Recent advances in dental implants

Electrochemical Polishing of Ti and Ti6Al4V Alloy in Non-Aqueous Solution of Sulfuric Acid

This paper reports the results of our study on electrochemical polishing of titanium and a Ti-based alloy using non-aqueous electrolyte. It was shown that electropolishing ensured the removal of surface defects, thereby providing surface smoothing and decreasing surface roughness. The research was conducted using samples made of titanium and Ti6Al4V alloy, as well as implant system elements: implant analog, multiunit, and healing screw. Electropolishing was carried out under a constant voltage (10-15 V) with a specified current density. The electrolyte used contained methanol and sulfuric acid. The modified surface was subjected to a thorough analysis regarding its surface morphology, chemical composition, and physicochemical properties. Scanning electron microscope images and profilometer tests of roughness confirmed significantly smoother surfaces after electropolishing. The surface profile analysis of processed samples also yielded satisfactory results, showing less imperfections than before modification. The EDX spectra showed that electropolishing does not have significant influence on the chemical composition of the samples.

Placement of immediate dental implants in extraction sockets exhibiting the apical pathosis. A meta-analysis

Objectives

It is commonly accepted that immediate implantation is the best option for patients since it shortens the time patients must wait for ultimate restoration and provides a predictable functional and aesthetic result. However, this approach is still controversial in patients with apical pathosis. The goal of this systematic review and meta-analysis was to determine the efficacy of immediate implant insertion in patients with apical pathosis.

Material and methods

Between 2000 and 2023, PRISMA-compliant keywords were used to search PubMed, MEDLINE, CENTRAL, and the Cochrane Library. All English-language clinical studies that met PICOS criteria were included in a manual search. The included studies' demographic profile and event data for immediate dental implantation success in patients with or without apical pathosis were meta-analyzed using RevMan. The implant survival rate was assessed using risk ratio of plaque index and bleeding index. Begg's test using MedCalc and RevMan risk of bias assessment assessed publication bias.

Results

A meta-analysis of 10 trials with 849 dental implantation patients found a substantial difference in initial implant placement success rates in infected sites. The pooled risk ratio for plaque index is 0.59 (95% CI: 0.36-0.96) with heterogeneity of Tau2 = 0.62, chi2 = 109.69, df = 11, I2 = 90%, z = 2.12, and p < 0.05. While, the pooled risk ratio for bleeding index is 0.77 (95% CI: 0.60 to 0.98) with Tau2 = 0.16, chi2 = 103.67, df = 11, I2 = 89%, z = 2.12, and p < 0.05. The pooled odds ratio of implant survival rate is 2.08 (95% CI: 1.56 to 1.79) with Tau2 0.16; chi2 52.43; df 9; I2 83%; z 4.93 and p < 0.05. As evidenced by the funnel plot and statistically insignificant Begg's test p values of 0.45.

Conclusion

The placement of immediate implants in locations affected by apical pathosis is a clinically beneficial surgery, resulting in favorable aesthetic and functional outcomes for patients.

Comprehensive Evaluation of Novel Biomaterials for Dental Implant Surfaces: An In Vitro Comparative Study

BACKGROUND

Dental implantology is continually evolving in its quest to discover new biomaterials to improve dental implant success rates. The study explored the potential of innovative biomaterials for dental implant surfaces, including titanium-zirconium (Ti-Zr) alloy, hydroxyapatite-coated titanium (HA-Ti), and porous polyetheretherketone (PEEK), in comparison to conventional commercially pure titanium (CP Ti).

MATERIALS AND METHODS

A total of 186 samples were harvested for the analysis. Biomaterials were thoroughly evaluated in terms of surface topography, chemical composition, biocompatibility, mechanical properties, osseointegration performance, and bacterial adhesion. Study methods and techniques included scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), cell culture variants, tensile tests, hardness measurements, histological analysis, and microbiological testing.

RESULTS

Surface topography examination showed significant disparities between the biomaterials: Ti-Zr had a better roughness of 1.23 μm, while HA-Ti demonstrated a smoother surface at 0.98 μm. Chemical composition evaluation indicated the presence of a Ti-Zr alloy in Ti-Zr, calcium-phosphorus richness in HA-Ti, and high titanium amounts in CP Ti. The mechanical properties assessment showed that Ti-Zr and CP Ti had good tensile strengths of 750 MPa and 320 HV. In addition, bacterial adhesion tests showed low propensities for Ti-Zr and HA-Ti at 1200 and 800 cfu/cm2, respectively.

CONCLUSION

Ti-Zr and HA-Ti performed better than the other biomaterials in surface topography and mechanical properties and against bacterial adhesion. This study emphasizes that multi-parameter analysis is critical for clinical decision-making, allowing for the selection of the currently available biomaterial, which could be conducive to the long-term success of the implant.

Evaluation and assessment of the survival of tooth implant supported prosthesis in tooth and implant supported rehabilitation cases with metal frameworks

INTRODUCTION

Over the years, implant therapy has been a commonly used treatment option for individuals who are partially or totally edentulous, with a long-term success rate of over 90%. With significant advancements in biomaterials and technology, implant dentistry can now conduct prosthetic rehabilitations in the majority of patients catering to all types of needs. However, in order to meet the demands of a patient base that is always growing, new trends in implantology are emerging in recent years that are focused on minimally invasive surgery and financial sustainability. In certain clinical scenarios, connecting teeth and implants to support fixed partial prosthesis (FPPs) may be a predictable and workable course of treatment.

MATERIALS AND METHODS

22 patients were selected for this study who had tooth and implant supported prosthesis placed as a final restoration. Out of these 22 patients; 12 were male and 10 were female patients. Implants were placed following proper protocol and if grafting procedures were required they were carried out. A second stage surgical procedure was carried out and delayed loading protocols were followed. The statistical analysis was done using the IBM SPSS 24.0, Chicago, USA. The survival of the implants and teeth were measured by the Kaplan Meier survival scale. Bone loss was assessed at baseline(upon loading), 12 months and 24 months.

RESULTS

The implant survival rate was measured at 6 months, 12 months, 18 months and 24 months. At 24 months, one implant showed failure, so the survival rate of the implants were 95.4%. Bone loss of 1 mm was seen around one implant at 12 months. Bone loss of 1 and 2 mm was present around two implants and one implant respectively at 24 months.

CONCLUSION

From the results of this study, we can conclude that tooth implant supported prosthesis show very good survival when used in rehabilitation cases.

Outcomes of treatment with short dental implants compared with standard-length implants: a retrospective clinical study

BACKGROUND

The size of dental implants is a key success factor for appropriate osseointegration. Using shorter implants allows the possibility of avoiding complex surgical procedures and reduces the morbidity of treatment. Shorter implants also enable implant-prosthetic rehabilitation after maxillofacial reconstructions where only limited bone is available. In this study, the success rates of short implants were examined and compared to those of standard-sized implants.

METHODS

Patients who received dental implants between 2007 and 2016 at the Department of Oro-Maxillofacial Surgery and Stomatology Semmelweis University were enrolled in the study. Several clinical parameters were recorded and supplemented with radiological examinations. The data were statistically analysed.

