OBJECTIVES: This study aimed to compare the effects of virtual adjustment on occlusal interferences in mandibular posterior single crown and three-unit bridge restorations by using the mandibular movement track and the movement parameters of a virtual articulator. METHODS: Twenty-two participants were recruited. Digital casts of the maxillary and mandibular arches were obtained using an intraoral scanner, and the jaw registration system was used to record the data of the mandibular movement track and the movement parameters of the articulator. Four kinds of restorations with 0.3 mm occlusal interferences were designed with dental design software. In particular, single crowns were designed for teeth 44 and 46, whereas three-unit bridges were designed for teeth 44-46 and 45-47, and the corresponding natural teeth were virtually extracted. Virtual adjustment of the restorations was performed using two dynamic occlusal recordings, namely, the mandibular movement track and the movement parameters of the virtual articulator. A reverse-engineering software was used to measure the root-mean-square of the three-dimensional deviation of the occlusal surfaces between natural teeth and the adjusted restorations. The differences between the two methods of virtual-occlusion adjustment were compared and analyzed. RESULTS: For the same group of restorations, the three-dimensional deviation of the mandibular movement track group were lower than those of the virtual articulator group, and the differences were statistically significant (P<0.05). For the four groups of restorations adjusted by the same method, the three-dimensional deviation of the 46-tooth single crown was the largest and the smallest three-dimensional deviation was that of the 44-tooth single crown. Statistical differences existed between the 44-tooth single crown and the other groups (P<0.05). CONCLUSIONS For the occlusal design of posterior single crown and three-unit bridge, the mandibular movement track could be a more effective approach to virtual occlusal adjustment than the movement parameters of the virtual articulator.
Humans ; Mouth, Edentulous ; Occlusal Adjustment ; Jaw Relation Record ; Dental Articulators ; Software

Objective: To investigate the influence of light and heavy bite force on the mandibular movement trajectories, and the influence of bite force on virtual occlusal pre-adjustment of digital full crown. Methods: From October 2021 to March 2022, 10 postgraduate volunteers (3 males and 7 females, aged 22-26 years) were recruited from Peking University School and Hospital of Stomatology. Maxillary and mandibular digital models of the participants were obtained by intraoral scanning. Jaw relations were digitally transferred under heavy bite force and mandibular movement trajectories under light and heavy bite force were recorded by jaw motion analyser. Three mandibular markers were chosen, namely the mesial proximal contact point of the central incisor (incisal point) and the mesial buccal cusp tips of the bilateral first molars. The three-dimensional displacements of the markers under two kinds of bite force in the intercuspal position (ICP), the sagittal projection of the three-dimensional displacements in the protrusive edge-to-edge position, and the coronal projection of the three-dimensional displacements in the lateral edge-to-edge position of upper and lower posterior teeth were measured. Single-sample t-test was used to compare the three-dimensional displacements and the corresponding sagittal projection and coronal projection with 0, respectively. The left maxillary central incisor and left mandibular first molar were virtually prepared by the reverse engineering software. Then dental design software was used to design digital full crown using the copy method. The mandibular movement trajectories under light and heavy bite force were separately used to guide virtual occlusal pre-adjustment. The three-dimensional deviations (mean deviations and root mean square) between the lingual surface of the left maxillary central incisor or the occlusal surface of the left mandibular first molar and that of the natural tooth before preparation were calculated (light bite force group and heavy bite force group), and the differences between the two groups were compared by the paired t-test. Results: Under the two kinds of bite force, the three-dimensional displacements of the markers in the ICP were (0.217±0.135), (0.210±0.133) and (0.237±0.101) mm, respectively; the sagittal projection of the three-dimensional displacements of the markers in the protrusive edge-to-edge position were (0.204±0.133), (0.288±0.148) and (0.292±0.136) mm, respectively; the coronal projection of the three-dimensional displacements of the mesial buccal cusp tips of the bilateral first molars in the lateral edge-to-edge position were (0.254±0.140) and (0.295±0.190) mm, respectively. The differences between the above displacements and 0 were statistically significant (P<0.05). The results of occlusal pre-adjustment showed that the mean deviations of the lingual surface of the left maxillary central incisor in the light and heavy bite force groups were (0.215±0.036) and (0.195±0.041) mm (t=3.95, P=0.004), respectively. The mean deviations of the occlusal surface of the left mandibular first molar were (0.144±0.084) and (0.100±0.096) mm (t=0.84, P=0.036), respectively. Conclusions: Both the light and heavy bite force have an influence on the mandibular movement trajectories. Virtual occlusal pre-adjustment of prostheses with mandibular movement trajectories under heavy bite force can obtain morphology of lingual or occlusal surfaces closer to the natural teeth before preparation.
Male ; Female ; Humans ; Bite Force ; Tooth ; Mandible ; Molar ; Occlusal Adjustment

