Journal of Advanced Prosthodontics最新文献

[This corrects the article on p. 302 in vol. 16, PMID: 39512875.].

Purpose: This study aimed to investigate the extent to which intraoral scanning are affected by clinical conditions, and whether ambient lighting and different color temperatures have an impact on the accuracy of intraoral scanner, as well as to evaluate scanning time.

Materials and methods: Twelve different environments were created using various ambient lighting conditions (0, 500, 1000 and 1500 lux) and color temperatures (white, blue and yellow). A partially edentulous mandibular model with two implants and a three-unit bridge was scanned under each environment until 10 digital models were obtained, and scanning times were recorded using a virtual stopwatch. A 3D analysis was performed on the obtained digital models, and the data were analyzed using a software. The generalized linear model analysis and Tukey multiple comparison test were used to analyse the data (P < .05).

Results: The effect of lux, color temperature, and scanning times on RMS data was found to be significant (P < .001). The mean RMS value was the highest in the 0 lux group and the lowest in the 500 lux group. Regarding the color temperature, the highest RMS value was in the white color group and the lowest in the yellow color group. Scanning times were similar among the 0, 500 and 1000 lux groups, with a significant increase in the 1500 lux group.

Conclusion: Different ambient lighting conditions and color temperatures have significant effect on the accuracy of intraoral scanning.

Purpose: This study aimed to investigate the relationships between reference planes and oral functions on the habitual and non-habitual chewing sides.

Materials and methods: Thirty-four subjects with no abnormalities in the maxillofacial region and oral functions were enrolled in this study. Relationships between angles between the reference plane (Frankfort horizontal plane, Camper's plane, and occlusal plane) and masticatory performance, occlusal force, and occlusal contact area by chewing side were examined. Regarding the measurement of reference planes, a creatively modified three-plane measuring device was used to measure angles between the reference planes. Images were taken from the right and left sides and angles between reference planes were measured. Masticatory performance was examined by measuring the amount of glucose extracted from a gummy jelly on the habitual and non-habitual chewing sides separately. Occlusal force and occlusal contact area were measured by occluding against pressure-sensitive film, and values on the habitual and non-habitual chewing sides were calculated and analyzed.

Results: The angle between Camper's plane and the occlusal plane correlated with masticatory performance on both the habitual chewing side (r = 0.47, P < .01) and the non-habitual chewing side (r = 0.36, P < .05). A correlation was observed between masticatory performance and occlusal force on the habitual chewing side (r = 0.46, P < .01).

Conclusion: Masticatory performance became higher as occlusal plane inclination increased. This result represents essential knowledge for prosthetic treatment.

Purpose: The aim of this study was to investigate microstrains around two non-parallel implant-supported prostheses and different abutment connections and positions under vertical static load using strain gauges.

Materials and methods: 4 models simulating the mandibular unilateral free-end were fabricated. 8 implants (4.0 × 10 mm and 5.0 × 10 mm) were inserted in the second premolar, perpendicular to the occlusal plane, and the second molar, tilted at 15°. Four groups were analyzed: engaging and angled abutments (control group), both non-engaging abutments, both screw-and cement-retained prosthesis (SCRP) abutments, and engaging and non-engaging abutments. Strain gauges were placed buccally, lingually, mesially, and distally adjacent to each implant. The restoration was cement-retained in the control group and screw and cement-retained in the rest. Zirconia bridges were fixed on the abutment with NX3, and a 300 N vertical static load was applied. Microstrains were recorded and analyzed.

Results: Both non-engaging abutments showed the highest compressive microstrains (-52.975), followed by engaging, angled abutment (-25.239). SCRP-SCRP abutments had the lowest compressive microstrains (-14.505), while the engaging, non-engaging abutments showed tensile microstrains (0.418). Microstrains in SCRP-SCRP and engaging, non-engaging groups were significantly lower than in the control group (α = .05). Premolar areas showed compressive microstrains (-47.06), while molar sites had tensile microstrains (+0.91), with microstrains in premolars being significantly higher than in molar area (α = .05).

Conclusion: The types of abutment connections and positions may have a potential effect on microstrains at the implant-bone interface. SCRP-SCRP abutments could be an alternative to use in non-parallel implant-supported prostheses when two implants make an angle of no more than 20 degrees.

