New clinical application of digital intraoral scanning technology in occlusal reconstruction:A case report

BACKGROUND Digital intraoral scanning,although developing rapidly,is rarely used in occlusal reconstruction.To compensate for the technical drawbacks of current occlusal reconstruction techniques,such as time consumption and high technical requirements,digital intraoral scanning can be used in clinics.This report aims to provide a way of selecting the most suitable maxillo-mandibular relationship(MMR)during recovery.CASE SUMMARY A 68-year-old man with severely worn posterior teeth underwent occlusal reconstruction with fixed prosthesis using digital intraoral scanning.A series of digital models in different stages of treatment were obtained,subsequently compared,and selected using digital intraoral scanning together with traditional measurements,such as cone beam computed tomography,joint imaging,and clinical examination.Using digital intraoral scanning,the MMR in different stages of treatment was accurately recorded,which provided feasibility for deciding the best occlusal reconstruction treatment,made the treatment process easier,and improved patient satisfaction.CONCLUSION This case report highlights the clarity,recordability,repeatability,and selectivity of digital intraoral scanning to replicate and transfer the MMR during occlusal reconstruction,expanding new perspectives for its design,fabrication,and postoperative evaluation.

A METHOD ANALYSING PHOTOCCLUSAL IMAGE WITH COMPUTER

Depending on the techniques of pattern recognition and image processing, we established a computer analytic system for photocclusal image. The analysing results made by this system are more accurate and reliable than those by the naked eye and grid for analysing photocclusal image. We analysed photocclusal images for a patient with prematurity of lower first right molar be fore and after occlusal adjustment with the system. The result appeared that occlusal adjustment mainly brought about distributive variation of occlusal stress rather than alteration of absolute value of overall occlusal force.

Efficacy of biofeedback therapy via a mini wireless device on sleep bruxism contrasted with occlusal splint:a pilot study

The putative causes of bruxism are multifactorial and there are no definite measures for bruxism management.The aim of this study was to evaluate the efficacy of biofeedback therapy on sleep bruxism,compared with occlusal splint.Twenty-four volunteers with sleep bruxism were divided into two groups：the GTB group that were treated with biofeedback therapy（n 512） and the GTO group that were treated with occlusal splint（n 512）.A mini pressure sensor integrated with a monitoring circuit by use of a maxillary biofeedback splint was fabricated.To foster the relaxation of the masticatory muscles and the nervous system,the wireless device received signals from bruxism events and vibrations alerted the bruxer when the threshold was exceeded.Total episodes and average duration of bruxism events during8 hours of sleep were analyzed with the monitoring program（TRMY1.0）.After 6 and 12 weeks,the episodes（P 50.001） and duration（P,0.05） in the GTB group declined dramatically.In contrast,there were no significant differences in the GTO group after the treatment（P.0.05）.Furthermore,the episodes had significant differences between the GTB group and the GTO group after the same period of treatment（P 5 0.000）.The results suggest that biofeedback therapy may be an effective and convenient measure for mild bruxers,when compared with occlusal splint therapy.The mini wireless biofeedback method may be of value for the diagnosis and management of bruxism in the future.

Resin infiltration of deproteinised natural occlusal subsurface lesions improves initial quality of fissure sealing

The aim of this ex vivo study was to evaluate the infiltration capability and rate of microleakage of a low-viscous resin infiltrant combined with a flowable composite resin(RI/CR) when used with deproteinised and etched occlusal subsurface lesions(International Caries Detection and Assessment System code 2). This combined treatment procedure was compared with the exclusive use of flowable composite resin(CR) for fissure sealing. Twenty premolars and 20 molars revealing non-cavitated occlusal carious lesions were randomly divided into two groups and were meticulously cleaned and deproteinised using Na OCl(2%). After etching with HCl(15%), 10 premolar and 10 molar lesions were infiltrated(Icon/DMG; rhodamine B isothiocyanate(RITC)-labelled) followed by fissure sealing(G-?nial Flo/GC; experimental group, RI/CR). In the control group(CR), the carious fissures were only sealed. Specimens were cut perpendicular to the occlusal surface and through the area of the highest demineralisation(DIAGNOdent pen, Ka Vo). Using confocal laser-scanning microscopy, the specimens were assessed with regard to the percentage of caries infiltration, marginal adaption and internal integrity. Within the CR group, the carious lesions were not infiltrated. Both premolar(57.9% ± 23.1%) and molar lesions(35.3% ± 22.1%) of the RI/CR group were uniformly infiltrated to a substantial extent, albeit with significant differences(P = 0.034). Moreover, microleakage(n = 1) and the occurrence of voids(n = 2) were reduced in the RI/CR group compared with the CR group(5 and 17 specimens,respectively). The RI/CR approach increases the initial quality of fissure sealing and is recommended for the clinical control of occlusal caries.

