Journal of Prosthetic Dentistry最新文献

The implementation of digital technologies may require the development of procedures or devices to connect the digital with the analog environment. The use of magnet-retained and printed mounting plates, combined with printed casts, has been described to transfer articulated scans to a physical articulator. Complete dentures (CDs) fabricated by using computer-aided designed and computer-aided manufacturing methods may involve castless workflows. Remounting procedures before the delivery of CDs is recommended to maximize stability and comfort and minimize recall appointments. The implementation of digital workflows enables the use of digital facebow records to mount the virtual definitive casts to the virtual articulator. These articulated casts, mounted in the virtual articulator, enable the design and fabrication of CDs. However, the procedures and devices required to remount these articulated dentures, manufactured by using milling or additive manufacturing methods, to the physical articulator remain necessary. This manuscript describes laboratory procedures for remounting printed CDs to the physical articulator by using 2 different magnet-retained, printed remounting casts. This technique enables laboratory remounting, which would be challenging without the clinical records obtained during the delivery appointment.

Statement of problem: Despite the increasing use of monolithic zirconia for complete arch implant-supported prostheses, evidence regarding their long-term survival, complication rates, and clinical predictability remains limited and heterogeneous.

Purpose: The purpose of this systematic review was to evaluate the survival and overall performance of monolithic zirconia complete arch implant-supported prostheses.

Material and methods: An electronic search was conducted in 9 databases following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines and registered on PROSPERO (CRD: 42025640173). Meta-analyses were performed using random-effects models (α=.05). Subgroup analyses evaluated the pooled proportion of prosthetic failures, implant longevity, and technical complications. The risk of bias was assessed using the Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool, and the certainty of evidence was graded according to the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach.

Results: Thirteen studies comprising 2841 prostheses and 3940 implants were included in this systematic review. The pooled proportion rate of monolithic zirconia complete arch prostheses in function at the last follow-up (12 to 62 months) was 99% (95% confidence interval [CI]): 97% to 100%; I²=72%, while implant longevity reached 100% (95% CI: 99% to 100%; I²=75%). The pooled technical complication rate was 14% (95% CI: 4% to 27%; I²=96%). Subgroup analyses revealed higher complication rates in veneered designs (up to 27%) compared with monolithic configurations (1% to 3%). Most studies presented a moderate to serious risk of bias according to ROBINS-I, mainly due to retrospective designs and confounding. The certainty of evidence was rated as low by GRADE, primarily because of methodological limitations and heterogeneity.

Conclusions: Monolithic zirconia complete arch implant-supported prostheses demonstrated high cumulative proportions of prostheses remaining in function and low rates of technical and biological complications within the reported follow-up periods.

Statement of problem: Data on the accuracy of digital scans for complete arch implant-supported restorations, particularly concerning how different scan body (SB) designs affect implant orientation transfer in dental computer-aided design (CAD) programs, are lacking.

Purpose: The purpose of this in vitro study was to assess the trueness of implant position transfer using various new SB designs in digital scans.

Material and methods: A master maxillary model was fabricated with 4 straight multi-unit abutments connected to parallel implant analogs. Digital scans were obtained using an intraoral scanner with 4 SB designs: the original SB (OS), a 3-dimensionally (3D) printed SB replicating the original design (POS), a 3D printed SB with an asymmetric hexagon (PHS), and a 3D printed SB with an asymmetric hexagon modified with horizontal and vertical projections (PHVS). Ten digital scans were acquired per group and saved as standard tessellation language (STL) files. The master model with original SBs was scanned using a reference scanner to generate a reference dataset. STL files were imported into the inspection software program to measure linear, angular, and 3D deviations between each scan and the reference. Statistical analysis was performed using 1-way ANOVA followed by pairwise comparisons with Bonferroni correction (α=.05).

Results: Significant differences were found among SB designs in linear, angular, and 3D deviations (P<.05). The PHS group (horizontal extensions) exhibited the lowest deviations compared with all other groups (P<.05). The POS group showed lower linear and angular deviations than PHVS.

Conclusions: The novel SB design with horizontal extensions (PHS) yielded the highest accuracy in linear, angular, and 3D measurements.

Statement of problem: Comparative studies assessing monolithic zirconia and metal-ceramic for implant-supported fixed prostheses remain limited.

