Inclination of the occlusal plane is associated with the direction of the masticatory movement path

Relationships between maxillofacial morphology and oral function on the habitual and non-habitual chewing sides

PURPOSE

This study aimed to investigate the relationships between reference planes and oral functions on the habitual and non-habitual chewing sides.

MATERIALS AND METHODS

Thirty-four subjects with no abnormalities in the maxillofacial region and oral functions were enrolled in this study. Relationships between angles between the reference plane (Frankfort horizontal plane, Camper's plane, and occlusal plane) and masticatory performance, occlusal force, and occlusal contact area by chewing side were examined. Regarding the measurement of reference planes, a creatively modified three-plane measuring device was used to measure angles between the reference planes. Images were taken from the right and left sides and angles between reference planes were measured. Masticatory performance was examined by measuring the amount of glucose extracted from a gummy jelly on the habitual and non-habitual chewing sides separately. Occlusal force and occlusal contact area were measured by occluding against pressure-sensitive film, and values on the habitual and non-habitual chewing sides were calculated and analyzed.

RESULTS

The angle between Camper's plane and the occlusal plane correlated with masticatory performance on both the habitual chewing side (r = 0.47, P < .01) and the non-habitual chewing side (r = 0.36, P < .05). A correlation was observed between masticatory performance and occlusal force on the habitual chewing side (r = 0.46, P < .01).

CONCLUSION

Masticatory performance became higher as occlusal plane inclination increased. This result represents essential knowledge for prosthetic treatment.

3D evaluation of sagittal inclination of the maxillary dentition in relation to facial landmarks: A cohort study

BACKGROUND

The determination of the maxillary occlusal plane presents a significant clinical challenge in the treatment of edentulous patients as well as it is critical for complex full-mouth reconstructions in dentate patients, including those with implant-supported rehabilitations. While the use of a Fox plane plate is standard in edentulous cases, its application in dentate patients lacks thorough documentation in existing literature.

PURPOSE

This clinical study assessed the sagittal position of the maxillary dentition in relation to facial landmarks using a digital three-dimensional analysis and evaluated the suitability and reliability of applying a simulated Fox plane plate, also known as an occlusal plane guide, in dentate patients.

MATERIALS AND METHODS

Eighty-one subjects were recruited at the Department of Prosthetic Dentistry of Goethe University Frankfurt, Germany, according to specific inclusion criteria. Intraoral and facial scans were obtained and analyzed using GOM Inspect Pro software (GOM, Braunschweig, Germany). The angles between the maxillary occlusal plane and three variations each of Camper's plane and ala-tragus line, relating to superior, middle, and inferior tragus points, were measured. These modified planes were then compared to a plane established by a simulated digital Fox plane plate, which was adapted to the maxillary anterior teeth and the lowest point of the posterior teeth in both quadrants.

RESULTS

A total of 81 subjects (58 female and 23 male) with a mean age of 23.9 years were evaluated in this study. No significant angular difference was found between the angles of the maxillary occlusal plane compared with superior Camper's plane, middle Camper's plane, or superior ala-tragus line (p >0.05). The smallest angle occurred between superior Camper's plane and the maxillary occlusal plane on both the right (3.443°) and left (3.535°) sides. The application of a Fox plane plate resulted in two different occlusal planes in 70% of patients, significantly deviating from the digitally determined plane (p <0.05).

CONCLUSION

Superior and middle Camper's planes, along with superior ala-tragus line, can be considered approximately parallel reference planes and are suitable for routine determining of the maxillary occlusal plane in restorative treatments. However, in contrast to digital evaluation methods, the application of a Fox plane plate in dentate patients showed high variability, indicating its low reproducibility due to its ambiguous positioning on the maxillary dentition. Clinical trial registration site: https://drks.de/search/de/trial/DRKS00030166.

Instrumental Occlusal Analysis in Migraine Patients: A Quantitative Cross Sectional Study

OBJECTIVES

This study aimed to investigate possible differences of functional occlusal variables between a group of migraine patients (MG) and a control group (CG).

