The first few articles introduced the skills of using the mouth mirror of the maxillary dental arch. Through the practice of the upper dental arch, I believe that everyone has mastered the basic skills of using the microscope, the skills of using the mouth mirror, and also learned how to solve the problems of depth of field and visual field. The practice in the district laid the foundation.
This article will first introduce the relatively easy operation skills of the mouth mirror in the left lower posterior area (for doctors who are accustomed to right-handed operation). After mastering the microscope operation in the upper and lower posterior area, the operation of the lower jaw anterior teeth is very easy. So I won’t repeat it.
Basic skills of mandibular dental arch mouth mirror
Practice time: 80 minutes
Materials to be prepared:
- Dental surgery microscope
- Teeth model (28 teeth)
- Medium-sized phones
- Crown preparation emery bur
- Ergonomic doctor chair
Goals to be achieved by the exercise:
- Further practice oral mirror skills in the lower right posterior area under the field of view of 2x-12x magnification
- Learn how to solve the problem of declining field of vision
Working position of the lower left posterior area
Dental chair: Adjust the chair position so that the backrest is at a 30° angle to the ground, and the operation area is located under the operating microscope.
Doctor: 10 to 12 o’clock.
Nurse: From 2 o’clock to 3 o’clock, put the strong straw tip into the patient’s mouth, and gently press the patient’s tongue to the lower right.
Microscope: Increase the angle between the microscope and the axial plane of the root canal.
Patient: Lie on your back, slightly to the right.
The above picture shows the recommended positions of physicians, nurses and patients during micro-root canal treatment in the lower left posterior area (pictures are demonstrations of positions, and rubber dams are recommended in actual treatment)
Across the arch or parallel to the arch
Inexperienced doctors often place the handle of the mobile phone parallel to the teeth, which will limit the field of vision in the mouth mirror and block their vision. If the position of the mobile phone handle is parallel to the dental arch, the situation shown in Figure 1 will appear; if the position of the mobile phone handle is shown in Figure 2, the visual field will be less affected. Therefore, it is more appropriate to place the mobile phone across the dental arch when preparing on the left side of the tooth.
Figure (1) shows the conventional method of paralleling the dental arch of the mobile phone handle. The display is not very good. The mobile phone handle blocks the line of sight at this position. Makes the grasp of the preparation area worse.
Figure (2) The handle of the mobile phone is operated across the dental arch, which less shields the prepared teeth. The cross-arch approach is more advantageous when preparing on the left side of the tooth.
Mandibular dental arch observation and operation skills
When operating the mandibular posterior teeth under a microscope, follow the principle of using the maxillary posterior oral mirror and make appropriate adjustments. During the operation of the posterior teeth of the mandible, the position of the mouth mirror is a semicircle that transitions from the 9 o’clock position to the 7 o’clock, 5 o’clock, and 3 o’clock positions on the tooth surface, and the mobile phone with the needle should be pointed away from the doctor instead of Pointing to the doctor like the upper jaw dental arch, which requires most of the mobile phone to extend to the fingertips, rather than contraction. Since the movement of the fingers is more suitable for contraction movement, you will find that the extension movement of the mandible will be more difficult. In addition, the mouth mirror also tends to deviate from the line of sight by 45 degrees. The field of view in the mouth mirror is getting closer and closer to the ellipse, and the field of view is getting smaller and smaller. This deficiency can be compensated by keeping the jaw plane as vertical as possible.
Figure (3) The positions of the four mouth mirrors of the posterior teeth of the mandible are shown in counterclockwise order at 9 o’clock, 7 o’clock, 5 o’clock, and 3 o’clock.
Observation of No. 19 tooth with 9 o’clock position
In this exercise, first refine the left side of tooth 19 (bottom left 6). The position of the mouth mirror is at 9 o’clock, and the horizontal position is consistent with the jaw plane. At this time, the teeth can be observed indirectly through the mouth mirror, or directly Some teeth were observed. The problem of direct observation is that only one tooth surface can be observed and prepared at a time. In order to observe each tooth surface, the patient or the microscope must be moved, and it is not easy to observe the line angle position by direct observation. Therefore, in order to prepare the distal, left and mesial teeth smoothly, indirect observation is necessary.
Figure (4) shows the 9 o’clock position of the mouth mirror.
Figure (5) The mouth mirror is located at the 9 o’clock position, horizontal to the jaw plane, and can simultaneously “indirect observation” and “direct observation”. Due to the limitation of direct observation, indirect observation is used more in follow-up work.
Figure (6) The mouth mirror can be observed at the 9 o’clock position of the tooth’s distal, mesial and left sides.
Observation of No. 19 tooth with 7 o’clock
The next lens position of No. 19 (bottom left 6) is 7 o’clock, where you can see the direction of the long axis of the bur or the long axis of the tooth. Note that there are very few dental tissues directly observed at this time, and through simple movement of the mouth mirror, the teeth can be seen in the mouth mirror to the maximum.
Figure (7) highlights the 7 o’clock position of the mouth mirror of tooth 19.
Figure (8) The mirror image along the long axis of the tooth can be observed at 7 o’clock.
Figure (9) The mirror image at 7 o’clock.
Figure (10) Tooth No. 19 observed at 7 o’clock by the mouth mirror.
Figure (11) Tooth No. 19 observed at 7 o’clock under a microscope.
Figure (12) No. 19 tooth shown at 7 o’clock in the mouth mirror.
Figure (13) Tooth No. 19 shown at 7 o’clock in the microscope.
Observation of No. 19 tooth with 3 o’clock position
Next, we will introduce the exercises on the right side of tooth 19 (lower left 6). Place the mouth mirror at 3 o’clock and 5 o’clock. When the rubber dam is not used, the tongue is often a factor affecting operation. When observing the right side of the tooth at 3 o’clock, the mouth mirror can be used as a retractor. When the right side of the tooth is reached, the mobile phone begins to appear completely in the mouth mirror. At this time, the blocking problem can be solved by moving the phone up and down. When operating on the posterior teeth, the mobile phone will be less blocked when crossing the long axis of the teeth than when it is parallel to the long axis of the teeth.
Figure (14) highlights tooth 19 at 3 o’clock.
Figure (15) Observe the No. 19 tooth at 3 o’clock under the microscope. At this time, the tongue will be blocked, which can be solved by using a mouth mirror as a retractor or using a rubber dam.
Figure (16) Observe the No. 19 tooth at 3 o’clock under the microscope. At this time, the mobile phone is completely in the mouth mirror. To avoid this blocking, you can move the mobile phone up or down to make the mobile phone cross the long axis of the tooth to get the best Vision.
Observation of No. 19 tooth at 5 o’clock position
When the bur reaches the lingual angle, the mouth mirror should be at 5 o’clock to show the right side of the tooth. The figure below shows the relationship between these.
Figure (17) highlights that the mouth mirror observes tooth 19 at 5 o’clock.
Figure (18) Observe tooth 19 at 5 o’clock with a mouth mirror.
Figure (19) When the mouth mirror is correctly placed at the 5 o’clock position, the No. 19 tooth under the microscope.
Figure (20) correctly use the mouth mirror to display the 9th tooth at 3 o’clock.
Figure (21) When the mouth mirror is correctly placed at the 3 o’clock position, the No. 19 tooth shown in the microscope.
Figure (22) correctly shows the No. 19 tooth at 5 o’clock with the mouth mirror.
Picture (23) shows the No. 19 tooth in the microscope when the mouth mirror is correctly placed at the 5 o’clock position.
The references for this article are taken from:
Rick Schmidt, Martin Boudro, “The Dental Microscope”