Effect of preparation design and endodontic access on fracture resistance of zirconia overlays in mandibular molars: An in vitro study.

PURPOSE: To evaluate the fracture resistance of zirconia overlays, considering various preparation designs and the presence of endodontic access. MATERIALS AND METHODS: Ninety translucent zirconia (5Y-PSZ) overlay restorations were divided into six groups (n = 15/group) based on different preparation designs, with and without endodontic access: chamfer margin 4 mm above the gingival level without (group 1) and with endodontic access (group 2); margin 2 mm above the gingival level without (group 3) and with endodontic access (group 4); overlay with no chamfer margin without (group 5) and with endodontic access (group 6). Restorations were bonded to mandibular first molar resin dies, and the groups with endodontic access were sealed with flowable resin composite. All restorations underwent 100,000 cycles of thermal cycling between 5°C and 55°C, followed by loading until fracture. Maximum load and fracture resistance were recorded. ANOVA with Tukey post-hoc tests were used for statistical comparison (α < 0.05). RESULTS: Fracture resistance significantly varied among overlay designs with and without endodontic access (p < 0.001), except for the no-margin overlays (groups 5 and 6). Overlays with a 2 mm margin above the gingival margin with endodontic access (group 4) exhibited significantly higher fracture resistance compared to both the 4-mm supragingival (group 2) and no-margin (group 6) designs, even when compared to their respective intact groups (groups 1 and 5). There were no significant differences between the no-margin and 4-mm supragingival overlays. CONCLUSION: The more extensive zirconia overlay for mandibular molars is the first choice since the 2 mm margin above the gingival level design withstood considerable loads even after undergoing endodontic access. A no-margin overlay is preferred over the 4-mm supragingival design as it preserves more tooth structure and there was no outcome difference, irrespective of endodontic access. Caution is warranted in interpreting these findings due to the in vitro nature of the study.

Effect of silicone-based sealers on fiber post retention: An in vitro study.

PURPOSE: The effect of a silicone-based sealer on fiber post retention has not been the subject of research and remains unclear. This study aimed to evaluate and compare the impact of a silicone-based sealer and an epoxy resin sealer on fiber post retention. MATERIAL AND METHODS: Forty extracted human mandibular premolars that were caries-free, single-rooted, and possessed straight single canals were the specimens of the present study. Teeth were randomly divided into two groups (n = 20 each). All specimens were prepared using gutta-percha. The sealer used in the first group was Guttaflow 2, while AH26 was used in the second group. Post spaces were prepared immediately after obturation for each specimen. Prefabricated fiber posts were luted in both groups using a self-adhesive resin cement (RelyX-U200). Each specimen was vertically secured using a universal testing machine (Instron Corp.) and a constant pull-out force at a loading rate of 0.5 mm/min was applied until the point of dislodgement. Data were analyzed using t-tests. RESULTS: A significant difference was found between the mean of maximum loads of the silicone-based sealer and epoxy resin sealer groups (p = 0.0001). The mean maximum load for the epoxy resin sealer group was 194.62 N, while that for the silicone-based sealer group was 111.64 N. CONCLUSION: Fiber post retention in teeth obturated using silicone-based sealer was inferior to that in teeth obturated with epoxy resin sealer. Therefore, the sealer used during obturation can significantly affect fiber post retention.

Integrating Analog and Digital Workflow to Fabricate Implant Mandibular Complete Overdenture with a Milled Titanium Bar: A Clinical Report.

Implant mandibular complete overdenture (IMCO) is a reliable prosthetic option. However, clinical and laboratory complications are associated with these restorations if not executed properly. In this clinical report, the combination of analog and digital workflow helps minimize the chairside time with fewer visits, which improves efficiency and patient satisfaction. Int J Periodontics Restorative Dent 2023;43:e111-e115. doi: 10.11607/prd.5975.

Decontamination of lithium disilicate ceramics using various photosensitizers, herbal and chemical disinfectants, and the effect of surface conditioners on bond strength values.

