The Effect of Finishing and Polishing with Proprietary Vs Interchanged Polishing Kits on the Surface Roughness of Different Ceramic Materials.

PURPOSE: To evaluate the surface roughness of glazed and polished monolithic ceramic materials and to use this as a baseline for comparison after adjustment and polishing with both the recommended kit for the specific materials as well as interchanged polishing kits. MATERIAL AND METHODS: Flat ceramic specimens (n = 150) were fabricated from IPS ZirCAD Prime, IPS E.max, and Vitabloc Mark II. The specimens were adjusted and polished using either the proprietary polishing kit for the material or interchanged kits. The surface roughness was objectively assessed using Atomic Force Microscopy (AFM) and profilometer. Subjective assessment of surface finish was performed using a scanning electron microscope (SEM). Gravimetric weight loss of each sample was measured before and after polishing using a digital microscale. The mean surface roughness and standard deviation was calculated for each ceramic- polisher pair. A factorial ANOVA was used to compare the mean surface roughness values in nanometers between multiple groups (α = 0.05). The subjective results from the SEM were reported as descriptive statistics RESULTS: The zirconia polishing system produced surfaces with the lowest surface roughness regardless of the ceramic material. The polisher-ceramic combination was found to have a statistically significant effect on both Ra and RMS values when the AFM was used (p = 0.039 and 0.010, respectively). CONCLUSION: The zirconia polishing system resulted in the lowest surface roughness values regardless of ceramic materials tested. The zirconia polishing system also did not result in significant gravimetric weight loss regardless of the ceramic material used.

Efficacy of rehabilitation of stage IV periodontitis patients with full-arch fixed prostheses: Tooth-supported versus Implant-supported-A systematic review.

OBJECTIVES: To evaluate the efficacy of implant-supported in comparison to tooth-supported full-arch prostheses in patients with stage IV periodontitis. MATERIALS AND METHODS: Systematic electronic search (CENTRAL/MEDLINE/SCOPUS) up to March 2020 was conducted to identify randomized controlled trials and cohort-like studies comparing/evaluating fixed full-arch rehabilitation on teeth or implants in patients with stage IV periodontitis. The primary outcome measure was loss of teeth/implants and restorations. Data extraction was performed to create evidence tables, and meta-analyses were carried out as appropriate. RESULTS: A total of 26 studies (31 publications) were identified but none addressed the scientific question in a controlled and randomized design. The risk of bias throughout the included studies was judged to be high, and meta-analyses demonstrated a high degree of heterogeneity. Mean-weighted observation periods in studies on tooth-supported restorations were significantly longer than in studies on implant-supported restorations. The predicted loss of teeth and tooth-supported full-arch restorations over 10 years was 1% and 5%, respectively. The 15-year estimates were 10% and 13%. Corresponding predictions for implants and implant-supported restorations for 10 years amounted to 4% and 6%, respectively. Technical complications were the most commonly reported and affected 8% of tooth-supported restorations (during 7.2 years) and 42% of implant-supported structures (during 2.6 years). Peri-implantitis- or peri-implantitis-like symptoms were observed at an estimated 9% of implants (after 3.1 years). CONCLUSIONS: Based on observational studies on full-arch rehabilitation of stage IV periodontitis patients, 10-year estimates of tooth loss were lower than the corresponding estimates for implants. Estimated loss of tooth- and implant-supported restorations at 10 years was similar. Technical complications were more prevalent at implant-supported when compared to tooth-supported restorations.

Linear and volumetric wear of conventional and milled denture teeth.

