The International journal of prosthodontics最新文献

Purpose: The investigation into the capacity of PEEK material clasps to deliver sufficient retention force, maintain morphological stability, and exhibit fatigue resistance over prolonged periods is of significant importance.

Material and methods: This study employed a fatigue testing machine to simulate clinical scenarios with varying concave depths (0.25mm, 0.50mm, 0.75mm) and conducted 7200 cycles of fatigue tests on clasps made of different materials. The initial retention force, dynamic changes in retention force, and deformation values of the clasps were measured and analyzed, and their surface morphology was observed using Scanning Electron Microscopy (SEM).

Results: The initial retention force of A-type PEEK clasps exhibited an increase with the concave depth, whereas no significant difference was observed in the initial retention force of B-type PEEK clasps at different concave depths. Following fatigue cycling, the retention force of PEEK clasps decreased more gradually compared to metal clasps, with PEEK-A clasps demonstrating more stable retention force in deeper concave conditions. Furthermore, after prolonged fatigue cycles, PEEK clasps exhibited smaller permanent deformation than metal clasps, and their surface remained smoother without evident wear or cracks.

Conclusions: In comparison to metal clasps, PEEK clasps offer more stable retention force and reduced permanent deformation in long-term clinical applications, making them more suitable for periodontal disease abutments with deeper concavity.

Objectives: This study aimed to investigate the effects of two differently colored (pink, yellow) effervescent Vitamin C tablets on discoloration and surface roughness of three denture base materials.

Materials and methods: Ninety disc-shaped samples (n=30) were prepared from heat-polymerized PMMA (Probase/HP), CAD/CAM-milled PMMA (M-PM Disc/CDCM), and 3D-printed resin (Dentabase/3DP). Samples were immersed in 200 mL water containing one effervescent Vitamin C tablet (Apexis Sambus Nigra or Sunlife Vitamin C) daily for 2 minutes at 24 °C for 30 days. Surface roughness (Ra) was measured using a contact profilometer, and color measurements were recorded with a spectrophotometer. Scanning Electron Microscope images were obtained at magnifications of 500×, 1000×, and 5000×. Data were analyzed using Wilcoxon Signed-Rank, Kruskal-Wallis, and Fisher-Freeman-Halton tests (p<0.05).

Results: Both vitamin solutions caused a significant increase in surface roughness and discoloration in all materials (p<0.001). 3DP samples showed higher roughness values compared to other groups at baseline and after immersion (p<0.001). All materials exhibited visible color changes after the immersion period.

Conclusion: Effervescent Vitamin C tablets may adversely affect the surface properties of denture base resins. Patients using such supplements, especially with 3D-printed prostheses, should be informed about potential changes in color and surface quality.

Purpose This study aimed to quantitatively compare the occlusal characteristics after delivery of mandibular first molar implant prostheses fabricated via a full-digital workflow with the occlusal characteristics of contralateral teeth. Methods Forty patients who had undergone single mandibular first molar implant surgery were enrolled. A full-digital workflow was employed to fabricate prostheses with titanium abutments and zirconia crowns, with crown morphological data sourced from the software's built-in database. Standardized occlusal adjustments were performed after prosthesis insertion. The posterior regions on the implant side (pre- and post-adjustment, P1 and P2) and on the contralateral side (T) were intraorally canned. By analyzing the average occlusal clearance (AOC), the minimum occlusal clearance (MOC), and the inclination of cusps (IC), the occlusal and morphological features of implant prostheses were compared with those of contralateral teeth. Additionally, the vertical occlusal adjustment amount (VOAA) of implant prostheses was measured. Results The AOC-P2 was 152.11 ± 61.34 μm and MOC-P2 was 123.43 ± 58.89 μm, with the ΔAOC(P2-T) was 95.03 ± 70.35 μm and the ΔMOC(P2-T) was 115.14 ± 61.60 μm. The mean inclination of all 5 cusps at P1 and P2 was 25.96 ± 3.77° and 17.39 ± 3.19°, respectively (p < 0.001), with a mean ICA-P2/ICA-T ratio of 0.89 ± 0.24. The mean inclination of the functional cusps at P2 was 18.81 ± 5.04° (ICF-P2/ICF-T: 1.08 ± 0.53), and that of the non-functional cusps was 15.26 ± 3.56° (ICNF-P2/ICNF-T: 0.79 ± 0.39). The average VOAA was 110.89 ± 56.72 μm. Conclusions: the occlusal clearance of the implant prosthesis post-adjustment was approximately 100 μm greater than that of the contralateral tooth, and the cusp inclination was about 89% compared to the contralateral tooth. These findings provided a theoretical foundation for the accurate digital occlusal design of single posterior implant prostheses in fully digital workflow. The tooth morphology database for this specific software may require additional modification to be utilized in the fabrication of implant restorations, especially through reduction of non-functional cusp inclination. Additionally, establishing a dedicated database for implant restoration fabrication is essential.