Treatment of condylar osteophyte in temporomandibular joint osteoarthritis with muscle balance occlusal splint and long-term follow-up:A case report

BACKGROUND Condylar osteophytes,a remodeling form of temporomandibular joint osteoarthritis(TMJ OA),mainly manifest as marginal angular outgrowths of the condyle.Previous researchers have advocated surgical removal of condylar osteophytes.Reports on the effect of occlusal splint on TMJ OA patients’joints have mostly focused on treatment with this splint,which can reduce the absorption of the affected condyle and promote repair and regeneration.However,the effect of the splint on the dissolution of condylar osteophytes has not yet been reported.CASE SUMMARY A 68-year-old female patient suffered from occlusal discomfort with left facial pain for 2 years.Cone beam computed tomography showed a rare osteophyte on top of her left condyle.She was finally diagnosed with TMJ OA.The patient refused surgical treatment and received conservative treatment with a muscle balance occlusal splint.The pain experienced by the patient on the left side of her face was relieved,and her chewing ability recovered after treatment.The osteophyte dissolved,and the condylar cortex remained stable during long-term follow-up observations.CONCLUSION The muscle balance occlusal splint could be a noninvasive means of treating condylar osteophytes in TMJ OA patients.

The occlusal plane in the facial context:inter-operator repeatability of a new three-dimensional method

The repeatability of a non-invasive digital protocol proposed to evaluate the three-dimensional（3D） position of the occlusal plane in the face is assessed.Dental virtual models and soft tissue facial morphology of 20 adult subjects were digitally integrated using a 3D stereophotogrammetric imaging system.The digital 3D coordinates of facial and dental landmarks were obtained by two different operators.Camper＇s（facial） and occlusal（dental） planes were individuated,and their 3D relationships were measured.The repeatability of the protocol was investigated and showed no significant differences in repeated digitizations.The angle between occlusal and Camper＇s planes was smaller than 26 in the frontal and horizontal projections.In the sagittal projection,the angle was observed to be,on average,4.9 6.The determined occlusal plane pitch,roll and yaw values show good agreement with previously published data obtained by different protocols.The current non-invasive method was repeatable,without inter-operator differences and can facilitate assessment of healthy subjects.

Maxillary denture flange and occlusal discrepancies of Vertex ThermoSens in comparison with conventional heat-cured denture base materials

This study was conducted to investigate the maxillary denture bases and occlusal discrepancies using the Vertex Thermosens in comparison with the conventional polymethyl-methacrylate materials. Twenty maxillary denture bases were prepared from the Vertex ThermoSens and a conventional heat-cured denture base materials. Acrylic maxillary second molars were arranged in their respective positions on the ridge. After curing of both types of denture bases, they were deflasked with their respective master casts. Reference points were prepared for measurements of the antero-posterior and cross-arch dimensions at the denture borders using caliper device. Furthermore, the teeth discrepancies were measured between reference points in the ligual aspect of the second maxillary molars. The recorded data was analyzed using SPSS statistical software version 20. The results showed initial shrinkage of both denture bases in the antero-posterior and cross-arch dimensions immediately after decasting. This contraction was compensated gradually during storage in water up to 2 weeks. Regarding the variable time, there was a significant difference between the tested materials. Moreover, the results revealed occlusal discrepancies and shifting of teeth inward immediately after decasting, followed by outward movement after storage in water for 2 weeks. Regarding the variables time and materials, there were significant differences. Both materials exhibited inward shrinkage in the antero-posterior and cross-arch dimensions immediately after decasting. Both denture bases showed inward shifting of teeth immediately after decasting, followed by outward movement after storage in water up to 2 weeks.