OBJECTIVE: The purpose of this study was to compare the linear and volumetric wear of conventional and milled double-cross-linked polymethyl methacrylate, nano-composite, and nano-ceramic infused resin posterior denture teeth. METHODS: Double-cross-linked polymethyl methacrylate (PMMA) premolar teeth were scanned and used to mill denture teeth from a double-cross-linked PMMA resin disc and a nano-composite with nano-ceramic infused resin disc. The specimens (n = 8: conventional double-cross-linked PMMA resin teeth-DCL, milled double-cross-linked PMMA resin teeth-DCL-CAM, conventional nano-composite infused resin teeth with four layers composed of composite and PMMA resin teeth-NC, and milled nano-composite and nano-ceramic infused resin teeth-NC-CAM) underwent chewing simulation in the biaxial fatigue testing machine at 1.53 Hz frequency, thermocycling between 5 and 55°C, and 49 N force against a Ø6mm steatite. After 250,000 cycles, the linear changes on the occlusal surfaces of the specimens were analyzed with pairwise comparison with Bonferroni post hoc test, and the volumetric changes of the specimens were analyzed with a one-way ANOVA with Bonferroni post hoc test (p < 0.05). RESULTS: The linear wear of the conventional and milled denture teeth was linearly correlated with the number of cycles between 50,000 and 250,000 cycles. After 250,000 cycles, NC had significantly more linear and volumetric wear (0.52 ± 0.10 mm and 4.29 ± 0.94 mm3 ) than DCL (0.18 ± 0.03 mm and 0.74 ± 0.14 mm3 ; p < 0.001) and NC-CAM (0.15 ± 0.03 mm and 0.35 ± 0.21 mm3 ; p < 0.001). DCL-CAM and NC-CAM had linearly and volumetrically equivalent wear to DCL (p > 0.05). NC-CAM had significantly less linear and volumetric wear (0.15 ± 0.03 mm and 0.35 ± 0.21 mm3 ) than DCL-CAM (0.24 ± 0.07 mm and 1.22 ± 0.61 mm3 ; p < 0.05). CONCLUSIONS: The conventional NC wore more than DCL, DCL-CAM, and NC-CAM. Both milled denture teeth wore an equivalent amount to conventional DCL. The wear between the conventional and milled DCL was equivalent. CLINICAL SIGNIFICANCE: Denture teeth selection can prolong the retreading process and decrease the occurrences of prosthetic complications. Milled denture teeth are good alternatives to conventional denture teeth with regards to their wear resistance.

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

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of the 2020 professional literature in restorative dentistry to inform busy dentists regarding noteworthy scientific and clinical progress over the past year. Each member of the committee brings discipline-specific expertise to this work to cover this broad topic. Specific subject areas addressed include prosthodontics; periodontics, alveolar bone, and peri-implant tissues; implant dentistry; dental materials and therapeutics; occlusion and temporomandibular disorders (TMDs); sleep-related breathing disorders; oral medicine and oral and maxillofacial surgery; and dental caries and cariology. The authors focused their efforts on reporting information likely to influence day-to-day dental treatment decisions with a keen eye on future trends in the profession. With the tremendous volume of dentistry and related literature being published today, this review cannot possibly be comprehensive. The purpose is to update interested readers and provide important resource material for those interested in pursuing greater detail. It remains our intent to assist colleagues in navigating the extensive volume of important information being published annually. It is our hope that readers find this work useful in successfully managing the dental patients they encounter.

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.

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 2018 dental literature is provided to inform busy dentists about progress in the profession. Developed by the Committee on Scientific Investigation of the American Academy of Restorative Dentistry, each author brings discipline-specific expertise to one of the 8 sections of the report including (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 that will likely influence day-to-day treatment decisions. Each review is not intended to stand alone but to update interested readers so that they may visit source materials if greater detail is desired. As the profession continues its march toward evidence-based clinical decision-making, an already voluminous library of potentially valuable dental literature continues to grow. It is the intention of this review and its authors to provide assistance in navigating the extensive dental literature published in 2018. It is our hope that readers find this work useful in the clinical management of patients moving forward.

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

PROBLEM: There are countless numbers of scientific studies published in countless scientific journals on subjects related to restorative dentistry. PURPOSE: The purpose of this article is to review pertinent scientific studies published in 2017 on topics of interest to restorative dentists. METHODS AND MATERIALS: The authors, considered to be experts in their disciplines searched the scientific literature in 7 different areas (prosthodontics, periodontics, dental materials, occlusion and temporomandibular disorders, sleep-disordered breathing, oral medicine and oral and maxillofacial surgery and dental caries). Pertinent articles were either identified and referenced or reviewed. RESULTS: A total of 437 articles in 7 disciplines were identified or reviewed. CONCLUSIONS: An impressive amount of scientific literature related to restorative dentistry was published in 2017. The evidence presented in this article can assist dentists in the practice of contemporary evidence-based dentistry.