MATERIALS AND METHODS

Each group included 50 individuals. Instrumental functional analysis and digital occlusal analysis were performed. Variables examined were condylar displacement from a reference position to maximum intercuspation; angular difference between the steepness of the articular eminence and the contra-lateral canine guidance; and angular difference between the steepness of the articular eminence and the ipsilateral central incisor guidance and occlusal plane inclination. Self-reported grinding and occlusal index were also investigated.

RESULTS

There were statistically significant differences in the extent of retral condylar displacement assessed both clinically [MG: 0.49 mm (SD 0.67 mm), CG: 0.29 mm (SD 0.27 mm), p = 0.012] and digital-mechanically [MG: 1.53 mm (SD 0.95 mm), CG: 0.9 mm (SD 0.66 mm), p = 0.001], the angular difference between the steepness of the articular eminence and the contra-lateral canine guidance [MG: 13.11° (SD 8.33°), CG: 9.47° (SD 7.08°), p = 0.021 and MG: 12.94° (SD 8.71°), CG: 9.44° (SD 8.70°), p = 0.017], and the occlusal plane inclination [MG: 11.16° (SD 4.66°), CG: 9.09° (SD 4.37°), p = 0.024]. Self-reported grinding (MG: 39/50, CG: 12/50, p < 0.001) and occlusal index [MG: 1.92 (SD 0.46), CG: 0.21 (SD 0.66), p < 0.001] were also significantly higher in migraineurs.

CONCLUSIONS

Articular and occlusal structures could play a role in migraine and thus should be considered in an interdisciplinary approach.

Morphological comparison of masseter muscle fibers in the mandibular rest and open positions using diffusion tensor imaging

BACKGROUND

The masseter muscle has a complicated multipennate internal structure and exhibits functional differentiation when performing various stomatognathic functions. It is important to understand the internal structural changes of the muscle during functioning to elucidate characteristic muscle disorders such as local myalgia. Diffusion tensor imaging (DTI) may be useful for investigating the internal structural features of muscle.

OBJECTIVES

To evaluate the features of masseter muscle fibers in human participants using DTI fiber tractography, and to elucidate the structural differences in the masseter muscle between the mandibular rest and open positions.

METHODS

Five healthy men (age 31±7 years) underwent DTI and T1-weighted MRI of the right masseter muscle in the mandibular rest and open positions. MR images were used as a reference for muscle layer segmentation (superficial, intermediate, and deep). DTI fiber tractography of the masseter muscle was performed and the orientation of the DTI fibers was analyzed in each layer using coordinates based on the Frankfurt horizontal plane.

RESULTS

The DTI fiber orientation of the deep layer significantly changed between the mandibular rest and open positions in the frontal plane (p<0.05, Wilcoxon rank sum test). However, no significant change was found in the superficial and intermediate layers.

CONCLUSION

DTI fiber tractography confirmed regional differences in the orientation change of the masseter muscle fibers between different mandibular positions. The results may support the existence of functional partitioning inside the masseter muscle and suggest that DTI may be useful for the evaluation of muscle fibers in multipennate muscles.

Comparison of two arbitrary cast transfer systems with a kinematic facebow for mounting a maxillary cast on a semiadjustable articulator

STATEMENT OF PROBLEM

The Kois Dento-Facial Analyzer (KDFA) is used by clinicians to mount maxillary casts and to evaluate and treat patients. Limited information is available for understanding whether the KDFA should be considered as an alternative to an arbitrary facebow.

PURPOSE

The purpose of this clinical study was to evaluate and compare maxillary casts mounted by using the KDFA with casts mounted by using the Panadent Pana-Mount Facebow (PMF) and a kinematic axis (KA) facebow.

MATERIAL AND METHODS

Fifteen participants were enrolled in the study. Three maxillary impressions were made of each study participant. One cast from each study participant was mounted on an articulator by means of the KDFA, PMF, and KA. A standardized photograph of each mounting was made, and the condylar center-incisor distance and the occlusal and incisal plane angles were measured. A randomized complete block design analysis of variance (RCBD) (α=.05) and post hoc tests (Tukey-Kramer HSD) were used to evaluate the occlusal and incisal plane angles and the condylar center-incisor distance.

