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

Purpose: This in vitro study aimed to investigate the effect of different grit sizes of dental burs on the marginal adaptation of lithium-reinforced glass-ceramic restorations. The objective was to determine if finishing with fine-grit burs after initial preparation with coarser-grit burs enhances the marginal adaptation of restorations produced using computer-aided design and computer-aided manufacturing (CAD-CAM) technology.

Materials and methods: Fifty impacted human molar teeth with intact enamel were extracted and divided into five groups (n = 10 per group). For group 1, a neutral band chamfer bur (107 µm) was used, while for group 2, a black band bur (181 µm) was used. A green band bur (151 µm) was used for group 3. For group 4, preparation was done using a black band bur and finished with the red band bur (46 µm), while for group 5, a green band bur was used for preparation and finished with the red band bur. Three-dimensional (3D) scans of the prepared teeth were obtained using an intraoral scanner (Virtuo Vivo, Dental Wings), and CAD software was used to design the crowns. The restorations were milled from lithium disilicate blocks (IPS e.max CAD, Ivoclar Vivadent) on a chairside milling machine (M10, Camcube). Marginal gap assessment on the buccal, mesial, palatal/lingual, and distal surfaces by a stereomicroscope at 20× magnification and with 840 LP/mm resolution was performed. The measurements were performed for 32 equidistant points per sample, totaling 1600 points. ImageJ software was used for the analysis. Additionally, scanning electron microscopy (SEM) was used on 10 samples for validation. Statistical analysis was conducted using the Kruskal-Wallis and Mann-Whitney U tests at the 0.05 significance level.

Results: There was a statistically significant difference in marginal adaptation between the different groups, with groups 4 (Black-Red) and 5 (Green-Red) showing a better marginal fit (p < 0.05). Within each group, no significant difference was observed between the buccal, mesial, distal, and palatal sides.

Conclusion: Finishing tooth preparation with a fine-grit red diamond bur after using coarser-grit burs significantly enhances the marginal adaptation of glass-ceramic restorations produced by CAD-CAM technology. This technique could lead to better clinical outcomes in patients treated with such restorations.

Purpose: This in vitro study compared initial retention forces and long-term degradation patterns of three attachment systems for mandibular implant-retained overdentures: solitary studs, milled bars with sleeves, and milled bars with studs.

Materials and methods: A simulated mandibular model with three parallel implants received overdentures incorporating each attachment system (n = 10 per group). To simulate 5 years of clinical use, specimens underwent 5400 insertion-removal cycles. Measurement of retention forces via vertical dislodgement (5 mm/min) was checked at 12 intervals. Statistical analysis included two-way repeated measures ANOVA and linear regression to study retention degradation patterns.

Results: Two-way repeated measures analysis of variance (ANOVA) revealed significant differences in retention stability (p<0.001). Bar systems demonstrated better durability, with bar-sleeves keeping 16.03 ± 0.22 N (86.5% loss) and bar-studs 19.90 ± 0.97 N (82.2% loss) after 5,400 cycles, compared to solitary studs' 5.38 ± 0.21 N (95.8% loss). Linear regression confirmed predictable degradation in bar systems (R²>0.84, slope: -7.23 to -7.03 N/cycle) versus erratic decay in solitary studs (R² = 0.46). Post-hoc tests showed no significant difference between bar subtypes (p = 0.567).

Conclusion: These findings suggest that, under in vitro conditions, splinted bar attachments, regardless of interface design, offer greater long-term retention durability than solitary systems, considering their use may be advantageous in adequate prosthodontic space. The predictable linear degradation pattern of bar systems in this in vitro model suggests a potential mechanical rationale for less frequent maintenance (e.g., clip/matrix replacement every 3-4 years), in contrast to the more rapid and erratic degradation observed for solitary studs, which would imply a need for more frequent intervention in a clinical setting.

Purpose: To describe the national panorama of outpatient procedures related to oral and maxillofacial prosthetic rehabilitation performed within the Brazilian Unified Health System between 2014 and 2024.

Materials and methods: An ecological, retrospective study was conducted based on secondary data from the Outpatient Information System of the Unified Health System, with analysis of production according to type of prosthesis, geographic distribution, approved values, and proportional rates per population.

Results: In the period analyzed, 17,052 procedures were recorded, with the highest volume in 2023. Ocular prostheses accounted for the largest contingent (10,854), followed by oculoplastic, mandibular, and nasal prostheses. The spatial distribution showed a concentration of care in the Southeast Region (11,674 procedures), with the state of São Paulo standing out. The proportional rates per million inhabitants ranged from 27.6 (Northeast) to 131.4 (Southeast). The financial values totaled R$3,383,613.34 in the period.