Purpose: This retrospective study aimed to compare the survival and success of metal-ceramic and monolithic zirconia implant-supported prostheses using a split-mouth design.

Material and methods: This study included 112 participants with 302 implant-supported prostheses. All participants had received both metal-ceramic (n=145) and monolithic zirconia (n=157) restorations between January 2018 and January 2024. Mechanical complications were recorded for all restorations. For the split-mouth analysis, the odds ratio was calculated using generalized estimating equations (GEEs). To compare the 5-year cumulative survival rates between groups, the Kaplan-Meier analysis and log-rank test (α=.05) were performed.

Results: The mean follow-up was 36 months. Of the 302 implant-supported prostheses, 12 metal-ceramic and 10 monolithic zirconia restorations failed. The 5-year cumulative survival rates were 90.9% (95% CI, 85.9% to 95.9%) for the metal-ceramic group and 90.0% (95% CI, 81.9% to 98.2%) for the monolithic zirconia group, with no significant difference (P=.653). Similarly, survival rates did not differ significantly for single crown (P=.240) or fixed partial denture (P=.647). According to GEE analysis, the odds ratio for mechanical complications between the groups was 1.11 (95% CI, 0.41 to 2.98). Although complications were more frequent in the metal-ceramic group, the difference was not statistically significant (P=.830).

Conclusions: In this retrospective split-mouth study, the 5-year cumulative survival rates and the incidence of mechanical complications did not differ significantly between metal-ceramic and monolithic zirconia implant-supported prostheses. Although metal-ceramic showed a higher number of complications, this difference was not statistically significant. Within the limitations of this study, monolithic zirconia may be considered a suitable material for implant-supported prostheses.

Statement of problem: Artificial intelligence (AI) has been applied to crown design and can produce acceptable morphology. However, occlusal morphology and contact area distribution generated by AI may differ from natural teeth. Whether they can approach ideal static and dynamic occlusion remains unknown.

Purpose: The purpose of this prospective clinical study was to assess whether using a technique based on the wear facets of antagonist teeth improved the performance of occlusal morphology and contact area distribution of AI generated crowns.

Material and methods: In the study, 23 participants were enrolled. Four types of crowns for maxillary first molars were analyzed: natural tooth (NA), technician designed crown (TE), AI generated crown (AT), and the Facets Align technique adjusted AT crown (FA). Occlusal morphology was evaluated by cusp inclination and root mean square (RMS). Occlusal contact area distribution was evaluated by area, F1-score, and occlusal contact separation distance. Finite element analysis (FEA) was used to analyze the stress distribution of the crowns. Statistical analysis was performed using the Friedman 2-way rank nonparametric test and Bonferroni post hoc tests (α=.05).

Results: The cusp inclination of AT was lower than that of NA (P<.01) on the distobuccal and distopalatal cusps. The occlusal contact area of AT was smaller than that of NA (P<.01). The occlusal contact separation distance of AT was the shortest during protrusive, working side, and nonworking side lateral movements (P<.01). FA did not differ significantly from NA and AT in cusp inclination. FA had smaller RMS (P<.01) and larger occlusal contact area (P<.001) than AT in several regions. FA improved the occlusal contact separation distance of AT during lateral movement on the working side (P<.05), while no significant difference was observed during protrusive and nonworking side lateral movement. The mean F1-score was 0.60 for FA, and the difference was significant between FA and AT (P<.001). As for finite element analysis (FEA), FA tended to exhibit higher stress and deformation values than AT but remained lower than NA.

Conclusions: The Facets Align technique optimized AI generated crowns in both static and dynamic occlusion when there were wear facets on the antagonist tooth.

This clinical report documented the prosthodontic rehabilitation of a 70-year-old man with extensive postoperative sequelae (fibrosis and mucosal adhesions) following pelveglossectomy and radiotherapy for oral squamous cell carcinoma. To overcome severe anatomic limitations impeding oral rehabilitation, a multidisciplinary protocol was implemented featuring 10 surgical sessions using a 980-nm diode laser for minimally invasive procedures, including fibrotic band release, adhesion reduction, and vestibular sulcus deepening (vestibuloplasty). Custom surgical and healing guides were essential to manage tissue remodeling and establish a favorable basal seat area for the definitive prostheses. The successful laser-assisted intervention allowed for the fabrication and insertion of complete dentures. The outcome included significant improvement in masticatory efficiency, speech, and facial esthetics, enhancing oral health-related quality of life (OHRQoL). The early involvement of the maxillofacial prosthodontist and the strategic use of high-power laser (HPL) therapy were determined to be critical for successful prosthetic rehabilitation in complex treatments after oncologic interventions.