Annual review of selected scientific literature: Report of the committee on scientific investigation of the American Academy of Restorative Dentistry.

This review was conducted to assist the busy dentist in keeping abreast of the latest scientific information regarding the clinical practice of dentistry. Each of the authors, who are considered experts in their disciplines, was asked to peruse the scientific literature in their discipline published in 2016 and review the articles for important information that may affect treatment decisions. Comments on experimental methodology, statistical evaluation, and the overall validity of conclusions are included with many of the reviews. The reviews are not meant to stand alone but are intended to inform the interested reader about what has been discovered in the past year. The readers are then invited to go to the source, if they want more detail.

Annual review of selected scientific literature: Report of the committee on scientific investigation of the American Academy of Restorative Dentistry.

STATEMENT OF PROBLEM: It is clear the contemporary dentist is confronted with a blizzard of information regarding materials and techniques from journal articles, advertisements, newsletters, the internet, and continuing education events. While some of that information is sound and helpful, much of it is misleading at best. PURPOSE: This review identifies and discusses the most important scientific findings regarding outcomes of dental treatment to assist the practitioner in making evidence-based choices. This review was conducted to assist the busy dentist in keeping abreast of the latest scientific information regarding the clinical practice of dentistry. MATERIAL AND METHODS: Each of the authors, who are considered experts in their disciplines, was asked to peruse the scientific literature published in 2015 in their discipline and review the articles for important information that may have an impact on treatment decisions. Comments on experimental methodology, statistical evaluation, and overall validity of the conclusions are included in many of the reviews. RESULTS: The reviews are not meant to stand alone but are intended to inform the interested reader about what has been discovered in the past year. The readers are then invited to go to the source if they wish more detail. CONCLUSIONS: Analysis of the scientific literature published in 2015 is divided into 7 sections, dental materials, periodontics, prosthodontics, occlusion and temporomandibular disorders, sleep-disordered breathing, cariology, and implant dentistry.

Retrospective Assessment of Endodontically Treated Teeth Replaced by Dental Implants.

INTRODUCTION: This study investigated endodontically treated teeth that were replaced by dental implants at the University of North Carolina (UNC) at Chapel Hill School of Dentistry. The primary objective of this study was to determine the reasons leading to the extraction of endodontically treated teeth and their subsequent replacement with dental implants. The secondary objective was to evaluate the proportion of these teeth that, according to experienced endodontists, could have been preserved. METHODS: The UNC-Chapel Hill's dental electronic health records between 2004 and 2019 were probed for implant placement that replaced root canal-treated teeth. Preextraction radiographs and clinical charts were examined to ascertain the primary reason related to the extraction and to compile a profile for each case. In cases in which endodontic failure was the primary reason for extraction, radiographs and clinical findings were evaluated by 2experienced endodontists to assess potential treatment options. RESULTS: Between 2004 and 2019, 29.3% (1564 of 5229) of teeth replaced by dental implants at UNC School of Dentistry had undergone root canal treatment, with the mandibular first molar being the most commonly replaced tooth. The leading reasons for extraction were recurrent caries associated with defective restoration (26.6%), fracture of coronal structure (21.5%), vertical root fracture (20.9%), compromised periodontal condition (13.8%), and endodontic failure (2.4%). Two experienced endodontists evaluated extractions due to endodontic failure and concluded that 61.7% of them could have been candidates for endodontic retreatment. CONCLUSION: Substantial loss of tooth structure was the leading cause of extraction of root canal-treated teeth, followed by vertical root fracture and periodontal disease. Although endodontic failure constituted a minor portion of the reasons for extraction, a considerable number of teeth were extracted due to vertical root fractures following root canal treatment. A significant proportion of the extracted teeth due to endodontic failure could have been considered as potential candidates for endodontic retreatment.

