Journal of Prosthodontics-Implant Esthetic and Reconstructive Dentistry最新文献

Purpose: Patients with bulimia nervosa or gastroesophageal reflux disease (GERD) are frequently exposed to gastric acid, which may cause tooth demineralization and degradation of dental ceramics. This in vitro study investigated the effect of simulated gastric acid on surface roughness and substance loss of two veneering porcelains subjected to different surface finishing protocols.

Materials and methods: Eighty ceramic discs were fabricated from feldspathic porcelain (VITA VM13; VITA Zahnfabrik) and fluorapatite glass-ceramic (IPS Emax Ceram; Ivoclar Vivadent) (n = 40 each). Discs (10 mm × 2 mm) were prepared, fired, and subdivided according to surface finishing: polishing or glazing (n = 20). Each subgroup was immersed in simulated gastric acid or artificial saliva (control) for 24 h at 37°C (n = 10). Surface roughness (Ra) was measured before and after immersion using a mechanical profilometer, and surface morphology was examined by scanning electron microscopy (SEM) as two additional specimens per subgroup were prepared to avoid profilometer-contacted areas. Substance loss was determined by weighing specimens before and after immersion using a digital balance. Data were statistically analyzed with three-way ANOVA, followed by Tukey's HSD test (α = 0.05).

Results: Both exposure medium and finishing protocol significantly affected surface roughness, with glazed specimens showing smoother surfaces than polished ones (p < 0.05). Finishing protocol also significantly affected substance loss after immersion in simulated gastric acid (p < 0.001). No significant difference was found between the two ceramic materials in terms of roughness or weight loss (p > 0.05).

Conclusion: Simulated gastric acid increases surface roughness and induces minor substance loss in veneering porcelains. Glazing provides more protection compared to polishing, maintaining smoother surfaces, and reducing degradation.

Purpose: To evaluate the five-year survival rate and complication spectrum of complete arch fixed implant-supported zirconia prostheses (CAFIPs) fabricated by a commercial dental laboratory in Dubai, UAE, aiming to identify principal modes of failure and technical challenges.

Materials and methods: This retrospective, cross-sectional study analyzed 3300 screw-retained, 3Y-TZP monolithic zirconia CAFIPs, with veneered porcelain limited to the gingival area, manufactured using standardized protocols between August 2019 and August 2024. Data on maxillary (n = 1900) and mandibular (n = 1400) prostheses, complications, reason for lab returns, and failure events were extracted from digital laboratory records. Remakes due only to technical or material failure were included. Survival analysis employed a life table approach, strictly excluding clinician- or patient-driven interventions to ensure unbiased outcomes.

Results: The five-year cumulative survival rate was 91.67%. The life span table analysis revealed a concerning trend of 2 events in year one increasing to 14 events in year five. Framework fractures (n = 38) were the leading failure cause, especially in prostheses with insufficient vertical space, while ceramic chipping (n = 4) affected mainly mandibular prostheses with excessive ceramic layering. Importantly, no cases of titanium cylinder debonding or fracture were observed, indicating mechanical reliability. Minor prosthetic complications included localized veneer chipping. Enhanced framework design and material handling were identified as improvement targets for long-term performance.

Conclusions: Full-arch fixed implant-supported zirconia prostheses exhibited excellent five-year durability. Most failures were related to framework issues or ceramic chipping, while technical problems with titanium components were absent. Continued improvements in design, manufacturing, and clinical protocols are needed to optimize longevity and patient outcomes.

Purpose: The purpose of this in vitro study was to investigate the effect of alcohol-free cleaning solutions on the mechanical properties and reliability of additively manufactured occlusal device resins, compared with isopropyl alcohol (IPA), while considering the influence of aging.

Materials and methods: Bar-shaped (64×10×3.3 mm) specimens were additively manufactured from two occlusal device resins (Freeprint Splint 2.0; FS, KeySplint Hard; KS) and divided into three groups based on the cleaning solution used (IPA, methylether solvent (MES), and a water-based solution) (N = 30). After postprocessing, each set of specimens was further divided into two groups based on their aging condition as nonaged or aged (n = 15). Specimens in nonaged subgroups were tested for 3-point flexural strength and microhardness, while those in aged subgroups were subjected to 5000 thermal cycles between 5°C and 55°C before testing. Both data sets were analyzed with a generalized linear model either with a normal distribution and identity link function (microhardness) or a gamma distribution and logarithmic link function (flexural strength). The maximum likelihood estimation method was used for the Weibull analysis of the flexural strength data and further evaluated with the chi-squared test (α = 0.05).

