement without therapeutic intervention. TMJ disc and associated attachment are crucial in the condylar cartilage regeneration after ICF.

Factors related to risk of recurrence and recurrence free survival in ameloblastoma of the Jaws: A single centre retrospective analysis

PURPOSE

Ameloblastoma is a benign tumor originating from odontogenic epithelium with a global incidence of about 0.5 cases per million persons per year. The overall recurrence rate of ameloblastomas range from 55% -90%. In this retrospective study we have analyzed the factors associated with recurrence and recurrence free survival in ameloblastoma of the jaws.

METHODS

Retrospective chart review of 10 years was done from records directory. All demographic data, data on diagnostic modalities, clinical presentations, radiology, management and histology were taken into consideration. Kaplan Meir estimator was used to evaluate recurrence rate and Cox regression analysis (univariate and multivariate) was used to evaluate the odds ratio to find out the possible factors influencing risk of recurrence and influence recurrence free survival. ROC curve (Receiver Operating Characteristic) was used to find out the optimal cut off point for size of the lesion in predicting recurrence. A p value of < 0.05 was considered statistically significant at 95% confidence interval.

RESULTS

A total of 75 patients had recurrence with a median follow up of 65 months. The overall 5 year RFS was 19.5%. Conventional ameloblastomas, cortical/ soft tissue invasion, conservative treatment and tumor size ≥ 4 cm were independent predictors of recurrence.

CONCLUSION

Aggressive treatment is preferred for conventional ameloblastomas ≥ 4 cm with cortical/ soft tissue invasion.

Comparative analysis of the fit quality of monolithic zirconia veneers produced through traditional and digital workflows using silicone replica technique: an in vitro study

BACKGROUND

The success of a restoration largely depends on the quality of its fit. This study aimed to investigate the fit quality of monolithic zirconia veneers (MZVs) produced through traditional and digital workflows.

METHODS

A typodont maxillary right central incisor was prepared. The maxillary arch with the prepared tooth was scanned with Trios 3 Pod intra-oral scanner (IOS), which served as a pattern to create thirty 3D resin models through printing. Additionally, thirty conventional impressions of the maxillary with the prepared tooth were taken using polyvinyl siloxane (PVS) impression material. These impressions were cast using dental gypsum products to create thirty stone dies, which were then scanned externally. Sixty MZVs were milled from multi-layered zirconia disks. The marginal and internal gaps of restorations were assessed using the silicone replica technique.

RESULTS

The highest marginal accuracy for both the conventional and digital impression groups was observed in the cervical area, with values of 74.6 μm and 61.9 μm, respectively. The smallest internal gaps for both groups were also recorded in the cervical area, at 109.9 μm for the conventional group and 109.7 μm for the digital group. The digital group exhibited better marginal fit, particularly in the incisal and mesial areas (79.3 μm and 75.7 μm, respectively), compared to the conventional group (88.1 μm and 90.8 μm). No statistically significant differences in internal fit were observed.

CONCLUSION

MZVs fabricated using the digital workflow exhibited superior marginal fit compared to those fabricated using the conventional workflow, though both techniques yielded clinically acceptable results.

Could Pulsed Wave Tissue Doppler Imaging Solve the Diagnostic Dilemma of Right Atrial Masses and Pseudomasses? A Case Series and Literature Review

Even if rarely detected, right atrial (RA) masses represent a diagnostic challenge due to their heterogeneous presentation. Para-physiological RA structures, such as a prominent Eustachian valve, Chiari's network, and lipomatous atrial hypertrophy, may easily be misinterpreted as pathological RA masses, including thrombi, myxomas, and vegetations. Each pathological mass should always be correlated with adequate clinical, anamnestic, and laboratory data. However, the differential diagnosis between pathological RA masses may be challenging due to common constitutional symptoms, as in the case of vegetations and myxoma, which present with fever and analogous complications such as systemic embolism. The implementation of transthoracic echocardiography (TTE) with pulsed wave (PW) tissue Doppler imaging (TDI) may improve the visualization and differentiation of intracardiac masses through different color coding of the pathological structure compared to surrounding tissue. More remarkably, PW-TDI can provide a detailed assessment of the specific pattern of motion of each intracardiac mass, with important clinical implications. Specifically, a TDI-derived pattern of incoherent motion is typical of right-sided thrombi, myxomas, and vegetations, whereas right-sided pseudomasses are generally associated with a TDI pattern of concordant motion synchronous with the cardiac cycle. An increased TDI-derived mass peak antegrade velocity may represent an innovative marker of the embolic potential of mobile right-sided pathological masses. During the last two decades, only a few authors have used TTE implemented with PW-TDI for the characterization of intra-cardiac masses' morphology and mobility. Herein, we report two clinical cases of totally different right-sided cardiac masses diagnosed using a multimodality imaging approach, including PW-TDI, followed at our institution. The prevalence and physiopathological characteristics of the most relevant RA masses and pseudomasses encountered in clinical practice are described in the present narrative review. In addition, we will discuss the principal clinical applications of PW-TDI and its potential value in improving the differential diagnosis of pathological and para-physiological right-sided cardiac masses.

Dental Implant Failure Risk in Patients with Bruxism-A Systematic Review and Meta-Analysis of the Literature

Background/Objectives: Recent research has indicated that placing dental implants in patients diagnosed with bruxism has led to higher rates of implant failure. This study aimed to provide more accurate knowledge about the relationship between bruxism and implant loss in patients (number, age, gender) with different numbers of implants and prosthetic restorations, considering the follow-up time, compared to non-bruxers. Methods: A systematic search was conducted in PubMed and Cochrane Library using the keyword combination "dental implant", "bruxism", and "implant failure". This search had no language or time restrictions. Results: The review included 15 papers, which were divided into four groups. The first group focused on studies regarding implant loss regardless of the superstructure. In the second group, research on implant-supported removable prostheses was examined. The third group consisted of a single study specifically addressing implant-supported single crowns. Lastly, the fourth group comprised two studies investigating implant-supported single crowns and fixed partial dentures. Only three out of the fifteen studies failed to find a correlation between bruxism and implant failure. The meta-analysis shows a significant pooled effect across the included studies, with an odds ratio of 4.68. Conclusions: Bruxism is a probable risk factor for mechanical issues in implant-supported prostheses and implant-supported crowns. Additionally, elevated failure rates have been documented in patients with bruxism.

Association between atherosclerosis and the development of multi-organ pathologies

Atherosclerosis is a chronic inflammatory disease affecting the vascular system, characterised by the accumulation of modified lipoproteins, immune cell aggregation and the development of fibrous tissue within blood vessel walls. As atherosclerosis impacts blood vessels, its adverse effects may manifest across various tissues and organs. In this review, we examine the association of atherosclerosis with Alzheimer's disease, stroke, pancreatic and thyroid dysfunction, kidney stones and chronic kidney diseases. In several cases, the reciprocal causative effect of these diseases on the progression of atherosclerosis is also discussed. Particular attention is given to common risk factors, biomarkers and identified molecular mechanisms linking the pathophysiology of atherosclerosis to the dysfunction of multiple tissues and organs. Understanding the role of atherosclerosis and its associated microenvironmental conditions in the pathology of multi-organ disorders may unveil novel therapeutic avenues for the prevention and treatment of cardiovascular and associated diseases.

Management of adverse effects following additively manufactured subperiosteal jaw implantation in the maxilla

OBJECTIVE

This expert opinion presents provisional guidelines for addressing complications associated with Additively Manufactured Subperiosteal Jaw Implants (AMSJI®) in patients with severe maxillary atrophy. AMSJI®'s custom design, supported by finite element analysis (FEA), allows precise placement that avoids critical anatomical structures and minimizes complications relative to alternative solutions.

MATERIALS AND METHODS

Data were gathered through firsthand experiences, direct communications, two structured surveys and insights from international workgroup meetings.

RESULTS

Minor complications, such as soft tissue recession with inflammation, can be managed through thorough patient selection and early intervention. Severe complications, such as ascending infections and mechanical issues (e.g., fractures of implant components), have been rare. Compared to zygomatic implants and bone grafting, AMSJI® demonstrates a favorable safety profile. Zygomatic implants may lead to severe issues like orbital cellulitis and diplopia, while bone grafting risks include graft resorption, loss, and donor site complications. To mitigate risks, selecting patients carefully and ensuring diligent follow-up are critical, especially in those with risk factors like smoking or bruxism. Improved imaging, planning, and FEA have further contributed to minimizing complications, reinforcing AMSJI®'s role in complex maxillary reconstructions and implant-supported prosthetics.

CONCLUSIONS

AMSJI® demonstrates high success rates but requires meticulous risk management. Key strategies involve carefully candidates by excluding those who are smokers, immunocompromised, or non-compliant, or diabetics with a history of infectious complications. Additionally, strict adherence to oral hygiene protocols is essential to optimize outcomes and minimize risks.Proactive management in these areas is crucial to optimize outcomes, ensure implant longevity, and support successful prosthetic rehabilitation.

Correlation between measured oral health and oral health-related quality of life in people with epidermolysis bullosa: a prospective cohort study

BACKGROUND

Inherited epidermolysis bullosa (EB) is a genetic disorder characterized by skin fragility and unique oral features. This prospective study aimed to analyze the correlation between oral health-related quality of life (OHRQoL) and the objectively measured oral health indices of people suffering from EB and within their subtypes.

