Ala-tragus Line Research Articles

“Occlusal Plane Orientor”: An Innovative and Efficient Device for Occlusal Plane Orientation

Correct occlusal plane orientation is a prerequisite in Prosthodontic reconstructive treatment therapy as it helps in achieving esthetics and phonetics anteriorly and forms a milling surface posteriorly where tongue and buccinator muscle position the food bolus during mastication. Activity of Muscles during clenching will be least, when the occlusal plane is made parallel to plane of lost natural teeth. Conventionally the ala-tragus line (Camper's plane) is used as a guide for assessment of the occlusal plane and fox plane is used to check the parallelism between the two. Occlusal plane orientor is a new device developed to mark occlusal plane parallel to ala-tragus line on maxillary occlusion rim, thereby saving clinician's time and increasing efficiency. Additionally, it is a useful tool for occlusal plane orientation in patients with facial deformity, absence of an eye or an ear.

Occlusal Plane Analyzer: A Customized Device for Determining the Occlusal Plane

ABSTRACTSince times immemorial, dentists have faced the challenge of providing accord between function and esthetics. The occlusal plane, lost in patients rendered edentulous, should be relocated if complete dentures are to be esthetically and functionally satisfactory. Changes in the plane of occlusion modify the physical and functional relationship of the oral musculature leading to an alteration in function, comfort and also the esthetic value. Considering the importance of the accurate establishment of the location and the effect of the inclination of the established occlusal plane on function, esthetics and speech, a method to conform it to the occlusal plane that existed in the natural teeth seems necessary. This paper describes a custom-made instrument to check for the parallelism of ala-tragus line to the occlusal plane and also to check for the parallelism of occlusal plane to interpupillary line.

A cephalometric study to determine the plane of occlusion in completely edentulous patients: part I.

To determine the relationship between the plane of occlusion and the Camper's line (ala-tragus line). Lateral cephalograms of 105 dentulous subjects were obtained after outlining the tragus and the base of the ala of the nose with radiopaque markers. Tracings of the cephalograms were done and the relationship between the plane of occlusion and the Camper's line (ala-tragus line) was noted. The most common tragal reference as a posterior landmark for determination of plane of occlusion was found to be below inferior (in 30.48% of subjects), and inferior (in 24.76% of subjects). The least common tragal reference was found to be above superior (in 3.82% of subjects) followed by superior of tragus and the point between superior and middle of the tragus (in 6.66% of subjects). The tragal reference in this study population was more towards the inferior of the tragus, with most of the times being below the inferior border. Therefore, the orientation of the plane of occlusion using the superior of tragus as a posterior landmark (according to the widely accepted definition of Camper's line) may be considered to be questionable. Further, the use of the tragus as a posterior landmark for the orientation of the plane of occlusion may be questioned on the basis of the findings of this study.

The Position of the Occlusal Plane in Natural and Artificial Dentitions as Related to Other Craniofacial Planes

This study aimed at determining the most reliable ala-tragus line as a guide for the orientation of the occlusal plane in complete denture patients by use of cephalometric landmarks on dentate volunteers. Analysis was made for prosthodontically related craniofacial reference lines and angles of lateral cephalometric radiographs taken for 47 dentate adults. Variables were determined and data were analyzed using SPSS (SPSS, Inc., Chicago, IL). Occlusal plane angle formed between the occlusal plane and Camper's plane had the lowest mean value in the angle formed with Camper's I, which represents the measure taken from the superior border of the tragus of the ear with a score of 2.1°. The highest was measured in the angle formed with Camper's III with a score of 6.1°, while the angle formed with Camper's II was 3.2°. The differences between the three planes in relation to the occlusal plane was significant (p < 0.001). The superior border of the tragus with the inferior border of the ala of the nose was most accurate in orienting the occlusal plane.

A study of parallelism of the occlusal plane and ala-tragus line.

