Anterior Guidance Research Articles

Can deep learning-designed anterior tooth-borne crown fulfill morphologic, aesthetic, and functional criteria in clinical practice?

ObjectivesThis study aimed to compare the design outcomes of anterior crowns generated using deep learning (DL)-based software with those fabricated by a technician using conventional dental computer-assisted design (CAD) software without DL support, with a focus on the evaluation of crown morphology, function, and aesthetics. MethodsTwenty-five in vivo datasets comprising maxillary and mandibular arch scans of prepared maxillary central incisors were utilized to design anterior crowns by using three methods: 1) a DL-based method resulting in as-generated outcome (DB), 2) a DL-based method further optimized by a technician (DM), and 3) a conventional CAD-based method (NC, control). Evaluations were conducted for crown morphology (total discrepancy volume (TDV), root mean square (RMS), positive average (PA) and negative average (NA) deviations), functional aspects (incisal path: deviations, length, and mean inclination), and aesthetics (crown width, height, width-to-height ratio, angular radius of mesioincisal line angle, proximal contact length, and tooth axis angle). ResultsSignificant differences in TDV ratio were noted between the DB–NC (32.3 ± 8.5 %) and DM–NC (26.5 ± 5.4 %) pairs (P = 0.006). No significant differences were observed in TDV between the DB–NC (65.3 ± 24.4 mm3) and DM–NC (54.3 ± 21.0 mm3) pairs (P = 0.095). For the entire palatal surface, significant differences in RMS and PA values were observed between the DB–NC and DM–NC pairs (P < 0.037). Significant differences in RMS values for the incisal half (P = 0.021) and in PA values for the cervical half (P = 0.047) of the palatal surface were also noted between these pairs. Significant differences in the deviation of the incisal path were observed between the DB–NC (290.4 ± 212.4 μm) and DM–NC (132.0 ± 122.3 μm) pairs (P < 0.001). However, no significant differences were found among the groups (DB, DM, and NC) in terms of the length and mean inclination of incisal paths or in aesthetic outcomes. ConclusionsA DL-based method can result in promising outcomes with clinically acceptable morphology and aesthetics for anterior crowns. Minor deviations in incisal path of the crowns may lead to anterior guidance discrepancies, which can be corrected by the dental technician at the design stage. Clinical significanceWith the potential of DL-based design methods in dental applications, integrating AI technology into dental CAD workflow can enhance the clinical efficiency and consistency of anterior crown design, although human intervention may be required to refine functional aspect.

A fully digital workflow to design anterior guidance for an implant-supported single crown using a modified patient-specific motion technique

Current methods for designing anterior guidance of anterior fixed prostheses are either complicated or lack accuracy. The article describes a fully digital workflow to design individualized anterior guidance of an implant-supported single crown by using a modified patient-specific motion technique. The technique aims to optimize the digital occlusal design workflow, thereby improving the occlusal fit and long-term stability of anterior fixed prostheses.

A case report of occlusal reconstruction for a generalized severe chronic periodontal disease with recovery anterior guidance by strategic anterior teeth extractions and implant prosthetics

A case report of occlusal reconstruction for a generalized severe chronic periodontal disease with recovery anterior guidance by strategic anterior teeth extractions and implant prosthetics

Is dynamic occlusal design necessary for anterior guidance recovery in the computer-aided design process? An in vitro study

ObjectivesThis study aimed to assess the effectiveness of patient-specific motion in restoring anterior guidance and to investigate the influence of occlusal plane position within a virtual articulator on the design of the anterior guide slope for incisors. MethodsTwenty participants' intraoral scan, occlusal plane position, and jaw motion data were recorded. The maxillary anterior teeth were virtually prepared, and the crowns were designed based on average virtual articulator (AVR), personalized virtual articulator (ART), and patient-specific motion (PSM). The anterior guide slope of maxillary central incisors (S1, S2, Sc, Sp) and the mesio-distal angle (MDA) of the canine of prostheses were compared to that of natural teeth (NAT). One-Way ANOVA was utilized to evaluate the effectiveness of the three methods in restoring the anterior guidance of maxillary anterior teeth. ResultsThe comparison of Sp and MDA showed no significant difference between the PSM and NAT groups (p > 0.05). However, Sp of the ART group was significantly smaller, while MDA was higher than that of the NAT group (p < 0.05). Sp did not differ significantly (p > 0.05) when the angle of the occlusal plane (AOP) was small. As the AOP increased, Sp of the ART and AVR groups were significantly smaller than that of the NAT group (p < 0.05). With a large AOP, Sp of the ART group was notably smaller than that of the NAT group (p < 0.05), while there was no significant difference between the AVR and NAT groups (p > 0.05). ConclusionsOcclusal design based on patient-specific motion proved more effective in restoring natural anterior guidance. The anterior guidance of prostheses designed using a virtual articulator was influenced by occlusal plane position. Clinical SignificanceThe utilization of a jaw motion tracer facilitated the transfer of personalized occlusal plane positions and recorded jaw motion, which can be integrated into the digital prosthetic workflow for virtual occlusion adjustment. Occlusal design based on patient-specific motion more effectively restored lingual guidance of maxillary anterior crowns.

