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Purpose: To measure the accuracy (trueness and precision) of the maxillomandibular relationship at centric relation position recorded by using 3 different intraoral scanners with or without an optical jaw tracking system., Material and Methods: A completely dentate volunteer was selected. Seven groups were generated: conventional procedure (control group), 3 IOSs: Trios4 (Trios4 group), Itero Element 5D Plus (Itero group), i700 (i700 group), and 3 groups with a jaw tracking system for each corresponding IOS system (Modjaw-Trios4, Modjaw-iTero, and Modjaw-i700 groups) (n = 10). In the control group, casts were mounted on an articulator (Panadent) using a face bow and a CR record captured with the Kois deprogrammer (KD). The casts were digitized by using a scanner (T710) (control files). In the Trios4 group, intraoral scans were obtained by using the corresponding IOS and duplicated 10 times. The KD was used to obtain a bilateral occlusal record at CR position. These same procedures were followed for the Itero and i700 groups. In the Modjaw-Trios 4 group, the intraoral scans acquired by using the corresponding IOS at MIP were imported into the jaw tracking program. The KD was used to record the CR relationship. For acquiring the specimens in the Modjaw-Itero and Modjaw-i700 groups, the same procedures were followed as in the Modjaw-Trios4 group, with the scans obtained with the Itero and i700 scanners respectively. The articulated virtual casts of each group were exported. Thirty-six inter-landmark linear measurements were used to calculate the discrepancies between the control and experimental scans. The data were analyzed by using 2-way ANOVA followed the pairwise comparison Tukey tests (α=0.05)., Results: Significant trueness and precision discrepancies were found among the groups tested (P<.001). The Modjaw-i700, Modjaw-iTero, Modjaw-Trios4, and i700 groups obtained the best trueness and precision among the groups tested, and the iTero and Trios4 groups obtained the worst trueness. The iTero group obtained the worst precision among the groups tested (P>.05)., Conclusions: The maxillomandibular relationship recorded was influenced by the technique selected. Except for the i700 IOS system, the optical jaw tracking system tested improved the trueness value of the maxillomandibular relationship recorded at CR position when compared with the corresponding IOS., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interest or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Purpose: To measure the effect of different tooth preparation finishing procedures (super-coarse grit, fine grit, and air-particle abrasion) and immediate dentin sealing (IDS) on the scanning accuracy of 4 intraoral scanners (IOSs)., Material and Methods: A tooth preparation for a full-coverage restoration was performed on an extracted mandibular molar using super-coarse diamond burs. Four groups were created depending on the tooth preparation finishing procedure: super-coarse grit (bur with a grit size of 150 µm) (SCG group), fine grit (bur with a grit size of 30 µm) (FG), air-particle abrasion with 27-µm aluminum oxide particles (APA group), and IDS (IDS group). Each group was divided into 5 subgroups according to the scanning system used to digitize the tooth preparation: laboratory scanner (control subgroup) (T710; Medit), Trios 4 (Trios subgroup), CS 3800 (CS subgroup), i700 wireless (i700 subgroup), and iTero Element 5D Plus (iTero subgroup) (n=20). For each subgroup, the control file was aligned with each experimental scan using the best-fit algorithm and an engineering program (Geomagic Control X). The discrepancy between the control and experimental files of each subgroup was computed by measuring the root mean square (RMS) error. Two-way ANOVA and Tukey tests were used to analyze the data (α=.05)., Results: Tooth preparation finishing procedures (P<.001) and the IOS assessed (P<.001) were significant predictors of the trueness and precision values obtained. The highest trueness and precision values were measured in the APA group, while the IDS group had the lowest trueness and precision. Additionally, the i700 subgroup obtained the highest trueness and precision values, while the CS and Trios subgroups had the lowest trueness and precision values., Conclusions: The different tooth preparations finishing procedures tested influenced on the scanning accuracy of the 4 IOSs considered. The air-particle abrasion procedure obtained the best accuracy values. The trueness discrepancies measured among all the subgroups was 19µm and the precision discrepancies measured among all the subgroups was 4.69 µm., Clinical Significance: The tooth preparation finishing procedure used can reduce the intraoral scanning accuracy of any of the intraoral scanners tested. The air-particle abrasion finishing procedure might be recommended for maximizing the scanning accuracy of the IOSs tested., Competing Interests: Declaration of Competing Interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Objectives: To assess the influence of implant angulation, humidity, and interimplant distance on the accuracy and scanning time of complete-arch implant scans., Methods: A definitive cast with 4 parallel implant abutment analogs (P group), and another cast with 4 angulated (up to 30 degrees) implant abutment analogs (NP group) were digitized by using a scanner (7Series) (reference scans). Two subgroups were created: dry (D subgroup) and wet (W subgroup). For the D subgroup, the casts were digitized without altering the surface humidity by using an intraoral scanner (IOS) (TRIOS 3). For the W subgroup, the cast surface was humidified with artificial saliva and digitized by using the same IOS. The interimplant distance discrepancies were assessed by computing linear and angular measurements. Trueness data was analyzed using 3-way ANOVA followed by the pairwise comparison Tukey tests. The Bartlett test, followed by the pairwise comparison tests, was used to assess the precision (α=.05)., Results: Regarding the trueness, implant angulation (P<.001) and inter-implant distance measurement (P<.001) influenced the linear discrepancies. Implant angulation (P=.002), humidity conditions (P<.001), and inter-implant distance (P=.001) influenced the angular discrepancies. Regarding the precision, significant differences in the variance of linear and angular measurements and inter-implant distances were found. Humidity conditions (P<.001) influenced the scanning time., Conclusions: Implant angulation, humidity, and interimplant distance influenced the accuracy and scanning time of complete-arch implant scans. Parallel implants resulted in higher trueness and precision values. Dry conditions resulted in slightly higher scanning trueness and precision and shorter scanning time., Clinical Significance: Drying the surface being scanned increases intraoral scanning accuracy and decreases intraoral scanning time., Competing Interests: Declaration of competing interest The authors did not have any conflict of interest, financial or personal, in any of the materials described in this study., (Copyright © 2022. Published by Elsevier Ltd.)