RESULTS

Compared with the occlusal plane angle (OPA), the KDFA mounted the maxillary cast at an angle that was statistically lower than those of PMF and KA (P<.001). The KDFA and the PMF condylar center-incisor distances were both significantly greater than that of KA (P=.01). No differences were found between the incisal plane angle (IPA) on maxillary casts mounted with the KDFA, KA, or PMF (P=.16).

CONCLUSIONS

The KDFA and PMF mounted the maxillary casts in a position that was farther from the axis when compared with the KA mounted casts. The KDFA resulted in a lower articulator OPA compared with both PMF and KA. No difference was found between the IPAs of the KDFA, PMF, and KA.

Masticatory Function Assessment of Adult Patients With Cleft Lip and Palate After Orthodontic Treatment

OBJECTIVE

To determine whether orthodontically treated patients with cleft lip and palate (CLP) possess a different masticatory function than those of untreated patients with normal occlusion.

DESIGN

Occlusal contact area, occlusal force, as well as masseter and anterior temporal muscular activity were measured during maximum voluntary clenching (MVC) tests. Mandibular left and right lateral movements during mastication were also assessed. To further elucidate the nature of masticatory function, especially to determine the rate of abnormal jaw movement patterns, a parametric error index (EI) was set. Finally, masticatory efficiency was evaluated with a glucose sensitive measuring device.

PARTICIPANTS

Fifteen patients with CLP who had previously completed the orthodontic treatments required to achieve an acceptable and more harmonious occlusion accepted to volunteer in this study along with 21 untreated patients who already possessed a normal occlusion.

RESULTS

Patients with CLP showed a significantly lower occlusal force, reduced occlusal contact area, and decreased masticatory efficiency as well as significantly higher EI value when compared with controls. However, there was no significant difference when analyzing muscle activity, although masticatory efficiency was significantly different between the 2 groups. Despite this result, the scores obtained by the patients with CLP in the masticatory efficiency tests were still in the normal range.

CONCLUSIONS

Orthodontic treatment for adult patients with CLP provides a satisfactory result for the patients' masticatory ability albeit significantly less ideal compared with untreated patients with normal occlusion.

The Occlusal Plane Inclination Analysis for Determining Skeletal Class III Malocclusion Diagnosis

Introduction

The occlusal plane is very important in the stomatognathic and aesthetic dentofacial system. Manipulation of the occlusal plane plays an important role in class III malocclusion correction. For this reason, the strategy in establishing the diagnosis, prognosis and treatment plan becomes more complex, so a more comprehensive analysis of the occlusal plane inclination as a parameter of diagnosis is needed for more effective and efficient treatments.

Aim

The aim of this study was to determine the comparison of occlusal plane inclination between class III and class I malocclusions and to knowing the correlation of occlusal plane inclination in class III malocclusions with the direction of facial growth.

Materials and Methods

Samples were secondary lateral cephalograms collected at the Universitas Airlangga (UNAIR) Dental Hospital in October 2017–2018. Cephalograms were traced using the Orthovision^TM software; then, the Mann–Whitney comparative statistical test (p<0.05) was carried out followed by the canonical correlation test.

Results

Differences in class III and class I malocclusions were found in the OP-AB and OP-FH angles. The OP-AB angle is the occlusal plane inclination which has the strongest correlation compared to others. OP-AB angle is strongly correlated with horizontal growth parameter, especially theSNB. The OP-AB angle is also correlated with vertical growth parameters: the Y axis and the Facial axis.

Conclusion

The OP-AB angle is a parameter that can distinguish between class III and class I malocclusions. The OP-AB angle has a strong correlation with vertical and horizontal growth directions.

