Journal of Prosthetic Dentistry最新文献

Statement of problem: Additive manufacturing (AM) and subtractive manufacturing (SM) have been widely used for fabricating resin-based fixed dental prostheses. However, studies on the effects of material type (AM or SM resin) and surface finishing (polishing or glazing) on the surface properties and biofilm formation are lacking.

Purpose: The purpose of this in vitro study was to investigate the effects of material type and surface finishing on the surface roughness, wettability, protein adsorption, and microbial adhesion of the AM and SM resins marketed for fixed restorations under artificial saliva-aged conditions.

Material and methods: Disk-shaped specimens (∅10×2 mm) were fabricated using 3 types of resins: AM composite resin with fillers (AMC), AM resin without fillers (AMU), and SM composite resin with fillers (SMC). Each resin group was divided into 2 subgroups based on surface finishing: polished (P) and glazed (G). Therefore, 3 polished surface groups (AMCP, AMUP, and SMCP) and 3 glazed surface groups (AMCG, AMUG, and SMCG) were prepared. Specimens were then categorized according to aging condition in artificial saliva. Surface roughness (Ra and Sa), contact angle, surface free energy (SFE), protein adsorption, and microbial adhesion were measured. The data were analyzed using a nonparametric factorial analysis of variances and post hoc tests with Bonferroni correction (α=.05).

Results: When nonaged, significant interactions between material type and surface finishing were detected for Ra, contact angle, SFE, protein adsorption, and microbial adhesion (P≤.008). AMCP showed higher Ra and microbial adhesion than AMUP and SMCP, and higher contact angle and protein adsorption than SMCP (P<.001). AMCG had lower SFE than AMUG (P=.005) and higher bacterial adhesion than SMCG (P<.001). AMC had higher Sa than AMU and SMC (P≤.006). When aged, significant interactions between material type and surface finishing were detected for Ra, Sa, protein adsorption, and microbial adhesion (P≤.026). The contact angle and SFE were significantly affected only by the material type (P≤.001), as AMC exhibited higher wettability than SMC (P≤.004). AMCP had higher Ra and microbial adhesion than AMUP and SMCP (P≤.003). AMCP had higher Sa and protein adsorption than SMCP (P≤.004). AMCG showed lower Ra and higher protein adsorption than AMUG (P≤.001).

Conclusions: Both material type and surface finishing significantly affected surface properties and biofilm formation. AMCP exhibited higher surface roughness, protein adsorption, and microbial adhesion compared with SMCP. Glazing may reduce the differences in surface-biofilm interactions between AMC and SMC.

This clinical report describes the nonsurgical treatment of a patient suffering from severe epistaxis associated with hereditary hemorrhagic telangiectasia (HHT). Unlike the permanent surgical closure of the nostrils, known as the Young procedure, this treatment option provides interim relief from nasal obstruction. It includes the use of cone beam computed tomography (CBCT) and computer-aided design (CAD) to create a patient-specific silicone nasal obturator without the need for an impression of the nasal cavity, thereby preventing irritation to the delicate nasal mucosa that could instigate epistaxis.

Statement of problem: Studies on the significance of intensity on speech production with a tongue prosthesis are lacking, despite this being an important criterion in speech production in patients with total glossectomy.

Purpose: The purpose of this cross-over clinical study was to assess acoustic signal intensity and frequency in patients with total glossectomy rehabilitated with mandibular dentures with 2 different attachment designs for the tongue prosthesis.

Material and methods: Seven participants initially received a mandibular denture with a tongue prosthesis attached using an acrylic resin plate. After a period of 3 months, the dentures were retrieved and modified by replacing the acrylic resin plate with a metal framework as an attachment to the tongue prosthesis to be used for another 3 months with no washout period. The intensity and acoustic energy frequency of acoustic signals were recorded and analyzed for both denture designs at insertion, after 1 month, and after 3 months using 2-way repeated ANOVA (α=.01). Patient satisfaction was evaluated at the end of the follow-up period using a questionnaire. Participants were asked about comfort, phonation, and deglutition ability. The McNemar test was used for all parameters (α=.01).

