Effects of occlusal forces on the peri-implant-bone interface stability

Association of Peri-Implant Keratinized Mucosa Width and Mucosal Thickness with Early Bone Loss: A Cross-Sectional Study

Objective: The objective of this study was to evaluate the effects of keratinized mucosa width (KMW) and mucosal thickness (MT) around dental implants on marginal bone loss (MBL). The evaluation was performed one year after loading by comparing clinical, radiographic, and biochemical parameters. Methods: The study included 87 implants in 87 patients undergoing regular follow-ups without hard or soft tissue augmentation one year after loading. Clinical measurements included plaque index (PI), gingival index (GI), bleeding on probing (BoP), probing depth (PD), KMW, and MT. MBL was assessed with periapical radiography. The peri-implant crevicular fluid (PICF) was analyzed for tumor necrosis factor-alpha (TNF-α), receptor activator of nuclear factor-kB ligand (RANKL), osteoprotegerin (OPG), and microRNA-27a. Results: The MBL of implants with thin MT (<2 mm) was higher than that of implants with thick MT (≥2 mm) (p < 0.05). A significant negative correlation (r: -0.217) was established between MT and MBL. No significant association was found between KMW and MBL (p > 0.05). No significant associations was found between KMW and MT with TNF-α, RANKL, OPG and RANKL/OPG (p > 0.05), with the exception of increased microRNA-27a levels in implants with KMW ≥ 2 mm (p < 0.05). Conclusions: Implants with a thick MT had a lower MBL. There may be an association between adequate KMW and high miRNA-27a levels. The relationship between MBL and miRNA-27a remains unclear.

Restoratively driven planning for implants in the posterior maxilla - Part 2: implant planning, biomechanics and prosthodontic planning a proposed prosthodontic complexity index

Restoratively driven implant planning in the posterior maxilla requires a comprehensive understanding of the anatomical and physiological changes of the alveolar bone following tooth extraction and sinus augmentation. As a part of restoratively driven planning, alveolar bone, inter-arch relationships, proposed crown-implant ratio and anticipated non-axial loading should be assessed pre-operatively. This helps determine the prosthodontic and surgical aspects of implant treatment, such as prosthesis design, implant number, implant angulation, implant length and the necessity for additional bone grafting procedures. However, currently no implant planning classification is restoratively driven and include these important prosthodontic considerations. Therefore, a new index - the Posterior Maxilla Prosthodontic Index - is defined to encourage restoratively driven implant planning in the posterior maxilla.

Prosthetic Design Factors Influencing Peri-Implant Disease: A Comprehensive Review

Peri-implant disease, encompassing peri-implant mucositis and peri-implantitis, presents a growing challenge in implant dentistry. This comprehensive review explores the intricate interplay between prosthetic design factors and the development of peri-implant disease. By analyzing the impact of prosthetic components on microbial colonization, mechanical stress, and soft tissue health, the review highlights their crucial role in disease prevention and management. Additionally, it emphasizes the significance of maintenance protocols, prosthetic adjustments, and patient education in ensuring favorable long-term outcomes. The review underscores the potential for future advancements in prosthetic design, including innovative materials and digital technologies, and stresses the importance of interdisciplinary collaboration in optimizing patient care. Overall, the review underscores the critical role of prosthetic design in addressing the complexities of peri-implant disease, offering insights for clinicians and researchers to enhance the success and longevity of implant-supported restorations.

Volumetric compression by heterogeneous scaffold embedding promotes cerebral organoid maturation and does not impede growth

Although biochemical regulation has been extensively studied in organoid modeling protocols, the role of mechanoregulation in directing stem cell fate and organoid development has been relatively unexplored. To accurately replicate the dynamic organoid development observed in nature, in this study, we present a method of heterogeneous embedding using an alginate-shell-Matrigel-core system. This approach allows for cell-Matrigel remodeling by the inner layer and provides short-term moderate-normal compression through the soft alginate outer layer. Our results show that the time-limited confinement contributes to increased expression of neuronal markers such as neurofilament (NF) and microtubule-associated protein 2 (MAP2). Compared with non-alginate embedding and alginate compression groups, volume growth remains unimpeded. Our findings demonstrate the temporary mechanical regulation of cerebral organoid growth, which exhibits a regular growth profile with enhanced maturation. These results highlight the importance and potential practical applications of mechanoregulation in the establishment of brain organoids. A record of this paper's transparent peer review process is included in the supplemental information.