METHODS

The German version of the Oral Health Impact Profile (OHIP-14G) was employed for the assessment of OHRQoL. Furthermore, all participants underwent a comprehensive clinical examination to evaluate their oral health via the Physical Oral Health Index (PhOX). Study participants were included through various self-help groups in Germany, regular appointments at the outpatient clinic for rare diseases with orofacial involvement, at the Department of Cranio-maxillofacial Surgery at the University Hospital Münster and through contact via social media.

RESULTS

A total of 33 individuals participated in the study. The study revealed that both OHRQoL and oral health were reduced. Individuals with dystrophic epidermolysis bullosa (DEB) were more negatively affected than were those in the junctional epidermolysis bullosa (JEB) and epidermolysis simplex (EBS) groups. The OHIP-G14 mean score of participants diagnosed with DEB was 25.2 (95% CI: 18.4-32.0; ± 13.7, range 5-49), and the PhOX mean score of DEB was 54.6 (± 15.7). A significant correlation was observed between PhOX and the OHIP score (rs = -0.54; p < 0.001).

CONCLUSIONS

The findings of this study corroborate the challenges faced by patients with EB in the oral domain and the deterioration of their OHRQoL. These results emphasize the necessity for dentists to engage comprehensively in disease management, encompassing routine examinations, preventive dental care and oral hygiene education. Consequently, enhanced communication is required not only between dental and dermatological teams but also with caregivers.

Chinese dentists' restorative preferences and choices for endodontically treated teeth: a representative survey

BACKGROUND

The optimal restoration protocol for endodontically treated teeth (ETT) remains a subject of debate. This survey aims to assess the current level of awareness, knowledge, and prevailing opinions among dental practitioners in China regarding the application of endocrown versus the post/core/crown ensemble for post-endodontic restoration strategies.

METHODS

A validated questionnaire, encompassing three sections, was distributed electronically to dentists practicing in China. The initial section collected demographic characteristics of the participants, while the subsequent sections assessed their knowledge and preferences regarding ETT restoration techniques in various clinical scenarios. Distribution of the survey was facilitated through the social media platform WeChat, with a total of 600 invitations sent out. Data analysis was conducted using SPSS Statistical Software, employing frequency and Chi-square tests to determine statistical significance at the P < 0.05 threshold.

RESULTS

A total of 400 valid questionnaires were collected. The amount of remaining tooth structure was identified as the most influential factor in determining the restoration strategies, contributing to 26.1%. Over 72.8% of the surveyed dentists acknowledged the reinforcing effect of intraradicular posts on ETT. More than half of the participants reported the application of endocrowns within their post-endodontics management. The preference for endocrowns was pronounced in cases where more than 50% of the tooth's structure remained or when occlusal space limitations were present. The Chi-Square test revealed that the participants' knowledge regarding endocrown restoration was significantly influenced by their age, educational background, and experience (p < 0.05).

CONCLUSIONS

The clinical decision-making process for the restoration of endodontically treated teeth (ETT) by dental practitioners primarily relies on the amount of remaining tooth structure. Most surveyed dentists believe that the presence of a post can reinforce ETT. A majority of participants consider the Endocrown as a viable alternative restorative treatment for ETT.

Antibiotic prophylaxis in oral implant surgery in Germany: a cross-sectional study

PURPOSE

Prophylactic antibiotics are used in dental implants to reduce infection risk and implant failure, especially benefiting patients with risk factors. However, evidence suggests that using clindamycin or extending antibiotics postoperatively has an unfavorable risk-benefit ratio.

METHODS

This national cross-sectional study analyzed antibiotic prophylaxis during implant insertion across Germany. Dentists from the German Society for Oral Implantology (DGOI) provided demographic information and data on the next 10 consecutive implant patients, including age, sex, risk factors, type of implantation, and antibiotic details.

RESULTS

103 dentists participated, providing data on 1040 patients. Most dentists were male and aged 30-64. Patients were evenly split between genders, with an average age of 51 years. Antibiotics were administered in 87.6% of all cases, more frequently for patients undergoing bone augmentation (OR 7.01, p < 0.0001), immediate (OR 3.11, p = 0.002) or delayed (OR 5.30, p < 0.0001) implant insertion, and those with cardiovascular disease (OR 3.24, p = 0.009). 74.8% of implantologists tended to use antibiotic prophylaxis routinely, while the remaining implantologists decided on a case-by-case basis. Implantologists primarily used aminopenicillins for 63.8% of prescriptions and clindamycin for the remaining 35.6%. Additionally, 78.8% of patients with prophylaxis received postoperative, multi-day treatments.

CONCLUSIONS

The study reveals extensive antibiotic use for perioperative prophylaxis in implant surgery, often not justified by current recommendations, particularly concerning the choice of antibiotic (e.g., clindamycin) and duration (e.g., postoperative use). Specialized clinical guidelines and targeted training for dentists on antibiotic prophylaxis are needed.

Deciphering odontogenic myxoma: the role of copy number variations as diagnostic signatures

In light of the lack of reliable molecular markers for odontogenic myxoma (OM), the detection of copy number variation (CNV) may present a more objective method for assessing ambiguous cases. In this study, we employed multiregional microdissection sequencing to integrate morphological features with genomic profiling. This allowed us to reveal the CNV profiles of OM and compare them with dental papilla (DP), dental follicle (DF), and odontogenic fibroma (OF) tissues. We identified a distinct and robustly consistent CNV pattern in 93.75% (30/32) of OM cases, characterized by CNV gain events in chromosomes 4, 5, 8, 10, 12, 16, 17, 20, and 21. This pattern significantly differed from the CNV patterns observed in DP, DF, and OF. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated potential links between this CNV patterns and the calcium signaling pathway and salivary secretion, while Gene Ontology (GO) term analysis implicated CNV patterns in tumor adhesion, tooth development, and cell proliferation. Comprehensive CNV analysis accurately identified a case that was initially disputable between OF and OM as OM. Our findings provide a reliable diagnostic clue and fresh insights into the molecular biological mechanism underlying OM.

Desmoplastic Ameloblastoma: A case report of rare pulmonary metastasis

Pulmonary metastasis of ameloblastoma is a rare associated with the histopathologically plexiform types of ameloblastoma. In this report, we present an exceptionally rare case of pulmonary metastatic ameloblastoma without local recurrence, emerging 12 years post-initial resection. A female patient, initially diagnosed with mandibular desmoplastic ameloblastoma, revealed masses in both lung fields of the lung on chest radiography, while chest computed tomography revealed more than 10 nodules in both lungs. Histopathological analysis of a lung biopsy specimen revealed a nest-like structure of tumor cells surrounded by highly columnar cells, exhibiting a palisade-like arrangement, and squamous metaplasia. Subsequently, the diagnosis of pulmonary metastatic ameloblastoma was confirmed through immunohistochemical examination. Despite clinical trial treatment with molecular targeted therapy for three years, the lung disease remained clinically stable. This case highlights the need for oral surgeons to recognize that pulmonary metastasis of desmoplastic ameloblastoma can manifest as a late recurrence, extending beyond a decade after initial curative surgery.

Anti-diabetic therapies on dental implant success in diabetes mellitus: a comprehensive review

Background and Objective

Dental implant therapy faces challenges in patients with Type 1 and Type 2 Diabetes Mellitus (T1DM and T2DM) due to adverse effects on bone metabolism and immune response. Despite advancements, diabetic patients face higher risks of peri-implantitis and compromised osseointegration. This review assesses the impact of anti-diabetic medications on implant outcomes, offering insights to bridge the gap between animal studies and clinical practice. By evaluating pharmacotherapeutic strategies in preclinical models, this review guides future research designs to improve implant success rates in diabetic individuals.

Method

A comprehensive literature review identified 21 animal studies examining the impact of anti-diabetic medications on dental and bone implants. These studies explored diabetes models, medication regimens, and designs to assess outcomes related to bone metabolism, osseointegration, and peri-implant tissue responses. The findings are systematically summarized, highlighting the scope, design, and procedures of each study. An example includes placing a dental implant in the molar region of a mouse, providing insight into preclinical approaches.

Results

Twenty-one animal studies, primarily using rodents, investigate various anti-diabetic medications on dental and bone implants. Interventions include insulin, aminoguanidine, voglibose, sitagliptin, exenatide, and metformin, analyzing outcomes like bone-implant contact (BIC), bone volume (BV), and counter-torque values in T1DM and T2DM models. The impacts of these medications on implant osseointegration under diabetic conditions are detailed, with their benefits and shortcomings assessed.

Discussion

The findings and challenges of existing animal studies on diabetes mellitus (DM) and implant osseointegration are presented. Despite T2DM prevalence, research primarily focuses on T1DM models due to easier experimental practicalities, limiting applicability. Inconsistent protocols in studies compromise reliability regarding anti-diabetic treatments' effectiveness on osseointegration. Standardized methodologies and long-term assessments of local drug delivery alongside systemic anti-DM treatments are crucial to manage DM-related complications in implant dentistry.

Conclusion

Insulin administration in short-term T1DM animal studies enhances implant osseointegration. However, the efficacy of non-insulin medications remains inconclusive. Rigorous experimental designs are needed to address inconsistencies and assess long-term impacts. Larger-sized (e.g., porcine) animal studies across various intraoral implant scenarios are required. Future research should focus on enhancing clinical applicability and improving implant stability in evolving conditions.