Background and aims Orientation of the occlusal plane is one of the most important clinical procedures in prostho-dontic rehabilitation of edentulous patients. The aim of this study was to define the best posterior reference point of ala-tragus line for orientation of occlusal plane for complete denture fabrication. Materials and methods Fifty-three dental students (27 females and 26 males) with complete natural dentition and Angel’s Class I occlusal relationship were selected. The subjects were photographed in natural head position while clenching on a Fox plane. After tracing the photographs, the angles between the following lines were measured: the occlusal plane (Fox plane) and the superior border of ala-tragus, the occlusal plane (Fox plane) and the middle of ala-tragus as well as the occlusal plane (Fox plane) and the inferior border of ala-tragus. Descriptive statistics, one sample t-test and independent t-test were used. P value less than 0.05 was considered significant. Results There was no parallelism between the occlusal plane and ala-tragus line with three different posterior ends and one sample t-test showed that the angles between them were significantly different from zero (p<0.05). However, the supe-rior border of ala-tragus line had the lowest mean angle, 1.80° (3.12) and was almost parallel to the occlusal plane. Conclusion The superior border of the tragus is suggested as the posterior reference for ala-tragus line.

Occlusal plane orientation: A statistical and clinical analysis in different clinical situations

Purpose: Orientation of the occlusal plane is important in a number of clinical situations. Using the reported soft and hard tissue landmarks is difficult and requires experience, as the landmarks are located on the face or by use of a cephalometric radiograph. Improper use of these landmarks may compromise the functional and esthetic result of prosthetic restorations. This study evaluated the reliability of the hamular notch/incisive papilla plane (HIP) in establishing the occlusal plane. Materials and Methods: Ninety healthy, Indian adults (60 dentate, 30 edentulous) participated in this study. The occlusal plane of the subjects was compared with their HIPs. In dentate subjects, the maxillary stone cast was mounted on the Wills surveyor with HIP, which was made parallel to the horizontal plane using the tripoding method. The vertical distance between the occlusal plane and floor of the surveyor was measured at four points. When the measured values were equal, the two planes were confirmed to be parallel for that situation. In turn, this relation confirmed the parallelism between the occlusal plane and HIP. In the edentulous subjects, the occlusal plane, established clinically using the ala tragal line, was compared with the HIP radiographically using lateral cephalograms. Paired t-test was used to test the equality of the mean differences at a 0.05 significance level. Results: The mean differences from the right canine were: 0.055 cm at the left canine, 0.05 cm at the right molar, and 0.065 cm at the left molar in dentate subjects and 0.001 cm between the incisive papilla and hamular notch in edentulous subjects. The HIP appeared parallel to the occlusal plane as the paired t-test showed no statistically significant difference (p > 0.05). Conclusion: In the population tested, the HIP was parallel to the occlusal plane. Therefore, this may be a viable reference in complete denture prosthodontics.

Relationship of anatomic landmarks with occlusal plane

Purpose : Evaluation of relationship between various anatomical landmarks and the occlusal plane in the natural dentition that could be used for establishing the occlusal plane in complete dentures. Methods : The study comprised of 100 dentulous subjects with all healthy permanent teeth in normal arch form and alignment. Three instruments were custom-made for the purpose : the occlusal plane analyzer to check the parallelism of the ala-tragus lines,and the interpupillary line, the buccinator groove relator and the level analyzer for the level of the linea alba buccalis with the occlusal plane. For the retromolar pad area a metallic scale was used. Results : Within limitations of this study, it was observed that, only 13% subjects showed occlusal plane parallel to the interpupillary line. The posterior reference point of Camper's line was middle point for 72% of males and superior point for 80% of females. Intraorally, 68% of subjects have the occlusal plane at the same level as that of buccinator groove and 77% of the subjects had the occlusal plane at the middle one-third of retromolar pad area. Interpretation and Conclusions : It was concluded that: the occlusal plane is parallel to Camper's plane posterior reference point as the superior point of tragus in females and middle point in males. The occlusal plane is not generally parallel to the interpupillary line. Intra-orally, the level of buccinator groove is reliable, while variations in retromolar pad area make it an unreliable landmark for orienting the occlusal plane.