Purpose: Studies about success of FPDs (fixed partial dentures) mostly include restorations built by different clinicians. This results in limited comparability of the data. The aim of this study was to evaluate complications of all-ceramic FPDs built by 1 dentist between 2011 to 2023.

Materials and methods: 342 all-ceramic FPDs were observed during follow-up care. 48 patients received 262 single crowns, 59 bridges and 21 veneers. Because of the different lengths of the bridges, units were defined as restored or replaced tooth. 465 units performed by the same dentist from Nov 2011 to Nov 2022 were included. Influencing factors "restoration", "construction", "abutment", "localization", "vitality" and "application period" were evaluated using Kaplan-Meier Analysis and Log-Rank Tests.

Results: 406 units (87.3 %) showed no complication. 7 correctable chippings (1.5 %) and 10 recementable decementations (2.1 %) occurred. Six decemented units got lost (1.3 %). 21 units failed due to fatal fracture (4.5 %). Crown margin complications, such as secondary caries, occurred in 15 units (3.2 %). Comparing the influencing factors resulted in higher complication rates of veneers (P < .001), of monolithic ceramics (P ≤ .050) and of molar-restorations (P = .047). The application period had no influence on the success and survival rate.

Conclusion: Overall, all-ceramic FPDs showed good clinical results. Although less complications were observed with modern restorations, these more often led to complete failure. To generate evidence-based recommendations, further studies are needed to evaluate the mid- and short-term success and survival of current all-ceramic restorations.

Purpose: This study assesses the impact of additional reference objects (RO) on the trueness and precision of distance and angle measurements between scan bodies in digital scans with four different intraoral scanners (IOS) in partially edentulous models.

Materials and methods: Maxilla models (Frasaco, Frasaco GmbH, Tettnang, Germany) with one (3-U) and two (4-U) missing posterior teeth were 3D printed and fitted with dental implants and scan bodies. Four intraoral scanners (Primescan (Dentsply Sirona, Charlotte, NC, USA) (PS), Trios 3 (3Shape) (T3), Trios 4 (3Shape) (T4), and CS3600 (Carestream Dentistry) (CS)) captured digital implant impressions with and without additional RO. Scans were aligned and assessed for distance and angulation measurements between scan bodies. Statistical analyses compared trueness and precision across model groups using the Student t-test and Welch's ANOVA.

Results: CS consistently showed the highest distance values across IOS devices in both the 4-U and 3-U models (P < .05), both with and without RO. The distance values were not considerably affected by the presence of RO (P > .05), except for a few isolated cases in the PS and CS groups of 3-U models. When measuring angles, CS usually showed greater values than the other IOS devices, especially when RO was present both in the 4-U and 3-U variants (P < .05).

Conclusion: The influence of additional reference objects on accuracy varies with different scanner types, irrespective of edentulous area length.

Purpose: This study aimed to evaluate the reliability and validity of a four-item questionnaire using a face rating scale to measure dental trait anxiety (DTA), dental trait fear (DTF), dental state anxiety (DSA), and dental state fear (DSF).

Materials and methods: Participants were consecutively selected from patients undergoing scaling (S-group; n = 47) and implant placement (I-group; n = 25). The S-group completed the questionnaire both before initial and second scaling, whereas the I-group responded on the pre-surgery day (Pre-day), the day of implant placement (Imp-day), and the day of suture removal (Post-day).

Results: The reliability in the S-group was evaluated using the test-retest method, showing a weighted kappa value of DTA, 0.61; DTF, 0.46; DSA, 0.67; DSF, 0.52. Criterion-related validity, assessed using the State-Trait Anxiety Inventory's trait anxiety and state anxiety, revealed positive correlations between trait anxiety and DTA/DTF (DTA, ρ = 0.30; DTF, ρ = 0.27, ρ: correlation coefficient) and between state anxiety and all four items (DTA, ρ = 0.41; DTF, ρ = 0.32; DSA, ρ = 0.25; DSF, ρ = 0.25). Known-group validity was assessed using the initial data and Imp-day data from the S-group and I-group, respectively, revealing significantly higher DSA and DSF scores in the I-group than in the S-group. Responsiveness was gauged using I-group data, showing significantly lower DSA and DSF scores on post-day compared to other days.

Conclusion: The newly developed questionnaire has acceptable reliability and validity for clinical use, suggesting its usefulness for research on dental anxiety and fear and for providing patient-specific dental care.

