A comparative study of two methods for the orientation of the occlusal plane and the determination of the vertical dimension of occlusion in edentulous patients

A Cephalometric Analysis Assessing the Validity of Camper’s Plane to Establishing the Occlusal Plane in Edentulous Patients

Complete denture fabrication requires multiple clinical and laboratory steps. One of the most critical clinical steps is establishing an anatomical occlusal plane based on hard and soft tissue references. The aim of this study was to determine whether age or gender affects the level of the Ala-Tragus plane to establish which reference point on the Tragus should be used when fabricating the occlusal plane in edentulous patients. Clinical photographs and lateral cephalometric radiographs with complete dentitions were taken from 58 volunteers at the DMD clinic at the University of Kentucky. Each photograph was superimposed over its corresponding cephalometric image. An analysis was conducted to establish the angle of the occlusal plane relative to the Ala-Tragus landmarks; this data was then grouped according to age and gender. The analysis shows that age and gender did not significantly affect where the Camper’s plane should be approximated for complete denture treatment. However, it was found that the most parallel line to the occlusal plane was Ala’s inferior border to the ‘Tragus’s inferior border. It should be noted that the volunteers’ skeletal classification was significantly related to a Cl III malocclusion tendency. Still, with this new information, functionality and esthetics can be more adequately addressed for patients undergoing complete denture treatment. Given our results, we suggest redefining the ‘Camper’s plane with a line extending from ‘Ala’s inferior border to the ‘Tragus’s inferior border instead of the superior border. Further consideration should be taken if the patient is a skeletal CL III malocclusion.

A Study for Determining the Inclination of the Occlusal Plane from the Mandibular Functional Trajectory

Background

During the fabrication of prostheses, the putative occlusal plane is generally determined based on morphological criteria such as Camper's plane. There is a possibility that morphological indexes deviate from their original positions over time. The current study investigated whether functional indexes could be used to determine occlusal planes instead of morphological indexes.

Objectives

The objectives of the present study were to investigate the relationship between the maxillary occlusal plane and mandibular functional trajectory and to consider a method for reconstructing a lost occlusal plane based on functional trajectories.

Methods

Thirteen healthy dentulous individuals were recruited for the study. Using a jaw motion tracking device with 6-degrees of freedom, the trajectories of the mandibular first molar and incisor during masticatory movement or tapping movements were measured.

Results

The closing angle of the mandibular first molar to the maxillary occlusal plane was converged and averaged 74.1° just below the intercuspal position, which is the terminal position of masticatory movement. This angle was positively correlated with the closing angle of the incisal point during tapping movement. The regression equation obtained was y = 0.37x + 45.99, where x was the closing angle of tapping movement and y was the closing angle of masticatory movement.

Conclusions

It was suggested that when determining lost occlusal plane, the occlusal plane can be derived using the closing angle of the incisal point during tapping movement.

Comparison of patient satisfaction between complete dentures fabricated using "conventional" and "cephalometric angular reconstruction" vertical dimension procedures: A multicenter randomized clinical trial

Aim

In Prosthodontics, during complete denture fabrication, conventional methods employed to determine occlusal vertical dimension require patient co-operation. Hence, the aim of the present study is to evaluate the clinical effectiveness of the 'cephalometric angular reconstruction' procedure in the calculation of these lost dimensions.

Settings and Design

Multicentric randomised clinical trial conducted in four dental hospitals.

Materials and Methods

Fully edentulous people who came to the hospitals for complete denture treatment were recruited into the study. Those who fulfilled the inclusion criteria were randomly assigned to two groups; Group 1: Dentures fabricated using a 'conventional' procedure and Group 2: Dentures fabricated using 'cephalometric angular reconstruction'. The patient's level of satisfaction was assessed on a scale of 1 to 5; 1-dissatisfaction to 5-excellent. The confounding factors that can influence the satisfaction were also recorded.

Statistical Analysis Used

The distribution of patient's satisfaction was assessed using Chi-square test, whereas the difference between the two groups was evaluated using Mann-Whitney test.