Conclusion: The national production of oral and maxillofacial prostheses has grown in recent years, with a predominance of ocular prostheses, a low supply of implant-supported prostheses, and regional concentration of care, indicating a need to expand and decentralize specialized services.

Purpose: To systematically review and meta-analyze clinical, in vitro, and finite-element studies assessing how ferrule height, width, and circumferential extent influence fracture resistance and survival of endodontically treated teeth.

Methods: This review followed PRISMA 2020 guidelines. Two reviewers conducted the screening, with a third resolving disagreements. Eligible designs included clinical studies, in vitro experiments, and finite-element analyses evaluating ferrule characteristics. Risk of bias was assessed using RoB 2, the Newcastle-Ottawa Scale, and CRIS/CONSORT-adapted criteria. Random-effects models were applied.

Results: Thirty-three primary studies (6 clinical, 18 in vitro, 9 finite-element) were included. Ferrule height ≥ 2 mm significantly improved fracture resistance (MD +165 N; 95% CI: 110-215). Ferrule presence increased clinical survival (RR 1.34; 95% CI: 1.12-1.59). Dentin thickness ≥ 1 mm and complete 360° ferrules provided the most favorable reinforcement, while partial ferrules with ≥ 2 opposing walls remained beneficial.

Conclusions: A ferrule height of 1.5-2.0 mm and dentin thickness ≥ 1 mm are associated with improved biomechanical and clinical outcomes. These findings should be interpreted within the context of variation in study designs and reporting quality. No restorative strategy matched the biomechanical reinforcement provided by a natural dentin ferrule.

Purpose: To investigate clinical outcomes and patient satisfaction of complete removable dentures fabricated with a hybrid workflow, utilized in a predoctoral dental clinic.

Materials and methods: Electronic chart records were reviewed for all patients who received complete dentures (CDs) fabricated utilizing the hybrid workflow from May 1, 2021, to December 31, 2024. Information on clinical outcomes and relevant patient factors was collected. Additionally, information on the need for a remake or reline of these prostheses was recorded. Finally, the Oral Health Impact Profile (OHIP) and the Oral Health Related Quality of Life (OHRQoL) score were recorded.

Results: A total of 213 completed OHIP-14 surveys were analyzed, with mean OHIP-14 scores of 9.23 (1 week), 7.02 (1 month), 6.90 (6 months), 6.97 (1 year), and 5.73 (2 years) (p < 0.05). Milled dentures met the threshold of clinical acceptability for all measured parameters across time points. Milled mandibular dentures showed poorer retention and stability than milled maxillary dentures, and the remake rate of milled maxillary immediate dentures was higher than that of milled dentures on healed ridges. Overall, 20% of milled immediate dentures and 4.8% of milled dentures on healed ridges required remakes, though only 5% of all immediate dentures needed remakes within 6 months. No significant trends were observed regarding patient gender, age, PDI classification, or opposing prosthesis type.

Conclusions: Digital dentures fabricated using a hybrid workflow in this study showed clinical acceptability and good patient satisfaction at 1 year, with higher patient satisfaction reported at 2 years. Milled mandibular dentures demonstrated lower retention and stability than maxillary dentures, and maxillary immediate dentures had higher remake rates than digital dentures made on well-healed ridges. Milled dentures are a reliable option for patients irrespective of gender, age, or PDI classification when fabricated by predoctoral dental students.

Marking dental prostheses and appliances enhances patient identification and the continuity of care. This article presents a technique using the Near Field Communication (NFC) technology. The low-cost miniature NFC chip, programmable through smartphones, can be embedded into dental prostheses or appliances to securely store and retrieve the patient's medical and dental information. This method allows immediate access to essential data in clinical and emergency situations, improves documentation, and provides a versatile solution for contemporary prosthodontic practice.

Purpose: The aim of this study was to assess the frequency of returns for maintenance among older adults who received complete dentures at the University of Iowa College of Dentistry. A secondary objective was to investigate associations between patient demographic characteristics, clinical factors, treatment variables, and the frequency of follow-up appointments.

Materials and methods: This retrospective cohort study evaluated 608 patients aged 65 years or older who received complete dentures between 2016 and 2021. De-identified data retrieved from electronic health records included follow-up appointments, age, gender, clinic type, provider type, insurance status, mental health condition, distance from the dental school, and number of prescribed medications. Adherence to follow-up appointments was categorized as "Never," "Once," "Intermittent," or "Always." Statistical analyses included Fisher's exact tests and a multinomial logistic regression model.