RESULTS

Thirty-four patients with a total of 60 implants were included. The average time after prosthetic loading was 39.33 ± 21.96 months in the group with 8-mm implants and 41.6 ± 27.5 months in the group with > 8-mm implants. No significant differences were observed between the two groups in terms of probing depth (short implants, 2.84 ± 0.09 mm; standard implants, 2.91 ± 0.35 mm) or mean marginal bone loss (short implants, 1.2 ± 1.21-mm mesially and 1.36 ± 1.47-mm distally; standard implants: 0.63 ± 0.80-mm mesially and 0.78 ± 0.70-mm distally).

CONCLUSIONS

In this study, the success rate of short dental implants was comparable to that of standard-sized implants. Consequently, it can be claimed that the long-term success of short dental implants does not differ significantly from the long-term success of standard implants.

Machine learning-guided exploration and experimental assessment of unreported compositions in the quaternary Ti-Zr-Cu-Pd biocompatible metallic glass system

Due to their outstanding elastic limit, biocompatible Ti-based bulk metallic glasses (BMGs) are candidate materials to decrease the size of medical implants and therefore reduce their invasiveness. However, the practical use of classical Ti-BMGs in medical applications is in part hindered by their high copper content: more effort is thus required to design low-copper Ti-BMGs. In this work, in line with current rise in AI-driven tools, machine learning (ML) approaches, a neural-network ML model is used to explore the glass-forming ability (GFA) of unreported low-copper compositions within the biocompatible Ti-Zr-Cu-Pd system. Two types of models are trained and compared: one based on the alloy composition only, and a second based on various features derived from the alloying elements. Contrary to expectation, the predictive power of both models in evaluating GFA is similar. The compositional space identified by ML as promising is experimentally assessed, finding unfortunately low GFA. These results indicate that the ML approach may be premature for specific composition tuning of amorphous metallic materials. We emphasise that the development of ML tools in GFA prediction requires an improvement of the dataset, in terms of homogeneity, size and GFA descriptors, which must be supported by increased reporting of high-quality experimental GFA measurements, both positive and negative. STATEMENT OF SIGNIFICANCE: Biocompatible Ti-based bulk metallic glasses (BMGs) are candidate materials for use in the next generation of minimally invasive dental implants where improved mechanical properties, such as high strength are required. Despite promising in vitro/vivo evaluations, implementation of alloys for practical applications is partly hindered by the presence of copper as the main alloying element. Recent studies have presented AI-guided and machine learning strategies as appealing approaches to understand and describe the glass forming ability (GFA) of BMG-forming compositions. In this work, we employ and evaluate the capacity of a machine-learning model to explore low-copper compositional spaces in the biocompatible Ti-Zr-Cu-Pd system. Our results highlight the limits of such a computational approach and suggest improvements for future designing routes.

Surface-Mediated Modulation of Different Biological Responses on Anatase-Coated Titanium

Various surface modification strategies are being developed to endow dental titanium implant surfaces with micro- and nano-structures to improve their biocompatibility, and first of all their osseointegration. These modifications have the potential to address clinical concerns by stimulating different biological processes. This study aims to evaluate the biological responses of ananatase-modified blasted/etched titanium (SLA-anatase) surfaces compared to blasted/acid etched (SLA) and machined titanium surfaces. Using unipolar pulsed direct current (DC) sputtering, a nanocrystalline anatase layer was fabricated. In vitro experiments have shown that SLA-anatase discs can effectively promote osteoblast adhesion and proliferation, which are regarded as important features of a successful dental implant with bone contact. Furthermore, anatase surface modification has been shown to partially enhance osteoblast mineralization in vitro, while not significantly affecting bacterial colonization. Consequently, the recently created anatase coating holds significant potential as a promising candidate for future advancements in dental implant surface modification for improving the initial stages of osseointegration.

Optimization of CBCT data with image processing methods and production with fused deposition modeling 3D printing

The present study has investigated the effect of the removal of artifacts in cone beam computed tomography (CBCT) images with image processing techniques to dental implant planning. The aim of this study has been to benefit from the novel image processing techniques and additive manufacturing technologies in order to change the existing approach in the usage of the 3D model in the orthogonal surgery, traumatic cases, and tumor operations and to solve the restrictions in surgical operations. In the study, firstly, 3 × 3, 5 × 5, and 7 × 7 kernel values were determined on the CBCT image data of the patient. The determined kernel values were applied on CBCT images by choosing median, median-mean-Gaussian (MMG), and bilateral filters, which are quite successful in removing noise in medical images. A thresholding process to separate teeth and bones from soft tissue regions on CBCT images, histogram normalization for a balanced color distribution, morphology operations to reduce noise areas, and tooth and bone boundaries were determined as closely as possible to patient anatomy. The original image and the images obtained from image enhancement techniques were compared. Results showed that the 3 × 3 median filtering method from three different kernel values out of three different image processing methods used in the study greatly improved the artifacts. It has also been shown that the availability of image processing and additive manufacturing methods on CBCT images has been shown to be a highly important factor before dental surgery planning.

A short review on minimally invasive implants

In the last 30 years, the use of dental implants to replace missing teeth has increased immensely. Brånemark pioneered the use of extensive surgical flaps to visualise the surgical field during implant surgery. Since then, several changes have been made to the flap design with aesthetic considerations now being incorporated. Such major innovations have contributed to the wide acceptance of flapless implant surgery. Therefore, it is of interest to describe the various techniques, requirements, advantages and disadvantages of minimally implant surgery.

New classification for bone type at dental implant sites: a dental computed tomography study

OBJECTIVE

This study proposed a new classification method of bone quantity and quality at the dental implant site using cone-beam computed tomography (CBCT) image analysis, classifying cortical and cancellous bones separately and using CBCT for quantitative analysis.

METHODS

Preoperative CBCT images were obtained from 128 implant patients (315 sites). First, measure the crestal cortical bone thickness (in mm) and the cancellous bone density [in grayscale values (GV) and bone mineral density (g/cm³)] at the implant sites. The new classification for bone quality at the implant site proposed in this study is a "nine-square division" bone classification system, where the cortical bone thickness is classified into A: > 1.1 mm, B:0.7-1.1 mm, and C: < 0.7 mm, and the cancellous bone density is classified into 1: > 600 GV (= 420 g/cm³), 2:300-600 GV (= 160 g/cm³-420 g/cm³), and 3: < 300 GV (= 160 g/cm³).

RESULTS

The results of the nine bone type proportions based on the new jawbone classification were as follows: A1 (8.57%,27/315), A2 (13.02%), A3 (4.13%), B1 (17.78%), B2 (20.63%), B3 (8.57%) C1 (4.44%), C2 (14.29%), and C3 (8.57%).

CONCLUSIONS

The proposed classification can complement the parts overlooked in previous bone classification methods (bone types A3 and C1).

TRIAL REGISTRATION

The retrospective registration of this study was approved by the Institutional Review Board of China Medical University Hospital, No. CMUH 108-REC2-181.

The effect of preoperative clindamycin in reducing early oral implant failure: a randomised placebo-controlled clinical trial

OBJECTIVES

To assess the effect of preoperative oral clindamycin in reducing early implant failure in healthy adults undergoing conventional implant placement.