Clinical and radiographic results of crestal vs. subcrestal placement of implants in posterior areas: A split-mouth randomized controlled clinical trial

OBJECTIVE

The objective of this study was to evaluate the peri-implant soft tissue and marginal bone loss (MBL) around implants with platform-switching and internal conical connection placed at crestal and subcrestal levels in posterior areas.

MATERIALS AND METHODS

Nineteen partially edentulous patients with at least two adjacent missing teeth in posterior areas unilaterally or bilaterally were included. Forty-two implants were placed randomly at the crestal or subcrestal (1 mm) level in a split-mouth design. Implant-supported fixed dental prostheses with screw retention were delivered after 4 months of healing. Clinical and radiological measurements were performed at implant placement (T0), restoration delivery (T1), and 1-year follow-up after loading (T2). MBL was calculated as the change in distance from the implant-abutment interface to the first radiographically visible bone-implant contact. A repeated-measures mixed ANOVA followed by a paired Student's t-test with the Bonferroni correction was used for statistical analysis. p < 0.05 was considered statistically significant.

RESULTS

Eighteen patients with thirty-eight implants completed the study at T2. The MBL was lower in the subcrestal group than in the crestal group (0.04 ± 0.08 vs. 0.17 ± 0.17 mm, p = 0.004). The peri-implant probing depth (PD) was 2.31 ± 0.48 mm in the subcrestal group and 1.92 ± 0.43 mm in the crestal group; this difference was statistically significant (p = 0.002). Intragroup comparison showed no significant differences in MBL, or PD around the crestal group and subcrestal group from T1 to T2.

CONCLUSION

After 1 year of functional loading, subcrestal placement of implants with platform-switching and internal conical connection showed lower MBL and was associated with greater PD and peri-implant soft tissue height than implants placed at the crestal level.

Prediction of Bone Healing around Dental Implants in Various Boundary Conditions by Deep Learning Network

Tissue differentiation varies based on patients' conditions, such as occlusal force and bone properties. Thus, the design of the implants needs to take these conditions into account to improve osseointegration. However, the efficiency of the design procedure is typically not satisfactory and needs to be significantly improved. Thus, a deep learning network (DLN) is proposed in this study. A data-driven DLN consisting of U-net, ANN, and random forest models was implemented. It serves as a surrogate for finite element analysis and the mechano-regulation algorithm. The datasets include the history of tissue differentiation throughout 35 days with various levels of occlusal force and bone properties. The accuracy of day-by-day tissue differentiation prediction in the testing dataset was 82%, and the AUC value of the five tissue phenotypes (fibrous tissue, cartilage, immature bone, mature bone, and resorption) was above 0.86, showing a high prediction accuracy. The proposed DLN model showed the robustness for surrogating the complex, time-dependent calculations. The results can serve as a design guideline for dental implants.

Depth of mucosal tunnel in peri-implant health during 12-month follow-up in patients with controlled periodontitis

BACKGROUND

The association between thickness of peri-implant mucosa, known as mucosal tunnel (MT) and related clinical parameters in bone-level implants has not been investigated.

METHODS

Posterior implants, in patients with controlled periodontitis, were evaluated at different time intervals: during uncovering surgery (T₀ ), 2-month after uncovering surgery (T_2M ) and 12-month after placement (T_12M ). Clinical parameters including vertical soft tissue height (VSTH), MT, tooth-implant discrepancy of bone level (DBL), pocket depth (PD), peri-implant marginal bone loss (MBL), emergence profile and emergence angle (EA) were collected, and the correlation were assessed at different time points.