Results

There was no significant difference either in the vertical dimension determined (P = 0.465) or the patient's level of satisfaction (P = 0.943) between the two groups. There was no influence of confounding factors considered in the present study on the satisfaction levels. There was no difference in the distribution of satisfaction levels based on the dentist's quality assessment (P = 0.243).

Conclusion

Complete dentures fabricated using cephalometric angular reconstruction procedure of vertical dimension determination were equivalent with respect to patient satisfaction, compared to those made using a conventional method. Hence, the new method can be clinically recommended during denture fabrication.

Vertical dimension of occlusion related to mandibular movement during swallowing

Background

Increasing the vertical dimension of occlusion (VDO) is a common procedure in complicated prosthodontic treatment. The swallowing technique had been verified as a functional method to determine the VDO. The purpose of this study was to investigate the association between increasing VDO and mandibular movement during swallowing.

Methods

26 females and 14 males were enrolled (age range: 21 to 30 year-old). Under different increased VDO (3, 5, and 8 mm), the mandibular trajectory during swallowing was measured by K7 Evaluation System (Myotronics®). When the subjects were instructed to salivary swallowing, the range of mandibular movement in vertical, anteroposterior and lateral directions were recorded.

Results

Increasing VDO significantly impacted the range of mandibular movement in lateral direction during swallowing (p < 0.0001, F value = 40.09). The average variance of the mandibular movement distance in lateral direction during swallowing raise 1.58 (p = 0.001); 3.59 (p = 0.0001) and 2.01 (p = 0.001) when th VDO was raised from 3 mm to 5 mm; from 3 mm to 8 mm and from 5 to 8 mm respectively. The range of mandibular movement was significantly correlated to the increasing VDO (p ≤ 0.05) under the analysis of the Post Hoc test.

Conclusions

VDO was closely correlated to the trajectory of mandibular motion during swallowing. The increase in VDO could change the extent of mandibular trajectory during swallowing if the increase was more than 3 mm. The range of mandibular motion when swallowing had positive correlative tendency as the VDO was increased.

Comparison of different impression techniques for edentulous jaws using three-dimensional analysis

PURPOSE

The purpose of this study was to compare two novel impression methods and a conventional impression method for edentulous jaws using 3-dimensional (3D) analysis software.

MATERIALS AND METHODS

Five edentulous patients (four men and one woman; mean age: 62.7 years) were included. Three impression techniques were used: conventional impression method (CI; control), simple modified closed-mouth impression method with a novel tray (SI), and digital impression method using an intraoral scanner (DI). Subsequently, a gypsum model was made, scanned, and superimposed using 3D analysis software. Mean area displacement was measured using CI method to evaluate differences in the impression surfaces as compared to those values obtained using SI and DI methods. The values were confirmed at two to five areas to determine the differences. CI and SI were compared at all areas, while CI and DI were compared at the supporting areas. Kruskal-Wallis test was performed for all data. Statistical significance was considered at P value <.05.

RESULTS

In the comparison of the CI and SI methods, the greatest difference was observed in the mandibular vestibule without statistical significance (P>.05); the difference was < 0.14 mm in the maxilla. The difference in the edentulous supporting areas between the CI and DI methods was not significant (P>.05).

CONCLUSION

The CI, SI, and DI methods were effective in making impressions of the supporting areas in edentulous patients. The SI method showed clinically applicability.

An evaluation of relation between the relative parallelism of occlusal plane to ala-tragal line and variation in the angulation of Po-Na-ANS angle in dentulous subjects: A cephalometric study

Aims:

The aim was to evaluate if any correlation exists between variation in angulation of Po-Na-ANS angle and relative parallelism of the occlusal plane to the different tragal levels of the ear in dentulous subjects.

Methodology:

A total of 200 subjects were selected for the study. A custom made occlusal plane analyzer was used to determine the posterior point of the ala-tragal line. The lateral cephalogram was shot for each of the subjects. The points Porion, Nasion, and Anterior Nasal Spine were located and the angle formed between these points was measured.