MATERIALS AND METHODS

We conducted a prospective, randomised, double-blind, placebo-controlled clinical trial in accordance with the ethical principles and Consolidated Standards of Reporting Trials statement. We included healthy adults who underwent a single oral implant without previous infection of the surgical bed or the need for bone grafting. They were randomly treated with a single dose of oral clindamycin (600 mg) 1 h before surgery or a placebo. All surgical procedures were performed by one surgeon. A single trained observer evaluated all patients on postoperative days 1, 7, 14, 28, and 56. Early dental implant failure was defined as the loss or removal of an implant for any reason. We recorded the clinical, radiological, and surgical variables, adverse events, and postoperative complications. The study outcomes were statistically analysed to evaluate differences between the groups. Furthermore, we calculated the number required to treat or harm (NNT/NNH).

RESULTS

Both the control group and clindamycin group had 31 patients each. Two implant failures occurred in the clindamycin group (NNH = 15, p = 0.246). Three patients had postoperative infections, namely two placebo-treated and one clindamycin-treated, which failed (relative risk: 0.5, CI: 0.05-5.23, absolute risk reduction = 0.03, confidence interval: - 0.07-0.13, NNT = 31, CI: 7.2-∞, and p = 0.5). One clindamycin-treated patient experienced gastrointestinal disturbances and diarrhoea.

CONCLUSIONS

Preoperative clindamycin administration during oral implant surgery in healthy adults may not reduce implant failure or post-surgical-complications.

CLINICAL RELEVANCE

Oral clindamycin is not efficacy.

TRIAL REGISTRATION

The present trial was registered (EudraCT number: 2017-002,168-42). It was approved by the Committee for the Ethics of Research with Medicines of Euskadi (CEIm-E) on 31 October 2018 (internal code number: 201862) and the Spanish Agency of Medicines and Medical Devices (AEMPS) on 18 December 2018.

Healing of particulate allografts mixed with platelet concentrates in ridge preservation and sinus lift: a prospective histomorphometric study

The objective of the present study was to evaluate the bone quality of sinus and alveolar grafts following filling with particulate allogenous bone (DFDBA 300-500μm) and platelet concentrate (platelet-rich fibrin, PRF). A prospective interventional clinical study was carried out. A total of 40 bone cores, 2mm in diameter, were taken from 21 patients: 22 from grafted alveoli, 7 from grafted sinus sites, and 11 from native bone used as a control. Fixed, paraffin-embedded samples were subjected to histological staining with hematoxylin-eosin and Masson's trichrome. Bone maturity of the samples was evaluated by two independent operators using histomorphometric analysis. There existed a greater proportion of lamellar neoformed bone than woven neoformed bone as the healing time increased. Moreover, there was also an increasing proportion of newly formed bone in the grafted sockets as a function of healing time (average: 41.22% ≤ 5 months, 55.89% ˃ 5 months). Resorption of DFDBA particles also appears to be correlated with healing time in the grafted socket (average: 15.43 ≤ 5 months, 13.72% ˃ 5 months). In conclusion, performing sinus lift and alveolar socket preservation techniques using DFDBA and PRF results in high quality, mature bone tissue according to histological criteria.

Three-dimensional radiographic assessment of bone changes around posterior dental implants at native bone site in Gansu Province, Northwest of China: A retrospective cohort study

PURPOSE

The aim of this study was to assess bone density and thickness changed following dental implant placement in the maxillary and mandibular jaws. Also, observe the form of bone loss around the implant and the relationship between preoperative bone density and bone thickness with bone loss around dental implants.

METHODS

65 patients, including 102 dental implants, were assessed in this study. CBCT was utilized to determine the bone condition (bone thickness and density at three levels (sub-crestal bone at 3 mm (CB3), 6 mm (CB6), and 9 mm (CB9)) before implant placement, and 2 to 3 years after placement, also determine the bone loss pattern.

RESULTS

The difference in bone thickness was 0.32 ± 0.50 mm at CB3, 0.18 ± 0.40 mm at CB6, and 0.14 ± 0.07 mm at CB9. The change buccal bone density at CB3, CB6, and CB9 were 344.5 ± 278.9, 260.5 ± 276, and 138.9 ± 313.9 HU, respectively, and the change in lingual bone density was 252.7 ± 247, 179.9 ± 244.1, and 281 ± 4063 HU, respectively. Only the CB3 level showed a significant decrease in bone thickness (p < 0.001), and a change in bone density was observed at the three levels (p < 0.001). The means of vertical and horizontal bone loss were 0.19 ± 0.23 mm and 0.18 ± 0.22 mm, respectively. Splinted or adjacent dental implants have more horizontal bone loss, with statistically significant (p < 0.001). Age, gender, and implant position were not statistically related to the outcome variables. There was a negative correlation between the preoperative status of the bone condition and pattern bone loss, as indicated by Pearson's correlation coefficient.

CONCLUSION

CBCT detected a significant bone thickness decrease was found only at the crestal third. A significant bone density increase was found at three levels around dental implants. Implant areas with higher bone thickness and density had less bone loss.

Sensory Changes Related to Dental Implant Placement: A Scoping Review

AIMS

To perform a scoping review of the literature to elucidate the occurrence of nerve damage related to dental implant placement and the factors causing the sensory changes.

METHODS

An extensive electronic search was conducted using the Cochrane Library, Medline via Ovid, PubMed, Wiley Online, Science Direct, CINAHL, and the Google Scholar databases from the year 1950 to 2020.

RESULTS

The search resulted in 1,067 articles, out of which 76 were selected for this review. The articles were categorized as literature review articles, retrospective studies, prospective studies, and case series/case reports. Altogether, 2,526 subjects were assessed retrospectively, with 5.27% transient and 1.39% persistent sensory changes, and a cohort of 2,750 subjects were followed prospectively, with 6.22% transient and 1.31% persistent sensory changes. A total of 336 subjects were enrolled in various case reports and case series, with 5.95% transient sensory changes and 84.52% persistent neurosensory changes. The articles included were not of high quality and have variations in their study designs and reporting procedures, with limited sensory change data to include in this study.

CONCLUSION

After surgical placement of dental implants in 5,612 patients, the incidence of transient sensory changes was 5.63%, and the incidence of persistent sensory changes was 6.33%. Factors affecting the incidence were: mandibular location of the implant, with the inferior alveolar nerve as the most commonly affected nerve. The common symptoms reported were paresthesia and dysesthesia. Age and gender were among other factors, for which data were not available in all the articles.

Current Undergraduate Dental Implantology Teaching in UK

Dental Implants are a popular treatment option for tooth replacement, with documented long-term success and survival rates of more than 95% over a period of 10 years. However, incorporating dental implantology into an undergraduate dental curriculum has issues associated. Therefore, the aim of this research was to examine and evaluate current undergraduate dental implantology education in the UK, investigate the amount of time allocated to this subject and analyse the barriers that are currently impeding the development of the programmes. An online questionnaire hosted by Online Surveys was designed, piloted, and sent to 16 dental schools providing undergraduate education in the UK. Ethical approval was gained from The University of Salford to conduct the study. Out of the 16 dental schools contacted, eight questionnaire responses were received, hence a response rate of 50% was achieved. The hours dedicated to the implant teaching programme varied from 3 h to 25 h, with a mean average of 11 h. It was identified from the results that no teaching of dental implantology was conducted in year 2; 12% of the schools responded that the subject was taught in year 1, 37% in year 3, 75% in year 4 and 50% in year 5. The methods used to deliver the programme were mainly lecture-based teaching, with only one dental school allowing students to place implants on patients. The main barriers to progression of the programme were financial (75%), followed by time limitations imposed by the curriculum (37%) and liability insurance (37%). However, there appears to be a consensus that further training beyond bachelor’s degree level is required to teach implantology effectively.