Association of anterior and posterior occlusal planes with different Angle and skeletal classes in permanent dentitions : A lateral cephalometric radiograph study

Objectives

Malocclusions affect about two-thirds of the population and orthodontic treatment is justified in 65% of these. However, the associations between anterior and posterior occlusal plane (AOP, POP) inclinations and Angle classification are lacking.

Patients and methods

In a retrospective study, lateral cephalometric radiograph tracings of 230 previously untreated Caucasians, aged 13 to 49 years, yielded inclines of the bisector occlusal plane, AOP, and POP. All inclinations were referenced to the Sella-Nasion line and the Frankfort horizontal and were assigned to the Angle classification as well as skeletal groups (retrognathic, neutral, prognathic). Quantile regressions were calculated.

Results

In the skeletal groups the angles between Sella-Nasion line and both AOP and POP were significantly different between the groups (p < 0.01), showing steep inclines in skeletal class II and flat inclines in skeletal class III. The angles Frankfort horizontal-to-POP and Frankfort horizontal-to-AOP showed the same trends but only the latter differed significantly between the groups (p = 0.02). Among the Angle groups, AOP inclinations did not differ significantly for both reference planes whereas POP inclinations were significantly different (p = 0.01 to Frankfort horizontal, p = 0.02 to Sella-Nasion). Angle class I patients showed the flattest POP.

Conclusion

Occlusal plane inclines, measured to Sella-Nasion, were more consistent than those referenced to Frankfort horizontal. Sella-Nasion related anterior and posterior occlusal plane inclinations were steep in skeletal class II and flat in skeletal class III patients over all quantiles. Using the Angle classification, anterior and posterior occlusal plane inclinations did not follow this principle.

A cephalometric analysis of Class II dentate subjects to establish a formula to determine the occlusal plane in Class II edentate subjects: A neo adjunct

Purpose:

Occlusal plane (OP) differs considerably in participants with skeletal Class I and Class II participants. In this study, cephalometrics has been used to help in the determination of orientation of the OP utilizing the nonresorbable bony anatomic landmarks in skeletal Class II participants and an attempt has been made to predict and examine the OP in individuals with skeletal class II jaw relationship.

Materials and Methods:

One hundred dentulous participants with skeletal Class II malocclusion who came to the hospital for correcting their jaw relationship participated in the study. Their right lateral cephalogram was taken using standardized procedures, and all the tracings were manually done by a single trained examiner. The cephalograms which were taken for the diagnostic purpose were utilized for the study, and the patient was not exposed to any unnecessary radiation. The numerical values obtained from the cephalograms were subjected to statistical analysis. Pearson's correlation of <0.001 was considered significant, and a linear regression analysis was performed to determine a formula which would help in the determination of orientation of the OP in Class II edentulous participants.

Results:

Pearson's correlation coefficient and linear regression analysis were performed, and a high correlation was found between A2 and (A2 + B2)/(B2 + C2) with “r” value of 0.5. A medium correlation was found between D2 and (D2 + E2)/(E2 + F2) with “r” value of 0.42. The formula obtained for posterior reference frame through linear regression equation was y = 0.018* × +0.459 and the formula obtained for anterior reference frame was y1 = 0.011* × 1 + 0.497. It was hypothesized that by substituting these formulae in the cephalogram obtained from the Class II edentate individual, the OP can be obtained and verified.

Conclusion:

It was concluded that cephalometrics can be useful in examining the orientation of OP in skeletal Class II participants.

Differences between the chewing and non-chewing sides of the mandibular first molars and condyles in the closing phase during chewing in normal subjects

OBJECTIVE

This study aimed to assess differences between the closing paths of the chewing and non-chewing sides of mandibular first molars and condyles during natural mastication, using standardized model food in healthy subjects.

DESIGN

Thirty-two healthy young adults (age: 19-25 years; 22 men, 10 women) with normal occlusion and function chewed on standardized gummy jelly. Using an optoelectric jaw-tracking system with six degrees of freedom, we recorded the path of the mandibular first molars and condyles on both sides for 10 strokes during unilateral chewing. Variables were compared between the chewing side and the non-chewing side of first molars and condyles on frontal, sagittal, and horizontal views during the early-, middle- and late-closing phases.