Comprehensive Overview of Interface Strategies in Implant Osseointegration

With the improvement of implant design and the expansion of application scenarios, orthopedic implants have become a common surgical option for treating fractures and end‐stage osteoarthritis. Their common goal is rapidly forming and long‐term stable osseointegration. However, this fixation effect is limited by implant surface characteristics and peri‐implant bone tissue activity. Therefore, this review summarizes the strategies of interface engineering (osteogenic peptides, growth factors, and metal ions) and treatment methods (porous nanotubes, hydrogel embedding, and other load‐release systems) through research on its biological mechanism, paving the way to achieve the adaptation of both and coordination between different strategies. With the transition of the osseointegration stage, interface engineering strategies have demonstrated varying therapeutic effects. Especially, the activity of osteoblasts runs almost through the entire process of osseointegration, and their physiological activities play a dominant role in bone formation. Furthermore, diseases impacting bone metabolism exacerbate the difficulty of achieving osseointegration. This review aims to assist future research on osseointegration engineering strategies to improve implant‐bone fixation, promote fracture healing, and enhance post‐implantation recovery.

Healing Process of Old Mandibular Condylar Head Fractures: A Report of Two Cases

A condylar head fracture in the mandible is often misdiagnosed as a contusion of the temporomandibular joint (TMJ). Moreover, they are often overlooked by general practitioners as the fragments are small, making them difficult to identify. This report describes 2 cases of old mandibular condylar head fractures: one involving an 84-year-old woman referred to our dental office with suspected medication-related osteonecrosis of the jaw; and another involving a 23-year-old man who visited with the chief complaint of slight pain in the left TMJ. An old condylar head fracture with dislocation or displacement was coincidentally found on panoramic radiographs obtained during dental treatment in both cases. No disturbances in mouth opening or masticatory forces were observed in either case. Analysis of injury status and imaging with X-rays and computed tomography revealed that the relationship between the dislocated/displaced condylar head and the mandibular fossa changed as the bone structure and muscle positions stabilized.

Long-term outcomes and complication rates of tooth-implant-supported fixed dental prostheses: A retrospective cohort study

PURPOSE

To examine the factors influencing the risk of biological and technical complications in tooth-implant-supported fixed dental prostheses (T-I-FDPs), focusing on location, configuration, and the impact of existing dental health conditions.

MATERIALS AND METHODS

A retrospective cohort study was conducted, accompanied by a follow-up clinical and radiological examination, involving 58 patients (37 women, 21 men; mean age: 63.4 years) who had received 68 T-I-FDPs at least 5 years earlier, at the Department of Prosthodontics, Centre of Oral Rehabilitation, Region Östergötland, Sweden. Correlations between implant placement specifics, arrangement of teeth and implants, and the presence of root-filled teeth on the incidence of complications were analyzed.

RESULTS

The analysis highlighted significant complication risk variance, based on the location in the jaw of the implant, with reduced risk for mandibular placements (Hazard ratio [HR] 0.37). Complex arrangements (HR 2.46) and the presence of root-filled teeth (HR 1.48) were associated with higher complication rates.

CONCLUSION

This study demonstrates that anatomical considerations and preexisting dental health significantly influence the risk of complications in T-I-FDPs. Mandibular implant placements showed a reduced risk of complications compared to maxillary placements. The presence of root-filled teeth and complex prosthesis configurations were associated with higher complication rates. These findings highlight the need for customized treatment strategies to mitigate risks and enhance long-term outcomes for patients with T-I-FDPs.

Accuracy of augmented reality navigated surgery for placement of zygomatic implants: a human cadaver study

Purpose

Placement of zygomatic implants in the most optimal prosthetic position is considered challenging due to limited bone mass of the zygoma, limited visibility, length of the drilling path and proximity to critical anatomical structures. Augmented reality (AR) navigation can eliminate some of the disadvantages of surgical guides and conventional surgical navigation, while potentially improving accuracy. In this human cadaver study, we evaluated a developed AR navigation approach for placement of zygomatic implants after total maxillectomy.

Methods

The developed AR navigation interface connects a commercial navigation system with the Microsoft HoloLens. AR navigated surgery was performed to place 20 zygomatic implants using five human cadaver skulls after total maxillectomy. To determine accuracy, postoperative scans were virtually matched with preoperative three-dimensional virtual surgical planning, and distances in mm from entry-exit points and angular deviations were calculated as outcome measures. Results were compared with a previously conducted study in which zygomatic implants were positioned with 3D printed surgical guides.

Results

The mean entry point deviation was 2.43 ± 1.33 mm and a 3D angle deviation of 5.80 ± 4.12° (range 1.39-19.16°). The mean exit point deviation was 3.28 mm (±2.17). The abutment height deviation was on average 2.20 ± 1.35 mm. The accuracy of the abutment in the occlusal plane was 4.13 ± 2.53 mm. Surgical guides perform significantly better for the entry-point (P = 0.012) and 3D angle (P = 0.05); however, there is no significant difference in accuracy for the exit-point (P = 0.143) when using 3D printed drill guides or AR navigated surgery.

Conclusion

Despite the higher precision of surgical guides, AR navigation demonstrated acceptable accuracy, with potential for improvement and specialized applications. The study highlights the feasibility of AR navigation for zygomatic implant placement, offering an alternative to conventional methods.

NLRP3 deficiency improves bone healing of tooth extraction sockets through SMAD2/3-RUNX2-mediated osteoblast differentiation

Impaired bone healing following tooth extraction poses a significant challenge for implantation. As a crucial component of the natural immune system, the NLRP3 inflammasome is one of the most extensively studied pattern-recognition receptors, and is involved in multiple diseases. Yet, the role of NLRP3 in bone healing remains to be clarified. Here, to investigate the effect of NLRP3 on bone healing, we established a maxillary first molar extraction model in wild-type and NLRP3KO mice using minimally invasive techniques. We observed that NLRP3 was activated during the bone repair phase, and its depletion enhanced socket bone formation and osteoblast differentiation. Moreover, NLRP3 inflammasome activation was found to inhibit osteogenic differentiation in alveolar bone-derived mesenchymal stem cells (aBMSCs), an effect mitigated by NLRP3 deficiency. Mechanistically, we established that the SMAD2/3-RUNX2 signaling pathway is a downstream target of NLRP3 inflammasome activation, and SMAD2/3 knockdown partially reversed the significant decrease in expression of RUNX2, OSX, and ALP induced by NLRP3. Thus, our findings demonstrate that NLRP3 negatively modulates alveolar socket bone healing and contributes to the understanding of the NLRP3-induced signaling pathways involved in osteogenesis regulation.

Patients' Preferences for the Treatment of a Single Missing Tooth in China: A Discrete Choice Experiment

Purpose

The main treatment options offered to patients to choose from when restoring a single missing tooth include tooth-supported three-unit fixed partial dentures (FPDs) and implant-supported single crowns (ISCs). However, due to the heterogeneity of current studies, it is difficult to objectively compare these two treatment strategies. In this study, a discrete choice experiment (DCE) was used to quantify the preferences of individuals undergoing restoration treatment for single tooth loss.

Patients and Methods

The DCE questionnaire was disseminated in a "snowball" fashion, with data collected from participants aged 18-60. Five important attributes of treatment were selected: (1) treatment procedure, (2) treatment time, (3) cost, (4) five-year survival rate, and (5) five-year complication rate. A conditional logit model was employed to ascertain the direction of participants' preferences for specific attribute levels and to derive their willingness to pay (WTP) through the principle of marginal utility.

Results

287 participants completed the questionnaire. The results of the questionnaire revealed that the five-year complication rate (42.42%) was the most important attribute, followed by cost (20.43%), five-year survival rate (14.23%), treatment time (13.44%), and treatment procedure (9.49%). Participants were willing to pay RMB$11076.2 (USD$1,772.2) to obtain a 10% extra reduction in the five-year complication rate, and RMB$7434.6 (USD$1,189.5) for a non-invasive treatment.

Conclusion

In the ranking of the relative importance of key factors affecting single missing tooth restoration, complication rates are most highly valued, suggesting that reducing the complication rate is a key issue to be addressed in prosthodontics. In addition, deriving the ranking of patients' concerns about key factors can help to improve doctor-patient communication and provide a reference for treatment technology development and medical decision-making.

Progress and Gaps in Respiratory Disease Research and Treatment: Highlights of the IRM 2024 in Shanghai

Respiratory diseases pose a major public health challenge globally, necessitating collaborative efforts between basic researchers and clinicians for effective solutions. China, which is heavily impacted by a broad spectrum of respiratory disorders, has made notable strides in both research and clinical management of these diseases. The International Respiratory Medicine (IRM) meeting was organized with the primary goal of facilitating the exchange of recent research developments and promoting collaboration between Chinese and American scientists in both basic and clinical research fields. This article summarizes key insights from IRM2024, held in Shanghai, where a wide range of topics were discussed, including lung tissue development, disease mechanisms, and innovative therapeutic strategies. By integrating perspectives from basic, translational, and clinical research, IRM2024 highlighted recent advancements, addressed persistent challenges, and explored future directions in respiratory science and clinical practice. The insights gained from IRM2024 are poised to be pivotal in shaping future research and therapeutic approaches, further reinforcing the global commitment to enhancing respiratory health and improving patient outcomes.

Cone beam computed tomography findings as prognostic factors for maxillary sinus membrane perforation during maxillary sinus augmentation

BACKGROUND

Maxillary Schneiderian membrane (SM) perforation is one of the complications of maxillary sinus (MS) augmentation. The aim of the present study was to analyse cone beam computed tomography (CBCT) findings to identify prognostic factors for SM perforation.

