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Purpose: To evaluate the distortion probability in impressions of completely dentate arches when different impression materials are used in relation to operator experience. Materials and Methods: A total of 28 students (Group A) and 7 dentists (Group B) performed three maxillary impressions on 28 participants, each using vinyl siloxane ether (VSE), polyether (PE), and irreversible hydrocolloid (IHC). Gypsum master casts were fabricated and subsequently digitized. Intraoral scans were taken as a control. Differences between master casts and intraoral scans were visualized with heatmaps, and planar deviations were investigated. If planar deviations > 120 µm were found, the impression was rated as "distorted." An additional superimposition using the casts from VSE or PE was performed to confirm the presence of distortions. The relative number of surfaces with distortions in each impression was calculated. The procedure was repeated for a distortion threshold of 500 µm. The statistical analyses included repeated measures ANOVA (RMA) and post hoc tests (a < .05). Results: When 120 µm was considered as the threshold for distortions, IHC impressions showed higher distortion probability than PE impressions in Group A (P = .003) and Group B (P < .0001). In Group B, PE showed a lower distortion probability than VSE (P = .02). There was no significant difference between the study groups (P = .42). Considering 500 µm as a threshold for distortions, there was no difference between impression materials (P = .17) or study groups (P = .53). Conclusions: There were no statistically significant differences in relation to operator experience. Different impression materials had a significant impact on distortion probability. PE impressions showed the lowest distortion probability. [ABSTRACT FROM AUTHOR]

Dental implants are commonly used to replace missing single teeth. However, esthetic rehabilitation of an adjacent tooth may also be required due to diastemas, crowding, or existing large direct restorations to improve the final esthetic outcome. With the advancements in ceramics and bonding techniques, minimally invasive esthetic approaches have become viable for compromised spacing issues. This case report describes a dental technique for the esthetic rehabilitation of compromised anterior spacing with a customized zirconia implant abutment at a maxillary central incisor site and a partial ceramic veneer bonded to the adjacent central incisor. [ABSTRACT FROM AUTHOR]

Advanced digital technologies have rapidly been integrated into prosthodontics to improve the digital workflow for prosthetic rehabilitation. The integration of 3D datasets acquired from various imaging sources such as intraoral scanners and facial optical scanners allows the creation of virtual patients to perform presurgical simulation and prosthetic rehabilitation. The presented technique introduced a straightforward protocol for aligning intraoral scans (Trios 4, 3Shape) to optical face scans (Face Hunter, Zirkonzahn) using a global best-fit algorithm of 3D evaluation software (GOM Inspect). Nasal geometry data were used as the matching reference to produce virtual dental patients. This integration protocol ensured that the intraoral scanner (Trios 4, 3Shape) was used not only to scan dental arches but also used effectively to scan the nose. These scans along with professional facial scans can be successfully aligned to produce virtual dental patients. As only a single fully dentate patient case with an alignment deviation of 243.6 µm was used, further research to evaluate the accuracy of this protocol is needed. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this prospective study was to determine the inter‐ and intraindividual variability in virtual single‐tooth implant positioning based on the level of expertise, specialty, total time spent, and the use of a prosthetic tooth setup. Materials and Methods: Virtual implant planning was performed on matched pre‐ and post‐extraction intraoral scans (IOS), and cone‐beam computed tomography scans of 15 patients. Twelve individual examiners, involving six novices and experts from oral surgery and prosthodontics positioned the implants, first based on anatomical landmarks utilizing only the post‐extraction, and second with the use of the pre‐extraction IOS as a setup. The time for implant positioning was recorded. After 1 month, all virtual plannings were performed again. The individual implant positions were superimposed to obtain 3D deviations using a software algorithm. Results: An interindividual variability with mean angular, crestal, and apical positional deviations of 3.8 ± 1.94°, 1.11 ± 0.55, and 1.54 ± 0.66 mm, respectively, was found. When assessing intraindividual variability, deviations of 3.28 ± 1.99°, 0.78 ± 0.46, and 1.12 ± 0.61 mm, respectively, were observed. Implants planned by experts exhibited statistically lower deviations compared to those planned by novices. Longer planning times resulted in lower deviations in the experts' group but not in the novices. Oral surgeons demonstrated lower crestal, but not angular and apical deviations than prosthodontists. The use of a setup only led to minor adjustments. Conclusions: Substantial inter‐ and intraindividual variability exists during implant positioning utilizing specialized software planning. The level of expertise and the time invested influenced the deviations of the implant position during the planning sequence. [ABSTRACT FROM AUTHOR]