Purpose: This study aimed to evaluate the clinical performance of implant-assisted removable partial dentures (IARPD) with surveyed crowns, also known as implant-crown-retained removable partial dentures (ICRPDs).

Materials and methods: Electronic searches of MEDLINE/PubMed, the Cochrane Central Register of Controlled Trials, the Web of Science, and the Korea Citation Index were performed according to the established search terms for ICRPD. A literature search was conducted for studies published in English or Korean until September 2023, using the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines.

Results: A total of 216 journals were searched, and 31 eligible studies were selected based on the inclusion and exclusion criteria. One systematic review included five case reports of ICRPD. Nine retrospective studies evaluated implant survival/success rate, implant failure cases, marginal bone loss, periodontal status, clinical complications, and patient satisfaction. Twenty-one case reports published in Korea showed good prognoses.

Conclusion: According to the findings of this systematic review, ICRPD has a reasonable survival/success rate, minimal bone loss, and high patient satisfaction.

Purpose: This cone-beam computed tomography (CBCT) study aimed to analyze the anatomical characteristics of alveolar bone at mandibular first molar (MFM) and their implications for immediate implant placement surgery.

Materials and methods: 100 patients with 140 MFMs were reviewed retrospectively. We first performed a 3D reconstruction of the patient's CBCT data to determine a reference plane with ideal implant placement and orientation. The following parameters of MFM region were analyzed: mesial-distal socket size (MD-SS), buccal-lingual socket size (BL-SS), root furcation fornix to inferior alveolar nerve (IAN) distance (RF-I), interradicular bone thickness (IRB), mesial/distal root apex to the IAN distance (MRA-I/DRA-I), thickness of the buccal/lingual bone of the mesial root (MR-B/MR-L), thickness of the buccal/lingual bone of the distal root (DR-B/DR-L).

Results: The MD-SS of MFM was 8.74 ± 0.76 mm, and the BL-SS was 8.26 ± 0.72 mm. The MR-B, DR-B was 1.01 ± 0.40 mm and 1.14 ± 0.50 mm, and the difference was statistically significant (P = .001). The values of the MR-L, DR-L were 2.71 ± 0.78 mm and 3.09 ± 0.73 mm, and the difference was also statistically significant (P < .001). The mean distance of RF-I was 15.68 ± 2.13 mm, and the MRA-I was 7.06 ± 2.22 mm, which was greater than that of DRA-I (6.48 ± 2.30 mm, P < .001). The IRB at 2 mm, 4 mm apical from the furcation fornix, and at apex level was 2.81 ± 0.50 mm, 3.30 ± 0.62 mm, and 4.44 ± 1.02 mm, respectively.

Conclusion: There is relatively sufficient bone mass in interradicular bone in height, but an adequate width is lacking for the bone between the mesial and distal root after the extraction of the MFM for immediate implantation. The thickness of the MFM buccal bone is relative thin, especially for the mesial root.

Purpose: The aim of this prospective clinical study was to compare the influence of palatal vault forms on accuracy and speed of intraoral (IO) scans in completely edentulous cases.

Materials and methods: Based on the palatal vault form, participants were divided into three equal groups (n = 10 each); Class I: moderate; Class II: deep; Class III: flat palatal vault. A reference model was created for each patient using polyvinylsiloxane impression material. The poured models were digitized using an extraoral scanner. The resultant data were imported as a solid CAD file into 3D analysis software (GOM Inspect 2018; Gom GmbH, Braunschweig, Germany) and aligned using the software's coordinate system to determine its X, Y, and Z axes. Five digital impressions (DIs) of maxilla were captured for each patient using an intraoral scanner (TRIOS; 3Shape A/S, Copenhagen, Denmark) and the resultant Standard Tessellation Language (STL) scan files served as test models. Trueness was evaluated by calculating arithmetic mean deviation (AMD) of the vault area between reference and test files while precision was evaluated by calculating AMD between captured scans to measure repeatability of scan acquisition. The scan time taken for each participant was also recorded.

Results: There was no significant difference in trueness and precision among the groups (P = .806 and .950, respectively). Average scan time for Class I and III palatal vaults was 1 min 13 seconds and 1 min 37 seconds, respectively, while class II deep palatal vaults showed the highest scan time of 5 mins.

Conclusion: Palatal vault form in edentulous cases has an influence on scan time. However, it does not have a substantial impact on the accuracy of the acquired scans.