Tilted Implants and Sinus Floor Elevation Techniques Compared in Posterior Edentulous Maxilla: A Retrospective Clinical Study over Four Years of Follow-Up

The aim of this study was to evaluate the implant survival rate, marginal bone loss, and surgical and prosthetic complications of implants placed through sinus floor elevation and tilted implants engaged in basal bone to bypass the maxillary sinus. Sixty patients were enrolled for this study. According to the residual bone height of the posterior maxilla, the sample was divided into three groups of 20 patients: Group A (lateral sinus floor elevation), Group B (transcrestal sinus floor elevation), and Group C (tilted implants employed to bypass the sinus floor). Follow-up visits were performed one week after surgery, at three and six months, and then once a year for the next 4 years. The outcomes were the implant survival rate, marginal bone loss, and surgical and prosthetic complications. Although Groups A, B, and C demonstrated implant survival rates of 83.3%, 86.7%, and 98.3%, respectively, the statistical analysis showed no statistically significant difference between groups. Statistically significant differences between groups were also not found concerning marginal bone loss, as recorded by intra-oral X-ray measurements during follow-up examinations. Regarding complications, it was not possible to perform a statistical analysis. To reduce possible surgical risks, implant placement in basal bone could be preferred.

Is There a Better Biomaterial for Dental Implants than Titanium?—A Review and Meta-Study Analysis

This article focuses on preclinical studies and reviews the available evidence from the literature on dental implant and abutment materials in the last decade. Specifically, different peri-implantitis materials and how surface modifications may affect the peri-implant soft-tissue seal and subsequently delay or hinder peri-implantitis are examined. This review analyzed more than 30 studies that were Randomized Controlled Trials (RCTs), Controlled Clinical Trials (CCTs), or prospective case series (CS) with at least six months of follow-up. Meta-analyses were performed to make a comparison between different implant materials (titanium vs. zirconia), including impact on bone changes, probing depth, plaque levels, and peri-implant mucosal inflammation, as well as how the properties of the implant material and surface modifications would affect the peri-implant soft-tissue seal and peri-implant health conditions. However, there was no clear evidence regarding whether titanium is better than other implant materials. Clinical evidence suggests no difference between different implant materials in peri-implant bone stability. The metal analysis offered a statistically significant advantage of zirconia implants over titanium regarding developing a favorable response to the alveolar bone.

Sealing Efficacy of the Original and Third-Party Custom-Made Abutments-Microbiological In Vitro Pilot Study

Implant–abutment connection (IAC) is a key factor for the long-term success and stability of implant-supported prosthodontic restoration and its surrounding tissues. Misfit between prosthodontic abutment and implant at the IAC leads to technical and biological complications. Two kinds of prosthodontic abutments are currently available on the market: original and third-party abutments. The aim of this pilot study was to test and compare the internal fit (gap) at the implant–abutment interface depending on the abutment fabrication method based on microbial leakage in static conditions and the need for the use of gap sealing material. Two groups of 40 implants were formed on the basis of the type of abutment. In each of the groups of two implant systems, two subgroups of 10 implants were formed. The tested subgroups consisted of 10 implants with sealing material and a negative control subgroups consisting of 10 implants without any sealing material. The test material, GapSeal (Hager and Werken, Duisburg, Germany) was applied in the test subgroups. The implant–abutment assemblies were contaminated with a solution containing Staphylococcus aureus and Candida albicans for 14 days under aerobic conditions. Results showed that there was no statistically significant difference regarding the microbial leakage between the original and third-party custom-made abutments, regardless of the use of sealing material. It can be concluded that the abutment fabrication method has no significant influence on sealing efficacy regarding the bacterial and fungal leakage in static conditions.

A comparative evaluation of the effect of platelet rich fibrin matrix with and without peripheral blood mesenchymal stem cells on dental implant stability: A randomized controlled clinical trial

Technological advances in the field of implantology have led to the concept of surface modifications to enhance implant stability by utilization of current concepts of tissue engineering and materials such as platelet concentrates and stem cells. The purpose of the present randomized controlled clinical trial was to evaluate and compare the effect of platelet rich fibrin matrix (PRFM) with and without peripheral blood mesenchymal stem cells (PBMSCs) on implant stability; by assessing the bone to implant contact (BIC) using resonance frequency analysis (RFA), insertion torque and also to establish and correlate the same with implant stability quotient (ISQ). A total of 15 patients with 30 sites ensuring a minimum of two dental implants adjacently placed in an edentulous area; with the age group of 25-50 years of both the sexes were categorized into Group 1 (dental implant with PRFM) and Group 2 (dental implant with PBMSCs embedded in PRFM). Insertion torque values at the time of dental implant placement and ISQ using RFA was recorded at 1 week, 1 month, and 3 months post operatively. There was no significant difference (p = 0.81) in Insertion torque values between both the groups (G1 and G2). Platelet rich fibrin matrix along with PBMSCs enhanced implant stability as higher and statistically significant ISQ values were noted at 1 week (p = 0.18), 1 month (p ≤ 0.001), and 3 months (p ≤ 0.001) intervals in the G2 group. Platelet rich fibrin matrix and PBMSCs showed promising results as a potential regenerative material for increasing and enhancing BIC and hence implant stability.

Thickness of the Buccal and Alveolar Bones Overlying Central Incisors: A Radiographic Iraqi Study

Background. Initial bone thickness has a substantial impact on the success of dental implant treatments. The objective of the current study was to analyze the thickness of the buccal and alveolar bone at the central incisors using CBCT in relation to gender and side to determine the anatomical features and choose the best implant treatment option for minimizing the surgical complications. Methods. One hundred CBCT images were investigated (50 females and 50 males, aged 20 to 50 years old). The buccal bone thickness and alveolar bone thickness were evaluated for right and left sides of each subject at three sites; C: crest (3 mm); M: middle (6 mm); A: apical (9 mm) from the cementoenamel junction. Results. The mean thickness of buccal bone was less than 2 mm on the incisors according to side and gender. Buccal bone thickness revealed a statistically significant difference between right and left sides at the apical point in both females and males with $p$ values of ( $p\le 0.001$ ) and (0.001), respectively. The buccal bone thickness displayed statistically significant differences between genders at all sites. The alveolar thickness demonstrated similar significant differences between genders except for the crest site. Conclusions. Iraqi participants had about 1 mm buccal bone thickness at 3 mm apical from the CEJ in right and left central incisors with a progressive rise in bone thickness to be less than 2 mm at the apex. Alveolar bone also showed the same increase in bone thickness from crest to apex. Bone thickness was greater in males than females. The present study provided valuable CBCT data on bone thickness of the esthetic maxillary region as a preoperative analysis for establishing an immediate implant treatment plan with aesthetically pleasing long-term outcomes.

An In vitro evaluation of effect of implant abutment on human gingival epithelial keratinocytes

Background:

Abutment surfaces are being designed to promote gingival soft tissue attachment and integration. This confirms implant survival for long term by forming a seal around the prosthetics.

Objectives:

This study was done to compare the biocompatibility of three implant abutments: titanium uncoated, Ti-nitride coated, and modified polyetheretherketone (PEEK) with human gingival keratinocytes.

