Double Crown-Retained Removable Prostheses Supported by Implants or Teeth and Implants: A Long-Term Clinical Retrospective Evaluation.

OBJECTIVES: The objective of this retrospective clinical study was to investigate the survival rates and complications of implant (I)-retained or tooth-implant (TI)-retained prostheses and abutments (teeth, implants) over a mean observation period of 11.26 years. The study also aimed to analyze the differences and complication rates between implant-retained double crown removable dental prostheses (I-DC-RDPs) versus tooth-implant-retained double crown removable dental prostheses (TI-DC-RDPs). MATERIAL AND METHODS: We reviewed the clinical data of 110 nonsmokers (mean age = 53.9 years) who received DC-RDPs in maxillary or mandibular arches. 153 teeth and 508 implants were used to restore partially edentulous (PE; TI-DC-RDPs; n = 53) and completely edentulous (CE; TI-DC-RDPs; n = 57) arches. Two designs of the distal extension were used: cantilevers (CANs) and saddles (SADs). Restorations were examined for abutment survival, mechanical, or biological complications. RESULTS: The 10-year survival rates were 99.3% (95% CI: 95.4-99.9%) for teeth and 99.3% (95% CI: 97.5-99.7%) for implants. The cumulative rates of TI- and I-RDPs free of technical complications were 77% and 86%, respectively. The risk of complications was not significantly different between the CAN and SAD subgroups of I-RDPs (p > 0.05). However, for TI-RDPs, technical complication risk was significantly higher in SAD type compared with CAN restorations (p = 0.02). CONCLUSIONS: I- and TI-DC-RDPs seem to be recommendable for restoration of CE or PE arches. The technical and biological complication rates were lower for I-DC-RDPs in the CE arches than for TI-DC-RDPs in the PE arches. Regarding the RDP design, CAN prostheses produced significantly fewer technical complications than did SAD prostheses.

Differences in Mechanical and Physicochemical Properties of Several PTFE Membranes Used in Guided Bone Regeneration.

Non-resorbable PTFE membranes are frequently used in dental-guided bone regeneration (GBR). However, there is a lack of detailed comparative studies that define variations among commonly used PTFE membranes in daily dental clinical practice. The aim of this study was to examine differences in physicochemical and mechanical properties of several recent commercial PTFE membranes for dental GBR (CytoplastTM TXT-200, permamem®, NeoGen®, Surgitime, OsseoGuard®-TXT, OsseoGuard®-NTXT). Such differences have been rarely recorded so far, which might be a reason for the varied clinical results. For that reason, we analyzed their surface architecture, chemical composition, tensile strength, Young's modulus, wettability, roughness, density, thickness and porosity. SEM revealed different microarchitectures among the non-textured membranes; the textured ones had hexagonal indentations and XPS indicated an identical spectral portfolio in all membranes. NeoGen® was determined to be the strongest and OsseoGuard®-TXT was the most elastic. Wettability and roughness were highest for Surgitime but lowest for OsseoGuard®-NTXT. Furthermore, permamem® was the thinnest and NeoGen® was identified as the thickest investigated GBR membrane. The defect volumes and defect volume ratio (%) varied significantly, indicating that permamem® had the least imperfect structure, followed by NeoGen® and then Cytoplast TM TXT-200. These differences may potentially affect the clinical outcomes of dental GBR procedures.

Development of a Clinically Relevant Index for Tooth Wear Treatment Needs.

BACKGROUND: This study aimed to develop a tooth wear classification system that combined the extent, severity, and aesthetic impact of tooth wear and correlated them with the most appropriate clinical management strategy. METHODS: Three hundred photographs were used to develop a classification tool that contained four levels of severity and aesthetic impact (0, 1, 2, and 3) in three age groups of patients. Ten examiners assessed and classified the cases using validated forms. Additionally, they selected the recommended treatment modality for each level. The analysis was conducted using a coefficient correlation test. RESULTS: The coefficient correlation for the severity was 0.81, 0.82 in the upper anterior and posterior segments, and 0.85 and 0.77 for the lower anterior and posterior segments, respectively. The aesthetic impact correlation coefficient was 0.84. Examiners had agreed that minor cases required monitoring or simple restorative interventions. The moderate-level cases had variety in the recommended management options depending on the aim of treatment. The severe level cases often required rehabilitation at an increased occlusal vertical dimension. CONCLUSION: Within the limitations of this preliminary study, a good agreement between the examiners was found using the provided tools. More strict criteria in the classification part of the tool can further improve the examiners' agreement.