Results: Only 3.6% of patients consistently adhered to follow-up recommendations, while 6.7% never attended any follow-up appointments. Insurance type and provider level were significantly associated with follow-up adherence. Medicaid patients had the lowest follow-up rates. Patients treated by predoctoral students showed significantly higher follow-up attendance compared to those treated by faculty or graduate students (Once vs. Never OR = 5.70, p < 0.001). Gender, clinic type, and mental health status were not significantly associated with follow-up behavior.

Conclusion: Strict adherence to follow-up recommendations was rare. Patients treated by predoctoral students and those not on Medicaid demonstrated higher rates of follow-up attendance in this dental school sample.

Purpose: This study aimed to determine the perceptibility and acceptability thresholds for the relative translucency parameter (RTP) of ceramic materials, using observer-based assessments under simulated clinical conditions. The null hypothesis was that no difference existed in RTP values for perceptibility and acceptability thresholds.

Materials and methods: Specimens of lithium disilicate in five translucency levels were fabricated into discs and anterior crowns. RTP was calculated using the CIEDE2000 color difference formula with black and white backings. Digital photographs of paired crowns on typodont models were presented to 30 dental clinicians in a controlled visual environment using a randomized Qualtrics survey. Observers judged translucency differences (perceptibility) and clinical appropriateness (acceptability). A repeated-measures logistic regression model was used to analyze observer responses.

Results: A significant relationship was found between Delta RTP (△RTP) and both perceptibility and acceptability judgments (p < 0.0001). Perceptibility thresholds were identified at -17.5, while acceptability thresholds were defined at 12.6. △RTP values exceeding 27 were consistently perceived as different, while values below 12 were often judged acceptable. The null hypothesis was rejected, confirming a statistical difference between perceptibility and acceptability judgments and their relationship to RTP.

Conclusion: Clinically relevant RTP thresholds for translucency perception and acceptability were established. These findings validate RTP as a meaningful and quantifiable tool for assessing esthetic differences in translucency among restorative materials. The results have implications for material selection and clinical decision-making in prosthodontics.

This case report highlights the experience of one maxillofacial surgical patient who delayed prosthodontic treatment for 7 years as they saved to self-fund access to a subsidized prosthodontic service. Without the benefit of a restored opposing dentition for a prolonged period of time, maxillary occlusal plane disruption occurred as a downstream clinical consequence. To manage the complexities arising from delayed presentation, the prosthodontic team developed a highly tailored treatment plan to meet the patient's unique clinical needs, which included fabrication of customized healing abutments, an implant indexing device, and a definitive removable implant-tooth-supported occlusal overlay prosthesis, which incorporated an atypical increase in the vertical dimension of occlusion (VDO) of 12 mm. Following 68 months of follow-up, the patient tolerated the increase in VDO well. Two minor technical complications occurred (denture tooth debond events) and one minor biological complication (localized peri-implant mucositis) within the follow-up period. This report underscores the role of timely prosthodontic involvement in interdisciplinary maxillofacial treatment pathways and advocates for the prioritization of equitable access to specialist prosthodontic services to mitigate preventable challenges in this vulnerable patient cohort.

Purpose: This study validated the alignment accuracy of a novel implant-retained fiducial marker system for aligning digital scans in edentulous mandibles MATERIALS AND METHODS: A mandibular master cast with four implant analogs was fabricated. A reference scan of scan bodies (attached to analogs via spherical fiducial markers) was captured using a calibrated desktop scanner with a fixed-position jig. Without moving the cast, scan bodies were replaced with a milled interim prosthesis (using the same fiducial markers) and rescanned to ensure perfect spatial correspondence. The scan body assembly was rescanned 10 times using the desktop scanner (negative control dataset), then 10 times with an intraoral scanner (IOS). All IOS scans were aligned to the reference prosthesis scan in dental computer-aided design (CAD) software using fiducial marker-based reference alignment. Both negative control and aligned IOS scans were compared to the reference scan using metrology software to compute 3D deviation metrics. Statistical analysis used Mann-Whitney U test and Hodges-Lehmann estimator (α = 0.05).

Results: Mann-Whitney U test revealed a statistically significant difference between groups (p < 0.001). Median RMS error for fiducial alignment was 85.8 µm, compared to 8.4 µm for the negative control. Hodges-Lehmann estimator median difference of -77.7 µm (95% CI: -82.4, -75.1 µm).

Conclusions: Despite statistical differences, the novel fiducial marker system achieved a mean alignment accuracy of approximately 85 µm, which is clinically acceptable. This in vitro study demonstrates technical feasibility. Clinical validation is warranted.