Experimental periodontitis and peri-implantitis in dogs.

AIM: To analyze the tissue reactions following ligature removal in experimental periodontitis and peri-implantitis in dogs. MATERIAL AND METHODS: Four implants with similar geometry and with two different surface characteristics (turned/TiUnite Nobel BioCare AB, Göteborg) were placed pair-wise in a randomized order in the right side of the mandible 3 months after tooth extraction in 5 dogs. Experimental peri-implantitis and periodontitis were initiated 3 months later by ligature placement around implants and mandibular premolars and plaque formation. The ligatures were removed after 10 weeks, and block biopsies were obtained and prepared for histological analysis 6 months later. RESULTS: It was demonstrated that the amount of bone loss that occurred during the period following ligature removal was significantly larger at implants with a modified surface than at implants with a turned surface and at teeth. The histological analysis revealed that peri-implantitis sites exhibited inflammatory cell infiltrates that were larger, extended closer to the bone crest and contained larger proportions of neutrophil granulocytes and osteoclasts than in periodontitis. CONCLUSION: It is suggested that lesions produced in experimental periodontitis, and peri-implantitis are different and that implant surface characteristics influence the inflammatory process in experimental peri-implantitis and the magnitude of the resulting tissue destruction.

Spontaneous progression of experimental peri-implantitis at implants with different surface characteristics: an experimental study in dogs.

AIM: To analyse spontaneous progression of ligature-induced peri-implantitis at implants with different surface characteristics. MATERIAL AND METHODS: Four implants with similar geometry and with two different surface characteristics (turned/TiUnite; Nobel Biocare AB) were placed pairwise in one side of the mandible in five dogs, 3 months after tooth extraction. Experimental peri-implantitis was initiated by placement of ligatures and plaque formation. The ligatures were removed when about 40% of the supporting bone was lost. After 6 months, block biopsies were obtained and prepared for histological analysis. RESULTS: The amount of bone loss that occurred during the plaque accumulation period after ligature removal was significantly larger at implants with a TiUnite surface than at implants with a turned surface. The histological analysis revealed that the vertical dimensions of the lesion and the pocket epithelium and the apical extension of the biofilm were significantly larger at TiUnite implants than at turned implants. CONCLUSION: It is suggested that the implant surface characteristics influence progression of peri-implantitis.

Implant surface characteristics influence the outcome of treatment of peri-implantitis: an experimental study in dogs.

AIM: To analyse the effect of surgical treatment of peri-implantitis without systemic antibiotics at different types of implants. MATERIAL AND METHODS: Four implants representing four different implant systems - turned (Biomet 3i), TiOblast (Astra Tech AB), SLA (Straumann AG) and TiUnite (Nobel Biocare AB) were placed in the left side of the mandible in six dogs, 3 months after tooth extraction. Experimental peri-implantitis was initiated by placement of ligatures and plaque formation. The ligatures were removed when about 40-50% of the supporting bone was lost. Four weeks later, surgical therapy including mechanical cleaning of implant surfaces was performed. No systemic antibiotics or local chemical antimicrobial therapy were used. After 5 months, block biopsies were obtained and prepared for histological analysis. RESULTS: Two of the TiUnite implants were lost after surgical therapy. Radiographic bone gain occurred at implants with turned, TiOblast and SLA surfaces, while at TiUnite implants additional bone loss was found after treatment. Resolution of peri-implantitis was achieved in tissues surrounding implants with turned and TiOblast surfaces. CONCLUSION: Resolution of peri-implantitis following treatment without systemic or local antimicrobial therapy is possible but the outcome of treatment is influenced by implant surface characteristics.

Spontaneous progression of ligatured induced peri-implantitis at implants with different surface characteristics. An experimental study in dogs II: histological observations.