Long-term follow-up of a patient with venlafaxine-induced diurnal bruxism treated with an occlusal splint:A case report

BACKGROUND Bruxism is a jaw-muscle activity characterized by the clenching or grinding of teeth. It can be divided into nocturnal bruxism and diurnal bruxism(DB). DB secondary to antidepressants is rare and refractory. Reports associated with antidepressant-induced DB are mostly anecdotal without long-term follow-up.The effect of drug intervention on antidepressant-induced DB is still contested.We herein report the first case of successful treatment of venlafaxine-induced DB with an occlusal splint.CASE SUMMARY This case report describes detailed 7-year follow-up of a patient with venlafaxineinduced DB treated with an occlusal splint. The patient who complained about involuntary daytime tooth grinding after taking venlafaxine for a period of 4 mo and was diagnosed with venlafaxine-induced DB. Subsequently, an occlusal splint with modified bilateral buccal-pterygoid pads was used to treat his tooth grinding and to protect the dental structures from tooth wearing. The patient reported remission of symptoms after several months of treatment. His grinding activity was gradually and stably controlled after 2 years, with an almost complete recovery from DB after 6 years.CONCLUSION The maxillary buccal-pterygoid splint can be used as a noninvasive approach to treat venlafaxine-induced DB.

Clinical Data-Driven Finite Element Analysis of the Kinetics of Chewing Cycles in Order to Optimize Occlusal Reconstructions Dedicated to Professor Karl Stark Pister for his 95th birthday

The occlusal design plays a decisive role in the fabrication of dental restorations.Dentists and dental technicians depend on mechanical simulations of mandibular movement that are as accurate as possible,in particular,to produce interference-free yet chewing-efficient dental restorations.For this,kinetic data must be available,i.e.,movements and deformations under the influence of forces and stresses.In the present study,so-called functional data were collected from healthy volunteers to provide consistent information for proper kinetics.For the latter purpose,biting and chewing forces,electrical muscle activity and jaw movements were registered synchronously,and individual magnetic resonance tomograms(MRI)were prepared.The acquired data were then added to a large complex finite element model of the complete masticatory system using the functional information obtained and individual anatomical geometries so that the kinetics of the chewing process and teeth grinding could be realistically simulated.This allows developing algorithms that optimize computer-aided manufacturing of dental prostheses close to occlusion.In this way,a failure-free function of the dental prosthesis can be guaranteed and its damage during usage can be reduced or prevented even including endosseous implants.

Influence of occlusal splint thickness on the position of mandible

Objective: To investigate the influence of occlusal splint thickness on mandibular movement. Methods: Stabilization occlusal splints of 3, 5 and 7 mm thickness were respectively used during clenching from light contact in intercuspal position and the movement of condyles and incisor point were recorded in 5 healthy subjects. Results:The condyles moved anteriorly and superiorly without wearing occlusal splint. When wearing the occlusal splints the condyles displaced anteriorly and inferiorly. The distance of displacement increased gradually with raising the thickness of splint, though the significant difference was just found in right condyle in superior- inferior movement. The condyles went again on a path of anterior and superior direction when subjects clenched from the displaced position. In right condyle the displacement was significantly greater at 7 mm splint than that at 3 mm splint both in anterior-posterior and inferior-superior direction, while in left condyle only in anterior-posterior direction. Meanwhile, the incisal point movement was larger at 7 mm splint than at 3 mm splint in inferior-superior direction. In tapping movement there were no significant differences in condyle movement between the different thickness of occlusal splint. However, the coefficient of variation in total cycle time was the greatest when wearing the splint of 7 mm. Conclusion: Occlusal splint of 7 mm has greater effect than that of 3 mm on condyle movement, but no obvious difference with occlusal splint of 5 mm. When occlusal splint of 7 mm is inserted, the stability of condyle might be influenced during tapping movement.