Survey of Dental Implant and Restoration Selection by Prosthodontists in Dubai.

BACKGROUND: With various surgical and prosthetic component designs being introduced in dental implants, decisions have to be made when choosing a system and a certain prosthodontic protocol. A survey of implant prosthodontic specialists has not been previously performed in the Middle East. AIM: This study aimed to determine selection criteria and choice of dental implants and restorations by prosthodontic specialists in the Emirate of Dubai, United Arab Emirates. MATERIALS AND METHODS: A validated 16-item questionnaire was used in the survey which included demographic information, implant training and experience, implant treatment planning, implant restoration, and implant system preference. The research protocol was approved by the Research and Ethics Committees of Hamdan Bin Mohammed College of Dental Medicine and Dubai Health Authority. Prosthodontists were identified from regulatory authority websites and contacted by e-mail with the questionnaire attached. RESULTS: A total of 84.6% (77) of the registered prosthodontists in Dubai completed the questionnaire with 66.2% reported practicing implant dentistry. Out of which, 54.9% reported surgically placing dental implants and 45.1% restore them only prosthetically. Prefabricated metal abutments were the most commonly selected abutments for single crowns (76.0%) and for fixed dental prostheses (66.7%). Screw retention is preferred mostly for single crowns (68.0%) and fixed dental prostheses (74.0%). Locators were the most commonly selected type of attachment for implant-retained/supported overdentures (49.0%). Conventional loading was the most selected type of loading in all oral conditions. CONCLUSION: Within the limitations of this study, it can be concluded that most prosthodontists in Dubai practice implant dentistry and more than half surgically place dental implants. Prefabricated metal abutments are the most selected type of abutments. Most prosthodontists use screw-retained implant restorations and prefer locator attachments for implant-retained/supported overdentures. Conventional loading is the most preferred implant loading method in all oral conditions. Implant company/system selections are various and there is no major preference for a certain system. The majority of prosthodontists select implant systems based on implant features, literature review, and simplicity of restorative kit.

Tooth-implant connection with fixed partial dentures in partially edentulous arches. A retrospective cohort study over an 11.8 year observation period.

BACKGROUND: The fixed tooth-implant connection remains a controversial issue. This private practice-based retrospective study aimed to evaluate the clinical outcomes of a contemporary fixed partial denture (FPD) design for connecting natural teeth and implants (TI-FPD), over an 11.8 years observation period. MATERIAL AND METHODS: The data of 91 partially edentulous patients (44 males and 47 females, mean age of 47.7 years) treated with a newly designed TI-FPD retained on 1 implant and 1 natural tooth were analyzed retrospectively. Teeth were covered with electroformed copings and a CAD/CAM made bridge was fixed over the abutments with provisional cement. Two different implant systems were used: Camlog (N=22; anterior areas) and Straumann tissue level (N=69; posterior areas). RESULTS: The survival rate for both implants and teeth was 100%. 19/21 (90%, 95%CI 82-95%), 16/21 (66%, 95%CI 66-84%), and 16/21 (66%, 95%CI 66-84%) patients were free of biological complications after 5 years, 10 years, and 15 years post-loading, respectively. 23/35 (90%, 95%CI 54-74%), 21/35 (61%, 95%CI 50-70%), and 21/35 (61%, 95%CI 50-70%) were free of technical complications following 5 years, 10 years, and 15 years post loading, respectively. CONCLUSIONS: Despite limitations of the study, the findings demonstrated that the use of a recently designed TI-FPD could be used for the tooth-implant connection in cases of partial edentulism and this may widen the treatment modalities by reducing the cost and need for extensive bone tissue augmentations. Further controlled longitudinal studies with larger patient groups are needed. Key words:Tooth-implant connection, dental implant, fixed partial dentures, complications, implant prosthodontics.