The International journal of prosthodontics最新文献

The study was aimed to retrospectively evaluate differences in marginal bone loss (MBL) between bone level (BL) implants, with (LMS) and without (noLMS) laser-microtextured collar surface, restored with screwed single crowns with different emergence profiles (EP) and emergence angles (EA). Materials and methods: A retrospective evaluation of records and radiographs of 90 patients scheduled for single implant therapy at the molar region over a period of up to 10 years after prosthetic restoration was performed. The radiographic MBL and clinical parameters were measured over time and statistically analyzed. Results: LMS implants presented a statistically significant higher cumulative success rate (97.7 % vs. 91.1%. p<.05) and lower mean MBL compared to noLMS (0.8mm vs. 1.7 mm, p<.05). Around noLMS BL implants an EA.

This dental technique presents a fully digital protocol for designing, fabricating, and assembling a mandibular denture with a resilient liner using readily available CAD/CAM software and 3D printing technologies. The digital method allowed denture teeth, denture base, and resilient liner as components to be designed and exported as separate files for additive manufacturing. It involves importing a cast into CAD software to create a T-shaped key, designing a 2 mm resilient liner with six positioning points, generating a mandibular denture base and alignment jig, 3D printing all components, post-processing, assembling with photopolymer, and final trimming and polishing. The additional cast and alignment jig design demonstrated ensured ease of component assembly and stable occlusion. The development of this novel technique using additive manufacturing advances the applications of the digital workflow in removable prosthodontics. The method is proposed as a potential solution to the problems associated with the traditional relining process, with a particular emphasis on its compatibility with additive manufacturing processes that utilise diverse methacrylate formulations, in contrast to conventional polymethylmethacrylates.

Purpose: To investigate the influence of the printing angle on the physicomechanical properties of PMMA.

Materials and methods: This systematic review included the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA 2020) and was registered with the Open Science Framework. Electronic searches were carried out in the PubMed/MEDLINE, SciELO, Scopus, Embase, and Science Direct databases. Risk of bias was analyzed using the Joanna Briggs Institute (JBI) instrument for quasiexperimental studies.

Results: Of the 1,917 studies identified, 25 were included and qualitatively assessed after the selection stages. Printing dental devices for prosthetic use in PMMA-based resins provides satisfactory performance, with better resistance to bending and fracture at 0 degrees. After polishing, the differences observed in surface roughness concerning the printing angle became insignificant. The different printing angles can influence the optical properties significantly, but other factors such as the composition of the resin can also influence these results.

Conclusions: Printing dental devices in PMMA-based resins provides satisfactory performance for prosthetic use. In general, better mechanical performance was attributed to a printing angle of 0 degrees compared to 45 and 90 degrees. Varying the printing angle can be a strategy for individualizing prosthetic devices according to the physical and mechanical needs presented by each type of clinical application.

Purpose: To evaluate resin-based posterior restorative materials by comparing the release of BPA, TEGDMA, HEMA, UDMA, and Bis-GMA monomers at 1 hour, 3 days, and 1 month.

Materials and methods: Five different materials were used in this study: Cerasmart (CS), Gradia-Plus Indirect (GI), G-ænial Posterior (GP), Formlabs 3D-Permanent Crown (FPC), and SonicFill 3 (SF). A total of 90 specimens 8 × 8 × 2 mm3 in size were prepared from all the materials. The specimens were immersed in a 75% ethanol/25% water solution and placed in an incubator for 1 hour, 3 days, and 1 month, after which the solutions were analyzed using high-performance liquid chromatography (HPLC). For the comparisons of data with normal distribution among the five different materials, repeated-measures ANOVA followed by Bonferroni post-hoc tests were applied (α = .05).

Results: Except for BPA release in the FPC material, all other materials exhibited an increasing release of monomers over time (P < .001). At all the measured time points, the material with the lowest monomer release was CS, while the highest release was observed in GP. The GI material exhibited the statistically significant highest release of BPA, TEGDMA, and Bis-GMA (P < .001), while the highest UDMA and HEMA release was observed in the GP material (P < .001).

Conclusions: The highest monomer release was observed for UDMA (0.8%) from the GP material at the end of 1 month. However, the monomer release from all examined materials remained well below the clinically acceptable range (1.5% to 5%).