RESULTS

On superior/inferior displacements, the chewing side first molar and condyle were positioned superior to those on the non-chewing side during the early- and middle-closing phases. Conversely, the first molar and condyle on the non-chewing side were positioned significantly superior to those on the chewing side during the late-closing phase. On anterior/posterior displacements, the chewing side mandibular first molar and condyle were positioned significantly posterior to those on the non-chewing side throughout all closing phases.

CONCLUSION

Our results showed the differences between the mandibular first molars and condyles on both sides with respect to masticatory path during natural chewing of a model food. These differences can be useful for informing initial diagnostic tests for impaired masticatory function in the clinical environment.

A new bite block for panoramic radiographs of anterior edentulous patients: A technical report

Purpose

Panoramic radiographs taken using conventional chin-support devices have often presented problems with positioning accuracy and reproducibility. The aim of this report was to propose a new bite block for panoramic radiographs of anterior edentulous patients that better addresses these two issues.

Materials and Methods

A new panoramic radiography bite block similar to the bite block for dentulous patients was developed to enable proper positioning stability for edentulous patients. The new bite block was designed and implemented in light of previous studies. The height of the new bite block was 18 mm and to compensate for the horizontal edentulous space, its horizontal width was 7 mm. The panoramic radiographs using the new bite block were compared with those using the conventional chin-support device.

Results

Panoramic radiographs taken with the new bite block showed better stability and bilateral symmetry than those taken with the conventional chin-support device. Patients also showed less movement and more stable positioning during panoramic radiography with the new bite block.

Conclusion

Conventional errors in panoramic radiographs of edentulous patients could be caused by unreliability of the chin-support device. The newly proposed bite block for panoramic radiographs of edentulous patients showed better reliability. Further study is required to evaluate the image quality and reproducibility of images with the new bite block.

Structural equation modeling for alteration of occlusal plane inclination

PURPOSE

Occlusal plane inclination is important to maintain a normal opening closing/biting function. However, there can be several causes that lead to alterations of the occlusal plane. The purpose of this study was to observe variations of occlusal plane inclination in adult patients, and to uncover the factors affecting changes in occlusal plane inclination with aging.

METHODS

Subjects were 143 patients. A cephalometric image was taken of these patients. In this study, our inquiry points were age, 3 variables on intra-oral findings, and 7 variables on cephalometric analysis. To evaluate the possible causes that affect occlusal plane inclination, factor analysis was carried out, and each component was treated as factors, which were then statistically applied to a structural equation model. Statistical analysis was carried out through the SPSS 20.0 (SPSS Inc., Chicago, USA).

RESULTS

In all patients, Camper-occlusal plane angle (COA) ranged from -25.7 to -4.9° (Mean±SD: -6.4±5.36). In the 60 patients who had no missing teeth, COA ranged from -11.6 to -4.9° (Mean±SD: -3.3±3.31). From the results of the structural analysis, it was suggested that the occlusal plane changes to counter-clockwise (on the right lateral cephalograms) with aging.

CONCLUSION

In this study, variations of occlusal plane inclination in adult patients were observed, and the factors affecting changes in occlusal plane inclination with aging were investigated via factor analysis. From our results, it was suggested that the mandibular morphology change and loss of teeth with aging influence occlusal plane inclination.

Changes of occlusal plane inclination after orthodontic treatment in different dentoskeletal frames

Background

The inclination of the occlusal plane (OP) is related to facial types and experiences physiological growth-related changes. The aims of this research were to determine if there were any differences in the inclination of OP in subjects with three types of skeletal malocclusion and to investigate the characteristics and differences of functional occlusal plane (FOP) compared to bisected occlusal plane (BOP).

Methods

A sample of 90 Caucasians patients was skeletal-classified into three (n = 30), and pre- and post-treatment cephalograms were digitized. Six linear and 8 angular cephalometric measurements were selected. The changes of OP inclination within each group and the differences among the three groups pre- and post-treatment were compared with paired t test and ANOVA test, respectively. The comparison and correlation between BOP and FOP were analyzed with paired t test and coefficient of correlation, respectively.