RESULTS

Forty-two patients with 60 implants were recruited, and 81.7% of the patients were Stage III-IV, Grade B-C generalized periodontitis. MT presented no significant difference in PD, VSTH, and MBL. Periodontitis Grade C and absence of bone regeneration were significant predictors for deep MT (>3 mm), and 5.85⁰ less EA at mesial side of implants (p = 0.02).The regression of analysis implied the increase of DBL 1 mm would cause 0.26 mm deeper MT, 1.7 times higher risk of having deep MT (p = 0.041; OR = 1.731; 95% CI:1.02-2.93) and 2.1 times higher risk of having circumferential PD > 4 mm (p = 0.019; OR = 2.1; 95% CI:1.13-3.92).

CONCLUSIONS

In bone-level implants, a correlation between MT and clinical parameters at 12-month follow-up was not found. However, history of periodontitis Grade C, absence of bone regeneration and tooth-implant discrepancy of bone level might define the depth of MT. Additionally, the depth of MT played a critical role in determining restorative design.

On Peri-Implant Bone Loss Theories: Trying To Piece Together the Jigsaw

This review aims to explore the plausibility of new theories on the etiopathogenesis of marginal bone loss (MBL) and peri-implantitis (PI) and to discuss possible underlying pathogenic mechanisms. The former concept of osteointegration of dental implants can now be conceptualized as a foreign body response histologically characterized by a bony demarcation in combination with chronic inflammation. Different risk factors can provoke additional inflammation and, therefore, pro-inflammatory cytokine release in soft tissues and bone, leading to an overpass of the threshold of peri-implant bone defensive and regenerative capacity. Progressive bone loss observed in MBL and PI is ultimately due to a localized imbalance in the receptor activator of nuclear factor kappaB ligand (RANKL)/Receptor activator of nuclear factor κ B (RANK)/osteoprotegerin (OPG) pathway in favor of increased catabolic activity. The genetic background and the severity and duration of the risk factors could explain differences between individuals in the threshold needed to reach an imbalanced scenario. MBL and PI pathogenesis could be better explained by the "inflammation-immunological balance" theory rather than a solely "infectious disease" conception. The link between the effect of biofilm and other risk factors leading to an imbalanced foreign body response lies in osteoclast differentiation and activation pathways (over)stimulation.

Mechanobiologically optimized Ti-35Nb-2Ta-3Zr improves load transduction and enhances bone remodeling in tilted dental implant therapy

The tilted implant with immediate function is increasingly used in clinical dental therapy for edentulous and partially edentulous patients with excessive bone resorption and the anatomic limitations in the alveolar ridge. However, peri-implant cervical bone loss can be caused by the stress shielding effect. Herein, inspired by the concept of “materiobiology”, the mechanical characteristics of materials were considered along with bone biology for tilted implant design. In this study, a novel Ti–35Nb–2Ta–3Zr alloy (TNTZ) implant with low elastic modulus, high strength and favorable biocompatibility was developed. Then the human alveolar bone environment was mimicked in goat and finite element (FE) models to investigate the mechanical property and the related peri-implant bone remodeling of TNTZ compared to commonly used Ti–6Al–4V (TC4) in tilted implantation under loading condition. Next, a layer-by-layer quantitative correlation of the FE and X-ray Microscopy (XRM) analysis suggested that the TNTZ implant present better mechanobiological characteristics including improved load transduction and increased bone area in the tilted implantation model compared to TC4 implant, especially in the upper 1/3 region of peri-implant bone that is “lower stress”. Finally, combining the static and dynamic parameters of bone, it was further verified that TNTZ enhanced bone remodeling in “lower stress” upper 1/3 region. This study demonstrates that TNTZ is a mechanobiological optimized tilted implant material that enhances load transduction and bone remodeling.

•

The mechanical properties and deformation mechanisms of Ti–35Nb–2Ta–3Zr alloys were studied.

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The cell biocompatibility, a layer-by-layer correlation of the finite element and X-ray Microscopy analysis were evaluated.

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Ti–35Nb–2Ta–3Zr implant improves load transduction and enhances bone remodeling in tilted implantation models.