The S3 level clinical practice guideline for the treatment of stage Ⅳperiodontitis, developed by the European Federation of Periodontology, was published in April 22, 2022 (DOI: 10.1111/jcpe.13639). According to the severity and complexity, stage Ⅳ periodontitis was grouped into four case types, and comprehensive treatment plans were formulated correspondingly in the guideline, including tooth splinting, occlusal adjustment, orthodontic therapy, restorative therapy, and personalized supportive periodontal care as well. The aim of present work is to intensively interpret the key points of the guideline and help the clinicians to understand this guideline better, in order to improve the treatment level of stage Ⅳ periodontitis in China.
Humans ; Periodontitis/therapy* ; Periodontics ; Tooth ; Occlusal Adjustment ; China

PURPOSE: The purpose of this in vitro study was to evaluate the effect of surface grinding and polishing procedures using high speed zirconia diamond burs with different grit sizes on the phase transformation and flexural strength of zirconia.
Dental Instruments ; Diamond ; In Vitro Techniques ; Occlusal Adjustment

This case report describes a technique in which endodontic treatment and permanent indirect restoration were completed in the same clinical appointment with the aid of a computer-aided design/computer-aided manufacturing (CAD/CAM) system. Two patients were diagnosed with irreversible pulpitis of the mandibular first molar. After access preparation, root canals were located, irrigation was performed until bleeding ceased, and the coronal tooth structure was prepared for indirect restoration. Then, utilizing an interim 3-mm build-up of the endodontic access cavity, a hemi-arch digital scan was performed with an intraoral scanner. Subsequent to digital scanning, restoration design was performed simultaneously with the endodontic procedure. The root canals were shaped using the Race system under irrigation with 2.5% sodium hypochlorite followed by root canal filling. The pulp chamber was subsequently filled with a 3-mm-thick composite resin restoration mimicking the interim build-up previously utilized to facilitate block milling in the CAD/CAM system. Clinical try-in of the permanent onlay restoration was followed by acid etching, application of a 5th generation adhesive, and cementation of the indirect restoration. Once the restoration was cemented, rubber dam isolation was removed, followed by occlusal adjustment and polishing. After 2 years of follow-up, the restorations were esthetically and functionally satisfactory, without complications.
Adhesives ; Cementation ; Computer-Aided Design ; Continental Population Groups ; Dental Pulp Cavity ; Endodontics ; Follow-Up Studies ; Hemorrhage ; Humans ; Inlays ; Molar ; Occlusal Adjustment ; Pulpitis ; Rubber Dams ; Sodium Hypochlorite ; Tooth

PURPOSE: The aim of this study was to evaluate the effect of occlusal adjustments on the surface roughness of yttria-tetragonal zirconia polycrystal (Y-TZP) and wear of opposing artificial enamel.
Dental Enamel ; Dental Porcelain ; Mastication ; Occlusal Adjustment

This article describes cases of applying non-surgical treatment including scaling and root planing, occlusal adjustment and tooth splinting of periodontally compromised lower anterior incisors Clinical and radiographic evaluations were performed over a 1–3-year period. All clinical parameters and radiographic bone levels improved in both cases. Dramatic regeneration of alveolar bone and lamina dura were observed on radiographic images, and no specific complications occurred during the follow-up period. Within the limitations of this study, these cases demonstrated the possibility of tooth rescue through non-surgical treatment and splinting of periodontally compromised teeth typically considered for extraction.
Bone Regeneration ; Dental Occlusion, Traumatic ; Follow-Up Studies ; Incisor ; Occlusal Adjustment ; Periodontal Splints ; Regeneration ; Root Planing ; Splints ; Tooth