Statistical Analysis Used:

Fischer's exact test was used to find the correlation between Po-Na-ANS angle and relative parallelism of the occlusal plane to the ala-tragal line at different tragal levels.

Results:

Statistical analysis showed no significant correlation between Po-Na-ANS angle and relative parallelism of an occlusal plane at different tragal levels, and an inferior point on the tragus was the most common.

Conclusion:

Irrespective of variations in the Po-Na-ANS angle, no correlation exists between the variation in the angulations of Po-Na-ANS angle and the relative parallelism of occlusal plane to the ala-tragal line at different tragal levels. Furthermore, in a large number of subjects (54%), the occlusal plane was found parallel to a line joining the inferior border of the ala of the nose and the inferior part of the tragus.

Digital Cephalometric Tracings by PRO-CEPH V3 Software for Comparative Analyses of Vertical Dimension in Edentulous Patients

BACKGROUND

Several methods, some physiological, some radiographical and some merely based on experience are taken upon by the practitioner to get him/her close to VDO in the edentulous patients. No single method can however claim to be the perfect answer. Lateral cephalograms have been a standard mode of determining the vertical dimensions in dentate and edentulous patients since the past. Due to unavoidable manual errors, there are chances of variations in the radiographic method too. Advancement in the digital technology has made recording jaw relations faster, simpler and more precise.

AIM

This study compared the vertical dimension of occlusion in edentulous patients recorded by using three different physiological methods with the aid of digital cephalometric tracings using indigenously developed PRO-CEPH V3 software.

MATERIALS AND METHODS

For the present study a total of 50 dentulous and 25 edentulous patients were selected through inclusion and exclusion criteria. A lateral cephalometric radiograph was taken for all the 50 dentulous subjects at Maximum Intercuspation (VDO) whereas three lateral cephalometric radiographs were obtained for all edentulous patients at the VDO following three different techniques- the Niswonger's method, Phonetics method and Swallowing threshold method. Cephalometric tracings were carried out using indigenously developed PRO-CEPH V3 software. Linear and angular measurement were made and analysed.

CONCLUSION

The indigenously developed software PRO-CEPH V3 is capable of making both the linear and angular measurement and therefore provide with relative credibility information regarding the possible VDO in the edentulous patients through cephalometric radiography.

Systematic assessment of the various controversies, difficulties, and current trends in the reestablishment of lost occlusal planes in edentulous patients

Accurate occlusal plane orientation is an essential factor in the fabrication of complete denture prosthesis. Over the years, it has received a number of methodologies by several researchers utilizing various anatomical landmarks however none of them is considered as perfect that could orient ideal occlusal plane. The presented literature review is an attempt to enlighten historical perspectives, pioneer researches, different controversies, difficulties and current trends for re-establishment of lost occlusal plane in edentulous patients. An extensive literature search was performed using Medline/PubMed interface and other scholarly research bibliographic databases using Medical Subject Headings. Studies describing research studies, case series and assorted clinical reports were retrieved and evaluated from 1963 to 2013. Most of the studies have suggest and evidence to consider Camper's plane for artificial orientation of occlusal plane however there is a substantial lack of genuine long term studies and authentic data that could recommend a single reliable landmark for perfect occlusal plane reorientation in a variety of cases.

Reliability of anatomic reference planes in establishing the occlusal plane in different jaw relationships: a cephalometric study

The purpose of this study was to evaluate the reliability of different anatomic reference planes in determination of Occlusal plane in dentulous and edentulous subjects with Angle's class I and class II Maxillomandibular relationship. Eighty subjects were included in the study which was divided into four Groups based on dentition and skeletal relationship. The Group I (n = 20) and Group II (n = 20) includes young and completely dentulous subjects in Angle's class I and class II relationship, respectively. The Group III (n = 20) and Group IV (n = 20) subjects were completely edentulous in Angle's class I and class II relationship, respectively. For all subjects, right lateral cephalograms were taken and cephalometric analysis was done and data obtained from cephalometric tracings were then statistically analyzed. The results showed no significant difference of angle between Occlusal plane and Frankfort Horizontal plane, Camper's plane and Palatal plane when Group I and Group III, and Group II and Group IV subjects were compared. The Frankfort Horizontal plane, Camper's plane and the Palatal plane may be used as a reliable guide to establish Occlusal plane in edentulous subjects in both Angle's class I and class II Maxillomandibular relationships.