Uncommon Restoration on Nonvital Premolar with Porcelain Inlay: A Case Report with Five-year Follow-up

Introduction: In fixed prosthodontics, the old paradigm on endodontically treated teeth leads to more fragilization due to the architectural preparation needed for a full coverage crown. Endodontically treated premolars with class II defects are common in daily practice. When only one proximal surface is affected, direct adhesive restorations are the most used. The use of porcelain inlay is quite uncommon in this situation despite its advantages. Case Presentation: This article illustrates a clinical case of a 31-year-old female with healthy teeth except for the non-vital first maxillary premolar, presenting a class II mesio-occlusal cavity. The occlusion exam revealed functional anterior guidance and canine guidance on both sides during lateral mandibular translation. Based on mini-invasive dentistry principles, the decision was to restore the nonvital bicuspid with a porcelain inlay. Although scientific literature did not report restoration of the premolars with a ceramic inlay in clinical practice, this option was retained. The realization of a porcelain inlay was described step by step. A follow-up up to 5 years was done. Results: The iatrogenic tooth fragilization was avoided by a mini-invasive approach. At the end of this follow-up period, there was no complication or complaint. The patient was satisfied with the final result. Conclusion: Porcelain inlay seems to be a good option to restore the occluso-proximal cavity on nonvital premolars in a context of a favourable occlusion. Porcelain inlay is respectful of the principles of minimally invasive dentistry and allows to achieve the objectives of function, aesthetics and biocompatibility. However, clinical studies should be conducted to investigate the longevity of porcelain inlay on ETPs.

A Comparison of Occlusal Schemes with Condylar Inclination and Anterior Guidance in Dentate Individuals.

To compare occlusal schemes with condylar inclination and anterior guidance in dentate individuals. A total of 26 dentate patients of Indian origin between the ages of 18 and 30 with canine-guided occlusion and 26 patients with group function occlusion were included in the study. The School of Articulator Munich (SAM) Axioquick system was used to assess the condylar guidance and eccentric tracings of the patients. For analyses, Student t test was used. For quantitative data, the means and SDs were calculated. For statistical analyses, the probability of type-I error of .05 was considered statistically significant. The mean condylar guidance for canine-guided and group function occlusion was 38.4 ± 12.7 degrees and 30.5 ± 12.5 degrees on the right side, respectively. On the left side it was 36.5 ± 13.0 degrees and 27.5 ± 12.0 degrees for canine-guided and group function occlusion, respectively, with a statistically significant difference (P &#61; .01). The condylar guidance, incisal guidance, Bennett angle, protrusion, left lateral and right lateral movement, and left and right lateral angles were analyzed statistically between the two types of occlusions. The results showed a statistically significant difference between the two groups for all parameters except right condylar guidance. Furthermore, all parameters were higher in the canine-guided occlusion group over group function occlusion. Within the study limitations, it was concluded that the condylar guidance was steeper in canine-guided occlusion than in group function occlusion. The eccentric parameters were steeper in canine-guided occlusion than in group function occlusion. This study showcases that the condylar guidance might not play a major role in determining the occlusal scheme but that the incisal guidance determines the occlusal scheme predominantly in Class 1 occlusion patients.

New anterior guidance induction through spontaneous gap closure after an increase in vertical dimension: a case report

New anterior guidance induction through spontaneous gap closure after an increase in vertical dimension: a case report

Evaluation of mid-buccal gingival recessions and occlusal interferences.