AIM: To assess and compare the antimicrobial efficacy of disinfectants on lithium disilicate ceramic (LDC) used in dental applications and shear bond strength (SBS) of LDC after using different conditioners hydrofluoric acid (HF), self-etching ceramic primers (SECP) and Neodymium-doped yttrium orthovanadate (Nd: YVO4). MATERIALS AND METHODS: One hundred and twenty LDC discs were fabricated by auto-polymerizing acrylic resin using the lost wax technique. S. aureus, S. mutans, and C. albican were inoculated on thirty discs (n = 30 each). Each group was further divided into three subgroups based on different disinfecting agents used (n = 30) Group 1: Garlic extract, Group 2: Rose Bengal (RB) activated by PDT, and Group 3: Sodium hypochlorite (NaOCl). An assessment of the survival rate of microorganisms was performed. The remaining thirty samples were surface treated using three different LDC surface conditioners (n = 10) Group 1: HF + Silane (S), group 2: SECP, and Group 3: Nd: YVO4 laser+S. SBS and failure mode analysis were performed using a universal testing machine and stereomicroscope at 40x magnification, The statistical analysis was conducted using one-way ANOVA and Post Hoc Tukey test. RESULTS: Garlic extract, RB, and 2% NaOCl sample displayed comparable outcomes of antimicrobial potency against C. albicans, S aureus, and S. mutans (p > 0.05). Furthermore, SBS analysis showed HF+S, SECP, and Nd: YVO4+S exhibited comparable outcomes of bond strength (p > 0.05). CONCLUSION: Garlic extract and Rose bengal activated by PDT can be contemplated as alternatives to the chemical agent NaOCl used for LDC disinfection. Similarly, SECP and Nd: YVO4 possess the potential to be used for the surface conditioning of LDC to improve the bond integrity with resin cement.

Efficacy of indocyanine green and methylene blue mediated-photodynamic therapy on peri-implant outcomes among diabetics with peri-implant mucositis.

BACKGROUND: This study aimed to assess the efficacy of indocyanine green (ICG)-mediated versus methylene blue (MB)-mediated photodynamic therapy (PDT) as an adjunct to conventional mechanical debridement (MD) on the peri­implant clinical, radiographic, microbiological, and immunological outcomes among diabetics with peri­implant mucositis (pi-M). METHODS: For this 3-month follow-up study, diabetics having pi-M were randomly divided into 3 groups: group-I (n = 20) subjects received only MD; group-II (n = 20) participants received ICG-mediated adjunct PDT; and group-III (n = 20) subjects received MB-mediated adjunct PDT. Peri-implant clinical (i.e., plaque index [PI], bleeding on probing [BOP], probing depth [PD]), radiographic (crestal bone loss [CBL]), microbiological (Fusobacterium nucleatum [F. nucleatum], Tannerella forsythia [T. forsythia], Prevotella intermedia [P. intermedia], Porphyromonas gingivalis [P. gingivalis], Aggregatibacter actinomycetemcomitans [A. actinomycetemcomitans]), and immunological (interleukin [IL]-6, IL-1ß, tumor necrosis factor-alpha [TNF-α]) outcomes were assessed at baseline and 3-month follow-up. RESULTS: Mean changes between baseline and 3-month follow-up in peri­implant clinico-radiographic parameters were significantly different between control (PI: 12.42±21.80%; BOP: 12.10±19.30%; PD: 0.45±0.41 mm; CBL: 1.10±1.02 mm) and test groups (ICG-mediated PDT [PI: 26.55±25.80%; BOP: 28.77±29.24%; PD: 0.84±0.62 mm; CBL: 1.98±1.85 mm] and MB-mediated PDT [PI: 27.24±26.15%; BOP: 27.71±28.16%; PD: 0.85±0.63 mm; CBL: 1.95±1.80 mm]), however comparable differences were observed in peri­implant PI, BOP, PD, and CBL between group-II and group-III participants (p>0.05). The proportions of T. forsythia were significantly reduced in group-II (4.78 × 104 colony-forming unit per milliliter [CFU/mL]) and group-III (4.76 × 104 CFU/mL) as compared to group-I (-4.40 × 103 CFU/mL) at 3-month follow-up (p = 0.02). No statistically significant differences were observed between the study groups regarding the proportions of the other assessed target bacterial species. For IL-6 (group-I: 210±108; group-II: 298±165; group-III: 277±121 pg/mL; p = 0.03), IL-1ß (group-I: 101±95; group-II: 84±98; group-III: 86±74 pg/mL; p = 0.02), and TNF-α (group-I: 336±121; group-II: 385±210; group-III: 366±198 pg/mL; p = 0.03) peri­implant sulcular fluid [PISF] levels, all three study groups demonstrated statistically significant reduction at 3-month follow-up. CONCLUSIONS: ICG-mediated and MB-mediated adjunctive PDT showed statistically significant improvements in peri­implant clinical, radiographic, microbiological, and immunological parameters as compared to conventional MD alone at 3-month follow-up among diabetics with pi-M. However, comparable outcomes were demonstrated by ICG-mediated and MB-mediated adjunctive PDT regarding the assessed peri­implant parameters.