Occlusal Plane Orientation: A Statistical and Clinical Analysis in Different Clinical Situations

Orientation of the occlusal plane is important in a number of clinical situations. Using the reported soft and hard tissue landmarks is difficult and requires experience, as the landmarks are located on the face or by use of a cephalometric radiograph. Improper use of these landmarks may compromise the functional and esthetic result of prosthetic restorations. This study evaluated the reliability of the hamular notch/incisive papilla plane (HIP) in establishing the occlusal plane. Ninety healthy, Indian adults (60 dentate, 30 edentulous) participated in this study. The occlusal plane of the subjects was compared with their HIPs. In dentate subjects, the maxillary stone cast was mounted on the Wills surveyor with HIP, which was made parallel to the horizontal plane using the tripoding method. The vertical distance between the occlusal plane and floor of the surveyor was measured at four points. When the measured values were equal, the two planes were confirmed to be parallel for that situation. In turn, this relation confirmed the parallelism between the occlusal plane and HIP. In the edentulous subjects, the occlusal plane, established clinically using the ala tragal line, was compared with the HIP radiographically using lateral cephalograms. Paired t-test was used to test the equality of the mean differences at a 0.05 significance level. The mean differences from the right canine were: 0.055 cm at the left canine, 0.05 cm at the right molar, and 0.065 cm at the left molar in dentate subjects and 0.001 cm between the incisive papilla and hamular notch in edentulous subjects. The HIP appeared parallel to the occlusal plane as the paired t-test showed no statistically significant difference (p > 0.05). In the population tested, the HIP was parallel to the occlusal plane. Therefore, this may be a viable reference in complete denture prosthodontics.

Superficial parotidectomy: antegrade compared with modified retrograde dissections of the facial nerve

We compared two techniques of superficial parotidectomy: conventional antegrade dissection of the facial nerve, and retrograde dissection. A total of 89 parotidectomies were included and the results presented of a retrospective case study during a six-year period. Superficial parotidectomy involves identification of the facial nerve. We present 49 parotidectomies in 45 patients using the conventional technique of antegrade dissection of the nerve, and 40 parotidectomies in 39 patients using retrograde dissection of the buccal branch of the facial nerve from 4 cm in front of the alatragal line to the main trunk of the nerve. The incidence of postoperative complications (facial nerve palsy, Frey syndrome, haematoma, and wound infection) were compared. The Facial nerve function was assessed by patient complaints and clinical examination. There was no significant difference in the incidence of postoperative complications between the groups. We describe an alternative technique for identifying the main trunk of the facial nerve.

A simple technique for marking the ala-tragal line

During complete denture fabrication, it is often necessary to use facial landmarks to assist in the proper contouring of the occlusion rims. One of the parameters in determining the maxillomandibular relationship is identification of the occlusal plane. This may be achieved by using an occlusal plane guide, which, after adequate and proper contouring of the maxillary occlusion rim, is made parallel to the Camper's plane 1 The glossary of prosthodontic terms. J Prosthet Dent. 1999; 81: 56-57 Google Scholar (ala-tragal line). Rough visualization of the ala-tragal line is a method of determining parallelism of the wax occlusion rim with the Camper's plane, but this may be difficult to determine when holding a ruler with one hand and attempting to keep it stationary. A simple, quick, and predictable method of visualizing the Camper's plane is proposed in this article.

Validity of soft tissue landmarks in determining the occlusal plane

The orientation of the occlusal plane is an important clinical procedure in prosthodontic treatment for edentulous patients. Various intraoral and extraoral landmarks have been used for the orientation of the occlusal plane, but none of them give sufficient guidelines for that purpose. Therefore, a study was carried out to ascertain the role of intraoral and extraoral soft tissue landmarks in determining the occlusal plane. 30 Indian subjects ranging in age from 19-23 years were selected from a group of approximately 200 dental students. The soft tissue landmarks considered in the study were retromolar pad, parotid papilla, commissure of the lips, buccinator groove, and ala-tragus line. An indigeneously fabricated Occlusal plane relator was used to find out the relative parallelism of the ala-tragus line and the occlusal plane. This device had a base with a vertical arm over which a sliding ball and socket joint was placed. This joint had a direct connection with the anterior occlusal plane indicator and ala-tragus line indicator. Absolute mean was taken of the two readings on ala-tragus line indicator on either side of the face. The line in which the difference between the two readings was least was parallel to the occlusal plane. The lower 1/3rd of the retromolar pad was observed to be consistent with the mandibular occlusal plane. The mean distance of the parotid papilla was 2.56 mm above the maxillary occlusal plane. The mean values of all readings of buccinator groove was 0.94 mm below the mandibular occlusal plane. In this study close correlation was observed between the mandibular occlusal plane and the commissure of the lips; the mandibular occlusal plane and the buccinator groove. The line drawn from the ala of the nose to the middle of the tragus was found to be parallel to the maxillary occlusal plane.