Results: Intensity mean ±standard deviation values for the acrylic resin plate group were 21.56 ±0.54 at insertion, 19.23 ±0.25 at 1 month, and 15.46 ±0.21 at 3 months. For the metal framework group, they were 19.05 ±0.19 at insertion, 16.88 ±0.16 at 1 month, and 13.98 ±0.09 at 3 months. The differences were statistically significant (P<.01).

Conclusions: The intensity of the sound (loudness) decreased in the metal framework group, which affects the ability to increase volume in a noisy environment. Participants showed higher satisfaction with the comfort of the metal framework design compared with the acrylic resin plate design. However, participants showed higher satisfaction with the deglutition ability while using the acrylic resin plate when compared with the metal framework.

Implants supporting a fixed prosthesis may fail leaving unfavorable implant distribution for a fixed prosthesis. This clinical report illustrates a treatment option for converting a failing fixed prosthesis into a mandibular complete overdenture by using a portion of the existing fixed implant prosthesis. The use of a resilient liner to retain a converted mandibular overdenture framework provided satisfactory results in the first year of clinical use.

Statement of problem: To create custom posts for endodontically treated teeth with a digital workflow, clinical guidelines governing digital scan techniques are needed. However, the evidence for the accuracy of intraoral scanners (IOSs) is limited for different tooth types and post space lengths.

Purpose: The purpose of this in vitro study was to evaluate the trueness of post space scans made with 2 different IOSs for various tooth types and post space lengths.

Material and methods: Three different tooth types (maxillary central incisor, maxillary first premolar, and maxillary first molar) with 4 different post space lengths (10, 11, 12, and 13 mm) were digitally designed and 3-dimensionally (3D) printed. For each specimen, scans of the post space were made with 2 different IOSs (TRIOS 4 and Primescan). With a computer-aided design (CAD) software program, each scanned post space was compared with the reference file used to 3D print the tooth specimens for trueness and % volume difference of the scanned areas. The 1-way Welch ANOVA and post hoc pairwise Welch t tests were used to analyze normally distributed data. The Kruskal-Wallis and post hoc Dunn tests were used to analyze nonnormally distributed data; when multiple tied values were found, a permutation test was used (α=.05).

Results: The TRIOS 4 IOS failed to capture the apical 2 mm of post space ≥10 mm. Primescan showed high trueness and volume capture of post space for maxillary central incisors and molars up to 13 mm and maxillary first premolars up to 12 mm in length. Within the same tooth type, statistically significant differences were found among the 4 different post space length groups for both trueness and volume capture (P<.05). For trueness, the median root mean square (RMS) ranged from 26 µm to 134 µm; central incisors had the highest trueness, followed by molars, then by premolars. The effect of different post-space lengths on trueness (RMS) varied by tooth type. The volume (%) of the scanned area had a mean percentage range from 76.3% to 100%; premolar teeth had the lowest volume results, followed by central incisors, then by molars.

Conclusions: The Primescan IOS can reliably scan post spaces of maxillary central incisors up to 13 mm, maxillary first premolars up to 11 mm, and maxillary first molars up to 12 mm. The TRIOS 4 IOS could not adequately scan post spaces ≥10 mm in length for all the tooth types examined.

Statement of problem: Gingival irritation is a common side effect of at-home bleaching, but how the design of the bleaching tray affects its occurrence is unclear.

Purpose: The purpose of this randomized clinical trial was to determine whether a direct relationship is present between the design of bleaching trays and the risk of gingival irritation during at-home bleaching treatments.

Material and methods: This clinical trial was registered at ClinicalTrials.gov. (NCT06371664). Seventy-two participants were randomly assigned to 2 experimental groups: extended bleaching tray (3 mm) and nonextended bleaching tray (1 mm). Over a period of 3 weeks, participants underwent a nightguard dental bleaching treatment (6 to 8 hours) using 16% carbamide peroxide gel. Gingival irritation was evaluated subjectively by participants daily and objectively by clinicians at each visit. Tooth sensitivity was recorded daily using a 5-point numerical scale. Tooth color measurements were also made with a dental spectrophotometer. The risk of gingival irritation and the risk and intensity of tooth sensitivity were analyzed with the Pearson chi squared test and Fisher exact test. The color analysis was conducted with the Student t test (α=.05).

