-
Journal of Advanced Pharmaceutical... Nov 2022Occlusal analysis is important to analyze any disharmony in occlusion. Atraumatic dental occlusion leads to evolution of T-scan. T-scan gives a valuable procedure for...
Occlusal analysis is important to analyze any disharmony in occlusion. Atraumatic dental occlusion leads to evolution of T-scan. T-scan gives a valuable procedure for clinical assessment and perception of occlusal problems. T-scan can also be used in periodontitis patients for checking the occlusal pattern. Occlusal problems and periodontal disease relationship remains controversial. Further research is needed to determine whether occlusal adjustment is necessary for periodontal treatment. The main aim of the study was to assess the occlusal pattern using T-scan in periodontitis patients. Thirty periodontitis subjects were taken and checked for occlusion using T-scan. The subject's age group was 35-55 years. The study included 15 males and 15 females. Plaque index, gingival index, attachment loss, probing depth, centric occlusion (CO), protrusion, right lateral, and left lateral were the parameters studied. Occlusal adjustments were needed to decrease and dissipate the abnormal occlusal forces. The significance of statistical tests for various movements are as follows: CO (right and left) ( = 0.077) > 0.05; protrusion (right and left) ( = 0.09) > 0.05; left side lateral (right side and left side) ( = 0.01) < 0.05; right lateral (right side and left side) ( = 0.00) < 0.05. CO and protrusion (right, left) for males and females are not significant. Left lateral and right lateral (right, left) for males and females were significant. The T-scan manages adequate specificity and sensitivity. Hence, these act as a distinctive tool for diagnosis and better unreliable when used intraorally. The T-scan method is definitely a valuable tool for examining and evaluating the occlusal contacts during maximal intercuspation.
PubMed: 36643123
DOI: 10.4103/japtr.japtr_225_22 -
Zhonghua Kou Qiang Yi Xue Za Zhi =... Jan 2023To 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...
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. 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 -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 -test. 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 (<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 (=3.95, =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 (=0.84, =0.036), respectively. 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.
Topics: Male; Female; Humans; Bite Force; Tooth; Mandible; Molar; Occlusal Adjustment
PubMed: 36642452
DOI: 10.3760/cma.j.cn112144-20220507-00243 -
British Dental Journal Jan 2023A palatogingival groove of the maxillary lateral incisor is an anatomic malformation, which always predisposes the tooth to pulpal and periodontal disease. The diagnosis...
A palatogingival groove of the maxillary lateral incisor is an anatomic malformation, which always predisposes the tooth to pulpal and periodontal disease. The diagnosis and treatment planning become complicated, with uncertain prognosis. Herein, we present an effective interdisciplinary management of a case of combined periodontal-endodontic lesions caused by palatogingival grooves. A series of treatment modalities were undertaken to preserve the two teeth, including root canal treatment, periodontal initial therapy, splinting the mobile teeth, occlusal adjustment, apical microsurgery, grinding and sealing grooves, and guided tissue regeneration. An apparent healing of the lesions was visible after 12 months. Therefore, interdisciplinary management of combined periodontal-endodontic lesions with palatogingival grooves of the maxillary lateral incisors is necessary for a favourable long-term outcome.
Topics: Humans; Incisor; Periodontal Diseases; Root Canal Therapy; Dental Pulp Necrosis; Dental Pulp; Tooth Root
PubMed: 36639473
DOI: 10.1038/s41415-022-5370-8 -
Zhonghua Kou Qiang Yi Xue Za Zhi =... Dec 2022The S3 level clinical practice guideline for the treatment of stage Ⅳperiodontitis, developed by the European Federation of Periodontology, was published in April 22,...
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.
Topics: Humans; Periodontitis; Periodontics; Tooth; Occlusal Adjustment; China
PubMed: 36509518
DOI: 10.3760/cma.j.cn112144-20220803-00437 -
The International Journal of... Feb 2024To evaluate the accuracy of intraoral scanners by comparing the marginal fit of 70 all-ceramic crowns fabricated from both conventional impressions and intraoral scans. (Randomized Controlled Trial)
Randomized Controlled Trial
PURPOSE
To evaluate the accuracy of intraoral scanners by comparing the marginal fit of 70 all-ceramic crowns fabricated from both conventional impressions and intraoral scans.