MATERIALS AND METHODS

50 CBCT scans were recruit for the analysis, 39 were suitable for analysis and met the inclusion criteria. Retrospective analysis of clinical and radiological CBCT findings of patients who underwent MS augmentation by lateral approach, divided into study group with SM perforation and control group without. Several radiological parameters were included MS lateral wall width, MS floor width, SM width, shape of the SM, level of MS ventilation, presence of septae, presence of blood vessels in the MS wall, the geometrical shape of the MS and sinus floor, presence of polyps and oroantral communication.

RESULTS

A thin MS floor, the presence of a Retention Pseudocyst, the presence of MS septae, a concave sinus floor and a triangular sinus shape are risk factors for perforation of the SM during open MS lift. Statistical significant difference between the groups were found regarding MS floor width.

CONCLUSION

Based on the results of this study, it can be concluded that careful analysis of CBCT reveals a number of significant radiological features that can be used to predict potential risks.

May dental implant macro and microgeometry modifications influence peri-implant bone repair in smokers? A randomized clinical trial

BACKGROUND

This split-mouth, double-masked, randomized clinical trial aimed at evaluating the impact of different macro geometries and nano topographical modifications on peri-implant bone repair in smokers.

METHODS

Thirty-two patients who smoked at least ten cigarettes/day, with the need of a single maxillary or mandibular implant bilaterally, received two implants randomly assigned to DA - Dual Acid-Etched implants (n = 32); HCAN - healing chambers and activated nano surface (n = 32). Implant stability quotient (ISQ) was evaluated 07, 30, 60, 90, and 120 days after implant placement. Levels of bone and angiogenic markers were quantified in the peri-implant fluid after 07, 15, 30, 90, and 120 days of implant insertion. HCAN implants have a higher ISQ than DA implants at 60 days (p < 0.05).

RESULTS

PLGF levels were lower for HCAN implants than for DA implants at 07-day period (p < 0.05). Besides, HCAN implants presented higher levels of OPG at 30 days and OPN, BMP-9, FGF-1, PLGF, and VEGF at 90 days, compared to DA implants (p < 0.05). The levels of EGF were higher for HCAN implants at 15, 90, and 120 days compared with DA implants (p < 0.05). HCAN implants also showed lower levels of TNF-α at 07 days in comparison to DA implants (p < 0.05) but had higher levels of DKK1 at 30 days, while DA implants presented higher levels of this marker at 90 days (p < 0.05).

CONCLUSION

Macro geometry and nano topographical modifications positively modulated the bone and angiogenic factors, resulting in higher production of these markers during early peri-implant bone healing and having a positive effect on implant stabilization in smokers.

TRIAL REGISTRATION

RBR-10gjvcyt; date of registration: 06/12/2023 (Retrospectively registered).

Mobile App Intervention Increases Adherence to Home Exercise Program After Whiplash Injury-A Randomized Controlled Trial (RCT)

OBJECTIVE

Can mobile app intervention via push notifications increase adherence to exercise and reduce disability and pain after a whiplash injury?

METHODS

A randomized controlled trial was conducted with concealed allocation, blinding of some assessors, and an intention-to-treat analysis. Participants who sustained whiplash injury at most 3 months prior were divided into active and control groups. Both groups completed a two-part physiotherapist-supervised physical therapy program (3-week break in between, ten sessions each, 5x/week). The program included TENS, therapeutic ultrasound, and exercises (breathing, ROM, deep neck flexor activation, and stretching). Both groups were encouraged to exercise at home. The active group additionally received push notifications through the mobile app once a day as a reminder to exercise. Outcomes were adherence to exercise (four-point Likert scale), physical functioning (NDI), pain intensity (VAS), perceived recovery (three-point Likert scale), work information, psychological functioning (PCS), and HRQoL (SF-12) at baseline and 6-month follow-up.

RESULTS

At month 6, when comparing the groups, the intervention group showed higher adherence to home exercise (3 [2-4] vs. 2 [2-4]; p = 0.005, median [IQR]) and improved HRQoL (∆SF-12) (20 [6-36] vs. 15 [9-23]; p = 0.038). Unlike the control group, the intervention group showed a significant decrease in pain catastrophizing (31%; p = 0.01). A multivariant analysis showed that mobile app intervention influenced adherence most (≈1 Likert point). The groups did not differ in NDI, pain VAS, perceived recovery, or work limitation.

CONCLUSIONS

Mobile app intervention increased adherence to home exercise, reduced pain catastrophizing, and increased HRQoL six months after a whiplash injury.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05704023.

Ossifying fibroma and juvenile ossifying fibroma: A systematic review on clinical and radiological parameters, treatment modalities and recurrence

Ossifying fibroma (OF) is a rare benign fibro-osseous neoplasm developing mostly in maxillo-facial bones. OF is divided in cemento-ossifying fibroma (COF), juvenile trabecular ossifying fibroma (JTOF) and psammomatoid ossifying fibroma (PSOF). The aim of this systematic review was to synthetize the existing literature on OF, investigating the clinical and radiological parameters related to the different forms of the disease, and to compare the treatment modalities according to their associated recurrence rate. Three databases were searched in March 2024, with an update in September 2024. Eligibility criteria included studies reporting on patients with OF, surgical treatment and follow-up data. Of the 2016 studies identified, 22 were retained after eligibility assessment. A total of 492 patients were included. Most OF presented with painless swelling. COF affected 61.1 % of women with a mean age of 29.5, JTOF presented in 55.7 % of male children, and PSOF had no predilection for sex with a mean age of 19.5 years. Enucleation and curettage were associated with an elevated recurrence rate in JTOF (12/30) and PSOF (10/16). PSOF (6 cases) and JTOF (15 cases) showed no recurrence with radical surgery. Same recurrence rates in COF were seen for conservative and radical surgery. Although radical surgery seemed to avoid recurrence in JTOF and PSOF, conservative surgery such as enucleation and curettage with additional peripheral ostectomy should be considered primarily to lessen the morbidity induced by radical resection. Close clinical and radiological follow-up should be undertaken to diagnose early recurrence.

The Influence of Patient-, Site-, and Implant-Related Factors on Marginal Bone Levels of Dental Implants in a Rural Population in China: A Retrospective Study

OBJECTIVES

Limited research is available on implant treatment outcomes in rural populations. This may be due to the presence of various barriers, such as access to oral health care, resources, health literacy, and education. The aim of this study was to evaluate the influence of patient-, site-, and implant-related factors on marginal bone levels of dental implants in a rural population in China.

MATERIAL AND METHODS

A retrospective study was conducted using data from a private dental office. Subjects included in this study received dental implants as part of their routine dental treatment. Information on age, gender, smoking status, diabetes, heart disease, jaw location, restorative type, loading protocol, survival rate, implant length, and diameter was collected. Marginal bone loss was recorded as the largest value at either the mesial or distal aspect on peri-apical radiographs. Descriptive and inferential statistics were performed along with linear regression analysis.

RESULTS

Overall, 428 implants were placed in 90 subjects over an average follow-up period of 453 days. No implant failures were recorded. The average marginal bone loss was 0.10 mm, with 80.6% of implants showing no marginal bone loss. The extent of marginal bone loss was greater in the mandible (0.13 ± 0.25) than in the maxilla (0.08 ± 0.19). An increase in implant diameter by 1 mm resulted in 0.08 mm of marginal bone loss, indicating wider diameter implants are associated with more bone loss. Age was also positively correlated with marginal bone loss, increasing by 0.002 mm per year. No differences were found for gender, smoking, diabetes, heart disease, restoration type, and immediate loading.

CONCLUSIONS

Dental implant therapy in a rural Chinese population demonstrated high survival rates and minimal marginal bone loss. Factors such as age, implant location, and diameter influenced bone loss. This study fills a critical gap in understanding implant outcomes specifically within rural settings, highlighting the need for tailored approaches to enhance patient access and care in these communities. Further research is needed to explore these relationships and assess implant outcomes in rural populations.

Effect of immediate all-digital restoration of single posterior implants: The SafetyCrown concept on patient-reported outcome measures, accuracy, and treatment time-A randomized clinical trial

OBJECTIVE

The SafetyCrown workflow facilitates the immediate restoration of posterior single sites with the one-abutment/one-time concept. This randomized clinical trial aimed to assess the direct effect of immediate restoration on dental patient-reported outcomes (dPROs), feasibility, implant accuracy, and time.

MATERIALS AND METHODS

Participants with a single posterior edentulous site for late implant placement underwent optical impressions, shade selection, and cone beam computed tomography. After virtual treatment planning, they were randomized into the test group and the control group. For the test group, individual definitive hybrid abutments were prefabricated. The next step was a fully guided surgery with printed guides. After the implant was placed using guided surgery, the abutment was inserted. A chairside CAD/CAM workflow was used to provide the patient with a provisional restoration. Implants in the control group were left submerged to heal. Oral health-related quality of life (OHRQoL) was assessed using the OHIP-G14, and dPRO was measured using a 10-item visual analog scale (VAS) questionnaire. Additional measurements of implant accuracy and time were performed. Follow-up was performed 7 to 10 days after implant placement.

RESULTS

Thirty-nine participants with 45 restorations were included (test group: 23, control: 22). Immediate restoration was successful in 21 out of 23 implants (91.3%) in the test group. Both groups exhibited decreased OHRQoL without significant intergroup differences, while patient satisfaction was high overall. Test group participants perceived higher benefits and satisfaction with immediate loading than participants in the control group. Implant accuracy averaged 0.60 mm at the shoulder and 0.95 mm at the apex. Operative time was longer in the immediate loading group (61.9 min) than in the control group (32.1 min) (p < 0.001).