Results: Subjectively, the risk of gingival irritation was 66.7% in the extended group and 47.2% in the nonextended group, showing no statistically significant difference (P>.05). However, objectively, the risk of gingival irritation was significantly higher in the extended group (88.9%) compared with the nonextended group (63.9%) (P=.01(95% CI 1.06 to 1.83). Tooth sensitivity intensity was significantly higher in the extended tray group (P<.001), although the design did not significantly influence the risk of tooth sensitivity (P>.05). No significant differences were found between groups regarding color change (P>.05).

Conclusions: The use of an extended bleaching tray design increases the risk of gingival irritation and the intensity of tooth sensitivity. Therefore, the nonextended tray is recommended to minimize adverse reactions.

Statement of problem: High-translucency zirconia and lithium disilicate are among the most used materials in contemporary fixed prosthodontics because of their excellent esthetic and mechanical properties. However, their different cementation techniques, physical properties, and biocompatibility profiles can influence the clinician's choice.

Purpose: The purpose of this in vitro study was to evaluate the mechanical strength and adhesive cementation techniques for zirconia and lithium disilicate materials through mechanical testing, including compressive and pull-out tests. The biocompatibility of these materials was also assessed.

Material and methods: A total of 72 human maxillary molars that were free from damage were embedded in acrylic resin and prepared 1 mm occlusal to the enamel-cementum junction. The specimens were divided into 3 groups: lithium disilicate (CAD), zirconia High-Translucency HT (CAD), and lithium disilicate (PRESS). Following the recommended cementation protocols, compression and pull-out tests were performed. Twelve disks of each group were fabricated to test the integration of gingival fibroblasts. Human gingival fibroblasts were isolated from gingival biopsies and cultured in Dulbecco modified Eagle medium (DMEM). Cell viability was determined using the 3-(4,5-di-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, serving as an indicator of cellular respiration.

Results: Zirconia was the most mechanically efficient material, with a high resistance value (2081.4 ±405.4 N). The pull-out test determined that CAD-CAM lithium disilicate had similar adhesive cementation strength (244.3 ±29.3 N) to the other groups. In terms of biocompatibility, all materials demonstrated good results, with lithium disilicate CAD emerging as the most biocompatible material. Statistically significant differences were observed between the zirconia HT material and lithium disilicate PRESS (P=.006) and between lithium disilicate CAD and lithium disilicate PRESS (P=.002).

Conclusions: All the monolithic restorations analyzed have shown excellent results in terms of mechanical properties, adhesion, and biocompatibility. Zirconia exhibited outstanding mechanical properties, making it an ideal choice for applications requiring high strength. To achieve adhesion results comparable with those of lithium disilicate, a protocol using airborne-particle abrasion and silane with 10-MDP is recommended. This approach ensures optimal adhesion, enhancing the longevity and effectiveness of the restoration.

Statement of problem: The static computer-aided implant system (S-CAIS), dynamic computer-aided implant system (D-CAIS), and robotic computer-aided implant system (R-CAIS) have been used to improve the accuracy of implant placement. However, the accuracy of freehand (FH),S-CAIS, D-CAIS, and R-CAIS implant placement has not been compared and verified under identical conditions.

Purpose: The purpose of this in vitro study was to compare the accuracy of dental implant placement using S-CAIS, D-CAIS, R-CAIS, and FH techniques under identical conditions.

Material and methods: A total of 60 standardized polyurethane resin models with missing mandibular teeth were prepared and divided into 4 groups: FH, S-CAIS, D-CAIS, and R-CAIS, each consisting of 15 models. Preoperative implant planning was performed using cone beam computed tomography (CBCT), and 2 implants were placed in each model using the FH, S-CAIS, D-CAIS, and R-CAIS techniques, respectively. Postoperatively, CBCT scans were made for analysis of the entry, apical, and angle deviations. The error results among groups were compared using 1-way analysis of variance or a nonparametric test. The Dunnett test was used for post hoc comparison (α=.05).

Results: The mean ±standard deviation values for entry deviation were 1.09 ±0.33 mm for the FH group, 0.72 ±0.33 mm for S-CAIS, 0.69 ±0.29 mm for D-CAIS, and 0.48 ±0.18 mm for R-CAIS (P<.05). The mean (quartiles) apical deviations were 1.01 (0.94 -1.22) for the FH group, and the mean ±standard deviation values were 0.87 ±0.07 mm for the S-CAIS group, 0.64 ±0.05 mm for D-CAIS, and 0.47 ±0.03 mm for R-CAIS (P<.05). The mean ±standard deviation values for angle deviation for the FH group were 2.74 ±0.84 degrees, 1.99 ±0.76 degrees for S-CAIS, 0.85 ±0.46 degrees for D-CAIS, and 0.53 ±0.20 degrees for R-CAIS (P<.05).