Dental malocclusions may cause disruption in occlusal harmony, and destructive interferences during mandibular functional movements can be seen. Ideal occlusal contacts during dynamic mandibular movements may be crucial for preventing the occurrence of mid-buccal gingival recession (mbGR). While determining mbGR risk factors in young adults, the effect of occlusal interferences on mbGR has not yet been focused on. Based on this gap, this field needs to be clarified with new studies. The aim of this case-control study was to evaluate the relationships between the presence, extent and severity of mbGRs to dental malocclusions, occlusal interferences in anterior (AG) and lateral guidance (LG) and to determine the potential risk indicators in a young population. A total of 149 dental students were comprised and 70 of them presented mbGR(s) and 79 did not (18-25 years, 4553 teeth). Periodontal status was assessed with full mouth bleeding (FMBS) and plaque score (FMPS), probing depth, clinical attachment level, recession depth and keratinised tissue width (KTW) by a periodontist. Malocclusions and occlusal interferences were evaluated by an orthodontist. Logistic regression analyses provided data on the effect of occlusal interferences and the other indicators towards mbGR. The mean of the number of teeth with mbGR(s) per subject was 4.3. The mean of the overall extent of teeth with mbGR(s) was 14.2%. FMBS, decreased KTW, self-reported bruxism, group function occlusion, increased contact number of all teeth and only premolars/molars in AG or LG and Class III malocclusions were significantly associated with the presence of mbGR. Decreased KTW presenting mbGR in the mandible and non-carious cervical lesion adjunct to mbGR significantly increased the odds of the severity of mbGR. Group function occlusion revealed higher mbGRs in premolar/molars than canine guided occlusion. Increase in the occlusal interferences in premolars/molars during lateral and anterior guidance may have an effect on the presence and severity of mbGR. Further studies should be designed to confirm these findings.

Influence of disclusion time reduction on changes in posterior implant prosthesis occlusion and its association with crestal bone loss: A clinical study

Statement of problemA prolonged period of high magnitude occlusal contact can be associated with rapid changes of the occlusal surfaces and, in turn, may lead to overloading of an implant-supported prosthesis. Crestal bone loss may be one of the repercussions of overloading, but the influence of disclusion time (DT) reduction (DTR) is unclear. PurposeThe purpose of this clinical study was to evaluate the role of DTR in preventing the occlusal changes and crestal bone loss at progressive time intervals of 1 week, 3 months, and 6 months in posterior implant-supported prostheses. Material and methodsTwelve participants with posterior implant-supported prostheses and opposing natural teeth were enrolled in the study. Occlusion time (OT) and DT were evaluated with the T-scan Novus (version 9.1). By performing immediate complete anterior guidance development (ICAGD) coronoplasty, prolonged contacts were selectively ground to achieve OT ≤0.2 seconds and DT ≤0.4 seconds in maximum intercuspal position and laterotrusion after cementation and during follow-up visits after 1 week, 3 months, and 6 months. Crestal bone levels were evaluated after cementation and at the 6-month follow-up. Repeated measures ANOVA and Bonferroni post hoc analysis were done for OT and DT. Student paired t test was done for crestal bone level evaluation (α=.05 for all tests). ResultsA significant decrease in OT from 0.59 ±0.24 seconds to 0.21 ±0.06 seconds (P<.001) and in DT from 1.51 ±0.6 seconds to 0.37 ±0.06 seconds (P<.001) were detected in posterior implant-supported occlusion immediately after attaining ICAGD and at the 6-month follow-up period. The mean crestal bone levels at the mesial and distal sides of the implant from day 1 (0.4 ±0.13 mm, 0.36 ±0.20 mm) to 6 months (0.40 ±0.13 mm, 0.37 ±0.19 mm) showed no significant changes (P>.05). ConclusionsMinimal occlusal changes in implant prosthesis and negligible crestal bone loss were observed up to 6 months by achieving DTR according to the ICAGD protocol.

Complete Occlusal Rehabilitation of a Grossly Decayed Natural Dentition Using Multiple Prosthodontic Options

Complete occlusal rehabilitation involves multiple disciplines and specialties of dentistry. Within Prosthodontics it requires meticulous planning of correcting existing occlusal problems and finding new biologically acceptable occlusal parameters which include centric occlusion, occlusal plane, aesthetic position of anterior teeth and vertical dimensions. Very less occlusal rehabilitations will be considered complete if the above parameters are not biocompatible with temporomandibular joint function. This case report of a 43-year-old housewife who presented with a chief complaint of grossly decayed natural teeth is one such case where the above parameters were all corrected. While extra oral parameters were within normal limits, intra oral dental condition was corrected by a series of extraction of teeth, endodontic (intentional and conventional), surgical crown lengthening and multiple prefabricated and cast post cores. The anterior guidance was established and corrected on the temporary restorations which was then transferred to the definitive restoration. Foundation restorations were built using multiple prefabricated fiber posts and custom made cast posts. Final restorations that included single crowns and multiple fixed partial denture were fabricated of metal ceramic. A cast partial denture was also part of the overall occlusal rehabilitation. At subsequent follow up, the patient was extremely satisfied with the outcome of the treatment.