CONCLUSIONS

Considering the limitations, the immediate restoration of late placed posterior implants using the described workflow proved feasible in 21 out of 23 cases. Both groups achieved high patient satisfaction with no differences in OHRQoL during the first week. Patients who received immediate loading rated the benefits very highly and were satisfied with the provisional restoration during the healing period.

Current trends and available evidence on low-level laser therapy for osteoradionecrosis: A scoping review

BACKGROUND

This scoping review explored current trends and available evidence in Low-Level Laser Therapy (LLLT) in the treatment and prevention of osteoradionecrosis.

METHODS

The search strategy was conducted in MEDLINE/PubMed, EMBASE, Web of Science, and grey literature on January 15, 2024, without language or time restrictions.

RESULTS

19 studies were included. The application of LLLT protocols was 58 % for therapeutic use, 21 % for preventive use, and 21 % for a combination of both. Regarding the use of antimicrobial photodynamic therapy (aPDT), 41 % of the studies employed this technique, which utilized methylene blue as the photosensitizer. For treatments associated with photobiomodulation, 57 % reported pharmacological treatment, 29 % surgical treatment, 11 % prescribed chlorhexidine mouthwashes, and 4 % other therapies. In vivo studies used diode lasers emitting low incident power densities in the near-infrared wavelength (67 %) at 780 to 904 nm. In comparison, case reports also used diode lasers emitting low incident power densities in the red and near-infrared wavelength (64 %) at 660 to 904 nm. The continuous emission mode was utilized in 83 % of in vivo studies and 17 % of the case reports. None of the studies included in this review reported all laser parameters.

CONCLUSIONS

In general, studies suggested that LLLT can be used for therapeutic and preventive applications in the management of osteoradionecrosis. However, clinical studies are case reports and the variability in laser parameters across the included studies poses challenges for establishing standardized treatment protocols. The lack of comprehensive data on laser parameters underscores the need for future research to focus on standardizing LLLT protocols and conducting well-designed, large-scale clinical trials. This approach will help to better evaluate the effectiveness of LLLT and potentially integrate it more reliably into clinical practice.

Premorbid Incidence of Mental Health and Substance Abuse Disorders in Facial Trauma Patients

Study Design

A retrospective study.

Objective

Facial trauma is a prevalent cause of morbidity and mortality with increasing incidence over recent decades. Few studies have examined the prevalence of mental health and substance abuse disorders at the time of diagnosis. Herein we investigate the psychosocial demographics associated with facial trauma.

Methods

The 2016 State Inpatient Database (SID) was used to identify patients with facial trauma from all hospitals in New York, Florida, and Maryland. A non-trauma control group undergoing elective same-day surgeries at ambulatory surgical centers in Florida, Kentucky, Nevada, North Carolina, New York, and Maryland was identified using the State Ambulatory Surgery and Services Database (SASD) from the Healthcare Cost and Utilization Project (HCUP). 777 patients were identified with facial trauma and compared to 500 patients without facial fractures.

Results

Patients with facial fractures were statistically significantly more likely to have a substance abuse disorder (OR 34.78, P < .001) or mental health disorder (OR 2.75, P < .001) compared to controls. Patients with facial fractures were significantly more likely to be black than white (OR 4.80, P < .001). Patients with facial fractures were significantly more likely to have Medicaid compared to Medicare (OR 2.12, P = .005).

Conclusions

Patients with facial fractures are more likely to have premorbid substance abuse and mental health disorders as compared to controls.

Exploring the mechanisms and current status of acupuncture in alleviating tumor metabolism and associated diseases: Insights from the central nervous system and immune microenvironment

Acupuncture, as a traditional Chinese medical treatment, has garnered increasing attention in recent years in fields such as tumor metabolism, the central nervous system, and the immune microenvironment. This paper aims to explore the fundamental principles, mechanisms, and research status of acupuncture therapy for tumor-related diseases. Firstly, we introduce the basic principles of acupuncture therapy, including the theories of meridians and its theoretical basis in tumor treatment. Secondly, we systematically review the mechanisms of acupuncture therapy for tumor-related diseases, discussing how acupuncture alleviates side effects such as pain, depression, fatigue, and gastrointestinal discomfort caused by conventional treatments through modulation of the immune microenvironment, central nervous system, and endocrine system. Subsequently, we discuss the current research status of acupuncture therapy for tumor-related diseases, as well as the application of current research methods and technologies in elucidating acupuncture mechanisms. Additionally, by combining clinical practice with different types of tumor-related diseases as experimental subjects, we demonstrate the application effectiveness and clinical practice experience of acupuncture in tumor treatment. Finally, a comprehensive assessment of acupuncture therapy for tumor-related diseases is provided, summarizing its limitations and prospecting future directions, including interdisciplinary collaboration and personalized treatment. In conclusion, acupuncture, as a feasible adjunctive therapy, is closely related to the central nervous system and the immune microenvironment, holding potential significant value in tumor treatment.

Association Between Proton Pump Inhibitor Use and the Severity of Periodontal Disease and Peri-Implantitis: A Systematic Review

This systematic review investigates the probable effect of proton pump inhibitor (PPI) use on the severity of periodontal disease and peri-implantitis and implant survival. We conducted a literature search in PubMed, Scopus, and Cochrane Central Library up to April 2024. Two review authors independently screened the title and abstracts and then the full texts of retrieved studies. Observational and clinical trial studies that assessed the association between PPI use and periodontal disease severity and peri-implantitis or implant survival were included. Data extraction from the included studies was done by 2 reviewers independently. Of 940 studies initially retrieved from online searching, 7 met the inclusion criteria. Three studies examined periodontitis, whereas 4 focused on peri-implantitis and implant longevity. On the contrary, evidence regarding the impact of PPI use on peri-implantitis and implant survival is conflicting. Therefore, more well-designed randomized controlled trials are warranted to come to a definite conclusion. Because PPIs alter the gut microbiome and affect bone, plus that the pathogenesis and etiology of periodontal disease are affected by bacteria within the periodontal pocket, it is hypothesized that they may affect periodontal pathogenesis.

Marginal Bone Loss Around the Implant: A Retrospective Analysis of Bone Remodeling Over Five Years of Follow-Up

INTRODUCTION

Bone remodeling around implants in implant-supported rehabilitation is a continuous debate with no consensus in the literature. This study aimed to investigate the implant- and patient-specific factors contributing to marginal bone loss near the implant.

MATERIALS AND METHODS

We included patients who had implant-supported prosthetic rehabilitation using one implant system, between 2014 and 2018, who had full follow-up documentation and orthopantomography over five years, and who had no unwell-controlled systemic pathologies that may influence bone metabolism.

RESULTS

Eighty-one patients who received 500 implants met the inclusion criteria. We observed approximately 1 mm of bone resorption at the five-year follow-up, with the first 0.78 mm of them being documented at the three-year follow-up. Adults younger than 60 years old had an increase in bone resorption by approximately 30%. No difference was seen between men and women. However, a slight increase in bone resorption at five years was seen in female patients older than 50 years old than in ones younger than 50 years (by 30%). The narrowest diameter (3.5 mm; p = 0.001) and anterior mandible (p = 0.008) had the highest bone resorptions. Contrarily, with an insertion depth of approximately 1 mm (p = 0.004), the splinted implant prosthesis (p = 0.21) and zirconia material of the prosthesis (p = 0.57) had the lowest bone remodeling. Moreover, patients younger than 60 years and female patients above 50 years had an increased bone resorption.

CONCLUSIONS

Bone remodeling is a multifactorial process. The treatment planning has to take into consideration both implant- and patient-specific factors.

Clinical results of two different three-dimensional plate types for the treatment of mandibular angle fractures: a retrospective analysis

OBJECTIVES

The purpose of this study was to compare two different designs of three-dimensional osteosynthesis plates for their suitability in the treatment of mandibular angle fractures in terms of sufficient fracture healing and concomitant complications.

MATERIALS AND METHODS

Retrospectively a total of 54 patients with 56 mandibular angle fractures were evaluated. Two different types of three-dimensional plates from the Medartis Trilock system were analyzed: (A) Square design plate (☐-plate) with a thickness of 1.0 mm, and (B) triangular-shaped 3D-plate (△-plate) with a thickness of 1.3 mm. Patient demographics, fracture mechanism and intraoperative details were recorded during an average follow-up period of 1 year.

RESULTS

The utilization of △-plates was observed to entail a considerably lengthier surgical time in contrast to ☐-plate systems (P = 0.037). The application of △-plate showed a tendency of higher incidence of major complications than ☐-plate (P = 0.06), as evidenced by the occurrence of non-union in 2 out of 22 cases, resulting in higher surgical revision rate for △-plate (P = 0.027).

CONCLUSION

Sufficient treatment of mandibular angle fractures is feasible by using 1.0 mm thick, square shaped three-dimensional plate systems. The use of thicker three-dimensional osteosynthesis plates seems to significantly increase the operating time and complication rates, whereby the geometry of the plate seems to have an influence.

CLINICAL RELEVANCE

The plate design could have an impact on treatment outcomes of mandibular angle fractures.

TRIAL REGISTRATION NUMBER

Not applicable.

A pattern of peri-implantitis affecting middle implants in 3-implant splinted prostheses

BACKGROUND

Previous investigators have noted an increased risk of crestal bone loss and failure of the middle implant of 3-implant-splinted (3-IS) fixed dental prostheses (FDPs). Possible causes have included ill-fitting prostheses, unhygienic prosthetic contours, and discrepancies in prosthetic platform heights.