Objectives: The primary aim of this in vitro study was to assess the effect of alveolar residual bone height in the posterior maxilla on the accuracy of the final implant position via free‐handed and static Computer‐Assisted Implant Placement (sCAIP). The secondary aim was to evaluate the influence of the maxillary sinus morphology on the accuracy of final implant position. Materials and Methods: Partially edentulous standardized maxillary models simulating three different residual bone heights and different sinus floor morphologies were investigated. One‐hundred eighty equally distributed implants, which were placed either free‐handed or sCAIP, constituted the study sample. 3D digital deviations were obtained by superimposing the post‐surgical scans on the initial treatment plan. Results: Angular and linear deviation assessment demonstrated higher implant position accuracy in the sCAIP group. sCAIP revealed similar outcomes independently of the alveolar bone height and sinus floor morphology. Contrarily, in the free‐handed group, alveolar bone height and sinus morphology statistically affected the final implant position. Non‐parametric three‐way ANOVA showed significance for implant placement protocol (p <.0001) and alveolar bone height (p ≤.02) when angular, and linear deviations were evaluated. Sinus morphology was statistically significantly associated with angular deviation (p =.0009). Conclusions: sCAIP demonstrated higher 3D implant position accuracy. Alveolar bone height (strongly) and sinus morphology are associated with the accuracy of final implant position when the free‐handed implant protocol is followed. However, these anatomical factors did not affect final implant position during sCAIP. [ABSTRACT FROM AUTHOR]

To evaluate 1-year survival and success rates of 6-mm short implants placed in mandibular molar sites with two different abutments (dome/ball) retaining existing removable partial dentures (RPDs). Materials and Methods: In 19 patients, 38 implants of 6-mm length were placed bilaterally. After 4 months, each participant received the dome abutment, which 2 months later was exchanged with the ball abutment. Clinical data were recorded at abutment connection (4 months postsurgery) and at 6 and 12 months postsurgery, including probing depth, bleeding on probing, presence of plaque, and standardized radiographs. Implant success was assessed using the following criteria: presence of pain, mobility, radiographic bone loss, probing depth, and the presence of exudate. For descriptive analyses, mean and SD values were calculated. Paired sample t tests and linear regressions with a significance level of α < .05 were applied to analyze the evolution of peri-implant parameters and the influence of implant placement depth. Results: The overall mean marginal bone level alteration (DMBL) was 1.05 ± 0.69 mm. A statistically significant marginal bone loss over time was observed at the mesial and distal aspects of all implants (P < .05). The implant survival rate was 100%. No implants showed pain, exudate, mobility, or probing depth > 7 mm. Three implants were classified as having satisfactory survival due to a DMBL > 2 mm (resulting success rate: 92.1%). No influence of implant placement depth was found. Conclusion: These short-term results suggest that short implants can be used in mandibular molar sites for additional posterior support of free-end RPDs. However, in individual cases, DMBL > 2 mm may occur. [ABSTRACT FROM AUTHOR]