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Mechanobiologically optimized Ti–35Nb–2Ta–3Zr alloy meets the clinical application requirements of tilted implant therapy.

Does implant location influence the risk of peri-implantitis?

Peri-implantitis is characterized by nonreversible and progressive loss of supporting bone and is associated with bleeding and/or suppuration on probing. Peri-implant disease is considered as the main etiologic factor related to implant failure. Peri-implant disease has a pathogenesis similar to that of periodontal disease, both being triggered by an inflammatory response to the biofilm accumulation. Although the prevalence of peri-implantitis has been evaluated by several clinical studies with different follow-ups, there are currently little data on the impact of implant location and the prevalence of peri-implantitis. The aim of this review, therefore, was to summarize the evidence concerning the prevalence of peri-implantitis in relation to implant location and associated risk predictors. Even though most studies evaluating the prevalence of peri-implantitis in relation to implant location are cross-sectional or retrospective, they suggest that the occurrence of peri-implantitis is most prevalent in the anterior regions of the maxilla and mandible. Moreover, it seems that there is a higher prevalence of peri-implantitis in the maxilla than in the mandible.

Craniofacial sutures: Signaling centres integrating mechanosensation, cell signaling, and cell differentiation

Cranial sutures are dynamic structures in which stem cell biology, bone formation, and mechanical forces interface, influencing the shape of the skull throughout development and beyond. Over the past decade, there has been significant progress in understanding mesenchymal stromal cell (MSC) differentiation in the context of suture development and genetic control of suture pathologies, such as craniosynostosis. More recently, the mechanosensory function of sutures and the influence of mechanical signals on craniofacial development have come to the forefront. There is currently a gap in understanding of how mechanical signals integrate with MSC differentiation and ossification to ensure appropriate bone development and mediate postnatal growth surrounding sutures. In this review, we discuss the role of mechanosensation in the context of cranial sutures, and how mechanical stimuli are converted to biochemical signals influencing bone growth, suture patency, and fusion through mediation of cell differentiation. We integrate key knowledge from other paradigms where mechanosensation forms a critical component, such as bone remodeling and orthodontic tooth movement. The current state of the field regarding genetic, cellular, and physiological mechanisms of mechanotransduction will be contextualized within suture biology.

Development of a new preclinical model to study early implant loss: a validation study in the beagle dog

Objectives

To develop a new preclinical model to study early implant loss, where local infection conditions would impair the implant osseointegration.

Materials and methods

Forty-eight smooth, 2.9-mm diameter experimental implants were placed in the mandible of 8 beagle dogs (3 in each side). In half of the animals (test group, n = 24 implants), the implants received ligatures around the implant-abutment connection. In the other half, no ligatures were placed (control group, n = 24 implants). Four weeks later, implants were extracted in a flapless approach and standard 3.3-mm diameter SLActive implants were placed into the same osteotomy site without any further drilling. Eight weeks after the second implantation, animals were sacrificed and analyzed in terms of implant survival.

Results

After 8 weeks of healing, 4 implants were lost in the control group and 14 in the test group. This corresponded to a 17.4% of early implant loss in the control group and 58.3% in the test. Most of the early failures occurred within the first 5 weeks of healing.

Conclusions

Implants placed in a pre-contaminated site present higher early loss than those placed in a non-contaminated site. This study represents a valid and robust preclinical model to study mechanisms and reduction of early implant loss as new technologies become available.

Clinical relevance

Scientific rationale for the study: There is lack of animal models to study early implant loss. Thus, a proposal of a new model is presented. With the validation of this model, new technologies can be implemented to prevent early implant loss.

Assessment of Quality of Life and Supporting Structures in Implant Retained Mandibular Overdenture: A 5-Year Cohort Study

Aim

To assess oral health-related quality of life (OHRQoL), marginal bone loss (MBL), and changes in soft tissue including probing pocket depth and implant stability in 2 implants retained mandibular overdentures during 5 years follow-up periods.

