Journal of Prosthetic Dentistry最新文献

Creating a natural appearance with proper shade matching is critical for achieving successful esthetic outcomes of dental ceramic restorations. Ceramic materials with high translucency are often preferred when restoring teeth with a normal stump shade. However, ceramic materials with increased opacity, such as zirconia, offer significant advantages when restoring discolored teeth. This video presentation describes 4 different ceramic material options that enable clinicians to effectively mask dark stump shades while maintaining the natural appearance of dental ceramic restorations.

A straightforward technique for a complete mouth rehabilitation under complete isolation using the resin stamp technique and planned and executed using a digital workflow is described. A preoperative scan was recorded under dental dam isolation, ensuring a controlled environment identical to that of the actual procedure and using the same isolation procedures. A virtual diagnostic waxing was designed, followed by the manufacturing of printed clear index guides relined with transparent silicone. For the restorative steps, packable and flowable composite resins were inserted into the relined guide and light polymerized. This technique enabled dental dam isolation, reduced silicone index deformation, and prevented adhesion issues between the printed indices and composite resin material.

Statement of problem: Bruxism (BX) involves repetitive or sustained dental movements by the masticatory muscles, potentially stressing the masticatory system. Despite this, diagnosis remains challenging. Understanding the impact of BX on the stomatognathic system is crucial for improving diagnosis and treatment.

Purpose: The purpose of this clinical study was to evaluate the fractal analysis of and mandibular radiomorphometric indices in panoramic radiographs of individuals with and without possible BX.

Material and methods: Panoramic radiographs and medical records from patients at the Federal University of Ceará's College of Dentistry were analyzed. Fractal analysis was conducted using the box-counting method on regions of interest in the mandible. The mandibular panoramic index, mandibular cortical index, gonial index, antegonial index, mental index, mandibular bone resorption index, mandibular notch index, mandibular condyle height index, and coronoid process index were obtained. The data were analyzed with a 95% confidence level.

Results: In 66 panoramic radiographs (33 with possible BX, 33 without BX), the antegonial index was lower in those with possible BX. Individuals with possible BX also exhibited more wear facets, marked mucosa, and facial fatigue. Fractal analysis values were lower in individuals with possible BX across 3 regions of interest. Statistically significant differences in trabecular bone morphology were observed between groups (P<.05).

Conclusions: Further research is needed to better understand the impact of BX on the stomatognathic system and to assess the applicability of fractal analysis and mandibular indices in evaluating mandibular bone in the panoramic radiographs of individuals with possible BX.

A 3-visit, facially guided, computer-aided design and computer-aided manufacturing (CAD-CAM) workflow for complete dentures is presented. The technique integrated 3-dimensional (3D) facial scanning and dynamic mandibular tracking and is applicable for patients with or without existing dentures for single-arch or dual-arch prostheses. Relined, functionalized interim bases stabilize occlusion rims, intraoral scans capture surface geometry, jaw tracking records with intercuspal position and excursions define the intermaxillary relation and constrain occlusal morphology within the functional envelope, while facial scanning provides face-referenced esthetics. A milled-wax trial restoration allows rapid, reversible refinements before monolithic fabrication. The approach supports individualized occlusion, improves predictability, and may reduce postinsertion adjustments.

Statement of problem: Despite the growing use of semidirect composite resin restorations, a consensus on the most effective surface treatment protocol for bonding them with luting agents is lacking.

Purpose: The purpose of this in vitro study was to evaluate the microtensile bond strength (μTBS) of semidirect composite resins bonded with a dual-polymerized luting agent under 6 different surface treatment protocols.

Material and methods: Composite resin blocks (Applic, Filtek Z250 XT, Vittra APS; N=180) were fabricated, microwave postpolymerized, and treated using combinations of airborne-particle abrasion (AA), phosphoric acid (PA), silane (S), and universal adhesive (U). Specimens were bonded with a dual-polymerized luting agent, sectioned into beam-shaped sticks (n≈28/group), and tested for μTBS either immediately or after aging (210 days in water at 37 °C + 25 000 thermocycles). Failure modes were classified, and representative specimens were analyzed by scanning electron microscopy. Data were analyzed using the Kruskal-Wallis, Dunn post hoc, linear mixed model, and chi-squared tests (α=.05).