Objectives: To pilot an exploration of older adults' future preferences using discrete choice experiments to understand who should provide dental examinations and treatment, where these services should be provided, and participants' willingness to pay and willingness to travel. Background: The proportion of older adults in the general population is increasing and is recognised as a pressing public health challenge. Materials and Methods: Older people aged 65 years and over were recruited into this study from the UK, Switzerland and Greece. Drawing on earlier stakeholder engagement, a set of choice experiments are developed to explore the future preferences of older people for dental examinations and dental treatment, as they anticipated losing their independence. These were presented to the participants using a range of platforms, because of the COVID pandemic. Data were analysed in STATA using a random‐effects logit model. Results: Two hundred and forty‐six participants (median age 70 years) completed the pilot study. There was a strong preference across all countries for a dentist to undertake a dental examination (Greece: β = 0.944, Switzerland: β = 0.260, UK β = 0.791), rather than a medical doctor (Greece: β = −0.556, Switzerland: β = −0.4690, UK: β = −0.468). Participants in Switzerland and the UK preferred these examinations to be undertaken in a dental practice (Switzerland: β = 0.220, UK: β = 0.580) while participants in Greece preferred the dental examination to be undertaken in their homes (β = 1.172). Greek participants preferred dental treatment to be undertaken by a specialist (β = 0.365) in their home (β = 0.862), while participants from the UK and Switzerland preferred to avoid any dental treatment at home (Switzerland: β = −0.387; UK: β = −0.444). Willingness to pay analyses highlighted that participants in Switzerland and the UK were willing to pay more to ensure the continuity of future service provision at a family dental practice (Switzerland: β = 0.454, UK: β = 0.695). Conclusion: Discrete choice experiments are valuable for exploring older people's preferences for dental service provision in different countries. Future larger studies should be conducted to further explore the potential of this approach, given the pressing need to design services that are fit for purpose for older people. Continuity of dental service provision is considered as important by most older people, as they anticipate losing their dependence. [ABSTRACT FROM AUTHOR]

Purpose: To analyze the influence of pristine matrix and O-ring dimensions on retention force and its reproducibility in single one-piece mini dental implants (MDIs) with ball patrices under in vitro conditions. Materials and Methods: Three different matrix/O-ring combinations (MH1, MH2, and MH3) were evaluated (n = 50 measurements each) on 1.8-mm-diameter implants. The matrices were manually mounted on the implants and subsequently removed in a vertical linear manner using a metal pin with two strain gauges, which recorded the maximum force during disconnection. The O-rings were exchanged after five disconnections, and the mean retention force was calculated, resulting in a total of 50 values for each matrix/O-ring combination. Mean and SD retention forces with 95% CI were calculated. ANOVA was used to test the global difference, and post hoc pairwise comparisons were subsequently applied. The level of significance was set at P < .05. Results: ANOVA (global P < .0001) and pairwise comparisons (all P < .001) demonstrated statistically significant differences between the three different matrix/O-ring combinations with mean values of 5.18 N (MH 1), 6.73 (MH 2), and 9.08 (MH 3). Within each combination, retention force variations of > 1 N could not be demonstrated; ie, by exchanging O-rings, a similar retention force can be reestablished. Conclusion: Matrix and O-ring dimensions have a significant influence on retention forces in one-piece MDIs. Pristine O-rings demonstrated highly reproducible initial retention forces in all matrices. [ABSTRACT FROM AUTHOR]