Methods

Forty completely edentulous patients with age 51-64 years were recruited for that longitudinal cohort study. Complete dentures were performed for all participants. Two implants (3.6 × 11.5 mm) were installed in the canine areas of the mandible. OHRQoL and MBL measures were performed every 1 year for 5 years, while clinical measures were made every 6 months for 60 months. Data were examined using repeated ANOVA and Friedman test.

Results

Thirty-seven patients had 74 implants; with mean age 56 ± 3.6 years; 43% females (n = 16) and 57% males (n = 21) accomplished the study. There were statistically significant differences in OHRQoL, MBL, and changes in soft tissue, including probing pocket depth and implant stability in 2 implants retained mandibular overdentures during 5 years follow-up periods, p ≤ 0.05.

Conclusion

Mandibular overdentures retained by 2 implants provide a positive long-term effect on OHRQoL, MBL, probing pocket depth, and implant stability.

Bone quality effect on short implants in the edentulous mandible: a finite element study

Introduction

The aim of this study was to verify whether the use of short implants could optimize stress distribution of bone surrounding implants in atrophic mandibles with different bone qualities.

Methods

A three-dimensional model of the atrophic mandible with three levels of bone quality was made using computer software. Short implants (6 mm) and standard implants (10 mm) were used in four designs: Design 1 "All-On four", Design 2 "All-On-four" with two short implants, Design 3 four vertical implants with two short implants, and Design 4 six short implants. The distal short implants were placed at the first molar position. All twelve models were imported into finite element analysis software, and 110 N oblique force was loaded on the left second premolar. Maximum principal stress values of peri-implant bone and the volumes of bone with over 3000 microstrians (overload)were analyzed.

Result

Stress values and volumes of overload bone increased in all four groups with the decline of bone quality. The highest stress values were found in the cortical bone surrounding the Design 1 inclined implant in two lower bone quality mandibles, and the lowest in Design 3. However, Design 1 had less overload bone tissue than all three designs with short implants.

Conclusion

Short implants placed posteriorly helped decrease stress values in peri-implant bone, while bone surrounding short implants had a high resorption risk in low bone quality mandible.

Occlusal change in posterior implant-supported single crowns and its association with peri-implant bone level: a 5-year prospective study

OBJECTIVES

This study aims to analyze the 5-year occlusal change in posterior implant-supported single crowns and the association between the relative occlusal force (ROF) and peri-implant bone level.

MATERIALS AND METHODS

Partially edentulous patients who had received implant-supported single crowns in the posterior region were included. Occlusal examinations with a computerized occlusion analysis system were conducted at 0.5, 3, 6, 12, 24, 36, 48, and 60 months after delivery of the implant-supported single crown. The ROFs of implant-supported single crowns, mesial adjacent teeth, and control natural teeth were recorded. Intraoral periapical radiographs were taken at each follow-up time to evaluate marginal bone level (MBL). Ordinary least square regression was used to analyze the association between ROF and MBL.

RESULTS

Thirty-seven posterior implant-supported single crowns in 33 participants (23.9 to 70.0 years) were followed up for 0.5 to 60 months [(42.4 ± 26.0) months]. The ROF of implant-supported single crowns increased from 2 weeks to 3 months (P < 0.01) and increased continuously between all two sequential time points from 6 to 36 months, with significant differences (P < 0.05). Then ROFs of implant-supported single crowns were significantly higher than those of control teeth at 48 and 60 months (P < 0.05). Regression analysis showed that ROF was significantly associated with MBL with a coefficient of 0.008 (P < 0.05).

CONCLUSION

The ROFs of posterior implant-supported single crown have significant change during 5 years' follow-up. The association between ROF and MBL has limited clinical significance.

TRIAL REGISTRATION

Chinese Clinical Trial Registry: ChiCTR-ROC-17012240.

CLINICAL RELEVANCE

The occlusion of implant-supported single crowns should be carefully monitored during follow-up examinations, and occlusal adjustment should be considered to prevent overloading.

An evaluation of the stress effect of different occlusion concepts on hybrid abutment and implant supported monolithic zirconia fixed prosthesis: A finite element analysis

PURPOSE

The aim of this study is to evaluate the effects of canine guidance occlusion and group function occlusion on the degree of stress to the bone, implants, abutments, and crowns using finite element analysis (FEA).