Radicular dens invaginatus (RDI) is a developmental malformation often associated with severe periodontal destruction and a poor prognosis. Currently, no standardized treatment guidelines exist for RDI. Due to the complex and variable anatomy of affected teeth, one of the primary challenges in managing RDI is accurately locating and debriding the invaginated region while preserving pulp vitality and maintaining dental structural integrity. Therefore, this case report presents a clinical decision-making approach for the digitally assisted management of RDI. A female patient's maxillary left canine was diagnosed with RDI, complicated by infection and periodontal tissue loss, while pulp vitality remained intact. To ensure precise localization and thorough debridement of the invaginated lesion while preserving pulp vitality and tooth integrity, a dual surgical approach was designed using digital technology. Following infection removal, bioactive materials were applied for cavity filling, and guided tissue regeneration was performed. After a one-year follow-up, pulp vitality was successfully maintained, and periodontal tissue healing was achieved.

Purpose: The present study aimed to compare the performance of seven AI chatbots (ChatGPT 3.5, 4, 4o, Gemini, Claude 3, Copilot, and Llama) with that of U.S. prosthodontic residents on the National Prosthodontic Resident Examination (NPRE) from 2011 to 2023.

Materials and methods: NPRE exam files and answer keys were obtained from the American College of Prosthodontists (ACP). AI-generated responses were collected using standardized prompts that requested only letter answer choices. Each chatbot's first response was recorded and compared to the official exam key. Performance was evaluated as the percentage of correct responses, and results were compared with the average scores of human participants. Statistical analysis included repeated measures ANOVA and Bonferroni post-hoc comparisons.

Results: Statistically significant differences were found between the different groups (p<0.001). ChatGPT 3.5 achieved the highest scores, followed by Claude 3 and Llama, while Copilot performed significantly worse than residents. Other chatbots demonstrated performance levels comparable to human participants, but with notable variability across AI models.

Discussion: The findings suggest that AI chatbots, particularly ChatGPT 3.5, can perform at or above the level of prosthodontic residents on standardized examinations. However, differences in chatbot capabilities, training data, and inconsistencies in performance raise concerns about reliability. While AI has potential as a supplementary learning tool, its use should be guided by critical evaluation.

Conclusions: AI chatbots demonstrate adequate performance on specialized academic exams, but variability across models highlights the need for further assessment before integration into dental education and professional practice.

Purpose: This clinical report aims to highlight the complications associated with cocaine use, particularly focusing on oronasal perforations, and demonstrate the efficacy of using a maxil-lary obturator for rehabilitating palatal defects to restore oral functions. Material and Meth-ods: A 60-year-old male patient with a history of cocaine abuse presented with an oronasal perforation in the hard and soft palate after multiple surgical interventions. He reported issues with hypernasal speech and difficulties swallowing. A prosthodontic approach was employed; a removable obturator was fabricated using impression techniques with care to minimize weight and maximize functionality.

Results: Post-delivery, the obturator successfully restored the patient's ability to speak and swallow normally, with significant improvements reported in aesthetic outcomes. Regular follow-ups demonstrated the prosthesis's stability.

Conclusion: The findings suggest that prosthetic rehabilitation with an obturator is a viable and effective solution for managing palatal perforations resulting from cocaine use, significantly improving oral functions and quality of life. This approach highlights the need for comprehensive treatment plans that include both prosthetic management and encouragement toward substance abstinence, emphasizing the multifaceted public health implications of cocaine addiction and its complications.

Background: Tooth loss leads to functional and psychological issues such as difficulty in chewing, changes in diet, and impaired speech. Research indicates that edentulism has a significant impact on oral health-related quality of life (OHRQoL). Prosthodontic treatments, such as removable and fixed partial dentures, as well as implant-supported prosthesis, help restore function and enhance quality of life.

Objectives: To compare the oral health-related quality of life among fixed and removable prosthesis and identify associated factors.

Methods: The urdu version of the validated OHIP-14 questionnaire was administered to the patients visiting the Prosthodontic department of Dow University of Health Sciences (DUHS). R-Studio software was used to analyze the gathered data.

Results: Out of a total of 222 patients who were included in the study, there were 118(53%) males and 104(47%) females with a mean age of 49.3±14.5 years. Distribution of OHIP-14 scores along with mean and standard deviation reveals that the majority of participants scored "Never" or "Hardly Ever" as their experience with using dental prosthesis.

Conclusion: In light of the findings, there is no significant difference in OHRQoL between fixed and removable dental prosthesis. The continued use of conventional removable dentures remains a viable and appropriate option in resource-constrained settings like Pakistan. Given the widespread economic limitations and the large proportion of the population belonging to lower socio-economic groups, promoting the use of affordable prosthetic solutions can help improve access to oral rehabilitation without compromising perceived quality of life.

Purpose: To evaluate the trueness of implant analog positions in digital implant models (DIMs) printed via two different technologies: Direct Light Processing (DLP) and Liquid Crystal Display (LCD).