Purpose: To assess the influence of the scan body geometry bevel location and implant angulation and position of complete-arch implant digital scans., Material and Methods: Two definitive casts with 4 implant analogs placed parallel (P group) or angulated up to 30° (NP group) were fabricated. Five subgroups were created based on the scan body geometry bevel position: facial, mesial, distal, lingual, or random (F, M, D, L, and R subgroup). Casts were digitized using a laboratory scanner (reference) (7Series Desktop Scanner) and an intraoral scanner (TRIOS 3). The implant position discrepancies between the reference and experimental scans were calculated. Data was analyzed using 3-way ANOVA and Tukey tests (α = .05)., Results: The scan body geometry bevel position (P < .001) and the inter-implant distance (P < .001) were shown as significant predictors of the linear discrepancies obtained. The L subgroup had a significantly lower discrepancy compared with the other subgroups. Implant angulation (P < .001), the scan body geometry bevel position (P < .001), and the inter-implant distance (P < .001) were all significant predictors on the angular discrepancies obtained., Conclusions: The scan body geometry bevel location and implant angulation and position influenced the accuracy of the IOS tested. The lingual orientation obtained significantly better accuracy values compared with the other positions. The parallel implant analog position obtained better accuracy than the angulated positions. Lastly, the implant positioned in the dental arch where the intraoral digital scan was finished obtained significantly higher distortion than the contralateral implant., (Copyright © 2022. Published by Elsevier Ltd.)