A case report of esthetic and occlusal rehabilitation for restoring anterior guidance with a fixed prosthesis

A case report of esthetic and occlusal rehabilitation for restoring anterior guidance with a fixed prosthesis

Occlusal Analysis in Natural Dentition: Systematic Review.

This study aimed to evaluate the effectiveness of conventional occlusal analysis in contrast with digital occlusal analysis in natural dentition. Occlusal analysis allows the identification of normal and abnormal occlusal contact points that alter the craniomandibular cervical system. We searched for articles with keywords [[dental occlusion]], [[natural dentition]], [[occlusal adjustment]], [[Immediate Complete Anterior Guidance Development]] [[mastication]], [[bite force]], [[premature contact]], [[occlusal balance]] [[articulating paper]]], [[spray]], [[Occlusal contacts]], and [[bite strength]]. They were considered observational , odds ratio and case control studies. We found 189 items. After evaluating the abstracts and full texts of the articles, 10 papers met the inclusion criteria. It was found that occlusal analysis allows the identification of the relationship between poor occlusion and the sensitivity of the teeth due to occlusal trauma, which is also related to temporomandibular joint pain in dynamic occlusion. The contacts of greater strength were observed in nonfunctional cusps, 48%, without ruling out the functional cusps, 24%. Despite being the universal method of occlusal control to date, the use of joint paper, remains subjective compared to the digital occlusal control device. Posture is considered directly related to occlusal trauma and temporomandibular disorders; without proper occlusal analysis, a clear diagnosis of the patient's joint condition cannot be obtained. Digital occlusal analysis is more objective than traditional occlusal analysis.

Digital workflow for a direct restorative procedure using a 4D virtual articulator

The purpose of this case report was to describe a procedure for 4D virtual mounting and how to develope static and dynamic occlusion through diagnostic waxing. A 16-years-old male patient with a recent history of anterior dental trauma presented with the complaint of esthetic and function restoration. The anterior guidance within the occlusal scheme in all anterior restoration should be considered as a relevant aspect as well as esthetics. A fully digital protocol was presented using a virtual articulator through the incorporation of data from 4D optical technology. The restorative therapy was carried out in the following phases: direct digital data collection acquisition, diagnostic waxing on a virtual model, and definitive restoration. The first step was the intraoral scan of both arches before treatment. The static interocclusal record was made in maximal intercuspal position by an Intraoral scanner and the dynamic one by new measuring system “Jaw Motion Analyser Optic System” (JmA (optic System/JMA; Zebris medical, Isny Germany), which aims at a complete digital workflow for the analysis of the occlusal scheme of mutually protected articulation. The 4D concept added a missing link, brought the digital workflow, and introduced patient-specific movements with kinematic digital facebow functionality. Esthetic and function digital waxing was made (Exocad GmbH) and a waxing cast was fabricated by 3D printing in addition a silicone index was produced from it. The direct composite restoration was made intraorally. This study seems to encourage furthermore clinical trials to validate the use of this methodology.

Metal ceramic restorations for full mouth rehabilitation in amelogenesis imperfecta

Amelogenesis imperfecta (AI) is a clinical condition of natural teeth in which enamel fails to mature due to which the patient faces sensitivity, attrition and poor aesthetics. The condition is genetically inherited and requires multidisciplinary treatment planning to achieve effective success. Treatment ranges from individual crowns to fixed partial dentures or implant-supported single crowns and is related to multiple factors like age and condition of remaining natural teeth. The use of metal and ceramic restorations in such cases requires knowledge and understanding of basic material science, which helps to improve the efficiency of the treatment. This article presents a case of a young adult male patient who presented with AI with a chief complaint of poor esthetics. Maxillary and mandibular teeth had undergone attrition with concomitant loss of anterior guidance. The occlusion was successfully established after restoring anterior guidance which was determined by the use of temporary crowns. Porcelain fused to metal restorations was given and the patient was put on a long-term follow-up. The patient was highly satisfied with the outcome of the rehabilitation.