Results: Aged KS had higher flexural strength than its FS counterpart when IPA and MES were used (P ≤ 0.014). MES led to the lowest flexural strength for aged FS, which had lower values than nonaged FS when MES and the water-based solution were used (p ≤ 0.002). Nonaged MES-cleaned KS had lower hardness than its FS counterpart (p<0.001). Water-based solution led to higher hardness than MES for aged KS, and aged KS had higher hardness than nonaged KS when the water-based solution and MES were used (p ≤ 0.028). KS mostly had higher reliability than FS; MES use tended to result in lower reliability among the aged specimens, and aging reduced the reliability of MES-cleaned FS and KS specimens as well as of FS specimens cleaned with a water-based solution (p ≤ 0.027).

Conclusions: Flexural strength, microhardness, and reliability of the KS resin were mostly similar to or better than those of the FS resin. Cleaning with MES or aging may compromise mechanical properties and reliability, depending on the resin.

Purpose: Implant diameter and increased crown height space (CHS) are factors that critically affect the fracture load of extra-narrow dental implant (ENDI) restorations. The present study aims to evaluate the effect of different CHSs on the fracture load and failure mode of ENDIs (2.9 mm).

Materials and methods: Thirty-three ENDIs were mounted and divided into three groups (n = 11) based on their CHS. The three study groups included Group A: 8 mm (control), Group L: 11 mm (long), and Group E: 14 mm (extra-long) CHS supported by ENDI. The abutments were torqued to 35 N-cm, and the zirconia crowns were cemented with resin cement. Thermocycling and chewing simulations were performed to simulate five years of aging. A fracture load assessment was performed using a static load on the anterior zirconia crowns at 30° to the implant axis until failure.

Results: The mean fracture loads of the study groups were 1010.9 ± 98.6, 854.9 ± 93.8, and 837.5 ± 107.7 N for Groups A, L, and E, respectively. The 8 mm samples showed the highest failure load (1010.9 ± 98.6 N), and the 14 mm samples showed the lowest loads (837.5 ± 107.7 N) prior to failure. The predominant mode of failure was deformation of the implant platform without crown failure at 100%, 90%, and 30% for Groups E, L, and A, respectively.

Conclusions: Within the limitations of this in vitro study, CHS significantly influenced the failure load of ENDI (2.9 mm)-supported cement-retained zirconia crowns, with increased CHS associated with reduced load-bearing capacity.

Purpose: To evaluate retention, masticatory performance, and patient satisfaction of complete mandibular dentures retained by four mini-implants (MIs) versus two standard implants (SIs) with functional-immediate loading, and to compare subjective and objective evaluations.

Materials and methods: Twenty-nine participants, classified according to the American College of Prosthodontists Classification as Class I or II, were edentulous for 6 months to 30 years, with a history of 0-3 previous dentures. Participants were allocated into three groups: Group S (n = 11) received two SIs (3.75 mm, Intrahex, Intra-Lock), Group M3 (n = 8), and Group M2.5 (n = 10) received four MIs (3 and 2.5 mm, respectively; Inclusive, Prismatik Dentalcraft). Outcomes were evaluated before loading and after 1, 3, 6, 12, and 18 months. Retention was measured with a digital force gauge, patient satisfaction using the McGill Denture Satisfaction Questionnaire, and masticatory performance with the single-sieve method. One-way ANOVA and paired t-test were used (p ≤ 0.05).

Results: Retention, masticatory performance, and patient satisfaction improved significantly across all groups (p < 0.01). No intergroup and intragroup significant differences were found, except for retention in Group S, which showed higher values than MI groups and decreased over time (p < 0.05).

Conclusions: According to the results of this study, all groups showed improved retention, masticatory performance, and patient satisfaction. Group S had better retention initially, but it decreased over time. Both MI groups demonstrated similar masticatory performance and patient satisfaction as Group S. MI groups exhibited similar outcomes. Subjective evaluation can be a sufficient alternative to objective tests.

Purpose: To develop and validate an integrated system combining grey relational analysis (GRA) with deep neural networks (DNNs) for personalized oral aesthetic color optimization, and to evaluate its performance compared to traditional color selection methods in dental restoration.