Materials and Methods:

The titanium-uncoated, titanium-nitride-coated, and modified PEEK discs (13 mm × 3 mm) were fabricated and compared with uncoated polyester cell culture discs, which were used as controls. These three implant abutments were evaluated for biocompatibility with respect to human gingival keratinocytes for viability, morphology, proliferation, and migration by scanning electron microscopy imaging and scratch wound healing assays. Measurements of roughness show changes between the investigated surfaces.

Results:

Keratinocytes cultured on all examined surfaces indicated adhesion and attachment. An assay of cell viability showed no substantial variances among the groups. The modified PEEK surface showed greater cell proliferation and migration among the three abutment materials.

Conclusion:

All three abutment material surface types showed similar epithelial biological responses. However, modified PEEK material showed the highest biocompatibility.

Periodontal treatment outcomes in smokers: A narrative review

Smoking is considered as the major environmental risk factor for periodontal diseases. Smokers have a higher risk for severe periodontitis with more periodontal tissue destruction, more gingival recession, and more susceptibility for tooth loss. The aim of this narrative review is to provide up-to-date evidence on the clinical outcomes of periodontal treatment in smokers. Electronic databases were searched for studies that compare the clinical outcomes in smokers and non-smokers following non-surgical and surgical periodontal treatment modalities and also during the supportive periodontal treatment. Clinical studies published before May 2021 were included in the review. Smokers have a higher risk for recurrence of periodontal disease and the response to non-surgical as well as surgical periodontal treatment is not as good as that of non-smokers. Moreover, there is a dose-response effect in the adverse effects of smoking on periodontal health. Compared to non-smokers, smoker patients with periodontitis tend to respond less favorably to non-surgical and surgical periodontal treatment, and exhibit recurrence more frequently during supportive periodontal treatment. Along with the periodontal treatment, smokers may be encouraged to quit. Long follow-up and the communication between the dentist and the patient give a great opportunity for such counseling.

Biomechanical and histological evaluation of four different implant macrogeometries in the early osseointegration process: An in vivo animal study

This study aims to evaluate the effects of implant macrogeometry on the early period of the osseointegration process, comparing four different implant models through biomechanical and histological analysis after implantation in rabbit tibiae. Twenty New Zealand rabbits were used, evaluated at two different times (21 and 28 days) after installation of the implant. Eighty implants with different macrogeometries were used, forming four groups (n = 20 per group): cylindrical implants Ø4.1 mm and 8 mm in length (STRc group); cylindrical-conical implants Ø4.1 mm and 8 mm in length (STRt group); tapered implants Ø4.3 mm and 8 mm in length (NOBt group); and tapered implants with healing chambers Ø4.0 mm and 8 mm in length (MAEt group). Ten samples from each group were analyzed at each proposed time. The initial implant stability quotient (ISQ) was measured by resonance frequency analysis, both at the time of installation and at the time of sacrifice. In the histological sections, the percentage of bone-implant contact (BIC%), newly formed bone, osteoid matrix, and medullary spaces were measured in the pre-determined cortical and medullary bone portion for each sample. The three tapered implant groups (STRt, NOBt, and MAEt) showed higher values for the analyzed parameters in the early osseointegration period, in comparison with the cylindrical implant group (STRc). In all parameters, the three tapered groups showed no difference (p > 0.05); however, all three tapered groups presented significant differences, when compared to the cylindrical group (p < 0.05). No correlation was detected between the parameters analyzed. Within the limitations of the present study, in all parameters analyzed, the tapered implants demonstrated greater results when compared to the cylindrical implants.

Comparison of the Mechanical Properties of Temporary Abutments Made of Polyetheretherketone and Photopolymeric Resin

Background:

Provisional abutments are widely used in the rehabilitation of dental implants as it allows the use of a provisional crown in order to restore patient aesthetics while the final restoration is being carried out; most of the temporary abutments available on the market are made of titanium alloygrade V (type Ti-6Al-4Va) and polyetheretherketone (PEEK), a material that exhibits very low adhesion to polymethylmethacrylate (PMMA).

Objective:

This research is aimed to compare the mechanical properties of commercially available PEEK abutments and abutments made using an additive technique with photopolymeric resin.

Methods:

Eighteen commercial temporary abutments manufactured in PEEK and eighteen experimental abutments manufactured by 3D printing using photopolymeric resin were used. The two groups of abutments were subjected to compression, bending and adhesion tests using six abutments of each type by test. Statistical analysis was performed with STATA 14 software. The data were analyzed by means of the Wilcoxon Mann-Whitney test, as these were two independent samples of reduced size. Values ​​lower than (p <0.05) were considered statistically significant in all tests and rejected the null hypothesis of equality between the group medians.

Conclusion:

The results indicate that it is possible to make abutments with good mechanical properties in photopolymeric resin (CLEAR FLGP04) using additive techniques to be used as temporary abutments.

Implants Survival Rate in Regenerated Sites with Innovative Graft Biomaterials: 1 Year Follow-Up

In thirteen different dental clinics in Singapore, Spain, Czech Republic and Italy, 504 patients were selected, and 483 dental implants were placed in maxillary sites after alveolar socket preservation (ASP) procedures with an autologous demineralized tooth extracted as graft material from an innovative Tooth Transformer device was obtained. All procedures used were reported in n°638 Ethical Committee surgical protocol of University of Chieti and approved. After 4 months, at dental implant placing, bone biopsies were performed to evaluate the histologic outcomes, and 12 months after implant loading, global implant survival rate, failure percentage and peri-implant bone loss were detected. After ASP, only 27 post-operative complications were observed and after 4 months, bone biopsy histomorphometric analysis showed a high percentage of bone volume (BV) 43.58 (±12.09), and vital new bone (NB) 32.38 (±17.15) with an absence of inflammation or necrosis areas. Twelve months after loading, only 10 dental implants failed (2.3%), with a 98.2% overall implant survival rate, nine cases showed mucositis (1.8%) and eight showed peri-implantitis (1.6%). At mesial sites, 0.43 mm (±0.83) of bone loss around the implants was detected and 0.23 mm (±0.38) at the distal sites with an average value of 0.37 mm (±0.68) (p > 0.568). Several studies with a longer follow-up will be necessary to confirm the preliminary data observed. However, clinical results seem to suggest that the post-extraction socket preservation procedure using innovative demineralized autologous tooth-derived biomaterial may be a predictable procedure to produce new vital bone able to support dental implant rehabilitation of maxilla edentulous sites.

Evaluating the osteogenic potential of insulin-like growth factor-1 microspheres on osteoblastic activity around dental implants in patients with type 2 diabetes mellitus using bone scintigraphy: A split-mouth randomized controlled trial

STATEMENT OF PROBLEM

Dental implants are susceptible to early failure when placed in patients diagnosed with type 2 diabetes mellitus. The osteoinductive potential of insulin-like growth factor-1 (IGF-1) has been widely investigated in animals with type 2 diabetes mellitus, but studies investigating the osteoinductive potential of IGF-1 around dental implants in patients diagnosed with type 2 diabetes mellitus are lacking.

PURPOSE

This randomized controlled trial was conducted to assess the osteogenic efficacy of poly(lactide-co-glycolide)- (PLGA) encapsulated IGF-1 microspheres around dental implants placed in patients diagnosed with type 2 diabetes mellitus.