METHODS & RESULTS

We identified four cases in which the middle implant of a 3-IS multiunit FDP suffered advanced bone loss, ultimately leading to implant removal. While more than one possible risk for implant failure existed in each case, a common thread was that the prosthetic platform of the middle implant for all patients was coronally positioned relative to the corresponding mesial and/or distal implants.

CONCLUSIONS

Splinting three adjacent implants into one prosthesis may add risk for a variety of reasons possibly including small differences in the heights of the three prosthetic tables.

KEY POINTS

Why are these cases new information? Our observations suggest that discrepancies between implant prosthetic platforms supporting 3-implant splinted, multiunit FDPs may be an added risk factor for middle implant failure. What are the keys to successful management of these cases? It is possible that small differences in apico-coronal implant positioning with 3-implant splinted multiunit FDPs may affect the success of the middle implants. What are the primary limitations to success in these cases? There is limited literature involving precise protocols and long-term outcomes of 3-implant splinted implant restorations. Studies comparing 3-implant splinted FDPs to other configurations are needed.

Evaluation of polyaryletherketone materials as post-core abutments for removable partial dentures: A finite element analysis

OBJECTIVE

The purpose was to compare the biomechanical behavior of single-piece post-core restorations made from polyaryletherketone materials with fiber post-core restorations when serving as abutments for RPD using finite element analysis (FEA).

METHODS

Phantom maxillary central incisor and mandibular second premolar were trimmed 1-mm coronally to cemento-enamel junction; root canals were enlarged and the teeth were scanned. Data was transferred to a solid modeling software.Twenty four models, including six post-core restorations:glass-fiber post/composite core (GFH/GFL) and single-piece post-core groups as, PEKK(PKH/PKL);Ti02-reinforced PEEK(TH/TL);ceramic reinforced PEEK(CeH/CeL);carbon fiber reinforced PEEK(CaH/CaL);glass fiber reinforced PEEK(GFPH/GFPL) with hybrid ceramic/lithium disilicate crowns on each tooth were constructed.Loads of 100 N for central incisor, and 300 N for premolar in a 45°oblique direction were applied to simulate masticatory forces. Clasp removal force of a RPD was simulated as 5 N vertically.FEA was employed to evaluate the von Mises stresses.Strain at cement layer was also investigated.

RESULTS

CaH/CaL groups revealed the lowest stress for both teeth at root while TH/TL groups revealed the highest stress. The lowest stress values in the post-core were in GFH/GFL groups while the highest stress occurred in the CaH/CaL groups for both teeth.

SIGNIFICANCE

Glass-fiber post-cores exhibited the lowest stresses in the post under masticatory and clasp removal forces. It may suggest a potentially lower risk of post fracture compared to polyaryletherketone group materials. TiO2-reinforced PEEK post-cores exhibited the lowest stresses among PAEK materials, indicating a potentially high fracture resistance.

Smoking in relation to early dental implant failure: A systematic review and meta-analysis

OBJECTIVE

To assess the association between smoking and early dental implant failure by conducting a systematic review and meta-analysis of observational studies.

DATA SOURCES

PubMed, Embase, Scopus, Web of Science, and Cochrane Central Register of Controlled Trials were systematically searched for reports of relevant studies addressing the relationship between smoking and early dental implant failure published between database inception and June 2024.

STUDY SELECTION

Thirty-two observational clinical studies published between 1994 and 2024 were included, with a total of 59,246 implants at implant level and 14,115 patients at individual level. At implant level, a meta-analysis of 21 included cohort studies showed that smoking was associated with increased risk of early dental implant failure compared with non-smoking (odds ratio [OR], 2.59; 95 % confidence interval [CI], 2.08-3.23). Three included studies reported that smoking was associated with higher maxillary early dental implant failure risk (OR, 5.90; 95 %CI, 2.38-14.66) than that of mandible (OR, 3.76; 95 %CI, 1.19-11.87). At individual level, meta-analysis of thirty cohort studies indicated that risk of early implant failure in smokers was 100 % higher than in non-smokers (OR, 2.00; 95 %CI, 1.43-2.80). Three case-control studies found that risk of early implant failure of smokers was 59 % higher than that of non-smokers (OR, 1.59; 95 %CI, 1.28-1.97).

CONCLUSIONS

Smoking was significantly associated with early dental implant failure, particularly at the maxillary location, at both implant and individual level. These findings suggest smoking cessation is a crucial factor in reducing risk of early dental implant failure.

CLINICAL SIGNIFICANCE

There is uncertainty about the extent to which smoking influences early dental implant failure, our meta-analysis of findings emphasize smoking was significantly associated with early dental implant failure, particularly at the maxillary location.

Predictive Factors of Dental Implant Failure: A Retrospective Study Using Decision Tree Regression

INTRODUCTION

Dental implants are routinely used to replace missing teeth. Therefore, the primary aim of the present study was to assess the single-unit implant failure rate over a period of seven years from 2015 to 2021, with a minimum of two years post-implant follow-up. The secondary aim was to identify the risk factors associated with implant failure using machine learning decision tree regression and Kaplan-Meier survival analyses.

MATERIALS AND METHODS

An eight-year retrospective study was conducted using the clinical records of 224 patients who received single-unit dental implants between January 2014 and December 2021, where risk factors for early (EIF) and late implant failure (LIF) were identified. The patients' clinical case records and radiographs were used to assess implant failure.

RESULTS

Smoking and peri-implantitis were principal contributors to failure (p=0.001). Implant failure was more common in males, the maxillary jaw, and posterior teeth, although these factors were not significantly associated with implant failure (p>0.05). The duration of failure was 16.87±4.6 months for LIF, in contrast to 5.71±1.38 months in EIF. Bruxism and peri-implantitis were correlated with diminished survival duration, especially when compounded by additional risk factors such as diabetes mellitus. Isolated peri-implantitis yielded an average failure duration of approximately 13.4 months, whereas bruxism intensified the failure interval to approximately 13.8 months. Kaplan-Meier survival analysis revealed that among the identified causes of failure, peri-implantitis and smoking were the predominant factors, followed by bruxism, diabetes, and complications related to osseointegration.

CONCLUSION

Age, sex, type of surgical procedure, sinus lift, and grafting procedures were not significantly associated with dental implant failure, whereas bruxism, peri-implantitis, lack of osseointegration, smoking, and type 2 diabetes mellitus were significant predictors.

Clinical efficacy of two vertical soft tissue augmentation techniques for peri-implant crestal bone level stability: A randomized clinical trial

OBJECTIVES

This study aimed to compare the efficacy of two techniques-acellular dermal matrix (ADM) grafting and tenting technique (TT)-for soft tissue height (STH) augmentation simultaneous to implant placement to minimize peri-implant crestal bone level (CBL) changes.

METHODS

Forty patients with a healed single mandibular posterior edentulous site with a thin soft tissue phenotype were enrolled. Twenty patients received simultaneously to implant placement ADM grafting, while the others received submerged healing abutment (TT). Clinical peri-implant soft tissue height and radiographic CBL changes were measured at restoration delivery and 1-year follow-up.

RESULTS

Both techniques effectively increased soft tissue thickness, resulting in a final average STH of 3.4 ± 0.5 mm after augmentation. On average, soft tissue increased by 1.6 ± 0.5 mm in group ADM and by 1.8 ± 0.4 mm in group TT after augmentation. In Group ADM, mesial CBL decreased from 0.4 ± 0.3 mm to 0.1 ± 0.2 mm, and distal CBL decreased from 0.5 ± 0.3 mm to 0.2 ± 0.3 mm over 1 year. In Group TT, mesial CBL remained stable at 0.3 ± 0.2 mm, while distal CBL reduced slightly from 0.5 ± 0.5 mm to 0.3 ± 0.2 mm. Both groups showed minimal changes in CBL, indicating great stability (pmesial = 0.003, pdistal = 0.004). TT was particularly effective in preventing mesial bone loss (pmesial = 0.019). The mesial CBL changes significantly differed between groups (p = 0.019), and not significantly at distal sites (p = 0.944). Neither treatment exhibited significant bone remodeling below the implant shoulder.

CONCLUSION

This study suggests that both techniques were successful in STH augmentation, and they may effectively reduce peri-implant crestal bone level changes, with TT being slightly superior. TT was more prone to post-surgical complications. This RCT was not registered before participant recruitment and randomization.

Clinicopathologic and imaging features of odontogenic myxomas: a multi-institutional study

PURPOSE

This study aims to report clinicopathologic and imaging features of odontogenic myxomas (OM), highlighting uncommon findings.

METHODS

Clinicopathologic and imaging data of OMs diagnosed in the five Brazilian diagnostic pathology centers were collected and analyzed.

RESULTS

The series comprised 42 females (68.9%) and 19 males (31.1%), with a 2.2:1 female-to-male ratio and a mean age of 34.5±15.4 years (range: 4-80). Clinically, most OMs presented as painless intraoral swelling (n = 36; 70.6%) in the mandible (n=37; 59.7%). Multilocular lesions (n=30; 83.3%) were more common than unilocular lesions (n=6; 16.7%). There was no statistically significant difference between the average size of unilocular and multilocular OMs (p=0.2431). The borders of OMs were mainly well-defined (n=24; 66.7%) with different degrees of cortication. Only seven tumors caused tooth resorption (15.9%), while 24 (54.5%) caused tooth displacement. Cortical bone perforation was observed in 12 (38.7%) cases. Morphologically, OMs were characterized mainly by stellate or spindle-shaped cells in a myxoid background (n=53; 85.5%). Surgical resection was the most common treatment modality (n=15; 65.2%), followed by conservative surgery (n=8; 34.8%). Outcomes were available in 20 cases (32.3%). Seven of these patients had local recurrence (35%). Enucleation was the treatment with the highest recurrence rate (4/7; 57.1%).