MATERIALS AND METHODS

This study included the implant-prosthesis system of a three-unit bridge made of monolithic zirconia and hybrid abutments. Three-dimensional (3D) models of a bone-level implant system and a titanium base abutment were created using the original implant components. Two titanium implants, measuring 4 × 11 mm each, were selected. The loads were applied in two oblique directions of 15° and 30° under two occlusal movement conditions. In the canine guidance condition, loads (100 N) were applied to the canine crown only. In the group function condition, loads were applied to all three teeth. In this loading, a force of 100 N was applied to the canine, and 200-N forces were applied to each premolar. The stress distribution among all the components of the implant-bridge system was assessed using ANSYS SpaceClaim 2020 R2 software and finite element analysis.

RESULTS

Maximum stress was found in the group function occlusion. The maximum stress increased with an increase in the angle of occlusal force.

CONCLUSION

The canine guidance occlusion with monolithic zirconia crown materials is promising for implant-supported prostheses in the canine and premolar areas.

Influence of osteoporosis and mechanical loading on bone around osseointegrated dental implants: A rodent study

This study aimed to evaluate the influence of estrogen deficiency and mechanical loading on bone around osseointegrated dental implants in a rat jaw model. The maxillary right first molars of 36 rats were extracted. One week later, the rats were divided into an unloaded group and a loaded group; short head implants and long head implants were inserted respectively. Nine weeks after implantation, the rats were further subjected to ovariectomy (OVX) or sham surgery. All animals were euthanized 21 weeks after OVX. Micro-computed tomography, histological and histomorphometrical evaluation were undertaken. Systemic bone mineral density and bone volume fraction decreased in OVX groups compared with the sham controls. Histomorphometrical observation indicated that unloaded OVX group showed significantly damaged osseointegration and bone loss versus the loaded OVX group. Both the bone density (BD) inside the peri-implant grooves and the percentage of bone-to-implant contact (BIC) were lower in the OVX groups than in the sham-surgery groups, although mechanical loading increased the BIC and BD in the loaded OVX group compared with the unloaded OVX group. An increased number of positive cells for tartrate-resistant acid phosphatase was observed in the OVX groups versus the sham controls. The percentage of sclerostin-positive osteocytes was lower under loaded compared with unloaded conditions in both the OVX groups and the sham controls. In conclusion, estrogen deficiency could be a risk factor for the long-term stability of osseointegrated implants, while mechanical loading could attenuate the negative influence of estrogen deficiency on bone formation and osseointegration.

Scientometric Analysis of Dental Implant Research over the Past 10 Years and Future Research Trends

BACKGROUND

We conducted a bibliometrics analysis to explore the recent trends in dental implant research which could help researchers have a clear grasp of the relevant research hotspots and prospects. Material and Methods. Altogether, 15,770 articles on dental implants, from January 1, 2010, to October 31, 2019, were selected from the Web of Science Core Collection. We used BICOMB software to extract the high-frequency MeSH terms and construct binary and coword matrices. gCLUTO software was used for biclustering and visual analysis, Ucinet 6 software for social network analysis, SCIMAT software for strategic diagram building, Citespace 5.5 software to form timeline visualization, and VOSviewer software, eventually, for bibliometrics cocitation network.

RESULTS

Altogether, 72 high-frequency keywords were extracted from the selected articles and 4 clusters and 7 subcategories were identified through biclustering analysis in the dental implant research field. The use of the strategic diagram also enabled us to find the research hotspot and development trends.

CONCLUSIONS

The survival rate of dental implants and subsequent restoration have always been the core focus of research. Sinus floor elevation and guided bone regeneration are worthy of constant exploration owing to their reliability. With continuous improvement in technology, immediate loading could become a future research hot spot.