MATERIAL AND METHODS

A split-mouth, randomized controlled trial was conducted in 10 participants diagnosed with type 2 diabetes mellitus and with bilaterally missing mandibular posterior teeth. The 20 sites were randomly allotted to receive the PLGA encapsulated IGF-1 or placebo microspheres followed by the placement of Ø3.8×11-mm implants. Osteoblastic activity was quantitatively assessed with bone scintigraphy scanning on the thirtieth, sixtieth, and 90th day after implant placement. The Shapiro-Wilks test was used to analyze the normality of data, followed by the independent t test to compare the experimental and placebo groups. Intragroup comparison was performed by using repeated-measures ANOVA and the post hoc Bonferroni test (α=.05).

RESULTS

Statistical analysis revealed that the mean osteoblastic activity was higher in the experimental group which received the PLGA-encapsulated IGF-1 than in the placebo group at the 30th, 60th, and 90th day after implant placement (P≤.001).

CONCLUSIONS

This randomized controlled trial indicated that the PLGA-encapsulated sustained release of IGF-1 microspheres enhanced the process of osseointegration in patients diagnosed with type 2 diabetes mellitus until the 90th day after implant placement.

Evaluation of the information provided by UK dental practice websites regarding complications of dental implants

Introduction Dental implants are a popular option for replacing missing teeth. When searching for information regarding dental implants, patients may first look to their dental practice website. The aim of this study was to assess the variance of patient information provided regarding implant complications on dental implant practice websites.Materials and methods Inclusion criteria for this study were dental practices within the Greater Glasgow & Clyde health board and practices with an active website. Completeness was assessed using a six-point score based on the British Association of Oral Surgeons 'Information for patients' leaflet and Association of Dental Implantology 'Considering dental implants? - A patient's guide to dental implant treatment' leaflet.Results In total, 90.7% (n = 107) of practices provided accessible implant information on their websites. However, only 37.3% (n = 44) mentioned one or more specified dental implant complications. Pain/discomfort was the most frequently stated complication (n = 41/118); implant failure was only mentioned by 19 practices (16%). The mean number of complications mentioned by the 118 practices offering dental implants was 1.1.Discussion As implant dentistry grows, there may be concerns over patient expectations. To overcome lack of quality assurance on the internet, dentists can provide factual information on their websites. They should be aware of their duty to provide material that is accurate, honest, informative and not potentially misleading.

Analysis of IL-1β, CXCL8, and TNF-α levels in the crevicular fluid of patients with periodontitis or healthy implants

BACKGROUND

Our study aimed to assess the level of IL-1β, CXCL8, and TNF-α in peri-implant sulcular fluid (PISF) collected from patients with no clinical symptoms of mucositis or peri-implantitis and compare them with cytokine concentration in gingival crevicular fluid (GCF) acquired from patients with healthy periodontium and those with varying severity of periodontitis.

METHODS

A total of 189 subjects were included in the study, and GCF/PISF samples were checked for IL-1β, CXCL8, and TNF-α levels using an ELISA test.

RESULTS

The IL-1β level in PISF in patients with implants was significantly lower than in GCF in patients with mild, moderate, or severe periodontitis. The CXCL8 level in PISF was considerably lower than in patients with moderate periodontitis. The TNF-α level in PISF in patients with implants was markedly higher compared to subjects with healthy periodontium or patients with mild periodontitis.

CONCLUSION

Analysis of cytokine levels may help describe the pathogenesis and early diagnosis of peri-implantitis and prevision in high-risk patients.

Scaffold-based developmental tissue engineering strategies for ectodermal organ regeneration

Tissue engineering (TE) is a multidisciplinary research field aiming at the regeneration, restoration, or replacement of damaged tissues and organs. Classical TE approaches combine scaffolds, cells and soluble factors to fabricate constructs mimicking the native tissue to be regenerated. However, to date, limited success in clinical translations has been achieved by classical TE approaches, because of the lack of satisfactory biomorphological and biofunctional features of the obtained constructs. Developmental TE has emerged as a novel TE paradigm to obtain tissues and organs with correct biomorphology and biofunctionality by mimicking the morphogenetic processes leading to the tissue/organ generation in the embryo. Ectodermal appendages, for instance, develop in vivo by sequential interactions between epithelium and mesenchyme, in a process known as secondary induction. A fine artificial replication of these complex interactions can potentially lead to the fabrication of the tissues/organs to be regenerated. Successful developmental TE applications have been reported, in vitro and in vivo, for ectodermal appendages such as teeth, hair follicles and glands. Developmental TE strategies require an accurate selection of cell sources, scaffolds and cell culture configurations to allow for the correct replication of the in vivo morphogenetic cues. Herein, we describe and discuss the emergence of this TE paradigm by reviewing the achievements obtained so far in developmental TE 3D scaffolds for teeth, hair follicles, and salivary and lacrimal glands, with particular focus on the selection of biomaterials and cell culture configurations.

Relationship between Cortical Bone Thickness and Cancellous Bone Density at Dental Implant Sites in the Jawbone

Dental implant surgery is a common treatment for missing teeth. Its survival rate is considerably affected by host bone quality and quantity, which is often assessed prior to surgery through dental cone-beam computed tomography (CBCT). Dental CBCT was used in this study to evaluate dental implant sites for (1) differences in and (2) correlations between cancellous bone density and cortical bone thickness among four regions of the jawbone. In total, 315 dental implant sites (39 in the anterior mandible, 42 in the anterior maxilla, 107 in the posterior mandible, and 127 in the posterior maxilla) were identified in dental CBCT images from 128 patients. All CBCT images were loaded into Mimics 15.0 to measure cancellous bone density (unit: grayscale value (GV) and cortical bone thickness (unit: mm)). Differences among the four regions of the jawbone were evaluated using one-way analysis of variance and Scheffe's posttest. Pearson coefficients for correlations between cancellous bone density and cortical bone thickness were also calculated for the four jawbone regions. The results revealed that the mean cancellous bone density was highest in the anterior mandible (722 ± 227 GV), followed by the anterior maxilla (542 ± 208 GV), posterior mandible (535 ± 206 GV), and posterior maxilla (388 ± 206 GV). Cortical bone thickness was highest in the posterior mandible (1.15 ± 0.42 mm), followed by the anterior mandible (1.01 ± 0.32 mm), anterior maxilla (0.89 ± 0.26 mm), and posterior maxilla (0.72 ± 0.19 mm). In the whole jawbone, a weak correlation (r = 0.133, p = 0.041) was detected between cancellous bone density and cortical bone thickness. Furthermore, except for the anterior maxilla (r = 0.306, p = 0.048), no correlation between the two bone parameters was observed (all p > 0.05). Cancellous bone density and cortical bone thickness varies by implant site in the four regions of the jawbone. The cortical and cancellous bone of a jawbone dental implant site should be evaluated individually before surgery.

Change in the Dominant Side of Chewing as a Serious Factor for Adjusting the Prophylaxis Strategy for Implant-Supported Fixed Dental Prosthesis of Bounded Lateral Defects

OBJECTIVE

 The main purpose of this article is to study the effect of a change in the dominant side of chewing after prosthetics with fixed structures on implants on the main indicators of osseointegration, adaptation to dentures, and the clinical dental status of patients.