The influence of the occlusal vertical dimension on masticatory muscle activities and hyoid bone position in complete denture wearers

PURPOSE

Long lasting usage of complete dentures causes lower occlusal vertical dimension, producing potential detrimental consequences. The aim of this study was to investigate how changes in vertical dimension during denture exchange affect muscular activity and hyoid bone position.

MATERIAL AND METHODS

Twenty-five edentulous, otherwise healthy patients (14 females, 11 males) aged 70.5 +/- 9 years, wearing their dentures over 5 years but no longer than 15 years (mean 9.8 +/- 5.2), were studied. New dentures were fabricated and the occlusal vertical dimension was recorded on cephalometric radiographs. Cephalograms were analyzed according to Ricketts. The relation of the hyoid bone position to the mandible was estimated. An evaluation of muscular activity was performed using the Biopak Electromyography Recording System synchronized with the T-Scan II Occlusal Analysis System.

RESULTS

The occlusal vertical dimension was higher with the new dentures compared with the old dentures. The transition to new dentures was accompanied by a change of the vertical position of the hyoid bone. Digastric muscle activity was lower with the new dentures in comparison with the old dentures.

CONCLUSIONS

Increase of the occlusal vertical dimension in complete denture wearers affects the hyoid bone position and masticatory muscle activity.

Kinesiographic study of deglutition in dentate individuals and complete denture wearers

Swallowing is used as a clinical method in prosthodontics to determine and record jaw relationships. The aim of this study was to perform a quantitative evaluation, in naturally dentate subjects and complete denture wearers, of three measurements associated with the mandibular position during the act of swallowing water: 1. intermaxillary distance on vertical axis; 2. anteroposterior deviation; and 3. lateral deviation. Two groups were selected: Group I (GI) included 40 subjects with complete dentition (mean age 45.27 yrs) and Group II (GII) included 40 bimaxillary edentate subjects, complete denture wearers (mean age 63.92 yrs). A kinesiographic instrument was used for analysis. Three records were taken for each measurement and a mean value obtained. It was concluded that: 1. intermaxillary distance on vertical axis and horizontal deviation were similar for both groups; 2. there was a significant intermaxillary distance on the vertical axis; and 3. for anteroposterior and lateral axis, results showed moderate deviation in relation to maximal intercuspation (MI).

Predicting vertical dimension with cephalograms, for edentulous patients

OBJECTIVES

To provide information on vertical dimension (VD), occlusal plane (OP), and size of future occlusal rims, through lateral Rx and cephalometric tracings that analyse and compare hard and soft tissue. To show that these measures are compatible with methods routinely used to prescribe for full.

DESIGN

Ten patients age range 53-81. Lateral Rx, with and without dentures, were taken and traced cephalograms were used to compare hard and soft tissue angles and planes.

MAIN OUTCOME MEASURES

Based on three cephalometric analyses: Rickets, and McNamara for skeletal, and Legan-Burstone for soft tissue, to identify the following landmarks: 13 skeletal points: N, ANS, PNS, Me, Xi, Pm, FC, Or, Po, A, B, Co, Gn and four soft tissue points: G, Gv, Sn, Me'; seven skeletal planes: HP, FP, NF, N-ANS-Me, A-B, ANS-Me, Co-Gn, and three soft tissue planes: G-Sn, Sn-Me', Sn-Gv, and six angles: N-FC-A, ANS-Xi-Pm, INF, IMP, 6NF, interincisor angle.

RESULTS

Stability in skeletal VD was observed with the proportion of 0.8 +/- 0.2 being present, between the middle third and lower third facial heights, N-ANS/ANS-Me. In addition, soft tissue proportion remained near 1, G-Sn,/Sn-Me. The length and position of first upper molar, upper and lower incisors were used to predict the OP. When compared with cephalograms of the same patient with dentures, similar measurements were observed.