Statement of problem: Although universal adhesives have been widely used, the role of silane in their formulations, especially regarding its chemical stability and interaction with functional monomers like 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP), and how these factors affect zirconia bonding remains unclear.

Purpose: The purpose of this in vitro study was to investigate the effect of universal adhesives (UAs) on the microshear bond strength (μSBS) and chemical interaction to zirconia immediately (IM) and after thermal aging (TC).

Material and methods: Zirconia polycrystals were sectioned into blocks (n=96), cut into segments, and sintered. The segments were randomly assigned to 7 experimental groups (n=10) according to the following independent variables: adhesive treatment, categorized by the presence of silane, as follows: silane-free adhesives: Ambar (AMB) and Adper Single Bond 2 (SB2); silane/MDP containing adhesives: Ambar Universal APS (AMU), Scotchbond Universal (SBU); Ambar Universal APS Plus (AMU+), and Scotchbond Universal Plus (SBU+); and time: immediate (24 hours) or after 10 000 TC. Alloy Primer, a 10-MDP containing zirconia primer, was used as the positive control group. Additionally, 26 zirconia slices were subjected to micro-Raman spectroscopy to assess the chemical interaction after bonding procedures. After surface treatment, cylindrical molds were filled with resin cement and polymerized. All specimens were tested for μSBS at a crosshead speed of 1.0 mm/minute. Data were analyzed using the Kruskal-Wallis and Mann-Whitney tests (α=.05).

Results: At the immediate time, AMU, SBU, AMU+, and SBU+ exhibited μSBS values statistically comparable with those of Alloy Primer (P>.05), whereas AMB and SB2 showed significantly lower μSBS (P<.05). After TC, all groups demonstrated a significant decrease in μSBS (P<.001). Nevertheless, AMU, AMU+, SBU, and SBU+ preserved higher residual μSBS than the control group, while AMB and SB2 dropped to 0 MPa. Raman analysis confirmed chemical interaction between the adhesives (AMU, AMU+, SBU, and SBU+) and the zirconia surface.

Conclusions: The use of 10-MDP-containing universal adhesives was effective for zirconia bonding, enhancing the immediate performance and improving long-term durability. However, the inclusion of silane in these adhesives did not significantly influence the bond strength to zirconia.

Statement of problem: The relationship between occlusal plane inclination and the position and dynamic behavior of the hyoid bone remains unclear despite the hyoid bone's critical role in oral and airway functions.

Purpose: This study aimed to investigate the influence of occlusal plane inclination on both the static position and dynamic behavior of the hyoid bone.

Material and methods: Cephalometric analysis evaluated the spatial relationship between the hyoid bone and the cranial base in the intercuspal position and mouth-opening positions. Correlations between occlusal plane inclination and hyoid-related parameters were analyzed using the Pearson or Spearman correlation coefficients, with partial correlation adjusted for age and number of missing posterior teeth.

Results: In the static evaluation, the occlusal plane inclination correlated positively with the cranial base-hyoid angle (∠CB-Hy), indicating that steeper planes were associated with a more posterior hyoid position. In dynamic evaluation, changes in the mandibular base hyoid angle (∠MB-Hy) showed a significant negative correlation with occlusal plane inclination (P=.007). Occlusal plane morphology also corresponded with differences in mandibular and hyoid movement.

Conclusions: Occlusal plane inclination affected both static alignment and dynamic movement of the hyoid bone, potentially influencing airway patency and oral function. Integrating these findings should contribute to prosthodontic diagnosis, treatment planning, and clinical practice.

The autogenous shell technique offers strong biological performance by combining the mechanical stability of cortical bone with the rapid revascularization of particulate autograft. However, the method is highly technique-dependent, particularly when performed concurrently with implant placement, as both the bone shell and implant require spatially accurate positioning. A technique involving a fully digital protocol delivering controlled, predictable, and prosthetically guided shell grafting with simultaneous implant placement is described.