Misfit of Implant-Supported Zirconia (Y-TZP) CAD-CAM Framework Compared to Non-Zirconia Frameworks: A Systematic Review.

Objective: The aim of the study was to systematically review the overall outcomes of studies comparing the misfit of yttria-stabilized zirconia (Y-TZP) CAD-CAM implant-supported frameworks with frameworks fabricated with other materials and techniques. Methods: An electronic literature search of English literature was performed using Google Scholar, Scopus, Web of Science, MEDLINE (OVID), EMBASE, and PubMed, using predetermined inclusion criteria. Specific terms were utilized in conducting a search from the inception of the respective database up to May 2022. After the search strategy was applied, the data were extracted and the results were analyzed. The focused question was: Is the misfit of the implant-supported zirconia CAD-CAM framework lower than that of non-Y-TZP implant-supported fixed restorations? Results: Eleven articles were included for qualitative assessment and critical appraisal in this review. In the included studies, Y-TZP CAD-CAM implant-supported frameworks were compared to Titanium (Ti), Ni-Cr, Co-Cr, PEEK and high-density polymer, and cast and CAD-CAM frameworks. The studies used scanning electron microscopy, one-screw tests, digital or optical microscopy, 3D virtual assessment, and replica techniques for analyzing the misfit of frameworks. Six studies showed comparable misfits among the Y-TZP CAD-CAM frameworks and the controls. Three studies showed higher misfits for the Y-TZP CAD-CAM frameworks, whereas two studies reported lower misfits for Y-TZP CAD-CAM implant frameworks compared to controls. Conclusion: Y-TZP CAD-CAM implant-supported frameworks have comparable misfits to other implant-supported frameworks. However, due to heterogeneity in the methodologies of the included studies, the overall numerical misfit of the frameworks assessed in the reviewed studies is debatable.

Influence of Acidic Environment on the Hardness, Surface Roughness and Wear Ability of CAD/CAM Resin-Matrix Ceramics.

This study aimed to measure the effect of storage environment on the hardness, surface roughness and wear ability of CAD/CAM resin-matrix ceramics. A total of 200 rectangular-shaped specimens were obtained by sectioning 5 CAD/CAM blocks; Crystal Ultra (CU), Vita Enamic (VE), Lava Ultimate (LU), Cerasmart (CS) and Vita blocks Mark II (MII). Microhardness and surface roughness were measured at baseline and after 7 days of immersion either in saliva or cola (n = 10). The wear ability of the CAD/CAM materials against steatite-ceramics antagonist was determined using a chewing simulator. The data were statistically analyzed using factorial ANOVA followed by post hoc Bonferroni multiple comparison tests (p < 0.05). The independent factors significantly influenced the microhardness and surface roughness (p < 0.05). The highest VHN was observed in MII at baseline (586.97 ± 13.95), while CU showed the lowest VHN after 7 days of immersion in cola (68.3 ± 1.89). On the contrary, the highest Ra was observed after 120,000 chewing cycles for the VE specimens (1.09 ± 0.43 µm) immersed in cola, while LU showed the lowest Ra at baseline (0.07 ± 0.01 µm). The highest % mass loss of the antagonist was observed with MII immersed in cola (1.801%), while CS demonstrated the lowest % mass loss of 0.004% and 0.007% in AS and cola, respectively. This study confirms that the surface properties of tested CAD/CAM materials are susceptible to degradation in an acidic environment except for hardness and wear of CS material.