Oral rehabilitation by applying appropriate anterior guidance and increasing the vertical dimension: A case report

Oral rehabilitation by applying appropriate anterior guidance and increasing the vertical dimension: A case report

T-Scan Guided Occlusal Equilibration as an Effective Treatment in the Management of Symptomatic Temporomandibular Disorders

Background: Temporomandibular disorders (TMDs) constitute clinical problems that involve the masticatory muscles, the temporomandibular joints, associated structures, or both. The etiology of TMDs is multifactorial. The association between occlusal interferences and TMD is controversial.. Objectives: This study is designed to evaluate the clinical outcome of T-Scan guided occlusal equilibration in patients suffering from TMD associated with occlusal discrepancies. Materials and Methods: A total of 15 patients clinically diagnosed with TMD based on the Diagnostic Criteria for Temporomandibular Disorders and with positive occlusal interferences were included in the study. The occlusal equilibration was achieved by performing T-Scan guided Immediate Complete Anterior Guidance Development. Results: The obtained data was subjected to statistical analysis using SPSS version 20.0 software. There was a statistically significant reduction in the occlusion time, i.e., from 0.77 ± 0.6 pre-treatment to 0.31 ± 0.2 post-treatment (P = 0.005), and also disclusion time, i.e., from 1.71 ± 1.09 pre-treatment to 0.11 ± 0.03 post-treatment (P = 0.000). There was a statistically significant reduction in the VAS score post-treatment (P = 0.000). Conclusion: T-Scan guided occlusal equilibration in TMD patients has resulted in significant improvement of symptoms. Hence, we emphasize the importance of the identification and correction of occlusal interferences in the management of symptomatic TMDs.

Incidence of Malocclusion among Young Patients with Gingival Recessions-A Cross-Sectional Observational Pilot Study.

Background and Objectives: Dental occlusion and gingival recession have been studied over the past years especially because of the increasing incidence of occlusal interferences in young patients. The purpose of this pilot study is to investigate any association between occlusal dysfunctions and gingival recessions. Data on gingival phenotype and previous orthodontic treatment were also collected to assess any correlation with the presence of gingival recession. Materials and Methods: Forty systemically healthy subjects, without signs of periodontitis and with gingival recessions, were included in the study. The following parameters were determined: location and extent of the gingival recession, gingival phenotype and functional occlusion by means of observing and registering the occlusal contacts in maximum intercuspation position, protrusive and lateral guidance. Results: Premolars were mostly affected in cases of working-side interferences during lateral guidance (71.19% of the affected teeth during left and 75% during right mandibular movements). The chi-squared exact test applied for the analysis of contingency tables revealed statistically significant associations between excursive interferences during lateral guidance and anterior guidance and the presence of gingival recession on the involved group of teeth. Conclusions: The results suggest that most gingival recessions might be associated with working-side interferences, the highest number of gingival recessions being associated with active interferences during lateral guidance.

Restoration of the anterior guide with the fixed prosthesis

The anterior guide is a functional entity, which is part of the set of guidance provided by the dento-dental joints to the mandibular kinematics, essential for the establishment of harmonious occlusal relations. The anterior guide is a key to understanding and reconstructing the occlusion, playing both a role of protecting the posterior teeth and guiding the functional movements of the mandible. Currently, it also represents an “exteroceptive feeler” creating a cone of access to the occlusion in intercuspation. The restoration of functional and protective anterior guidance is therefore essential for the balance of the masticatory system. This rehabilitation can only be achieved by examining and accurately diagnosing the occlusion relationships maintained by the anterior teeth, associated with a reasoned therapeutic approach validated by a test phase. After a brief description of the anterior function and its role, this article aims to detail, through a clinical case, the procedure to follow for the restoration of a functional anterior guide.

Chinese guideline for the diagnosis and treatment of childhood obstructive sleep apnea (2020).

Chinese guideline for the diagnosis and treatment of childhood obstructive sleep apnea (2020).

Full mouth rehabilitation for severely worn dentition using fixed prostheses and tooth-supported partial overdenture: a case report.

Rehabilitation of severely worn dentition represents a significant clinical challenge, especially when the restorative space is not sufficient. Creating restorations that fulfil the aesthetic, occlusal and functional parameters are essential to long-term success. This case report describes a 48-year-old male, who had severely worn dentition, which resulted in collapsed vertical dimension. The initial treatment involved careful planning, stabilization of existing dental diseases and construction of provisional prostheses at increased vertical dimension. Once the compatibility of the new vertical dimension had been confirmed, permanent reconstruction was performed. As with all full mouth prosthetic rehabilitation cases, equal-intensity centric occlusal contacts on all teeth and an anterior guidance in harmony with functional jaw movements were critically taken into account in each treatment phases.