Laser Indicated Occlusal Plane Device: A Novel Technique for Occlusal Plane Orientation : Contemporary Clinical Dentistry

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Case Report

Laser Indicated Occlusal Plane Device: A Novel Technique for Occlusal Plane Orientation

Natarajan, Keerthika; Krishnan, Murugesan; Srinivasan, Suganya; Venkat, Gowtham; Balasubramanian, Muthukumar

Author Information
Contemporary Clinical Dentistry 14(1):p 84-86, Jan–Mar 2023. | DOI: 10.4103/ccd.ccd_647_21
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Abstract

Parallelism to the ala-tragus line is commonly used as a guide for the orientation of the occlusal plane with the help of a fox plane. The accuracy of parallelism is affected by improper judgment or patient movement. This report describes a method with a modified fox plane that aids in occlusal plane determination. The device is placed in the patient’s mouth with the maxillary occlusal rim to determine parallelism to the ala-tragus line and interpupillary line. The adjustments are made until the laser light on the device runs parallel to the ala-tragus line, and the spirit bubble is centered between the lines of the tube. This technique facilitates direct visualization of parallelism, thereby avoiding parallax errors.

Introduction

Occlusal plane is the average plane established by the incisal and occlusal surfaces of the teeth; it is not a plane but represents the planar mean of the curvature of these surfaces.[1] Plane of orientation is one of the important factors of Hanau’s Quint.[2] The occlusal plane also acts as a guide for teeth arrangement for the construction of a dental prosthesis.[3]

Parallelism to the line joining the inferior border of the ala of the nose and the superior border of the tragus of the ear, known as the ala-tragus/Camper’s line, is the most commonly used reference for establishing the occlusal plane in completely edentulous patients. The ala-tragus line is preferred due to its reliability, repeatability, and ease of visualization.[4] Conventionally, a fox plane (stainless steel or plastic frame with two parallel wings and a center mouthpiece) is used to determine the parallelism to the ala-tragus line.[5] However, this technique can lead to errors due to the indirect visualization of parallelism. The accuracy can be affected due to parallax errors, movement of patient’s head, and inexperience of the clinician. To address this, a modification of the fox plane with the addition of laser lights has been designed which has been discussed in the report.

Procedure

An acrylic fox plane was initially used as a template to design a metal fox plane with the addition of extensions on either side to support the laser lights [Figure 1]. An electrical circuit was established to supply power to the lights when turned on. The device consists of the following parts [Figure 2]: (a) custom-made fox plane (medical grade aluminum alloy), (b) adjustable horizontal and vertical extensions (industrial-grade steel), (c) two 650-nm red line laser (MOKCUM, China), (d) power unit (3V lithium-ion coin cell, CR2032, Duracell), (e) button switch 1.5 A (Jia Teng, China), and (f) spirit bubble level acrylic vial (QASE, China). The laser light used in the device projects a vertical red line on any surface and can be manually adjusted to sharpen the focus.

F1
Figure 1:
Laser Indicated Occlusal Plane Device
F2
Figure 2:
Schematic diagram of device (a) Custom-made fox-plane (b) Adjustable horizontal and vertical extensions (c) 650 nm red line laser (d) Power unit - 3V Lithium-ion coin cell (e) Button switch (f) Spirit bubble level acrylic vial
F3
Figure 3:
Laser light in line with ala-tragus line after occlusal rim correction

The procedure using this device is similar to the conventional denture-making process and differs only while determining the occlusal plane. The device was used on a completely edentulous patient during the jaw relation procedure. The occlusal rims were adjusted according to the desired vertical dimension, labial fullness, and lip support for the patient. A trial of the device is done before placing the occlusal rim with the laser light switched on which projects a straight line directly on the patient’s face. The thumbscrews in the extensions can be used to adjust the level of projections according to the patient’s lower facial height such that it passes through the ala-tragus line. Once that is established, the maxillary occlusal rim is then placed in the patient’s mouth, and the device is positioned on the occlusal rim, and held with the operator’s or patient’s hand against the rim. The rims are then adjusted until the laser light accurately passes through the ala-tragus line [Figure 3]. Finally, to check parallelism to the interpupillary line, it is ensured that the bubble in the spirit level is in the center and between the lines of the spirit vial [Figure 4].

F4
Figure 4:
Checking anteriorly with spirit level

Discussion

While using the regular fox plane, the parallelism is determined by viewing from different angles and squinting one eye. Clinicians may additionally use a scale, tongue blade, or a line marked on the patient’s face to be able to visualize the parallelism directly. An opinion from an assistant is also taken to cross-check the assessment. To address this, various design modifications of the occlusal plane device have been attempted using additional plates parallel to the interpupillary line such as Camper’s plane indicator and occlusal plane indicator.[6–8] The use of laser lights to project a bright line on the patient’s face allows direct visualization of the parallelism. Such laser lights have also been utilized in orthopantomography machines for accurate patient positioning. The advantages of this technique are the reduced chances of errors in judgment, eliminates the need for an additional reference line, and the need for assistance. The patient has the freedom to move his head slightly, thus improving patient comfort without significantly disturbing the clinicians work during the procedure. It could be helpful to dental students who often doubt their judgments and improve the learning curve. The device can also be used in occlusal plane assessment in dentulous patients prior orthodontic treatment and in the case of patients with unilaterally missing ears. The lasers used in the device belong to Class 2 (International Electrotechnical Commission – IEC classification) visible laser and are considered safe for use, and eye protection is afforded by aversion response.[9] However, it is advisable to educate the patient to avoid directly staring into the light source.

Conclusion

The technique for occlusal plane determination using the device discussed in the report improves the accuracy of the clinical procedure by facilitating direct visualization of parallelism, thereby avoiding parallax errors.

Ethical clearance

The device was approved by the institutional review board, and prior consent of the patient has been taken for the use of photographs.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that their name and initials will not be published, and due efforts will be made to conceal the identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

The development of the device was self-funded.

Conflicts of interest

The prototype of device has been published by the Intellectual Property of India Patent No: 201641040160 by the authors.

References

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3. Spratley MH. A simplified technique for determining the occlusal plane in full denture construction. J Oral Rehabil 1980;7:31–3.
4. van Niekerk FW, Miller VJ, Bibby RE. The ala-tragus line in complete denture prosthodontics. J Prosthet Dent 1985;53:67–9.
5. Shetty S, Zargar NM, Shenoy K, Rekha V. Occlusal plane location in edentulous patients:A review. J Indian Prosthodont Soc 2013;13:142–8.
6. Kazanoglu A, Unger JW. Determining the occlusal plane with the Camper's plane indicator. J Prosthet Dent 1992;67:499–501.
7. Santana-Penin UA, Mora MJ. The occlusal plane indicator:A new device for determining the inclination of the occlusal plane. J Prosthet Dent 1998;80:374–5.
8. Husseinovitch I, Chidiac JJ. A modified occlusal plane device. J Prosthet Dent 2002;87:240.
9. Smalley PJ. Laser safety:Risks, hazards, and control measures. Laser Ther 2011;20:95–106.
Keywords:

Complete dentures; jaw relation; occlusal plane

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