Purpose: To evaluate the accuracy of impression methods using an intraoral scanner and the conventional method based on the implant number and angulation with multiple implants.

Materials and methods: Six implants were placed in the maxillary edentulous typodont using 3D-modeling software. Eight implants were placed in another maxillary edentulous typodont. The implant placement angulation for each model was different. 3D designing and printing were performed to produce reference models. These models were scanned to obtain reference scan data (RSD). In the conventional impression method, reference models were used, and a gypsum model was produced. Scan data was obtained by the lab scanner (Group CI). Models were scanned, and the scan data was obtained (Group IS). The distance and angulation deviation were compared.

Results: In models with six implants, the mean values of all distance and angulation deviations were less in Group CI than in Group IS (P < .05), except for the distance deviation in Model 6-20. In models with eight implants, the mean values of distance and angulation deviations were less in Group CI than in Group IS, except for the distance deviation in Model 8-20, and significant differences were observed between the two groups for Models 8-0, 8-10, and 8-20 (P < .05).

Conclusions: In cases where multiple implants are placed in the completely edentulous arch in vitro, conventional impressions are more accurate than intraoral scans. In cases lacking implant parallelism, intraoral scans can be used as a replacement for conventional impressions.

Purpose: To compare the precision and accuracy of traditional alginate impressions and digital optical impressions taken by second-year dental students using reverse-engineering technology. The null hypothesis posited no significant difference in the accuracy between the two methods when performed by inexperienced operators.

Materials and methods: In total, 20 dental students performed 128 impressions: 64 traditional alginate impressions (Group A) and 64 digital impressions using an intraoral scanner (Group B). The impressions were analyzed and compared to reference models created by an expert operator. Data were captured using a reverse-engineering software (Geomagic Control X), and precision was evaluated through 3D and point-by-point analyses. Statistical analyses, including paired t tests and Wilcoxon signed-rank test, were conducted to compare the deviations from the reference model.

Results: The digital impressions demonstrated superior accuracy compared to traditional alginate impressions, with significantly smaller deviations from the reference model. Digital impressions consistently exhibited higher precision and trueness, so the null hypothesis was rejected. Statistical significance was found at key points, with P < .05 for all comparisons.

Conclusions: This study demonstrates that digital impressions provide significantly greater accuracy and precision than traditional alginate impressions, with lower deviations and higher reproducibility. The findings highlight the dimensional instability of alginate impressions and reinforce the advantages of digital intraoral scanning for standardization and consistency in clinical practice. Intraoral scanners provide more precise and accurate impressions than traditional methods, even when used by inexperienced operators. This study supports the integration of digital impression techniques into dental education to enhance student proficiency and improve clinical outcomes.

Purpose: To investigate the shear bond strength of composite resin in five different ceramic repair systems for three different ceramic materials.

Materials and methods: A total of 225 monolithic zirconia (Zr), lithium disilicate (LDS), and cobalt-chromium (CoCr) specimens with feldspathic porcelain (FP) veneer were fabricated (N = 75 per material). The specimens underwent thermocycling and were randomly divided into five groups for the following intraoral repair systems (n = 15): (1) Clearfil Ceramic Primer Plus, Kuraray Noritake; (2) iBond Intraoral Repair Kit, Kulzer; (3) VOCO Cimara, VOCO Dental; (4) Ceramic Repair System Kit, Ivoclar Vivadent; and (5) Ultradent Porcelain Repair Kit, Ultradent Products. After surface conditioning, composite was applied using a cylindrical mold, and a second round of thermocycling was performed. Each specimen was then subjected to shear load until failure. Microshear bond strength was compared using one-way ANOVA (Tukey test, α < .05).

Results: The type of porcelain repair kit significantly affected the shear bond strength. For Zr, the repair systems from Kulzer and VOCO had significantly higher shear bond strength than the other systems (P < .001), without significant difference between Kulzer and VOCO. For the LDS and CoCr with FP, hydrofluoric acid had the highest shear bond strength (P < .001).

Conclusions: For zirconia, a 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) system should be used. The results also suggest that a cleaning bur may be beneficial. For glass-based ceramics and FP, etching with hydrofluoric acid remains the method of choice.

Purpose: To investigate associations between self-reported bruxism, masticatory muscle pain, and bowel symptoms and their relationship to the nine dimensions of the Symptom Checklist-90-Revised (SCL-90-R).