Prevalence and risk indicators of peri-implant diseases in a group of Moroccan patients

BACKGROUND

To report the prevalence of peri-implant diseases in a North African patient population, and to assess the concurrent associations of patient- and implant-level characteristics with probing depth and bone loss around dental implants METHODS: A total of 642 implants in 145 subjects were followed up for a mean 6.4 years. At the last follow-up visit the subjects were examined clinically and radiographically to assess the status of peri-implant tissues and teeth. Data analysis used the generalized linear mixed models RESULTS: The prevalence of peri-implant mucositis and peri-implantitis were 82.1% and 41.4% at the subject level, and 68.4% and 22.7% at the implant level, respectively. Inadequate plaque control, peri-implant inflammation, history of previous implant failures, and pain/discomfort at the implant site were significantly associated with both outcomes (increased probing depth and bone loss). Diabetes mellitus, inadequate implant restoration, single restorations (versus multi-unit), cement-retained restorations, and presence of occlusal wear facets on teeth were significantly associated with one of the two outcomes. Implants placed in the lower anterior jaw region had the most favorable outcome. Smoking, history of periodontitis, and type of implant surface did not show significant associations with higher frequency of peri-implant diseases in the multivariable analysis.

CONCLUSIONS

Peri-implant diseases are prevalent in this North African patient population. Multiple subject- and implant-level variables were associated with peri-implant diseases. Risk assessment of these effects should consist of a concurrent inclusion of these factors in multivariable analyses that also adjust for the complex variance structure of the oral environment.

Influence of restorative design on the progression of peri-implant bone loss: A retrospective study

BACKGROUND

Clinical data on the restorative designs affecting the early progression of peri-implantitis are scarce. The aim of this retrospective study was to evaluate the influence of several restorative factors (e.g., restoration emergence angle, and internal screw length/diameter) on the marginal bone loss around implants with peri-implantitis.

METHODS

Implants diagnosed with peri-implantitis having 1- (T1) and 2-year (T2) follow-ups were included. In addition, within 6 months pre-diagnosis (Tb), all cases required to have full documentation in which no evidence of peri-implantitis was not indicated. Changes in marginal bone levels (MBLs) from Tb to T1 and from T1 to T2 were evaluated. The effect of several variables on MBLs changes was assessed via univariate and multivariate generalized estimating equations.

RESULTS

Eighty-three bone-level implants from 65 patients were selected. The mean follow-up before peri-implantitis diagnosis was 99.47 ± 47.93 months. The radiographic mean marginal bone loss was 1.52 ± 1.33 mm (Tb to T1) and 0.58 ± 0.52 mm (T1 to T2). Restoration emergence angle and frequency of maintenance visits significantly affected MBLs from Tb to T1. Besides, 66.3% of the included implants' bone levels were in a zone within 1 mm of the apical end of the internal screw at T1 and remained in this zone during the second follow-up year.

CONCLUSIONS

Significant marginal bone loss occurred in the early post-diagnosis period of peri-implantitis, which could be affected by the restoration emergence angle. Peri-implant MBLs were frequently located in a zone within 1 mm of the apical end of the internal screw.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

This comprehensive review of the 2019 restorative dental literature is offered to inform busy dentists regarding remarkable publications and noteworthy progress made in the profession. Developed by the Scientific Investigation Committee of the American Academy of Restorative Dentistry, each author brings discipline-specific expertise to 1 of 8 sections of the report: (1) prosthodontics; (2) periodontics, alveolar bone, and peri-implant tissues; (3) implant dentistry; (4) dental materials and therapeutics; (5) occlusion and temporomandibular disorders; (6) sleep-related breathing disorders; (7) oral medicine and oral and maxillofacial surgery; and (8) dental caries and cariology. The report targets important information likely to influence day-to-day dental treatment decisions. Each review is not intended to stand alone but to update interested readers so that they may visit source material when greater detail is desired. As the profession moves toward evidence-based clinical decision-making, an incredible volume of potentially valuable dental literature continues to increase. It is the intention of this review and its authors to provide assistance in negotiating the extensive dental literature published in 2019. It is our hope that readers find this work useful in the clinical management of dental patients.