CONCLUSIONS

It was possible to provide information on skeletal, facial proportions, VD, OP, and rim size using cephalograms for edentulous patients.

A comparison of the accuracy of two methods used by pre-doctoral students to measure vertical dimension

STATEMENT OF PROBLEM

Measuring vertical dimension is a soft-tissue measurement. Therefore, inaccuracy may occur.

PURPOSE

The purpose of this study is to compare the accuracy of the Willis gauge method with the caliper method.

MATERIALS AND METHODS

The Willis gauge measures the distance between the septum of the nose and the chin. The caliper method measures the distance between reference points on the tip of the nose and the chin. Twenty predoctoral students applied both methods 10 times in measuring the rest vertical dimension (RVD) and the occlusal vertical dimension (OVD) of a single edentulous patient. The measurements obtained from one experienced clinician were selected as controls for the interocclusal distances (IOD) for the Willis and the caliper methods, respectively. One-sided t tests and a 1-sided nonparametric test were used to determine significant differences between the 2 methods (alpha=.05).

RESULTS

The variances in the RVD values for the Willis gauge method were higher than for the caliper method for most students. A Wilcoxon signed rank test showed that the accuracy of the OVD measurements for the caliper method was significantly better than for the Willis gauge method (P=.001). This was not the case for the RVD measurements (P=.073). The average IOD for the Willis method was significantly higher than the control IOD (P=.026). The average IOD for the caliper method was not significantly larger than the control (P=.1303).

CONCLUSION

This study showed that the use of the caliper method by predoctoral students was a significantly more reliable method of measuring the OVD for the patient evaluated.

Report on the determination of occlusal vertical dimension and centric relation using swallowing in edentulous patients

When constructing a complete denture, the correct vertical dimension of occlusion (VDO) and centric relation (CR) can be difficult to determine. The aim of this study was to compare the swallowing technique used to determine the maxillomandibular relationship with a conventional technique. Fifteen edentulous patients were selected, each having a complete denture. The VDO and CR were assessed using acrylic base plates and a Boley gauge. First, the VDO was established by means of the vertical dimension of rest (VDR) and interocclusal rest space, and the CR was obtained by mandibular manipulation. Secondly, the VDO and the antero-posterior mandibular position were determined using swallowing. All measurements were repeated three times and the average was calculated. The results showed that (i). the VDO determined by means of the swallowing method was reproducible and significantly higher than the one established from the VDR (P < 0.01), and (ii). the swallowing position was located 2 mm anterior to CR (P < 0.01) and was moderately reproducible. This study suggests that swallowing can be used to determine the vertical position but no as a reference position in the sagittal plane.

Regulation of mandibular postures: mechanisms and clinical implications

This review argues that (1) the habitual mandibular position is constantly variable and so cannot be considered as a craniomandibular reference point, (2) there is no unique centric relation, (3) mandibular posture greatly depends on head posture, (4) clinical evaluation of the occlusal vertical dimension is mostly empirical, and (5) neither the vertical dimension at rest nor the centric relation can be determined by means of existing instrument-based clinical methods. However, some physiological conditions exist that facilitate the recording of craniomandibular position.

A study of the occlusal plane orientation by intra-oral method (retromolar pad)

Reliability of the intra-oral method which orientates the occlusal plane to terminate at the upper level of the retromolar pad was studied. Thirty individuals all with natural teeth and 34 complete denture wearers participated in the study. Stone casts were mounted in the S.A.M. 2 articulator by a quick mount face bow transfer. The angle between the occlusal plane and the articulator horizontal plane was measured in both groups. The angle was 9.42 degrees +/- 4.1 degrees in dentate individuals and 8.53 degrees +/- 2.8 degrees in complete denture wearers. No statistically significant difference was found between the groups (t = 0.72, P > 0.05). Therefore, the method can be advocated for a wide clinical use, as it is a simple method and places the artificial occlusal plane very close to the position of the natural plane of occlusion.