Materials and methods: Data from three separate validated questionnaires-Bowel Symptom Questionnaire (BSQ) to classify bowel status, Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) to determine self-reported bruxism and masticatory muscle pain on palpation, and SCL-90-R for psychometric assessment-were collected for each patient. BSQ used the Rome II criteria to identify the presence or absence of bowel symptoms but did not analyze subsets of bowel symptoms. Chi-square tests were used to test for pairwise associations between bruxism, masticatory muscle pain, and bowel status. Multiple logistic regression analysis was used to identify the independent predictors of bruxism and bowel symptoms.

Results: Data from 246 surveys were collected for self-reported bruxism, muscle pain, and bowel status, of which 191 patients completed the SCL-90-R. There was significant association between self-reported bruxism and muscle pain (P = .004) and betwen self-reported bruxism and bowel symptoms (P = .020). Bowel problems were identified in 53% of patients, and 48% of patients presented with both self-reported bruxism and bowel problems. There was no significant association between bowel symptoms and muscle pain. Multiple logistic regression analysis identified muscle pain and bowel symptoms as independent predictors of self-reported bruxism, and somatization was identified as the sole independent predictor of bowel symptoms.

Conclusions: These data establish a possible relationship between self-reported bruxism and bowel symptoms, necessitating education and the formulation of clinical practice guidelines for interdisciplinary care of this group of patients.

Purpose: To investigate shear bond strengths (SBSs) of denture repair materials using different polymerization methods to a 3D-printed denture base (DLP) compared to an autopolymerized polymethyl methacrylate denture base (PMMA).

Materials and methods: DLP and PMMA disks were fabricated, roughened using #400 silicon carbide abrasive paper, and treated with the primer/bonding of the respective repair material. An autopolymerized denture repair material (PER) or a light-polymerized denture relining material (MRB) was polymerized on the disks. All specimens were stored in distilled water at 37°C for 24 hours. Half of the specimens underwent thermocycling (TC; 5,000 cycles, 5 to 55°C). SBS testing was conducted (n = 20 per group), and the fracture pattern was analyzed. The SBS data were analyzed using nonparametric Kruskal- Wallis tests and Weibull distributions with the maximum likelihood estimation.

Results: MRB specimens showed significantly higher SBS and Weibull characteristic strength values than PER specimens (P < .001), irrespective of the denture base material. No statistical differences were observed in Weibull modulus among the specimens, except PMMA-MRB specimens, which showed the highest values (P < .001). Thermal aging tended to decrease these values; however, no significant differences were observed between the non-TC and TC groups. Adhesive failure was dominantly observed in the specimens, except DLP-MRB specimens, which shifted to cohesive failures within the denture base.

Conclusions: The repairability of the DLP specimens was comparable to those of the PMMA specimens. Thus, denture repair of the DLP denture base could be treated in the same manner as a conventional PMMA denture base.

Purpose: To systematically evaluate and compare the clinical performance of translucent zirconium dioxide 3-, 4-, and 5-unit fixed dental prostheses (FDPs) in the posterior dentition with either a monolithic design or with veneered buccal cutbacks (semimonolithic).

Materials and methods: A total of 31 patients treated by general practitioners received 31 translucent zirconium dioxide FDPs, randomized to be either monolithic or semimonolithic with a porcelain-veneered buccal cutback. The design choice was blinded. Clinical evaluations were made using the California Dental Association (CDA) criteria, and a questionnaire was used to obtain patient-reported outcomes and to compare them to ratings from the dentists.

Results: Mean follow-up time was 48.7 months (SD = 7.7). No FDP fractured during the observation period, and no chip-off fractures could be detected. The overall success rate was 85.2%. One monolithic FDP was found with caries, and one semimonolithic FDP was endodontically treated, giving an overall survival rate of 92.6%. Two FDPs, both semimonolithic, failed due to loss of retention and caries. Both patients and dentists rated the FDPs favorably regarding the esthetic outcome and function, but the patients scored them higher than the dentists in this respect.

Conclusions: Within the limitations of the study, both monolithic and semimonolithic yttria-stabilized zirconium dioxide FDPs seem to be a reliable choice of treatment for 3- to 5-unit restorations in the posterior dentition. The esthetic advantages of a porcelain veneer compared to a monolithic design might, however, be of less importance in the posterior regions for most patients.