The orientation of the occlusal plane in Cantonese patients

The purpose of this study was to investigate the relationship between the occlusal plane and the Frankfort plane, and the true horizontal plane and the ala-tragal line in Cantonese patients. Clinically significant variations were found in the relationship between the occlusal plane, and the Frankfort plane and true horizontal plane. The mean orientation of the occlusal plane and the line from the ala to the lower border of the tragus were parallel, but there was a wide variation which suggests that this guideline is unreliable.

A study of occlusal relationships and the incidence of myofacial pain

A survey of 123 subjects (dental students) was performed to evaluate quantitative data that may be of value in the incidence and treatment of myofacial pain. Social statistics, subjective and objective symptoms, and the influence of occlusal interferences on these symptoms were quantitated and recorded. The data indicated that, of 123 subjects, 26% had maximum intercuspation of the teeth at terminal hinge closure, 42% had maximum intercuspation of the teeth with the condyles located symmetrically anterior to terminal hinge, and 32.5% had maximum intercuspation of the teeth with asymmetric variations of the condyles anterior to terminal hinge. Averages were obtained for the maximum intercuspal opening, the condylar inclination, and the distance anterior from the terminal hinge of both condyles in symmetrical and asymmetrical variations. The location of the transverse (terminal hinge) axis from the external auditory meatus was measured on the ala-tragus line. These latter averages indicate that a significant occlusal discrepancy can result from prevailing techniques of locating an arbitrary hinge axis 10 to 13 mm anterior from the external auditory meatus. The results showed that most subjects demonstrated, both subjectively and clinically, symptoms of neuromuscular dysfunction without occlusal interferences. Therefore, it may be concluded that treatment modalities considered within the first 6 weeks should be conservative and reversible to eliminate or decrease myofascial trigger zones and their areas of referred pain. Alteration of the existing occlusion and maxillomandibular relations may be adjusted with caution, if necessary.

The use of the ala-tragus line for occlusal plane determination in complete dentures

Abstract This investigation compares the location of the occlusal plane which exists in the natural dentition with the prosthetic plane when orientated according to the ala-tragus line. The results show a variation between the orientation of the two planes, which supports the view that the prosthetic plane, determined in this manner, is not a reliable indicator for the position of the occlusal surfaces of the artificial teeth.

The effect of anteroposterior inclination of the occlusal plane on biting force

With the experimental design of this study the following conclusions were reached. 1. Biting force during maximum clenching was the greatest when the occlusal plane was made parallel to the ala-tragus line. It decreased when the occlusal plane was inclined about 5 degrees anteriorly or about 5 degrees posteriorly. 2. The efficiency of biting force exertion during maximum clenching showed the best value when the occlusal plane was made parallel to the ala-tragus line. 3. Muscle activity during clenching at various given forces was least when the occlusal plane was made parallel to the ala-tragus line. The anteroposterior inclination of the occlusal plane tends to affect the biting force, and the method with the ala-tragus line seems to be the most reasonable for occlusal plane orientation.