MATERIALS AND METHODS
A total of 70 posterior teeth requiring single-crown restorations randomly underwent either intraoral scanning or conventional impression-taking, followed by laboratory scanning of the casts in a parallel-group randomized controlled trial (RCT). Subsequently, 70 monolithic all-ceramic crowns were CAD/CAM fabricated; only the impression technique differed. The marginal fit, internal fit, adjustment time required for insertion and occlusal contacts, and visual analog scale (VAS) scores assessing dentists' satisfaction with the crowns were clinically evaluated by a calibrated examiner who was blinded to the groups. Data were analyzed using independent samples t test and likelihood-ratio test or Fisher exact test. All tests were performed with α = .05.
RESULTS
The mean marginal fit with intraoral scanning (57.94 Å} 22.51 μm) was better than with diagnostic cast scanning (82.98 Å} 21.72 μm). The difference was statistically significant (P = .000). The differences in internal fit, adjustment time for crown insertion and occlusal contacts, and VAS scores were also significant, and the secondary outcomes were in favor of intraoral scanning.
CONCLUSIONS
Within the limitations of this clinical trial, CAD/CAM-fabricated single-tooth restorations in the posterior region produced with an intraoral scanning technique using TRIOS were found to be a more accurate, efficient alternative to restorations based on conventional impressions in combination with the laboratory scanning technique.
Topics: Humans; Dental Porcelain; Dental Impression Materials; Dental Impression Technique; Dental Prosthesis Design; Dental Marginal Adaptation; Crowns; Computer-Aided Design
PubMed: 36484666
DOI: 10.11607/ijp.8143 -
Annals of African Medicine 2022The orientation of the occlusal plane forms the basis for the arrangement of teeth conducive to satisfactory esthetics and function, making it one of the most important...
INTRODUCTION
The orientation of the occlusal plane forms the basis for the arrangement of teeth conducive to satisfactory esthetics and function, making it one of the most important clinical procedures in prosthodontic rehabilitation. This study aimed to analyze and compare the vertical distance between the anterior attachment of lingual frenum (AALF) and the incisal edge of mandibular central incisors among three races in Malaysia.
MATERIALS AND METHODS
The sample consisted of 63 dentate subjects (21 Malays, 21 Chinese, and 21 Indians) who were chosen based on the inclusion criteria. Two models were made using irreversible hydrocolloid impressions, and an average of the value was obtained. Lingual frenum was recorded in function. Casts were fabricated with dental stone. AALF was marked and the vertical distance was measured using a caliper.
RESULTS
In Malays, the mean and standard deviation of the vertical distance were 14.2 ± 0.9 mm, with a range of 12.3-16.0 mm; in Chinese were 14.4 ± 0.9 mm, with a range of 12.0-16.9 mm; and in Indians were 15.1 ± 1.0 mm, with a range of 13.0-17.2 mm. The difference among the three races regarding the distance between AALF and the incisal edge of mandibular central incisors was statistically significant (P < 0.05). Among the three races, Malays and Indians have the greatest mean difference.
CONCLUSION
According to the results of the current study, the distance between AALF and the incisal edge of mandibular central incisors might be a proper criterion for the initial adjustment of occlusal rims. The values obtained from three different races were significantly different from one another, hence a different range of values was used to establish occlusal height for different races.
Topics: Humans; Dental Occlusion; Mandible; Incisor; Malaysia
PubMed: 36412348
DOI: 10.4103/aam.aam_174_21 -
Journal of Dentistry Jan 2023To investigate the impact of the occlusal contact situation and occlusal adjustment on wear, roughness, and fracture force of molar crowns.
OBJECTIVES
To investigate the impact of the occlusal contact situation and occlusal adjustment on wear, roughness, and fracture force of molar crowns.
MATERIALS AND METHODS
CAD/CAM crowns (lower right first molar, n = 64; 4 groups à 8, 3Y-TZP zirconia and resin composite) and corresponding antagonists (upper right first molar; 3Y-TZP zirconia) were manufactured. Crowns were constructed according to two principles of occlusion (group "T": Peter K. Thomas' "point-centric" cusp-to-fossa tripodization concept, with 15 contact points; group "RA" Sigurd P. Ramfjord and Major M. Ash, "freedom in centric" concept with four contacts). On one half of the crowns, occlusal adjustment was performed (groups "T adjusted" and "RA adjusted"). All crowns underwent combined thermal cycling (TC) and mechanical loading (ML) (ML: 1.2 × 10 cycles, 50 N, 2 Hz, mouth opening 1 mm; TC: 2 × 3000 cycles, 5/55°C). Wear area and depth of each contact point on the occlusal surfaces of crowns and antagonists were determined using a digital microscope. Surface roughness (R, R) was measured in and besides (reference) the worn area (3D laser-scanning microscope). Fracture force of the crowns was determined (statistics: Levene-test, one-way-ANOVA; Bonferroni-post-hoc-test; between-subjects effects, Pearson correlation, α=0.05).