Purpose: To compare the load-to-failure values of different ceramic CAD/CAM implant crown materials with drilled screw-access holes with and without cyclic loading applied. Materials and Methods: Forty zirconia abutments with a titanium base were pre-loaded onto implants to support maxillary right first premolar crowns milled from four different CAD/CAM ceramic materials (zirconia-reinforced lithium silicate, hybrid ceramic, lithium disilicate, and zirconia; n = 10 each). After cementing the crowns, the screw-access channels were prepared by drilling through the occlusal surfaces. Half of the specimens were subjected to cyclic loading for 5 million cycles at 2 Hz (n = 5/material). After cyclic loading, vertical loads were applied until failure. The load-to-failure values of all crowns were recorded and statistically analyzed. Two-way ANOVA was used with restricted maximum likelihood estimation and Tukey-Kramer adjustments (α = .05). Results: During cyclic loading, the zirconia abutment under one lithium disilicate specimen cracked at 2 million cycles, and a zirconia-reinforced lithium silicate crown also fractured. Results for the load-to-failure test series showed statistical differences between the materials. Zirconia resulted in significantly higher failure loads when compared to the other materials (P < .001). Cyclic loading did not significantly affect the load-to-failure values. Conclusion: Cyclic loading did not significantly influence the load to failure of any of the materials tested. Zirconia crowns with drilled screw access channels cemented on zirconia abutments with a titanium base had higher load-to-failure values compared to the other ceramic crown materials. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of cooling on the reverse torque values of different abutments in bone-level and tissue-level implants. The null hypothesis was that there would be no difference in reverse torque values of abutment screws when cooled and uncooled implant abutments were compared. Materials and Methods: Bone-level and tissue-level implants (Straumann, each n = 36) were placed in synthetic bone blocks and subdivided into three groups (each n = 12) based on the abutment type (titanium base, cementable abutment, abutment for screw-retained restorations). All abutment screws were tightened to 35 Ncm torque. In half of the implants, a dry ice rod was applied on the abutments close to the implant-abutment connection for 60 seconds before untightening the abutment screw. The remaining implant-abutment pairs were not cooled. The maximum reverse torque values were recorded using a digital torque meter. The tightening and untightening procedure was repeated three times for each implant including cooling for the test groups, resulting in 18 reverse torque values per group. Two-way analysis of variance (ANOVA) was used to analyze the effect of cooling and abutment type on the measurements. Post hoc t tests were used to make group comparisons (a = .05). The P values of post hoc tests were corrected for multiple testing using the Bonferroni-Holm method. Results: The null hypothesis was rejected. Cooling and abutment type significantly affected the reverse torque values in bone-level implants (P = .004) but not in tissue-level implants (P = .051). The reverse torque values of bone-level implants significantly decreased after cooling (20.31 ± 2.55 Ncm vs 17.61 ± 2.49 Ncm). Overall mean reverse torque values were significantly higher in bonelevel implants compared to tissue-level implants (18.96 ± 2.84 Ncm vs 16.13 ± 3.17 Ncm; P < .001). Conclusion: Cooling of the implant abutment led to a significant decrease in reverse torque values in bone-level implants and may therefore be recommended as a pretreatment before the application of procedures to remove a stuck implant part. [ABSTRACT FROM AUTHOR]

Purpose: To assess the effect of tooth morphology on the amount of tooth structure removal and the effect of different assessment methods on the detected amount of removed tooth structure. Materials and Methods: Eight test groups (n = 10 each) of standardized artificial teeth were prepared for partial and full crowns. All teeth were prepared by the same operator following predefined preparation parameters. Tooth structure removal was measured by using three different assessment methods: digital volumetric analysis (DVA), weight analysis (WA), and combined computer-aided manufacture-weight analysis (CAMWA). Nonparametric repeated-measures ANOVA and post hoc analyses were used to determine the influence of tooth morphology and assessment method on the detected amount of tooth structure removal. Results: For partial-crown preparations, only tooth morphology had a significant impact on the detected amount of tooth structure removal (P < .0001), but not the different assessment methods used (P = .08); tooth structure removal was not significantly different between the canine and incisor groups, but was significant for all other groupwise comparisons. For full-crown preparations, the tooth morphology (P = .047) and different assessment methods (P = .01) had an impact on the detected tooth structure removal; however, only a few groupwise comparisons reached the significance level. Conclusion: The amount of tooth structure removal depended on tooth morphology and the type of assessment method, which should be taken into account when comparing results across studies. The detected amount of tooth structure removal was below the values described in the literature independent of the assessment method used. [ABSTRACT FROM AUTHOR]