Purpose: To analyze the influence of the restorative material type (definitive and interim) and its surface treatment (polished or glazed) on the scanning accuracy of an intraoral scanner., Material and Methods: A mandibular dental typodont containing 3 typodont teeth (left second premolar and left first and second molars) was used for testing. Ten groups were created based on the crown material: typodont tooth (control group), gold (G group), zirconia (Z group), lithium disilicate (LD group), hybrid ceramic (HC group), composite resin (CR group), conventional PMMA (CNV-PMMA group), bis-acryl composite resin (CNV-BA group), milled PMMA (M-PMMA group), and additively manufactured bis-acryl-based polymer (AM-BA group). Except the G group, groups were subdivided into polished (P subgroups) or glazed (G subgroups). Each specimen was digitized by using an extraoral scanner (D1000; 3Shape A/G) and an intraoral scanner (TRIOS 4; 3Shape). Each reference scan was used to measure the discrepancy with the corresponding 15 intraoral scans by calculating the root mean square (RMS) error (Geomagic; 3D Systems). The Welch ANOVA and Games-Howell tests were selected to examine trueness (α=0.05). The F-test with Bonferroni correction was used to evaluate precision., Results: Significant trueness and precision differences were found (P<.001). The G-P subgroup had the lowest trueness values, while the CNV-PMMA-P, M-PMMA-P, and AM-BA-P subgroups had the highest trueness values. Significant RMS mean discrepancies were computed when comparing polished and glazed specimens fabricated with the same material (P<.001). The CNV-PMMA-G subgroup had the lowest precision values, while the CNV-BA-P subgroup had the highest precision values (P<.001)., Conclusions: The type and surface finishing of the restorative materials tested influenced the scanning accuracy of the IOS tested. The lowest trueness values were found in the high noble alloy specimens, while the highest trueness values were measured in conventional and milled PMMA and additively manufactured bis-acryl-based polymer polished specimens. Except for zirconia crowns, higher trueness values were found in polished specimens when compared with glazed crowns. The CNV-PMMA-G subgroup had the lowest precision values, while the highest precision values were measured in the CNV-BA-P subgroup., Clinical Significance: Definitive and interim materials tested decrease intraoral scanning accuracy. Furthermore, polishing instead of glazing definitive and interim material assessed might be preferable to maximize intraoral scanning accuracy., (Copyright © 2022. Published by Elsevier Ltd.)

Objectives: To evaluate whether the cutting-off and rescanning procedures have an impact on the accuracy (trueness and precision) of the intraoral digital scan., Methods: A right quadrant digital scan (reference scan) of a participant was obtained using an intraoral scanner (IOS) (TRIOS 4; 3Shape A/S, Copenhagen, Denmark). The reference scan was duplicated 135 times and divided into 3 groups based on the number of rescanned mesh areas: 1 (G1 group), 2 (G2 group), and 3 (G3 group) mesh holes. Each group was subdivided into 3 subgroups depending on the mesh hole diameter: 2 mm- (G1-2, G2-2, and G3-2), 4 mm- (G1-4, G2-4, and G3-4), and 6 mm- (G1-6, G2-6, and G3-6) (n = 15). A software program (Geomagic; 3D Systems, Rock Hill, SC, USA) was used to assess the discrepancy between the reference and the experimental scans using the root mean square (RMS). Kruskal-Wallis and post hoc multiple comparison Dunn's tests were used to analyze the data (α=0.05)., Results: Trueness ranged from 5 to 20 µm and precision ranged from 2 to 10 µm. For trueness assessment, Kruskal-Wallis test revealed significant differences on the RMS error values among the groups tested (P<.05). The G3-6 group obtained the lowest trueness and lowest precision values, while the G1-2, G1-4, G2-2, G2-4, and G3-2 groups computed the highest trueness and precision values. When comparing groups with the same number of rescanned mesh holes but with different diameter, the higher the diameter of the rescanned mesh hole, the lower the trueness values computed; however, when comparing groups with the same diameter of the rescanned mesh hole but with differing number of rescanned mesh holes, no significant differences were found in the RMS values among the groups. For the precision evaluation, Levene's test showed a lack of equality of the variances, and therefore of the standard deviations. The F-test with Bonferroni correction identified significant differences between the SDs between group G3-6 and all the other groups. When comparing instead the interquartile range (IQRs) due to the non-normality of the data, groups G1 and G2 also showed lower IQR values or higher precision than groups G3., Conclusions: Cutting-off and rescanning procedures decreased the accuracy of the IOS tested. The higher the number and diameter of the rescanned areas, the lower the accuracy., Clinical Significance: Cutting-off and rescanning procedures should be minimized in order to increase the accuracy of the IOS evaluated. The intended clinical use of the intraoral digital scan is a critical factor that might determine the scanning workflow procedures., (Copyright © 2021. Published by Elsevier Ltd.)