The Trial Denture

1. Many difficult situations can be avoided if the dentist keeps constantly aware of the physiologic, the psychologic, and the artistic factors involved in the construction of dentures, whether they be partial or complete. 2. No one would think of buying an automobile without getting adequate instruction in how to drive; neither should a patient expect to wear artificial restorations without training and practice. 3. The dentist at the try-in should check: a. The bases for fit and extension. b. Thin labial flange at frenum area. c. Posterior palatal seal and length of upper. d. Posterior tooth position for height of plane, relation of plane to alatragus line, tongue room, and ridge relation. e. Anterior tooth position for lip support, length, and relation to lower lip. f. Entire setup for vertical dimension of the face, test balance and simultaneous tooth contacts in all desired positions. If discrepancies exist between the articulator and the mouth, make new jaw relation records. g. Check palatal contour and incisor positions in speaking. “F” and “V” sounds to test the upper incisors, sibilant sounds for vertical dimension and lower-to-upper incisal relationships. h. Wax-up for support and proper external form. If tori exist on upper or lower, be sure there is sufficient thickness to allow relief later on. i. Be sure to repeat and continue instruction of the patient in his understanding and handling of the new dentures. Now, in addition to all these checks the dentist makes, he must constantly anticipate the thoughts and attitudes of the patient and interpret them for better rapport and ultimate patient understanding. No stage in complete dentures is anticipated with such mixed emotions as is the try-in. No stage is so significant to the future success or failure of the patient to take dentures in his stride. No stage has so much potential for making the person happy or sinking him into the depths of despair. The return of self-confidence, the pride in appearance, the sparkle and drive that return to a patient when the restorations are enthusiastically accepted are a wonderful reward for dentistry well done.

Position of the occlusal plane in natural and artificial teeth

A roentgenographic cephalometric investigation was conducted to compare the position of the occlusal plane of the artificial teeth with that of the natural teeth which existed before the remaining teeth were extracted. The occlusal plane of the trial dentures was first oriented to parallel the alatragus line and then modified so the occlusal surfaces of the second molars were placed at the level of the middle third of the retromolar pad. This location of the artificial occlusal plane was found to be at a lower level than the natural one in the posterior region. Hence, our findings indicate that the occlusal plane should be positioned so the second molars are placed at the level of the upper third of the retromolar pad.

The occlusal plane in relation to facial types

1. The mean location of the occlusal plane of the dentitions of 53 dental and dental hygiene students was studied. The Schwarz mirror-photographic method was used, and the facial type was determined according to the Simon classification. The mean ala-tragus line, and the relation of it to the occlusal plane was studied for Simon's six facial types. 2. Data of this study indicate that, among the different facial types studied, the line connecting the lowest point of the ala of the nose to the inferior margin of the tragus is nearly parallel to the occlusal plane. This line is referred to as Camper's plane when used by prosthodontists. The correlation between facial types and the location of the occlusal plane, when considered from the lateral aspect, was also indicated. 3. A comparison of the results of this study with those of other investigators indicate that our results are reasonable. 4. The method used in this study is clinically applicable to complete denture construction.

The Try-in

1. Many difficult situations can be avoided if the dentist keeps constantly aware of the physiologic, the psychologic, and the artistic factors involved in the construction of dentures, whether they be partial or complete. 2. No one would think of buying an automobile without getting adequate instruction in how to drive; neither should a patient expect to wear artificial restorations without training and practice. 3. The dentist at the try-in should check a. The bases for fit and extension. b. Thin labial flange at frenum area. c. Posterior palatal seal and length of upper. d. Posterior tooth position for height of plane, relation of plane to ala-tragus line, tongue room and ridge relation. e. Anterior tooth position for lip support, length and relation to lower lip. f. Entire setup for vertical dimension of the face, test balance and simultaneous tooth contacts in all desired positions. If discrepancies exist between the articulator and the mouth, make new jaw relation records. g. Check palatal contour and incisor positions in speaking. “F” and “V” sounds to test the upper incisors, sibilant sounds for vertical dimension and lower-to-upper incisal relationships. h. Wax-up for support and proper external form. If tori exist on upper or lower, be sure there is sufficient thickness to allow relief later on. i. Be sure to repeat and continue instruction of the patient in his understanding and handling of the new dentures. Now, in addition to all these checks the dentist makes, he must constantly anticipate the thoughts and attitudes of the patient and interpret them for better rapport and ultimate patient understanding. No stage in complete dentures is anticipated with such mixed emotions as is the try-in. No stage is so significant to the future success or failure of the patient to take dentures in his stride. No stage has so much potential for making the person happy or sinking him into the depths of despair. The return of self-confidence, the pride in appearance, the sparkle and drive that return to a patient when the restorations are enthusiastically accepted are a wonderful reward for dentistry well done.