Conclusions: R-CAIS is a reliable implant placement method, demonstrating better implant accuracy compared with the S-CAIS, D-CAIS, and FH techniques.

Statement of problem: Although the use of artificial intelligence (AI) seems promising and may assist dentists in clinical practice, the consequences of inaccurate or even harmful responses are paramount. Research is required to examine whether large language models (LLMs) can be used in accessing periodontal content reliably.

Purpose: The purpose of this study was to evaluate and compare the evidence-based potential of answers provided by 4 LLMs to common clinical questions in the field of periodontology.

Material and methods: A total of 10 open-ended questions pertinent to periodontology were posed to 4 distinct LLMs: ChatGPT model GPT 4.0, Google Gemini, Google Gemini Advanced, and Microsoft Copilot. The answers to each question were evaluated independently by 2 periodontists against robust scientific evidence based on a predefined rubric assessing the comprehensiveness, scientific accuracy, clarity, and relevance. Each response received a score ranging from 0 (minimum) to 10 (maximum). After a period of 2 weeks from initial evaluation, the answers were re-graded independently to gauge intra-evaluator reliability. Inter-evaluator reliability was assessed using correlation tests, while Cronbach alpha and interclass correlation coefficient were used to measure overall reliability. The Kruskal-Wallis test was employed to compare the scores given by different LLMs.

Results: The scores provided by the 2 evaluators for both evaluations were statistically similar (P values ranging from .083 to >;.999), therefore an average score was calculated for each LLM. Both evaluators gave the highest scores to the answers generated by ChatGPT 4.0, while Google Gemini had the lowest scores. ChatGPT 4.0 received the highest average score, while significant differences were detected between ChatGPT 4.0 and Google Gemini (P=.042). ChatGPT 4.0 answers were found to be highly comprehensive, with scientific accuracy, clarity, and relevance.

Conclusions: Professionals need to be aware of the limitations of LLMs when utilizing them. These models must not replace dental professionals as improper use may negatively impact patient care. Chat GPT 4.0, Google Gemini, Google Gemini Advanced, and Microsoft CoPilot performed relatively well with Chat GPT 4.0 demonstrating the highest performance.

Statement of problem: Scientific evidence to determine the clinical performance of angled screw channel (ASC) versus straight screw channel (SC) implant-supported prostheses is lacking.

Purpose: This systematic review and meta-analysis investigated the mechanical and biological complications of ASC compared with those of SC implant-supported prostheses.

Material and methods: A systematic search was conducted by following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guideline in the PubMed, Embase, and Web of Science databases and was supplemented with a manual search for clinical studies reporting the mechanical and biological complications of ASC compared with those of SC implant-supported prostheses. The search was focused on porcelain fracture, screw loosening or fracture, marginal bone loss (MBL), and pink esthetic score (PES). The data were extracted from selected articles and compounded to estimate the complications with a 95% confidence interval (CI) using a random effects meta-analysis. The publication bias was assessed using the Cochrane Risk of Bias and Newcastle-Ottawa Scale (α=.05).

Results: A total of 4217 records were identified, and 14 studies were selected for quantitative synthesis of 629 participants with 658 ASC and 166 SC implant-supported prostheses. The meta-analyses of comparative studies showed no statistically significant difference in mechanical complications between ASC and SC prostheses, with odds ratio (OR) of 1.75 (95% CI=0.71-4.34, P=.224). Porcelain fracture and screw loosening were the most common complications with ASC prostheses. In addition, no statistically significant difference was found between ASC and SC prostheses in the MBL (mean difference=-0.07, 95% CI=-0.15-0.01, P=.077) and PES (mean difference=-0.19, 95% CI=-0.90-0.52, P=.593).

Conclusions: The clinical performance of ASC may be comparable with that of SC implant-supported prostheses in terms of mechanical and biological complications. However, the moderate level of evidence necessitates further research to validate these findings.