MATERIALS AND METHODS

 In a clinical trial, an analysis was made of the adaptation of 64 patients to intraosseous implant-supported fixed dentures and 56 apparently healthy volunteers. The examination complex included determination of the functionally dominant side of chewing, gnathodynamometry and electromyography indicators of masticatory muscles, and radiological osseointegration criteria. The overall treatment outcomes were evaluated using a visual analogue scale and an objective medical questionnaire, "Prognosis of Adaptation to Orthopedic Structures."

RESULTS

 Patients were divided into two subgroups: with a change in the dominant side of chewing after completion of orthopaedic treatment (40 cases) and without a change in the dominant side of chewing (24 cases). In the second subgroup of patients, in contrast to the first subgroup, relatively better indicators of gnathodynamometer and electromyography were observed. So, in the first group, gnathodynamometry indicators on the dominant side were 255.7 N and in the second group 225 N after 9 to 12 months. Electromyography indices amounted to (198.5 μV s) to (166.3 μV s) after 9 to 12 months. Bone density remained at the required level, and overall treatment outcomes were higher. Namely, the compact plate of the alveolar ridge was preserved, and the condition of the bone tissue around the implants testified to stable osseointegration. The participation of surface masticatory muscles in adaptation of patients to intraosseous implant-supported fixed orthopaedic structures and the necessity and importance of changing the dominant chewing side for the general outcomes of orthopaedic treatment have been discussed.

CONCLUSIONS

 It has been established that a change in the functionally dominant chewing side is accompanied by relatively unstable indicators of chewing function, which is combined with increased loads on the installed prostheses during 3 to 6 months of adaptation. This must be taken into account when planning an individual patient adaptation complex for dental orthopaedic structures.

Antibiotic dosage prescribed in oral implant surgery: A meta-analysis of cross-sectional surveys

This study aimed to assess the dosage and types of antibiotics prescribed in oral implant surgery, compare them among the different subpopulations (country and prescription regimens) and against the evidence-based recommended dosage: a 2-gram single preoperative dose of amoxicillin. A meta-analysis of cross-sectional surveys was conducted, which reports the overall dosage (and type) of antibiotics prescribed in combination with implant placement. PubMed, Cochrane, Science, Direct, and EMBASE via OVID were searched until April 2019. Three reviewers independently undertook data extraction and risk of bias assessment. The outcome variable was set on the average of prophylactic antibiotics prescribed per oral implant surgery. Overall, 726 participants from five cross-sectional surveys, representing five different countries were finally included. Amoxicillin was the most prescribed antibiotic. On average, 10,724 mg of antibiotics were prescribed per implant surgery. This average was significantly (p<0.001) higher than 2,000 mg. Overall, amoxicillin doses were significantly higher than 2,000 mg (9,700 mg, p<0.001). All prescribed amoxicillin regimens independently contained more than 2,000 mg, including those comprising only preoperative amoxicillin (2,175 mg, p = 0.006). Exclusive preoperative antibiotic regimens were the only subgroup with prescription dosages below this threshold (p = 0.091). Significant variations in antibiotic prescriptions were found among different countries and antibiotic regimens (p<0.001). In conclusion, the average dose of antibiotics prescribed per oral implant surgery was larger than the evidence-based recommended dose in healthy patients and straightforward conditions. In addition, variations in the average antibiotic dosages were found among different countries and prescription regimens.

Surfce Functionalized via AdLAMA3 Multilayer Coating for Re-epithelization Around Titanium Implants

The peri-implant epithelium (PIE) forms a crucial seal between the oral environment and the implant surface. Compared with the junctional epithelium (JE), the biological sealing of PIE is fragile, which lacks hemidesmosomes (HDs) and internal basal lamina (extracellular matrix containing laminin332, IBL) on the upper part of the interface. In the study, we aim to prepare a coating with good biocompatibility and ability to immobilize the recombinant adenovirus vector of LAMA3 (AdLAMA3) for promoting the re-epithelization of PIE. The titanium surface functionalized with AdLAMA3 was established via layer-by-layer assembly technique and antibody-antigen specific binding. The biological evaluations including cell adhesion and the re-epithelization of PIE were investigated. The results in vitro demonstrated that the AdLAMA3 coating could improve epithelial cell attachment and cell spreading in the early stage. In vivo experiments indicated that the AdLAMA3 coating on the implant surface has the potential to accelerate the healing of the PIE, and could promote the expression of laminin α3 and the formation of hemidesmosomes. This study might provide a novel approach and experimental evidence for the precise attachment of LAMA3 to titanium surfaces. The process could improve the re-epithelization of PIE.

Titanium Alloys for Dental Implants: A Review

The topic of titanium alloys for dental implants has been reviewed. The basis of the review was a search using PubMed, with the large number of references identified being reduced to a manageable number by concentrating on more recent articles and reports of biocompatibility and of implant durability. Implants made mainly from titanium have been used for the fabrication of dental implants since around 1981. The main alloys are so-called commercially pure titanium (cpTi) and Ti-6Al-4V, both of which give clinical success rates of up to 99% at 10 years. Both alloys are biocompatible in contact with bone and the gingival tissues, and are capable of undergoing osseointegration. Investigations of novel titanium alloys developed for orthopaedics show that they offer few advantages as dental implants. The main findings of this review are that the alloys cpTi and Ti-6Al-4V are highly satisfactory materials, and that there is little scope for improvement as far as dentistry is concerned. The conclusion is that these materials will continue to be used for dental implants well into the foreseeable future.

Prosthetically driven immediate implant placement at lower molar area; an anatomical study

PURPOSE

To examine the effectiveness and safety of immediate implant placement (IIP), we evaluated the risk of lingual plate perforation (LPP) and mandibular canal perforation (MCP) associated with posterior mandible anatomy using cone beam computed tomography (CBCT) images.

MATERIALS AND METHODS

A morphological study of the molar sockets of 135 patients (age: 18-84 y) was done and its relationship to the mandibular canal was investigated. The risk of LPP and MCP was recorded as yes or no. Mandibular cross-sectional morphology was defined as one of three types (U-P-C) using the criteria of Chan et al.

RESULTS

The risk of LPP was significantly higher for second molars (p = 0.0001), and the risk increased with age (p = 0.039). There was a strong relationship between the risk of LPP and cross-section type U (p = 0.0001). The mean root to alveolar canal (RAC) distance (mm) of males was significantly higher than that of females. The mean RAC value was 5.02 mm for males and 3.49 mm for females. There was no statistically significant relationship between the risk of MCP and sex. There was a significant relationship between the risk of MCP and cross-section type U (p = 0.0001). Although the MCP risk was higher in second molars, there was no statistically meaningful relation between MCP and tooth type.

CONCLUSION

The results suggest that IIP in the mandibular molar area carries a high risk of MCP and LPP. Based on the elevated level of risk, a delayed implant protocol should be considered.