Materials and methods: Using a priori power analysis, 150 patients (70 males, 80 females; mean age 31.5 ± 7.2 years) were recruited for this study. For VITA shade classification, GRA was performed on 15 clinical variables (tooth color, facial/gingival parameters, demographics, preferences) which were weighted and these therefore formed the features of a DNN (15→128→64→32→16 neurons in 4 hidden layers) with 16-class output. The system exhibited a clinical accuracy of 93.2% against a consensus of prosthodontists (82.7%) on spectrophotometry alone. Technical accuracy (ΔE00 ≤ 2.0) was recorded as 94.7%.

Results: An integrated system was found to have an accuracy of 93.2% (95%CI: 90.6-95.8) for tooth color recommendation. This output was significantly better than the accuracy of visual assessment (68.5%) and spectrophotometric measurement (82.7%) (p < 0.001). Age-specific analysis revealed younger patients (20-35 years) preferred brighter shades (B1, A1), while older patients showed greater acceptance of natural color variations. This approach offers clinicians an evidence-based decision-making tool that improves both efficiency (processing time reduced from 180s-45s) and patient satisfaction (increased from 72.3%-91.4%).

Conclusion: The combined application of GRA and DNN provides a recommendation support tool for optimizing the oral cavity's aesthetic color and designing personalized aesthetic treatment plans. Future studies in a multicenter setting would test generalizability.

This case series describes the prosthodontic treatment of five patients who were treated with surgical resection, with or without flap reconstruction, and had remaining oronasal fistulas following their maxillary neoplasms. All five patients obtained spontaneous closure of their partial maxillectomy defects following the use of a maxillary protective removable dental prosthesis that did not engage the fistula.

Purpose: To compare the cost-efficiency of digitally designed and manufactured removable complete dentures (RCDs) with conventionally fabricated RCDs through a systematic review and meta-analysis.

Methods: A comprehensive electronic and manual search was performed in PubMed, Embase, Web of Science, and Scopus up to February 10, 2025. Eligible studies included clinical trials and cohort studies comparing cost-related outcomes of digital and conventional RCD workflows. Primary outcomes were laboratory, clinical, and total costs; secondary outcomes included the number of treatment sessions. Meta-analyses were conducted using random-effects models. Risk of bias was evaluated using standardized tools.

Results: Four retrospective studies and one prospective study, including 184 patients, met the inclusion criteria. No statistically significant differences were observed between digital and conventional workflows in laboratory costs (mean difference [MD]: -239.77 (2025 USD); p = 0.1063), clinical costs (MD: 74.39 (2025 USD); p = 0.4514), total costs (MD: -357.76 (2025 USD); p = 0.2577), or treatment sessions (MD: -1.47; p = 0.3514). Operator experience significantly influenced clinical costs (p < 0.0001) and the number of sessions (p = 0.0001).

Conclusion: Within the limitations of the available evidence, digital and conventional workflows for RCD fabrication demonstrated comparable cost-efficiency. Although digital workflows may reduce the number of sessions when performed by experienced clinicians, the current evidence is insufficient to establish a clear cost-efficiency advantage.

Alveolar bone morphology drives the edentulous patient's rehabilitation. In edentulism, maxillary resorption is often in three vectors: superiorly, medially, and posteriorly, leading to a prosthetically unfavorable pseudo-class III ridge relationship. Longstanding edentulism, especially in the context of ill-fitting dentures, can result in severe maxillary atrophy. Rehabilitation of the severely atrophic maxilla remains a challenge, frequently requiring extensive bone grafting procedures in combination with endosseous dental implants. Graftless options, using longer endosseous and/or tilted dental implants placed into the nasal, pyriform rim, pterygoid process, and zygomatic bone, have been developed to solve this treatment dilemma. These options have specific patient anatomy limitations, can be technique sensitive, and can result in increased patient morbidity. Digitally planned, custom-milled, and rigidly fixated subperiosteal implants offer a recently introduced immediate fixed option when conventional solutions fail or are contraindicated. Cone-beam computed tomography (CBCT) and computer-aided design and computer-aided manufacturing (CAD-CAM) redefine a controversial 70-year-old concept, using prosthodontic reverse-engineering to offer stability, reduced morbidity, and improved patient satisfaction. Long-term follow-up for the use of this technique in fixed definitive restorations is not available at this time.