Management of disorder of temporomandibular joint syndrome using elastic resin occlusal pad: a clinical observation

Objective To investigate the possibility of occlusal pad in treating disorder of temporomandibular joint syndrome.Methods We treated 25 patients with disorder of temporomandibular joint syndrome using occlusal pad made of elastic resin,and evaluated the effects.Results Total effective rate was 96%.Clicking and pain dissappeared in all patients.Conclusion Occlusal pad made of elastic resin could be used for treating disorder of temporomandibular joint syndrome in clinic.

The Relation between the Preferred Chewing Side and Occlusal Force Measured by T-Scan III System

Occlusal force has the main role in determining the teeth health in general and determining the chewing, muscle and TMJ function. The objective of this study was to find if there was any relation between the preferred chewing side and the force, measured by T-scan III system. The total number of 90 (46 female and 44 male) dental students was included in this study. They were asked whether their preferred chewing side was right, left or both. Afterwards, the occlusal forces in habitual occlusion, using T-Scan III Electronic device (IP-CO position mode, MA-mode, MA sensitivity setting) were measured. The data were presented as Mean ± SD. Spearman correlation was used to find the correlation between the occlusal force and chewing side. Differences in P 0.05) and the right side (r = 0.143, P > 0.05) according to the preferred chewing side. In this study, the relation between the preferred chewing side and occlusal force was found.

Orthodontic Management of Occlusal Prematurity in Early Mixed Dentition

Premature contact is one of the most well-known occlusion disorders and can interfere mandibular movement remarkably. The masticatory system has ability to respond with the wide range of adaptive modalities. These adaptations can be functional, structural and/or behavioral. Therefore, this system, like any biological system, cannot be viewed as a rigid and immutable. This paper presents a clinical case which is demonstrating orthodontic management of occlusal prematurity in early mixed dentition by using a protrusive arch wire.

Surgical Manipulation of the Occlusal Plane in Class III Deformities: 5 Features to Help Planning

Class III malocclusion is one of the most common deformities that requires correction through orthodontic-surgical treatment. These patients present different facial patterns depending on the occlusal plane angulation. These patients may benefit from surgical manipulation of the occlusal plane, because only bite correction does not always lead to the improvement of the facial deformity. The purpose of this paper is to show the surgical manipulation of the occlusal plane in Class III patients based on five features: 1) facial type, 2) upper incisor display at rest, 3) dental exposure during smile, 4) soft tissue support, and 5) chin projection. The surgical manipulation of the occlusal plane can improve the esthetic outcome in the treatment of class III deformities, and careful evaluation of the five features described could be a helpful planning method.

Proposed score for occlusal-supporting ability

In our previous studies, we developed the normal periodontal ligament index (nPLI) and residual periodontal ligament index (rPLI) to estimate residual periodontal ligament support for individual teeth during treatment planning for partially edentulous patients. To illustrate the applicability of the nPLI and rPLI, an occlusal-supporting ability (OSA) score calculated using these indices for the remaining teeth corresponding to Eichner’s subclasses of partial edentulism was charted by numerically assessing the average occlusal support. This OSA score based on the nPLI and rPLI is proposed as a suitable tool for epidemiologic research on the progression of tooth loss and the survival of prostheses. The Ethics Committee for Epidemiologic Study of Hiroshima University approved the study protocol (No. 331).

About gravity and occlusal forces in the jaws: Review

Mechanical forces resulting from gravitation seem to be essential for structural adaptation and remodeling of skeletal bones. These forces have the capability of delivering powerfully distorting stimuli to skeletal bones in a very short time, several times a day, in a uniform direction. Facial and jaw bones are not subjected to gravity impact forces. These bones need a mechanism of "compensation" for this deficiency. The goal is achieved by a unique mechanism that substitutes for gravity impact forces- the mechanism of occlusal load transmission to the bone via the periodontal apparatus space. In cases of early loss of teeth and loss of periodontal ligament this mechanism will be missing resulting in premature bone aging.