CONCLUSIONS

OM has a predilection for the posterior region of the jaws of female adults. Despite their bland morphological appearance, they displayed diverse imaging features. Clinicians must include the OM in the differential diagnosis of osteolytic lesions of the jaws. A long follow-up is needed to monitor possible recurrences.

Dentigerous Cyst and Glandular Odontogenic Cyst: A Rare Combination of Coexisting Pathologies

A dentigerous cyst (DC) is the most common developmental cystic lesion of the jaws. Histologically, these cysts derive from the odontogenic epithelium that includes the reduced enamel epithelium, epithelial cell rests of Serres, and epithelial cell rests of Malassez. Radiographically, DCs are usually presented as well-defined radiolucencies associated with the crown of an unerupted tooth at the level of the cementoenamel junction (CEJ). Glandular odontogenic cysts (GOCs) are classified under the same category as DCs. Radiographically, glandular odontogenic cysts (GOCs) may appear as unilocular or more commonly as multilocular radiolucencies with well-defined margins. It is evident that there is a significant overlap in the radiographic features of the two pathologies. This case report describes one of those cases. A 49-year-old male patient was referred for a cone beam computed tomography (CBCT) imaging series for the evaluation of possible pathology in areas #17-#19 and ramus to the Graduate Oral and Maxillofacial Radiology Clinic, Health Science Center, San Antonio, University of Texas. The radiographic interpretation revealed a well-defined corticated low-density lesion in the left mandibular molar-ramus region. The mandibular canal was intact and traceable but displaced buccally and inferiorly. The radiographic findings were suggestive of a slow-growing odontogenic process, most likely cystic. Marsupialization and incisional biopsy of the lesion were carried out, which was highly suggestive of GOC. Two months after the initial incisional biopsy, it was decided that enucleation and curettage, as well as extraction of #17, #18, and #19, should be carried out. The enucleated specimen was sent to the histopathology laboratory for evaluation. The second biopsy showed a dentigerous cyst associated with impacted #17. Histopathology continues to be, statistically, the most reliable method for diagnosing these types of abnormalities. However, in certain cases, such as this one, the accuracy of histopathological examination may falter due to overlapping characteristics and different histopathological features based on the location of acquisition of the specimen. The initial radiographic estimation included the differential diagnosis of a DC as a second differential and, although contradicted by the first biopsy result, was eventually supported by the second final biopsy of the entire specimen. Although DCs do not tend to recur, the need for regular follow-ups should not be underestimated, neither by the attending clinician nor by the patients themselves. In conclusion, the radiographically proven, uneventful wound healing constitutes the only reassurance for the patient's well-being.

Survival and prosthetic complications of monolithic ceramic implant-supported single crowns and fixed partial dentures: A systematic review with meta-analysis

STATEMENT OF PROBLEM

Monolithic ceramic implant-supported restorations have been used to rehabilitate partially edentulous patients. However, knowledge of the survival and prosthetic complications of single crowns (SCs) and fixed partial dentures (FPDs) is limited.

PURPOSE

The purpose of this systematic review with meta-analysis was to evaluate the clinical performance of monolithic ceramic implant-supported SCs and FPDs in terms of survival and prosthetic complication rates.

MATERIAL AND METHODS

The systematic review was registered on the prospective register of systematic reviews (PROSPERO) (CRD42017078568). Five electronic databases were independently searched by 2 authors for articles published until May 2022. In addition, a hand search was performed in the nonpeer-reviewed literature, specific journals, and reference lists of included articles. A single-arm meta-analysis was performed by using the R program. The risk of bias and quality were assessed using the Cochrane risk of bias tools and the Newcastle-Ottawa scale.

RESULTS

Twenty-eight studies were included in the quantitative synthesis. A total of 1298 monolithic ceramic implant-supported restorations (1116 SCs and 182 FPDs) were evaluated in 1193 participants, with a median observation time of 24 months (range: 12 to 72 months). Meta-analysis indicated the proportion of failures and prosthetic complication rates of 2% (95% confidence interval [CI]: 1% to 4%) for SCs. No difference was observed for monolithic zirconia and lithium disilicate SCs. In the FPDs, only monolithic zirconia was considered, with 1 failure reported totaling the proportion of failures of 0% (0% to 1%) and complication rates of 4% (0% to 12%). The most complications reported for both types of restorations were screw loosening, debonding, and minor chipping and were considered repairable. The included studies showed a low risk of bias and good quality.

CONCLUSIONS

The use of monolithic ceramic implant-supported SCs, independent of ceramic material, and monolithic zirconia implant-supported FPDs should be considered an effective and safe treatment option because of favorable short-term survival and low prosthetic complications. However, additional well-conducted studies with a longer-term follow-up and direct comparison between veneered restorations are recommended to reassess clinical performance.

Clinical Report of the Immediate Placement Implants in Patients Aged 80 and Over: Five Cases and a Short Review

With the population aging, the proportion of elderly individuals is expected to increase, and the proportion of individuals over 80 is also likely to increase. Given that the population is aging and life expectancy is increasing, elderly patients who have lost their teeth will also increase. Impaired masticatory function caused by tooth loss is a risk factor for cognitive decline and frailty, and neglecting to treat tooth loss is a critical issue. In this report, 5 patients over 80 requested dental implants for new missing teeth and underwent immediate implant placement. All patients were treated by the same surgeon using the same technique, materials, and dental implants. Five elements were measured for the peri-implant bone from the cone-beam computed tomography images. All patients were followed for 3 or more years and exhibited good progress without any abnormal findings in their oral cavities or notable radiographic abnormalities such as bone absorption or peri-implantitis. Compared with conventional treatment with delayed placement, combining immediate implant placement and regenerative medicine for fixed superstructures may be the better option for missing tooth replacement if the conditions are suitable. Thus, this treatment modality may improve the quality of life in elderly patients, especially super elderly patients.

Development of reduced volume endosseous cuspid tooth implant using topology optimization by SIMP technique for improved osseointegration

The article aims to design and develop a topology-optimized endosseous cuspid tooth implant of the maxilla region. The manuscript presents a numerical analysis of the resulting von Mises stresses and effective strain resulting in the topology-optimized implant with occlusal loading of 110 N. Solid Isotropic Material with Penalization (SIMP) method is employed for topology optimization and four different models, namely model-1, model-2, model-3, and model-4, are developed based on volume reduction rates of 8%, 16%, 24%, and 32%, respectively. FEA results highlight that the maximum stress and strain in the screw increases with volume reduction rates. The comparative analyses of the resulting stresses in the compact and cancellous bone along with the strain in the screw led to the conclusion that model-1, model-2, and model-3 resulted in moderate stresses on compact and cancellous bone compared to the original model of the implant. However, the screw and bones are subjected to maximum stress and strain in the model-4. The study concludes that model-2, with 16% reduced volume and 14.2% reduced mass as compared to the original implant, may be considered as the optimized design of the model. The resulting model offers a significant reduction in the weight and volume with a minor increase in effective stress and strain without negatively impacting the functionality and bio-mechanical performance of the implant. The optimized dental implant prototype is also fabricated as a proof of concept by the Fused Deposition Modelling process.

Association Between the Treatment Modality of Pediatric Subcondylar Fractures and Functional Outcomes at the Six-Month Follow-Up: A Retrospective Pilot Study

BACKGROUND

The choice of treatment for subcondylar fractures in children and adolescents remains a controversial issue. The aim of this study was to evaluate the association between the treatment modality of subcondylar fractures and functional outcomes at the six-month follow-up.

METHODS

This retrospective study examined a cohort of children and adolescents with unilateral or bilateral subcondylar fractures treated at a level 1 trauma center over a five-year period. Radiological assessments of ramal height shortening (RHS) and subcondylar fracture angulation (SFA) were conducted using cone beam computed tomography. A total of 28 patients met the inclusion criteria, which required participants to be 18 years of age or younger, have a follow-up period of at least six months, and present with an initial SFA of less than 45°. Subcondylar fractures were classified into three categories: Class I (RHS <2 mm and/or SFA <10°), Class II (RHS ≥2 mm and ≤15 mm and/or SFA ≥10° and ≤35°), and Class III (RHS >15 mm and/or SFA >35°). Functional outcomes, including maximal mouth opening, lateral movements, and protrusive movements, were assessed at the six-month follow-up. Reference values specific to children and adolescents were applied to distinguish between normal and limited mandibular motion. The relationship between treatment modality and functional outcomes was analyzed using logistic regression, with adjustments made for age, sex, and fracture classification.  Results: Twenty-eight patients (67.9% male; mean age 14.0±4.0 years) met the inclusion criteria. Of these, 53.6% (n=15) were treated with open reduction and internal fixation, while 46.4% (n=13) underwent closed reduction. The choice of treatment modality significantly influenced patient prognosis. Closed reduction was strongly associated with improved functional outcomes, specifically in the vertical range of movement (odds ratio (OR)=16.4; P=0.047), lateral range of movement (OR=18.7; P=0.044), and overall combined functional outcomes of vertical, lateral, and protrusive movements (OR=10.9; P=0.028).

CONCLUSION

This preliminary study suggests a correlation between treatment modality and functional outcomes at the six-month follow-up. Open reduction and internal fixation of subcondylar fractures in children and adolescents may carry a higher risk of poor functional outcomes. The findings support closed reduction as the preferred approach for Class I-III cases with subcondylar fracture fragments angulated between 0° and 45°.