RESULTS
The resin composite crowns yielded significantly higher mean values for wear area and depth (p < 0.001) and lower fracture forces (p < 0.001). Resin composite surfaces showed increased roughness after TCML while zirconia exhibited smoothened surfaces. The occlusal design significantly impacted wear depth (p = 0.012) and fracture force (p < 0.001). Resin composite crowns with fewer contact points (group RA) showed more wear and lower fracture force. Adjusted resin composite crowns showed increased wear areas and depths (p = 0.009-0.013). For zirconia crowns, the adjustment impacted wear area (p = 0.013), wear depth (p = 0.008), and fracture force (p = 0.006), with adjusted zirconia crowns exhibiting more wear and lower maximum forces until fracture. Zirconia wear depth was also impacted by the occlusal design (p = 0.012). Antagonistic wear was influenced by the restorative material, the occlusal contact pattern, and the adjustment.
CONCLUSIONS
The investigated materials show strongly varying performances with zirconia being significantly influenced by the adjustment, while for resin composites, contact design and adjustment had a major impact.
CLINICAL RELEVANCE
The results show the necessity of adapting occlusal design and adjustment in order to improve roughness, wear, and stability of zirconia and resin composite crowns.
Topics: Humans; Dental Porcelain; Occlusal Adjustment; Materials Testing; Crowns; Zirconium; Composite Resins; Computer-Aided Design
PubMed: 36403693
DOI: 10.1016/j.jdent.2022.104364 -
Journal of Dentistry Jan 2023This prospective crossover clinical trial aimed to compare the complete-digital and -analog workflows in terms of occlusal adjustment of 3-unit tooth-supported fixed... (Clinical Trial)
Clinical Trial
AIM
This prospective crossover clinical trial aimed to compare the complete-digital and -analog workflows in terms of occlusal adjustment of 3-unit tooth-supported fixed dental prostheses, operator, and patient preferences.
MATERIALS AND METHOD
This study included twelve patients receiving fourteen 3-unit posterior FDPs. 2 FDPs were made for each restoration site: one fabricated in complete-digital workflow comprising intraoral scan with static bite registration (Trios 3) and a monolithic zirconia FDP (test); the other fabricated in complete-analog workflow comprising conventional impression/face-bow transfer and a porcelain-fused-to-metal FDP (control). The FDPs (n=28) were intraorally/provisionally fixed, and quadrant-like intraoral scans were taken for every FDP before & after their occlusal adjustments. Pre- and post-adjustment scans of each FDP were then superimposed using best-fit alignment (GOM Inspect) to measure the volumetric occlusal adjustment amount (mm) (3Matic) (Mann Whitney U, α=0.05). The patient and operator experience for digital and analog workflows were evaluated using visual analog scales (Wilcoxon test, α=0.05).
RESULTS
Mean occlusal adjustments were 7.63 mm [±7.02] and 25.95 mm [±39.61] for test and control groups, respectively. The volumetric adjustment difference was clinically noticeable but not significant (P=0.12). The impression and digital workflow adjustment were perceived more favorably by both operator (P=0.003, P=0.046, respectively) and the patients (P=0.003, P=0.002, respectively).
CONCLUSIONS
Within the limitations of this clinical study, the complete digital workflow with digital static bite-registration provided high occlusal accuracy for short-span tooth-supported FDPs. In addition, the patient and operator preferences significantly favored the digital workflow.
CLINICAL SIGNIFICANCE
Complete-digital workflow employing intraoral scanning and model-free fabrication of monolithic-Zr short-span tooth-supported FDPs offers an effective treatment modality with sufficient occlusal accuracy. Therefore complete-digital workflow is a valid alternative for complete-analog workflow comprising conventional impression, face-bow transfer, and use of a semi-adjustable articulator.
Topics: Humans; Computer-Aided Design; Dental Prosthesis Design; Occlusal Adjustment; Prospective Studies; Workflow; Zirconium; Cross-Over Studies
PubMed: 36403691
DOI: 10.1016/j.jdent.2022.104365 -
International Journal of Environmental... Oct 2022In obstructive sleep apnoea (OSA), treatment with mandibular advancement devices (MADs) reduces patients' Apnoea-Hypopnoea index (AHI) scores and improves their...