This in vitro study evaluated the bond strength of a self-adhesive luting cement after using four different techniques to remove surface contamination on dentin. Extracted human molars were flattened to expose the dentin surface and prepared for full crown preparation. Acrylic temporary crowns were fabricated and placed using temporary cement. The specimens were stored at room temperature with 100% relative humidity for seven days. Following removal of the temporary crowns, the specimens were randomly divided into four groups, and excess provisional cement was removed with (1) a hand instrument (excavator), (2) prophy with a mixture of flour pumice and water (3) aluminous oxide abrasion with a particle size of 27 microm at 40 psi and (4) aluminous oxide abrasion with a particle size of 50 microm at 40 psi. The microstructure morphology of the tooth surface was evaluated and residual materials were detected using SEM and EDS analysis of randomly selected specimens. The ceramics were treated with 9.5% hydrofluoric acid-etch and silanized to the prepared dentin prior to cementing with self-adhesive resin cement (RelyX Unicem, 3M ESPE). The shear bond strength was determined at a crosshead speed of 0.5 mm/minute. The results were analyzed with one-way ANOVA, followed by Tukey's test. Particle abrasion treatment of dentin with an aluminous oxide particle provided the highest values of bond strength, while hand instrument excavation was the lowest (p < 0.05). Aluminous oxide particle size did not significantly influence the bond strength at 40 psi. The use of low pressure and small particle abrasion treated dentin as a mechanical cleansing protocol prior to definitive cementation increased the bond strength of self-adhesive resin-luting cement to dentin following eugenol-containing temporary cement.

The VELscope is an important aid in patient assessment, and when added to a well-thought out clinical assessment process that takes into consideration the age of the patient and risk factors that include tobacco, alcohol, and immunologic status, it increases the clinician's ability to detect oral changes that may represent premalignant or malignant cellular transformation. False positive findings are possible in the presence of highly inflamed lesions, and it is possible that use of the scope alone may result in failure to detect regions of dysplasia, but it has been our experience that use of the VELscope improves clinical decision making about the nature of oral lesions and aids in decisions to biopsy regions of concern. Where tissue changes are generalized or cover significant areas of the mouth, use of the scope has allowed us to identify the best region for biopsy. As with all clinical diagnostic activities, no single system or process is enough, and all clinicians are advised to use good clinical practice to assess patients and to recall and biopsy lesions that do not resolve within a predetermined time frame. Lesions that are VELscope-positive and absorb light need to be followed with particular caution, and if they do not resolve within a 2-week period, then further assessment and biopsy are generally advised. It is much better to occasionally sample tissue that turns out to be benign than to fail to diagnose dysplastic or malignant lesions. In our fight to protect patients from cancer, the VELscope improves our odds for early detection, hopefully resulting in fewer deaths from oral cancer.

Due to remodeling of the edentulous ridge following tooth extraction, clinicians and dental technicians face a variety of challenges when attempting to deliver an aesthetic fixed partial denture for the anterior maxilla. An implant-supported, screw-retained fixed partial denture provisional restoration can be utilized in order to manipulate the pontic site with predictable success. This technique can create the illusion of pontics emerging from the soft tissue, creating a natural-looking effect for seating of the definitive restoration.

The master blueprint for indirect restorations is the final impression. The challenge for the clinician is to establish a protocol that ensures a predictably excellent final impression. The purpose of this article is to provide a protocol that integrates the many detailed steps of impression making, from patient comfort to dental laboratory communication. Understanding the biology of the dentogingival junction, dental materials and their interactions, and proper technique all contribute to the final results.

The creation of an esthetic implant restoration with gingival architecture that harmonizes with the adjacent dentition is a formidable challenge. The predictability of the peri-implant esthetic outcome may ultimately be determined by the patient's own presenting anatomy rather than the clinician's ability to manage state-of-the-art procedures. To more accurately predict the peri-implant esthetic outcome before removing a failing tooth, 5 diagnostic keys are discussed. These keys include relative tooth position, form of the periodontium, biotype of the periodontium, tooth shape, and position of the osseous crest.