PURPOSE: The purpose of this study was to evaluate the deformation of the complete denture artificial teeth arrangement after festooning over time. MATERIALS AND METHODS: 10 wax dentures of equal teeth arrangement and equal gingival contour were used in this study. Festooning of the wax dentures were conducted and 3D model scans were conducted every 10 minutes for 120 minutes. Interdental transverse distances were measured with the scanned images. Statistical analyses were performed with SPSS Ver. 22. 0. RESULTS: Interdental transverse distance between teeth varied from 0.0999 mm to 0.1787 mm. Mean rate of deformation showed statistically significant change between the 40 – 50 minute interval and 50 – 60 minute interval and between the 50 – 60 minute interval and 60 – 70 minute interval. No statistically significant change of the mean rate of deformation was observed later on. CONCLUSION: Monitoring of the interdental transverse distance for 120 minute after festooning have shown the deformation and displacment of the artificial teeth arrangement. From after the 60 – 70 minute interval after festooning, the mean deformation showed no statistically significant change of the mean rate of deformation was observed. Within the limitations of this in vitro study results suggest that the final occlusal adjustment in wax denture before complete denture curing should be proceeded at least 60 minutes later after festooning.
Denture, Complete ; Dentures ; In Vitro Techniques ; Occlusal Adjustment ; Tooth ; Tooth Movement ; Tooth, Artificial

PURPOSE: The purpose of this study was to evaluate and compare three polishing systems on the surface roughness and phase transformation of monolithic zirconia. MATERIALS AND METHODS: 100 disk shaped specimens (10 mm diameter, 3 mm thickness) were fabricated from monolithic zirconia blocks. 20 specimens were left as a control group and remaining specimens were grinded by diamond bur to simulate the occlusal adjustments. Grinded specimens were randomly divided into 4 groups: group G (no polishing), group M (Meisinger, zirconia polishing kit), group E (EVE Diacera, zirconia polishing kit), and group P (EVE Diapol, porcelain polishing kit). Surface roughness was measured with profilometer and surface topography was observed with SEM. XRD analysis was performed to investigate the phase transformation. Statistical analysis was performed with one-way ANOVA and Tukey's post hoc tests at a significance level of P=.05. RESULTS: All polishing groups showed a smoother surface than group G. Among 3 polishing systems, group M and group E exhibited a smoother surface than the group P. However, no significant differences were observed between group M and group E (P>.05). Grinding and polishing did not cause phase transformations in zirconia specimens. CONCLUSION: Zirconia polishing systems created a smoother surface on zirconia than the porcelain polishing system. Phase transformation did not occur during the polishing procedure.
Dental Instruments ; Dental Porcelain ; Occlusal Adjustment

PURPOSE: Fractures, occlusal adjustments, or marginal corrections after removing excess composite cements result in rough surfaces of all-ceramic FPDs. These have to be polished to prevent damage of the surrounding tissues. The aim of this study was to evaluate the roughness of zirconia, silicate-ceramic, and composite after polish with different systems for intraoral use. MATERIALS AND METHODS: Each set of 50 plates was made of zirconia, silicate-ceramic, and composite. All plates were ground automatically and were divided into 15 groups according to the treatment. Groups Zgrit, Sgrit, and Cgrit received no further treatment. Groups Zlab and Slab received glaze-baking, and group Clab was polished with a polishing device. In the experimental groups Zv, Sv, Cv, Zk, Sk, Ck, Zb, Sb, and Cb, the specimens were polished with ceramic-polishing systems “v”, “k”, and “b” for intraoral use. Roughness was measured using profilometry. Statistical analysis was performed with ANOVA and Scheffé-procedure with the level of significance set at P=.05. RESULTS: All systems reduced the roughness of zirconia, but the differences from the controls Zgrit and Zlab were not statistically significant (P>.907). Roughness of silicate ceramic was reduced only in group Sv, but it did not differ significantly from both controls (P>.580). Groups Cv, Ck, and Cb had a significantly rougher surface than that of group Clab (P < .003). CONCLUSION: Ceramic materials can be polished with the tested systems. Polishing of interface areas between ceramic and composite material should be performed with polishing systems for zirconia first, followed by systems for veneering materials and for composite materials.
Ceramics ; Occlusal Adjustment ; Silicates