BACKGROUND
In obstructive sleep apnoea (OSA), treatment with mandibular advancement devices (MADs) reduces patients' Apnoea-Hypopnoea index (AHI) scores and improves their sleepiness and quality of life. MADs are non-invasive alternatives for patients who cannot tolerate traditional continuous positive airway pressure (CPAP) therapy. The variability of responses to these devices makes it necessary to search for predictors of success. The aim of our study was to evaluate the presence of mandibular torus as a predictor of MAD efficacy in OSA and to identify other potential cephalometric factors that could influence the response to treatment.
METHODS
This was a retrospective cohort study. The study included 103 patients diagnosed of OSA who met the criteria for initiation of treatment with MAD. Structural variables were collected (cephalometric and the presence or absence of mandibular torus). Statistical analysis was performed to evaluate the existence of predictive factors for the efficacy of MADs.
RESULTS
A total of 103 patients who were consecutively referred for treatment with MAD were included (89.3% men); the mean age of the participants was 46.3 years, and the mean AHI before MAD was 31.4 (SD 16.2) and post- MAD 11.3 (SD 9.2). Thirty-three percent of patients had mandibular torus. Torus was associated with a better response (odds ratio (OR) = 2.854 ( = 0.035)) after adjustment for sex, age, body mass index (BMI; kg/m), the angle formed by the occlusal plane to the sella-nasion plane (OCC plane to SN), overinjection, and smoking. No cephalometric predictors of efficacy were found that were predictive of MAD treatment success.
CONCLUSIONS
The presence of a mandibular torus practically triples the probability of MAD success. This is the simplest examination with the greatest benefits in terms of the efficacy of MAD treatment for OSA.
Topics: Male; Humans; Middle Aged; Female; Mandibular Advancement; Occlusal Splints; Quality of Life; Retrospective Studies; Sleep Apnea, Obstructive; Treatment Outcome
PubMed: 36361031
DOI: 10.3390/ijerph192114154 -
Clinical Oral Investigations Mar 2023The purpose of this self-controlled clinical study was to evaluate the trueness of occlusal contacts of chairside CAD/CAM crowns fabricated using different ceramic...
OBJECTIVES
The purpose of this self-controlled clinical study was to evaluate the trueness of occlusal contacts of chairside CAD/CAM crowns fabricated using different ceramic materials.
MATERIALS AND METHODS
Ten volunteers (8 females, 2 males, average aged 20-30) were recruited in this study registered in the Clinical Trials Registry (#NCT05346744). After tooth preparation on tooth 36 or 46, an optical scan unit (CEREC Omnicam, Sirona Dental Systems, Germany) was utilized to perform the intraoral scanning. For each volunteer, 6 crowns were fabricated via the chairside CAD/CAM process (CEREC, Sirona Dental Systems, Germany) using the following materials: InCoris TZI (ZIR), Celtra Duo (CD), e.max CAD (EMA), UP.CAD (UP), Enamic (ENA) and Hyramic (HY). The microhardness of the milled surfaces was measured through a Vickers hardness Tester (HVS-50Z, Trojan, China). Together with the amount of occlusal adjustment, the occlusal contact trueness at both milling and postprocessing stages were quantitatively analyzed by using a high-precision scanner (ATOS, GOM Technologies, USA) and a reverse engineering software (Geomagic Control, 3D Systems, Rock Hill, SC). The times of chairside occlusal adjustment were also recorded. Data were analyzed by one-way analysis of variance (ANOVA) and ANOVA with randomized block design followed by Bonferroni test (p = 0.05).
RESULTS
Significant differences were found in surface microhardness of the materials tested (CD > EMA ~ UP > ENA > HY > ZIR, p < 0.05). Regarding the occlusal contact trueness at milling stage, ZIR showed the lowest (p < 0.05), while no significant difference was found among others (p > 0.05). At postprocessing stage, except for ENA, the occlusal contact trueness of ZIR was significantly lower than that of others (p < 0.05). As for occlusal adjustment amount, ZIR was lower than CD and ENA (p < 0.05). In addition, ENA, HY and ZIR required fewer times of occlusal adjustment than EMA, UP and CD.
CONCLUSIONS
The type of chairside CAD/CAM ceramic materials affected the occlusal contact trueness throughout the process of manufacturing and the amount of clinical occlusal adjustment as well. Zirconia exhibited the worst occlusal contact trueness at both milling and postprocessing stages, while the amount of occlusal adjustment was the least, which recommended the least occlusal compensation.
CLINICAL RELEVANCE
For better trueness, different negative occlusal offsets are suggested to be applied in the design process, so as to suit the material of the restoration.
Topics: Humans; Dental Prosthesis Design; Ceramics; Crowns; Computer-Aided Design; Occlusal Adjustment; Software; Dental Porcelain
PubMed: 36333533
DOI: 10.1007/s00784-022-04764-8