Differential Healing Patterns of Mucosal Seal on Zirconia and Titanium Implant

Zirconia implants have become an alternative to titanium implants due to several advantages. The zirconia implant is relatively esthetic and highly resistant to bacteria. While biomaterial studies for zirconia implants have considerably accumulated, in vivo studies have not yet progressed. In the present study, the functional and biological properties of zirconia implants were analyzed thorough in vitro and in vivo studies. The proliferation properties of periodontal cells on the discs of machined surface titanium, hydroxyapatite coated titanium and zirconia were analyzed, and zirconia was shown to be favorable. In addition, small implant fixtures that can be applied to the jawbone of mice were manufactured and transplanted to C57BL/6 mice. The adhesion molecules expression patterns in peri-implant mucosa suggest a stronger mucosal seal and more adequate prevention of peri-implant epithelium (PIE) elongation in the zirconia implant when compared with other conventional materials. Differential laminin-332 expression in peri-implant mucosa of zirconia implants seems to regulate the PIE elongation. In conclusion, zirconia was found to be promising and advantageous with regards to the mucosal seal. And biological width (BW) of peri-implant mucosa is more desirable in zirconia implants compared to conventional titanium implants.

Biomechanical behavior of extra-narrow implants after fatigue and pull-out tests

STATEMENT OF PROBLEM

Narrow implants have limited indications, and implant fracture may occur when these indications are not followed.

PURPOSE

The purpose of this in vitro study was to investigate the mechanical behavior of a 2.9-mm-diameter implant using a fatigue limit test and to investigate the Morse effect of 2 different Morse taper systems, 2.9-mm-diameter (FAC group) and 3.75-mm-diameter (CM group) implants, using a pull-out test. The null hypothesis was that the tensile strengths of the components for both systems would be similar.

MATERIAL AND METHODS

The fatigue properties of 13 specimens under 6 loads were determined. The test was performed at 15 Hz and for 5×10⁶ cycles. In the pull-out test, the specimens were divided into 2 groups (n=8), the FAC group (2.9-mm-diameter) and the CM group (3.75-mm-diameter). Statistical analysis for the pull-out test was performed with the Student t test (α=.05).

RESULTS

Thirteen specimens underwent the fatigue test. Only 5 did not fail when subjected to the frequency and number of cycles examined. Three of the specimens did not fail under a load of 130 N. The pull-out test showed a significant difference between the FAC and CM groups (P<.001).

CONCLUSIONS

According to the fatigue test, the extra-narrow implant (Facility; Neodent) was compatible with the low masticatory effort regions, as indicated by the manufacturer. The better performance of the FAC group in the pull-out test may be due to its design, which promotes the pure Morse effect in the implant-abutment interface, and the angulation of its internal conical portion.

Efficacy of Collagen-Based Membranes in Alveolar Bone Augmentation

Collagen-based membranes (CBMs) have similar permissive bone formation capabilities when compared to non-absorbable membranes. CBMs have been classified as non-cross-linked membranes (NCLMs) and cross-linked membranes (CLMs) depending on whether the cross-linking between the collagen fibers was artificially increased. The purpose of this study is to evaluate the bone maintenance capacity between NCLMs and CLMs by comparing resorption of regenerated bone. The inclusion criteria consisted of: (1) The use of a CBM, either being an NCLM or CLM for coverage of grafted bone; (2) follow-up for more than one year; (3) the presence of the patient's orthopantomographic X-ray (OPTG) immediately following the installation of implants and one year after. The bone resorption observed in the OPTG was determined by measuring the number of exposed threads of the implant. The number of thread exposures in the implant was compared according to CBM types. OPTGs taken immediately following the installation of implants and at one year after installation were compared. The subject of the measurement was always the implant in which the greatest number of exposed threads were present in each patient. A total of 56 subjects and 97 implants were used in this study. There was no significant difference between NCLM and CLM groups (p > 0.05). However, there was a statistically significant difference (p = 0.02) between the groups when a bone graft was applied to both the maxilla and the mandible. The average number of thread exposures was less than 1.5. In this study, no comparison was made between commonly known causes of bone loss and membrane types.

Do short implants have similar survival rates compared to standard implants in posterior single crown?: A systematic review and meta-analysis

BACKGROUND

Short implants have been presented as an option for posterior rehabilitation in cases of poor bone height.

PURPOSE

To compare the survival rate of short implants and standard implants when used in posterior single crowns, in addition to reporting marginal bone loss, prosthetic failures, and surgical complications.

MATERIALS AND METHODS

Electronic search (PubMed, LILACS, Cochrane Library, Scopus, and Web of Science) and hand search were performed to identify all randomized controlled trials (RCTs) and controlled clinical trials (CCTs) that evaluated both short and standard implants in posterior single crowns.

RESULTS

Out of 345 articles identified by both electronic and hand search, four studies were selected (one CCT and three RCTs). The meta-analysis for the survival rate showed that there was no significant difference between the short implants and the standard ones (P = 1.00; RR:1.00; CI:0.97-1.03) performed with three RCTs for a one-year follow-up. The mean marginal bone loss ranged from 0.1 mm to 0.54 mm. Only one study reported the presence of prosthetic failures and surgical complications.

CONCLUSIONS

The survival rate of short implants was similar to the standard ones in posterior single crowns, for the one-year follow-up period. They also presented low surgical complications, prosthetic failures and marginal bone loss, being a predictable treatment for single rehabilitation in posterior tooth loss.

Silk Protein-Based Membrane for Guided Bone Regeneration

Silk derived from the silkworm is known for its excellent biological and mechanical properties. It has been used in various fields as a biomaterial, especially in bone tissue engineering scaffolding. Recently, silk protein-based biomaterial has been used as a barrier membrane scaffolding for guided bone regeneration (GBR). GBR promotes bone regeneration in bone defect areas using special barrier membranes. GBR membranes should have biocompatibility, biodegradability, cell occlusion, the mechanical properties of space-making, and easy clinical handling. Silk-based biomaterial has excellent biologic and mechanical properties that make it a good candidate to be used as GBR membranes. Recently, various forms of silk protein-based membranes have been introduced, demonstrating excellent bone regeneration ability, including osteogenic cell proliferation and osteogenic gene expression, and promoting new bone regeneration in vivo. In this article, we introduced the characteristics of silk protein as bone tissue engineering scaffolding and the recent application of such silk material as a GBR membrane. We also suggested future studies exploring additional uses of silk-based materials as GBR membranes.

Biomechanics of Immediate Postextraction Implant Osseointegration

The aim of this study was to gain insights into the biology and mechanics of immediate postextraction implant osseointegration. To mimic clinical practice, murine first molar extraction was followed by osteotomy site preparation, specifically in the palatal root socket. The osteotomy was positioned such that it removed periodontal ligament (PDL) only on the palatal aspect of the socket, leaving the buccal aspect undisturbed. This strategy created 2 distinct peri-implant environments: on the palatal aspect, the implant was in direct contact with bone, while on the buccal aspect, a PDL-filled gap existed between the implant and bone. Finite element modeling showed high strains on the palatal aspect, where bone was compressed by the implant. Osteocyte death and bone resorption predominated on the palatal aspect, leading to the loss of peri-implant bone. On the buccal aspect, where finite element modeling revealed low strains, there was minimal osteocyte death and robust peri-implant bone formation. Initially, the buccal aspect was filled with PDL remnants, which we found directly provided Wnt-responsive cells that were responsible for new bone formation and osseointegration. On the palatal aspect, which was devoid of PDL and Wnt-responsive cells, adding exogenous liposomal WNT3A created an osteogenic environment for rapid peri-implant bone formation. Thus, we conclude that low strain and high Wnt signaling favor osseointegration of immediate postextraction implants. The PDL harbors Wnt-responsive cells that are inherently osteogenic, and if the PDL tissue is healthy, it is reasonable to preserve this tissue during immediate implant placement.