Materials & methods: Twenty-one replicate casts were reproduced from an educational implant model with six key-position implants; fourteen DIMs through the educational model (EM) scanning and 3D-printing by DLP and LCD 3D-printers (group DLP and group LCD; n=7/group); and seven stone models by pouring the EM open-tray impressions (group Stone). All casts were scanned to generate their standard tessellation language (STL) files. The STL of the EM laboratory scanning provided the reference data. Medit compare deviation analysis software was used to assess the positional trueness of implant analogs. ANOVA for repeated measures and he paired t-test were used for intragroup comparisons, and the three groups were compared using the one-way analysis of variance and Bonferroni's post hoc test (P≤0.05).

Results: Group DLP exhibited greater vertical deviations, and group Stone exhibited greater horizontal deviations (P≤0.05). The highest deviation recorded was for the vertical displacement in group DLP (0.488±0.090mm), and the least was for group Stone vertical displacements (0.032±0.008mm) (P=0.000). Comparing the mean difference of apex/shoulder vertical displacements between groups indicated greater tilting of the vertical axis in group DLP (0.504±0.096), followed by group LCD (-0.285±0.040), then group stone (-0.167±0.026) (P=0.000).

Conclusion: Regarding implant-analog positional trueness, the stone casts are more accurate than the 3D-printed models; however, 3D-printed DIMs generated via intraoral scanning, and printed using LCD technology showed close accuracy findings.

Background: Immediate implant placement with delayed loading and delayed/late implant placement in conjunction with immediate loading are established treatment concepts in the posterior maxilla/mandible. In contrast, immediate placement along with immediate loading in the posterior maxilla/mandible has not sufficiently been documented. Such a treatment concept relies on an implant design rendering a high primary stability and a relative wide prosthetic platform. Consequently, hybrid design implants or tissue level implants are thought to be suitable for such a treatment approach. The present proof of concept study aimed to utilize a hybrid/tissue level implant design for immediate placement and immediate loading in the posterior region applying a digital workflow.

Material & methods: Twelve patients with a single tooth in the posterior maxilla or mandible to be extracted were consecutively recruited. A CBCT examination and an intraoral scan were performed and the digital data was used to fabricate a surgical guide and a provisional restoration for immediate loading. A flapless extraction was performed and an implant with a hybrid design was inserted in the extraction socket applying a fully guided protocol. A prefabricated screw-retained provisional prosthesis was then inserted in full occlusion. After 2-3 months a final intra oral scan was performed and a definitive prosthesis inserted. Patient reported outcome measures (PROMs), marginal bone loss (MBL) and probing depth (PD) values was recorded over a period of 6 months. Statistical analyses were performed using Paired 't' test.

Results: Stable clinical (mean PD 2.8+0.5mm) and biological (mean PI 4.9% +5%) outcomes were observed for all implants rendering a 100% success and survival rate. PROMs were 9.5 ± 0.5 at baseline and 9.7 ± 0.4, at 6 months of follow-up.

Conclusion: The use of hybrid design implants placed immediately and subjected to immediate loading presents a viable treatment option in the posterior maxilla and mandible. Randomized controlled clinical trials should be performed with a larger sample size to further recommend such an approach for daily clinical use.

Purpose: This study aimed to evaluate the color and translucency changes of conventional, milled, and three-dimensional (3D)-printed provisional restorative materials (PRMs) after cigarette smoke exposure and brushing.

Materials and methods: A total of 120 disc-shaped (Ø6 mm × 2 mm) specimens were fabricated from conventional (CN; GC TempSmart), milled (ML; FusionCeram), and 3D-printed (PR; GC TempPRINT) PRMs (n=40 per material). Specimens were randomly divided into smoke-exposed (S) and control (C) groups (n=20). After 20 days of exposure (20 cigarettes/day, 2-second puffs, 60-second intervals) or artificial saliva storage, specimens underwent brushing simulation (15 strokes/day) to form S-BR and C-BR subgroups. Color and translucency were measured at baseline (T0), post-exposure (T1), and post-brushing (T2) using a spectrophotometer. Color change (∆E00), translucency change (∆TP00), and translucency parameter (TP00) were calculated. Data were analyzed using two-way robust ANOVA (5% trimmed means) and Tukey's post hoc test (α = .05).

Results: ML exhibited significantly lower ∆E00 values than CN and PR after cigarette smoke exposure (P < .001). Brushing reduced discoloration in all smoking groups, especially for ML (P < .05). PR showed the highest ∆TP00 values across groups, differing significantly only from ML (P = .008). ML consistently demonstrated the highest TP00 values across all groups (P < .001), indicating superior translucency retention.

Conclusions: Cigarette smoke adversely affected the optical properties of PRMs, particularly in conventional and 3D-printed resins. Milled materials exhibited superior resistance to discoloration and translucency change. Although brushing did not completely reverse staining, it effectively reduced discoloration, particularly in milled materials.