Sinonasal Specific Bone Lesions, Including Fibro-Osseous and Select Odontogenic Lesions

Sinonasal bone lesions encompass a diverse spectrum, ranging from nonneoplastic and benign conditions to aggressive, malignant neoplasms. These lesions can affect individuals across various age groups, from pediatric to adult patients. Recognizing these entities is crucial, given the variability in treatment approaches, recurrence rates, and prognoses. This review explores the common and uncommon but distinctive bone lesions affecting the sinonasal region, highlighting key clinical, radiographic, morphologic, and genetic features for each. Additionally, we provide helpful tips on distinguishing and accurately classifying each lesion within its relevant differential diagnoses.

Treatment strategies for dental implant removal: A literature review

Dental implants have been widely used with success, but long-term usage sometimes leads to implant loss. The purpose of this review was to summarize the etiology of early and late failure requiring dental implant removal and the treatment strategies for the removal of failed implants and reimplantation. Early failures are often caused by patient-related factors, such as smoking, diabetes, radiotherapy, bone quality, and periodontitis of the remaining natural teeth. The most common cause of late failure is peri-implantitis, followed by implant fracture and implant malpositioning. Implants should be removed if they are mobile or if their superstructure cannot be maintained (e.g., implant fracture). For peri-implantitis, implant removal should be determined based on the patient's age and esthetic needs, the implant site, and the severity of bone loss. Many reports have been published on implant removal techniques. The reverse torque technique should always be the first choice because of its low invasiveness. The weighted survival rate for the replacement of failed implants is 86.3%, with a much lower survival rate after the second or subsequent implantations. Therefore, patient-specific problems, such as smoking habits and bruxism, should be checked before reimplantation and controlled to the greatest extent possible.

Electronic Cigarettes and Peri-Implantitis: An Umbrella Review

Electronic cigarettes (e-cigarettes) are offered to consumers as a healthier option than traditional tobacco. However, the long-term effect of non-heat-burning tobacco and e-cigarettes on periodontal and peri-implantitis is unknown. The present review evaluates the impact of electronic cigarettes on peri-implantitis and compares the results with traditional cigarettes and nonsmokers. Systematic/meta-analysis studies were searched in PubMed, MEDLINE, EMBASE, Cochrane Library, and Google Scholar until December 30, 2022. Five systematic/meta-analysis studies were identified based on the search strategy in the selected databases. The overall quality assessment of the studies showed acceptable evidence with high quality. All systematic review studies showed that compared with traditional tobacco smoke, electronic cigarettes might reduce or not change the clinical inflammatory symptoms of periodontitis and peri-implantitis, such as bleeding on probing, probing depth, peri-implant bone loss, and response to treatments. Electronic cigarettes contain nicotine, which can harm periodontal and implant health. On the other hand, a wide range of oral health consequences may be associated with using e-cigarettes. E-cigarette is a potential risk factor for the healing process and the results of implant treatment.

Trueness and surface characteristics of 3-dimensional printed casts made with different technologies

STATEMENT OF PROBLEM

Three-dimensional (3D) printers should be capable of fabricating products with high accuracy for potential use in a wide range of dental applications. The trueness and surface characteristics of 3D-printed casts made with different technologies remain unclear.

PURPOSE

The purpose of this in vitro study was to evaluate the trueness and surface characteristics of 4 types of dental casts printed using 6 different 3D printers.

MATERIAL AND METHODS

Four dental casts prepared for intracoronal and extracoronal restorations were printed using 6 different 3D printers-2 printers of each printing technology (FDM: Creator, Lugo; DLP: D2, ND5100; SLA: Form 2, Form 3). The printed casts were scanned to obtain standard tessellation language (STL) data sets that were superimposed onto the reference to evaluate their trueness (n=15). Trueness was measured based on overall deviations for each cast and for sectional deviations within the cavities. For qualitative evaluation, the surface characteristics of the 3D-printed casts were analyzed by using a digital camera, stereomicroscope, and scanning electron microscope. Statistical analyses were conducted using the Kruskal-Wallis test, followed by multiple Mann-Whitney U tests for pairwise comparisons among groups (α=.05).

RESULTS

The overall median trueness values were lowest with the Form 3 (27.9 μm), followed by the ND5100 (30.0 μm), Lugo (37.1 μm), D2 (41.4 μm), Form 2 (46.9 μm), and Creator (83.3 μm) (P<.05). Sectional deviations within the cavity were generally greater than overall deviation. Macroscopic and microscopic images showed that the reproduced casts had the smoothest surface with the SLA, followed by the DLP and FDM printers. Horizontal layers were more discernible with the FDM printer.

CONCLUSIONS

The trueness of the 3D-printed casts was influenced by the type of tooth preparation and was printer dependent. Among the tested 3D printers, the Form 3 produced the most accurate casts, while the Creator produced the least accurate casts.

Assessment of the application of a novel three-dimension printing individualized titanium mesh in alveolar bone augmentation: A retrospective study

OBJECTIVE

To assess the clinical and radiographic outcomes of alveolar ridge augmentation using a novel three-dimensional printed individualized titanium mesh (3D-PITM) for guided bone regeneration (GBR).

MATERIALS AND METHODS

Preoperative cone-beam computed tomography (CBCT) was used to evaluate alveolar ridge defects, followed by augmentation with high-porosity 3D-PITM featuring circular and spindle-shaped pores. Postoperative CBCT scans were taken immediately and after 6 months of healing. These scans were compared with preoperative scans to calculate changes in bone volume, height, and width, along with the corresponding resorption rates. A statistical analysis of the results was then conducted.

RESULTS

A total of 21 patients participated in the study, involving alveolar ridge augmentation at 38 implant sites. After 6 months of healing, the average bone augmentation volume of 21 patients remained at 489.71 ± 252.53 mm3, with a resorption rate of 16.05% ± 8.07%. For 38 implant sites, the average vertical bone increment was 3.63 ± 2.29 mm, with a resorption rate of 17.55% ± 15.10%. The horizontal bone increment at the designed implant platform was 4.43 ± 1.85 mm, with a resorption rate of 25.26% ± 15.73%. The horizontal bone increment 2 mm below the platform was 5.50 ± 2.48 mm, with a resorption rate of 16.03% ± 9.57%. The main complication was exposure to 3D-PITM, which occurred at a rate of 15.79%.

CONCLUSION

The novel 3D-PITM used in GBR resulted in predictable bone augmentation. Moderate over-augmentation in the design, proper soft tissue management, and rigorous follow-ups are beneficial for reducing the graft resorption and the incidence of exposure.

Comparison of Strengths of Mandibular Angle Fractures Following Different Plate Designs: A Human Cadaver Study

Study Design

This institutional cross-sectional study using cadaveric mandibles aimed to measure and compare the strengths of three plating designs utilized in osteosynthesis of mandibular angle fractures.

Objective

There have been prior studies on angle fracture fixation though few biomechanical studies on human cadaveric specimen. This study aims to directly compare the biomechanical strength of different plating designs to the mandibular angle fracture using a human cadaveric specimen substrate.

Methods

After receiving an angle osteotomy and either single plate, two plate, or 3D plate fixation, the specimens underwent biomechanical testing using the Instron 5565 mechanical testing unit. The primary outcomes measured were peak load at which permanent deformation started, displacement value at peak load, and load necessary for a specific amount of displacement at 1, 3, 5, and 7 mm.

Results

There were 15 hemi-mandibles in each group. Based on data analysis of all the specimens, there were no significant differences in the mandibular height, ramus width, mandibular thickness, angle height, and gonial angle between the hemimandibles.. This study demonstrated a statistically significant increased strength performance of the 3D plate over the single plate fixation and the 2-plate over the single plate fixation. The results between 2-plate and 3D plate were in similar values.

Conclusions

In terms of biomechanical strength, the 3D plate and two plate designs outperform the single plate design to mandibular angle fractures. There are various anatomical and patient specific situations that can aid in selection between them. In the absence of the favorable angle fracture and patient, biomechanical strength to the method of fixation selection needs to be considered.

Fracture resistance of ultratranslucent multilayered zirconia veneers with different facial thicknesses

To assess the fracture resistance of computer-aided design and computer-aided manufacturing (CAD/CAM) ultratranslucent multilayered zirconia (5Y-YZP) veneers with varying facial thickness. Sixty translucent zirconia veneers were designed and milled using a chairside CAD/CAM system for maxillary central incisors. The butt joint incisal veneer tooth preparations consisted of 1.00 mm incisal reduction, 0.40 mm chamfer margin, and three different facial reductions; 0.50, 0.75, and 1 mm, respectively. The ceramic veneers were cemented to printed resin dies and subjected to thermal cycling. Subsequently, the restorations were loaded with compressive loading force, and fracture occurrences were recorded. Scanning electron microscope (SEM) images of the fractured specimens were captured. The fracture resistance varied among the veneers with different facial thicknesses. Ultratranslucent zirconia veneers with a facial thickness of 1.00 mm exhibited the highest fracture resistance values (742.15 N), followed by those with 0.75 mm facial thickness (673 N). Minimally invasive veneers with 0.50 mm thickness displayed similar fracture resistance as thicker veneers with 0.75 mm. However, veneers with 1.00 mm thickness displayed the highest values. SEM fracture patterns for 0.50 and 0.75 mm display similar and fewer crack lines than 1.00 mm veneers. RESEARCH HIGHLIGHTS: Minimally invasive zirconia veneers exhibit similar fracture resistance to thicker veneers.