Results

The BOP angle increased in all of the three groups but only had statistically significant differences in skeletal class II patients in a mean of 1.51° (p < 0.05). The FOP-SN angle showed stability (p > 0.05) in all three groups. The inclination of FOP was closely related to that of BOP (p < 0.001) but revealed discrepancies in each group.

Conclusions

BOP and FOP were statistically significantly steeper in class II subjects compared to the other two groups both before and after treatment. The BOP angle statistically significantly increased by 1.51° in skeletal class II patients. BOP was a more reproducible reference plane compared to FOP during cephalometric tracing process, while FOP showed stability in orthodontically treated patients with all three skeletal patterns.

Electronic supplementary material

The online version of this article (doi:10.1186/s40510-014-0041-1) contains supplementary material, which is available to authorized users.

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 2° in the frontal and horizontal projections. In the sagittal projection, the angle was observed to be, on average, 4.9°. 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.

Orthodontic-orthognathic surgical treatment in a patient with Class II subdivision malocclusion: occlusal plane alteration

Despite the different orthodontic treatment options for patients with Class II subdivision malocclusions, the involvement of the skeletal structures is significant. It is desirable to combine orthodontic and surgical treatment to achieve a stable and better esthetic result, as illustrated in this case report. The occlusal plane was canted to the right as a part of the patient's facial asymmetry. Consequently, a 3-mm differential impaction of the maxilla on the left side allowed occlusal plane leveling. Mandibular rotation with advancement on the right side corrected the right Class II malocclusion. The successful attainment of the treatment goals was accomplished through teamwork and integration between the orthodontist and the maxillofacial surgeon.

Masticatory features, EMG activity and muscle effort of subjects with different facial patterns

It has been suggested that craniofacial morphology plays an important role in masticatory function, however, there are controversies and unsolved questions that still require elucidation. The aims of this study were to evaluate masticatory performance, mandibular movement, electromyographic (EMG) activity and muscle effort of masseter and anterior temporal muscles during mastication. Seventy-eight dentate subjects were selected and divided into three groups according to vertical facial pattern: brachyfacial, mesofacial and dolichofacial. Silicon-based material was used for chewing tests. Masticatory performance was determined by a 10-sieve method, and masticatory movements during mastication were assessed using a 3D mandibular tracking device. Electromyographic activities of masseter and anterior temporal muscles were evaluated during mastication, and muscle effort was calculated by the percentage of activity required for mastication based on maximum muscle effort. Data were analysed using anova and anova on-ranks tests. Dolichofacial subjects presented significantly poorer masticatory performance (6·64±2·04; 4·33±0·70 and 3·67±0·63), slower rate of chewing (1·34±0·27, 1·18±0·22 and 1·21±0·20 cycles per second) and larger posterior displacement during mastication (6·22±2·18; 5·18±1·87 and 5·13±1·89) than meso- and brachyfacial individuals, respectively. No statistical difference was detected among groups for the other masticatory movement parameters. There was no difference in absolute EMG amplitudes of masseter and anterior temporal muscles during mastication among groups, but the relative effort of both muscles was higher in dolichofacial, followed by meso- and brachyfacial subjects (masseter: 39·34± 2·25; 36·87±4·05 and 33·33±4·15; anterior temporal: 38·12±1·61; 38·20±8·01 and 35·75±2·48). It was concluded that the vertical facial pattern influences masticatory performance, mandibular movement during mastication and the effort masticatory muscles required for chewing.

[Occlusal plane control in hyperdivergents: regarding one case]

Management of occlusal plane inclination in the sagittal dimension is one of the main concerns of practitioners. Inclination maintenance or correction can condition the success and stability of treatment. By means of a clinical case, we will attempt to discuss the different aspects of management from diagnosis to treatment, bearing in mind the local and regional context. The adopted treatment plan takes into consideration the functional and esthetic issues specific to Moroccan patients without neglecting soft tissue harmony.