Effects of sleep bruxism on functional and occlusal parameters:a prospective controlled investigation

This study was conducted to verify the results of a preceding retrospective pilot study by means of a prospective controlled investigation including a larger sample size. Therefore, the aim of this clinical investigation was to analyze the relationship between sleep bruxism and several functional and occlusal parameters. The null hypothesis of this study was that there would be no differences among sleep bruxism subjects and non-sleep bruxism controls regarding several functional and occlusal parameters. Fifty-eight sleep bruxism subjects and 31 controls participated in this study. The diagnosis sleep bruxism was based on clinical criteria of the American Academy of Sleep Medicine. Sixteen functional and occlusal parameters were recorded clinically or from dental study casts. Similar to the recently published retrospective pilot study, with a mean slide of 0.77 mm （s.d., 0.69 mm） in the sleep bruxism group and a mean slide of 0.4 mm （s.d., 0.57 mm） in the control group, the evaluation of the mean comparison between the two groups demonstrated a larger slide from centric occlusion to maximum intercuspation in sleep bruxism subjects （Mann-Whitney U-test; P=O.O08）. However, following Bonferroni adjustment, none of the 16 occlusal and functional variables differed significantly between the sleep bruxism subjects and the non-sleep bruxism controls. The present study shows that the occlusal and functional parameters evaluated do not differ between sleep bruxism subjects and non-sleep bruxism subjects. However, as the literature reveals a possible association between bruxism and certain subgroups of temporomandibular disorders, it appears advisable to incorporate the individual adaptive caoacitv of the stomatognathic svstem into future investigations.

Condylar and Occlusal Changes after High Condylectomy and Orthodontic Treatment for Condylar Hyperplasia

Condylar hyperplasia（CH） of human temporomandibular joint（TMJ） often occurs unilaterally, and causes occlusal disturbance and facial asymmetry. The purpose of this study was to compare the effects of high condylectomy with and without postsurgical orthodontic treatment. Forty patients were diagnosed as having active CH and treated with high condylectomy. Patients in group A（n=24） took the postsurgical orthodontic therapy immediately after surgery, and those in group B（n=16） did not take orthodontic therapy. For both groups, the mandibular ramus height on the affected side was decreased significantly after surgery. Orthodontic treatment promoted maxillary alveolar remodeling significantly by depressing alveolar bone of the affected side and increasing alveolar bone of the nonaffected side. Better improvement for facial midline deviations was observed in group A than in group B. In both groups, the condylar remodeling was observed and manifested by the smoothening of condylar surface and returning of condyle to normal position in glenoid fossa. It was concluded that high condylectomy in the treatment of active CH of TMJ improved the functional occlusion and facial aesthetic. Postsurgical orthodontic therapy could more effectively enhance maxillary alveolar and condylar remodeling, and more rapidly and meticulously establish the stable occlusal and normal position of condyle than the spontaneous remodeling.

Comparisons of Condylar Movements with the Functional Occlusal Clutch and Tray Clutch Recording Methods in CADIAX~ system

Aim The purpose of this study is to compare the effects of the two clutches on recording the condylar movement. Methodology Ten subjects （6 women,4 men; mean age 25.4 years） participated in the study. The mandibular move-ment,sagittal condylar inclination angle,and transversal condylar inclination angle of each subject were recorded with the CADIAX？ using the two clutches,respectively. The characteristics of the tracings of the protrusion,opening,and mediotrusion were analyzed with the t-test statistics at α = 0.05 level. The Kappa values were calculated for an assessment of the congruence of the tracings. Results The results showed that the contour,direction,and dimension of the tracings in the two clutches were approxi-mately same,but the tracings determined by the functional occlusal clutch were more regular and congruent. In the group segment recorded with the tray clutch,opening/ closing paths of one subject showed crossed and time curves of three subjects appeared peak-like changes of velocity,but none were statistically different （P0.05）. Conclusion The research suggests that the functional occlusal clutch should be preferred in the evaluation of the mandibular function,as the tracings with the tray clutch are more likely to produce false positive results.

Study on the Effect of Occlusion Rate on the Deformation of Non-Vegetarian Occlusal Piles

In order to investigate the force characteristics of the occlusal pile, this paper takes the underground garage support project of Nanchang Bayi Square as the research background and studies the bending moment of the occlusal pile after the excavation process of the foundation pit through the model test. The test results show that the bending moment of the pile increases and then decreases with the increase of soil depth under horizontal load, and the bending moment reaches the maximum near the excavation surface of the foundation pit;the test results can provide a reference for the design of occluded pile body in practical engineering.