Influence of dental college funding and time established on the satisfaction of dental graduates with their undergraduate experience in Saudi Arabia.

OBJECTIVE: With the emergence of graduates from all government and private-funded dental colleges in Saudi Arabia (SA), it is pressing to explore the graduates' satisfaction with the dental undergraduate education and training they received. The aim of the present study was to investigate the graduates' satisfaction with their education and training according to college funding arrangements (government vs private-funded) and time since establishment (established- >15 years vs new-<15 years). METHODS: A piloted, electronic questionnaire was emailed to all the members of the Saudi Dental Society who had graduated from government and and private dental colleges in SA (2,185 registrants). RESULTS: The response rate was 36.4%, with 580 government-funded college graduates (72.9%) and 216 private college graduates (27.1%) having completed and returned the questionnaire. The distribution of participants between established and new colleges was 'established' 396 (49.8%) and 'new' 400 (50.2%). Levels of dissatisfaction were recorded for graduates from established and new, government-funded and private colleges. The levels of dissatisfaction were greater amongst the graduates of established and government-funded colleges. CONCLUSION: The findings of the present study indicate concerning levels of dissatisfaction with important aspects of dental education in SA. It is suggested that there is a pressing need for more integration of basic and clinical sciences and an emphasis on hands-on training. National coordination of arrangements for dental curricula could make a major contribution to addressing the problems identified.

Integration of intraoral scanning and conventional processing to fabricate a definitive obturator: A dental technique.

Clinical challenges occur when treating patients with maxillofacial defects with digital technology. This report describes a technique that combines intraoral scanning to fabricate a milled record base along with the conventional processing to fabricate a definitive maxillary obturator prosthesis.

Prosthodontic Rehabilitation for a Patient with Down Syndrome: A Clinical Report.

Patients with Down syndrome can present with a variety of oral manifestations such as hypodontia, periodontal disease, premature tooth loss, reduced salivary flow, crowding of teeth in both arches, and decreased occlusal vertical dimension. The intellectual ability of people with Down syndrome varies widely. They present with a mild-to-moderate intellectual disability that restricts their ability to communicate and adjust to their environment, which can add complexity in the overall dental treatment. There is little information in the literature regarding the prosthodontic rehabilitation for patients with Down syndrome in combination with dental implant placement. An implant-assisted removable partial dental prosthesis can be a cost-effective treatment alternative for carefully chosen patients with Down syndrome. This article presents the treatment of a 44-year-old male patient with Down syndrome and a moderate intellectual disability who presented with congenital and acquired tooth loss with significant occlusal discrepancies. The treatment included a prosthodontic approach that used a single dental implant, which will be described and illustrated in this article.

Prosthodontic rehabilitation with monolithic, multichromatic, CAD-CAM complete overdentures in an adolescent patient with ectodermal dysplasia: A clinical report.

Ectodermal dysplasia is a rare, hereditary, congenital disease that affects the normal development of certain tissues and structures of ectodermal origin. The disease is manifested to different degrees of severity and may involve the nose, eyes, hair, nails, sweat glands, and enamel. This report describes a 14-year-old boy with ectodermal dysplasia, rehabilitated with monolithic, multichromatic maxillary and mandibular computer-aided design and computer-aided manufacturing (CAD-CAM) acrylic resin complete overdentures.

Prosthodontic Rehabilitation of an Ectodermal Dysplasia Patient with Implant Telescopic Crown Attachments.

Telescopic crown attachments have been successfully used in completely and partially edentulous patients. This type of attachment provides retention, support, and stability with optimal hygiene for the removable dental prosthesis (RDP). With the emergence of CAD/CAM technology, telescopic crown attachments can be virtually designed and milled precisely to ensure a passive fit of the attachment parts and maximal functionality of the RDP. This article reviews both the clinical outcome and prosthodontic rehabilitation of telescopic crown attachments of an edentulous ectodermal dysplasia patient with solitary rigid conical telescopic crown attachments.