Results: Surface treatment was the main factor influencing μTBS. Protocols including AA generally produced higher values; omitting AA (PA+S+U, PA+U, U) was associated with lower μTBS versus AA+PA+S+U (P<.01). Applic showed no significant differences among protocols with either condition (P≥.12) and no change with aging (P>.999). For Filtek Z250 XT, AA+PA+S+U was significantly higher than PA+U and U in the immediate condition (P≤.002) and higher than PA+U after aging (P=.02). For Vittra APS, no differences were detected immediately; after aging, AA+PA+S+U was significantly higher than PA+S+U, PA+U, and U (P≤.007), and AA+U was higher than PA+U (P=.04). The mixed model confirmed lower μTBS for Vittra APS compared with Applic (estimate -6.63 MPa; P<.01). Aging showed a statistically similar overall effect (P=.47). Adhesive failures predominated, and failure distribution was significantly influenced by all factors (P≤.05).

Conclusions: Airborne-particle abrasion enhanced bonding to semidirect composite resins. Composite resin type and surface treatment affected bond strength, while aging had no overall effect.

A dental laboratory remount-free technique for fabricating 3-dimensional (3D) printed complete dentures is presented. The method streamlines the workflow by eliminating the laboratory procedures required in conventional manufacturing to correct occlusal errors. This approach may reduce the fabrication errors, minimize postdelivery adjustments, and enhance patient comfort.

Statement of problem: Colonization of Candida on dental restorative materials presents a significant risk for dental structures and oral mucosa, particularly in immunocompromised individuals or those with poor oral hygiene.

Purpose: This study aimed to investigate the adhesion and biofilm formation of Candida albicans (C. albicans) on 6 commonly used dental restorative materials: composite resin, amalgam, lithium disilicate, zirconia, heat-polymerized acrylic resin, and cobalt chromium (Co-Cr) alloy.

Material and methods: Surface characteristics, including roughness and hydrophobicity, were evaluated using atomic force microscopy and contact angle measurements. The Candida biofilm formation was evaluated using crystal violet assays as optical density (OD). The expression of adhesion and biofilm-forming genes (ALS1, ALS3, and HWP1) was quantified via real-time quantitative polymerase chain reaction (qPCR). The morphology of Candida biofilm on the surface of different materials was also investigated using scanning electron microscopy (SEM).

Results: The order of materials in terms of surface roughness was composite resin>amalgam >Co-Cr alloy>zirconia>lithium disilicate>acrylic resin, and in terms of contact angle was amalgam>composite resin=Co-Cr alloy>acrylic resin>zirconia>lithium disilicate. The composite resin and amalgam exhibited the highest surface roughness and hydrophobicity, correlating with increased C. albicans adhesion (OD of 0.43) and biofilm formation (OD of 0.88). In contrast, smoother and more hydrophilic materials like lithium disilicate demonstrated lower Candida colonization (OD of 0.28). The expression of tested adhesion-related genes was significantly elevated on surfaces with high roughness and hydrophobicity. Furthermore, C. albicans appeared as isolated cells on composite resin and lithium disilicate, while it was uniformly distributed on acrylic resin, zirconia, and Co-Cr alloy. On amalgam, it formed short biofilms in surface grooves.

Conclusions: The results emphasize the importance of selecting restorative materials with smoother, hydrophilic surfaces to minimize candidal colonization.

Statement of problem: Intraoral scanning systems have been replacing conventional workflows in dentistry as the primary method of documentation, diagnosis, and treatment. Despite their growing adoption, the accuracy of complete arch scans remains a critical challenge.

Purpose: The aim of this clinical study was to evaluate and compare the precision and trueness of 6 current intraoral scanners (IOS) for complete arch recording using a conventional high-precision impression technique as the control group.

Material and methods: In 10 participants, 3 complete arch scans of the maxillary and mandibular jaws were obtained using 6 IOSs - Emerald S (EME); MEDIT i900 (MED); Primescan (PRI); Primescan 2 (PS2); Aoralscan 3 (SHI); TRIOS 5 (TRI) - and 1 conventional impression (CONV) technique. CONVs were poured and digitized using a laboratory scanner. Precision was assessed from intragroup pairwise comparison, while trueness values were calculated by comparing IOS scan data with the corresponding conventional impressions using (90_10)/2-percentile values. Statistical analyses were performed using Welch ANOVA followed by Games-Howell post hoc tests and a linear mixed-effects model (P=.05).