Relevant Design Aspects to Improve the Stability of Titanium Dental Implants

Post-extractional implants and immediate loading protocols are becoming much more frequent in everyday clinical practice. Given the existing literature about tapered implants, the objective of this paper was to understand whether implant shape had a direct influence on the results of the insertion torque (IT) and implant stability quotient (ISQ). Seven tapered implant prototypes were developed and distributed into three groups and compared with a control cylindrical implant-VEGA by Klockner Implant System. The implants were inserted into bovine bone type III according to Lekholm and Zarb Classification. The sample size was n = 30 for the three groups. Final IT was measured with a torquemeter, and the ISQ was measured with Penguin Resonance Frequency Analysis (RFA). Modifications done to the Prototype I did not reveal higher values of the ISQ and IT when compared to VEGA. In the second group, when comparing the five prototypes (II-VI) with VEGA, it was seen that the values of the ISQ and IT were not always higher, but there were two values of the ISQ that were statistically significantly higher with the 4.0 mm diameter Prototypes II (76.3 ± 6.1) and IV (78 ± 3.7). Prototype VII was the one with higher and significant values of the ISQ and IT. In both diameters and in both variables, all differences were statistically significant enough to achieve the higher values of primary stability values (IT and ISQ). Given the limitations of this study, it can be concluded that when there is an increase of the diameter of the implant and body taper, there is an increase of the ISQ and IT, showing that the diameter of the implant is an important criteria to obtain higher values of primary stability.

Concepts for prevention of complications in implant therapy

The use of dental implants is nowadays a well-accepted and highly predictable treatment modality for restoring the dentition and reestablishing the masticatory function of edentulous and partially edentulous patients. Despite the high predictability and excellent long-term survival rates reported for implant therapy, complications may still occur and can jeopardize both short- and long-term success. The present paper provides an overview on the most important aspects related to the etiology, prevention, and management of complications associated with implant therapy. Data from the literature indicate that a number of factors, such as surgical trauma, implant diameter, type of implant-abutment connection, abutment disconnection and reconnection, presence of microgap, and implant malpositioning, can substantially influence the biologic processes of bone remodeling and biofilm formation, thus increasing the rate of short- and long-term hard- and soft-tissue complications. Other factors, such as excess cement at cement-retained prosthetic restorations, abutment mobility, and infections (e.g. peri-implant mucositis and peri-implantitis) caused by bacterial biofilm, are further causes for complications and failures. More recent evidence also indicates that besides the need for sufficient bone volume surrounding the implant, the presence of an adequate width and thickness of attached mucosa may improve biofilm control and limit crestal bone resorption. Furthermore, emerging evidence points also to the pivotal role of human factors as one of the most important causes of complications in implant dentistry. It can be concluded that clinicians need to consider all biologic and biomechanical factors affecting implant placement and survival, as well as undergo adequate training to improve their surgical skills to control and prevent implant complications. Careful patient selection and control of environmental and systemic factors, such as smoking, diabetes etc., coupled with an accurate surgical and prosthetic planning, enable a better prevention and control of infections.

Implant-borne rehabilitation for alveolar dental cleft: Retrospective analysis of thirty-nine cases

INTRODUCTION

Dental rehabilitation of patients with alveolar-dental cleft sequelae is a crucial issue in the final stages of functional and aesthetic management of these patients. The objectives of this study are to establish the success of implant-supported rehabilitations for patients with alveolar dental cleft sequelae followed in the Department of Maxillofacial Surgery and Stomatology of Lille University Hospital and the reasons for not using this type of rehabilitation for others.

MATERIALS AND METHOD

Patients treated between January 2009 and December 2018 with implant-supported prostheses at an alveolar dental cleft site were included. Dental implants were placed after a complementary alveolar bone graft. Clinical and radiological criteria regarding periodontal, occlusal and prosthetic status were studied.

RESULTS

A total of 12 implants in 8 patients were placed. One of these implants was lost, resulting in an implant survival rate of 91.7%. All patients were able to benefit from functional rehabilitation.

DISCUSSION

The present results demonstrate the interest and reliability of implant rehabilitation in these patients. They furthermore highlight financial factors as a barrier to using this solution among the majority of patients in care.