AIM: The aim of the present study was to analyze tissue reactions to plaque formation following ligature removal in experimental peri-implantitis at commercially available implants in dogs. MATERIAL AND METHODS: Mandibular premolars and the three anterior premolars in both sides of the maxilla were extracted in six Labrador dogs. After 3 months, four implants representing four different implant systems--groups A (turned), B (TiOblast), C (SLA), D (TiUnite)--were placed in a randomized order in the right side of the mandible. Three months after implant installation, experimental peri-implantitis was initiated by placement of ligatures and plaque formation. The ligatures were removed when about 40-50% of the supporting bone was lost. After the subsequent 24-week period of continued plaque accumulation, block biopsies containing implants and their surrounding tissues were obtained and prepared for histological analysis. RESULTS: All types of implants exhibited extensive inflammatory cell infiltrates and large associated crater-formed osseous defects. The lesions were consistently characterized by insufficient encapsulation of pus and biofilm layers and the inflammatory cell infiltrates extended apical of the pocket epithelium. The presence of numerous osteoclasts indicated active tissue destruction. The vertical dimension and the overall surface area of the infiltrated connective tissue (ICT) were larger at implants of group D than at other implant types. CONCLUSION: It is suggested that spontaneous progression of peri-implantitis is associated with severe inflammation and tissue destruction.

Local risk indicators - Consensus report of working group 2.

In implant dentistry, plaque control and oral hygiene practices are essential to limit the risk of complication and failure in the long term. All conditions around an implant in function that influence the load and pathogenicity of the microbiota are considered local risk indicators. They concern the prosthetic suprastructure design and the possibility for the patient to easily access each implant for plaque removal. Use of cemented prostheses should be limited to avoid excess cement acting as a foreign body and leading to peri-implant disease. The crown margins should be supramucosal, and the connection should be precise to avoid a gap between the implant and the suprastructure. Every implant system is characterised by a specific design, surface texture and connection type. These features may influence peri-implantitis development and progression, and the clinician should consider the risk of infection when selecting an implant. The soft-tissue conditions around the implant, the width of keratinised mucosa, and the phenotype and thickness of the mucosa are also considered major risk indicators, as the presence of any mucosal defect around an implant can increase plaque accumulation and result in tissue inflammation. The pathogenicity of the microbiota around an implant is primarily dependent on pocket depth. Deep pockets around implants should be avoided and, if present, closely monitored and/or reduced. Proximity to natural teeth presenting endodontic and/or periodontal lesions may result in implant contamination, but the influence of the type of edentulism on perio-pathogen presence is still unclear. These local conditions around an implant have a clear influence on peri-implant diseases development and progression, but there is still only limited evidence regarding their role as true risk indicators.

Spontaneous progression of peri-implantitis at different types of implants. An experimental study in dogs. I: clinical and radiographic observations.

AIM: The aim of the present study was to analyze tissue reactions to plaque formation following ligature removal at commercially available implants exposed to experimental peri-implantitis. MATERIAL AND METHODS: Six Labrador dogs about 1 year old were used. All mandibular premolars and the three anterior premolars in both sides of the maxilla were extracted. After 3 months four implants representing four different implant systems with different surface characteristics--implant group A (turned), B (TiOblast), C (sandblasted acid-etched; SLA) and D (TiUnite)--were placed in a randomized order in the right side of the mandible. Three months after implant installation experimental peri-implantitis was initiated by placement of ligatures in a submarginal position and plaque accumulation. At week 12, when about 40-50% of the supporting bone was lost, the ligatures were removed. During the subsequent 24-week period plaque accumulation continued. Radiographic and clinical examinations were performed during the 'active breakdown' period (plaque accumulation and ligatures) and the plaque accumulation period after ligature removal. The experiment was terminated at week 36. RESULTS: The bone loss that took place during the 'active breakdown' period varied between 3.5 and 4.6 mm. The additional bone loss that occurred during the plaque accumulation period after ligature removal was 1.84 (A), 1.72 (B), 1.55 (C) and 2.78 mm (D). CONCLUSION: Spontaneous progression of experimentally induced peri-implantitis occurred at implants with different geometry and surface characteristics. Progression was most pronounced at implants of type D (TiUnite surface).