Results: Precision values ranged from 21 ±4 µm for CONV up to 82 ±38 µm for group EME. CONV showed significantly higher precision compared with all IOSs (P>.05). No significant difference was found among PRI, PS2, MED or between SHI and TRI (P>.05). Trueness values ranged from 41 ±10 µm (PRI) up to 96 ±29 µm (EME). A significant effect of scanner group on trueness was found (P<.001), but no significant differences were detected between MED and PS2, between PRI and PS2, or between SHI and TRI (P>.05).

Conclusions: For dentate complete arch recordings, the standard remains conventional high-precision material. Among IOSs, significant differences concerning accuracy were found for complete arch scans, but they did not exceed 100 µm.

Statement of problem: Loss of periodontal ligament-mediated mechanoreception after tooth extraction compromises tactile sensibility and occlusal control. Implant-supported prostheses partially restore this function through osseoperception, but the extent and influencing factors of active tactile sensibility (ATS) in single-implant restorations remain unclear.

Purpose: The purpose of this systematic review was to compare ATS between a single implant opposing a natural tooth and contralateral natural tooth-to-tooth contacts in functional occlusion and to evaluate clinical factors influencing implant-mediated sensory rehabilitation.

Material and methods: This review followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2020 guidelines (PROSPERO registration: CRD420251104655). Electronic searches of the PubMed, Scopus, and Web of Science databases, supplemented by manual searches, identified clinical studies published up to June 2025. Inclusion criteria were human investigations reporting quantifiable ATS thresholds in a single implant opposing a natural tooth and contralaterally natural tooth pairs via psychophysical testing (such as foil detection). Data extraction included study design, implant variables, testing protocols, and outcomes.

Results: Six studies were included: 4 randomized controlled trials, 1 prospective cohort, and 1 cross-sectional study. Reported ATS thresholds for implants ranged from 10 to 100 µm, while natural teeth showed lower thresholds (<10 to 50 µm). Immediate loading protocols yielded earlier and greater tactile feedback than delayed loading. Implant location (anterior versus posterior) showed inconsistent effects. Implant-supported prostheses opposing natural teeth exhibited better tactile sensibility than implant-supported prostheses occluding against other implant-supported prostheses. No consistent effects of age or sex were identified. Longitudinal studies reported progressive improvement in ATS with functional loading.

Conclusions: Osseointegrated implants develop functional tactile sensibility over time, although thresholds remain higher than those of natural teeth. Immediate loading and occlusion against natural antagonists accelerate neuroplasticity.

Statement of problem: The conventional waxing method of designing occlusion relies on the skill of the dental laboratory technician and the use of articulating paper, resulting in limited accuracy. However, the clinical effects of computer-aided design (CAD) occlusal contacts and clearance in implant-supported crowns remain insufficiently investigated.

Purpose: The purpose of this randomized clinical trial was to compare the effects of CAD occlusal contacts and clearance with those of the waxing method in posterior implant-supported single crowns.

Material and methods: Sixty patients with a single missing posterior tooth scheduled for an implant-supported crown were enrolled and randomized into 2 groups. After making impressions and pouring definitive casts, crowns with an 80-μm occlusal clearance for light contacts were designed. The control group used the waxing method with articulating paper to design the occlusion, while the test group adopted a digital antagonist tool after cast scanning. The designed occlusal clearance was calculated by using digital casts of the designed crowns. Occlusal clearance of finished crowns on the definitive casts was evaluated with a silicone interocclusal record. During delivery, the crowns were scanned, and the occlusion was evaluated. Occlusal adjustment indicators were calculated. The independent-samples t test, Mann-Whitney U test, and Pearson chi-squared test were used to analyze the statistical differences (α=.05).

Results: Compared with the control group, the test group showed significantly lower mean ±standard deviation maximum occlusal adjustment distance (361.0 ±126.1 µm versus 451.5 ±179.3 µm, P=.037), but the root mean square (RMS) in the 2 groups was not significantly different (P=.121). The test group demonstrated significantly higher median (interquartile range) minimum designed occlusal clearance (72.4 [6.0] μm versus 26.1 [54.2] μm, P<.001) and lower median (interquartile range) RMS of occlusal clearance of finished crowns (116.2 [117.1] μm versus 227.3 [126.4] μm, P=.005) than the control group, both of which were closer to the design value (80 µm). Patient satisfaction before adjustment was significantly higher in the test group than in the control group (P=.005). Adjustment time and volume, lateral interference, and occlusal contact scores in the 2 groups were not significantly different (P>.05).

Conclusions: Compared with the waxing method, CAD occlusion for implant-supported single crowns reduced occlusal adjustment distance, controlled occlusal clearance closer to the design value, and improved initial patient satisfaction.