The previous article introduced the working position of the upper left posterior area and the observation of the upper left posterior teeth with a mouth mirror. This article will introduce the relatively difficult use skills and working position of the mouth mirror in the upper right posterior area.
Basic skills of maxillary dental arch mouth mirror
Practice time: 80 minutes
Materials to be prepared:
1.Dental surgery microscope
2.Teeth model (28 teeth)
4.Crown preparation emery bur
5.Ergonomic doctor chair
Goals to be achieved by the exercise:
1.Further practice oral mirror skills in the posterior teeth area under the field of view of 2x-12x magnification
2.Understand the theory of “left and right” tooth surface
3.Preliminary study of microscope mirror clock theory
4.Learn the position of the mouth mirror from 9 o’clock to 3 o’clock
Working position of the upper right posterior area
Dental chair: Slightly raise, adjust so that the patient’s lower jaw plane is parallel to the ground plane, and the upper jaw plane is at a 45° angle to the ground plane, and the operation area is under the operating microscope.
Doctor: At the 11 o’clock position, at an angle of 65° to the long axis of the patient or dental chair.
Nurse: At 2 o’clock to 3 o’clock, a strong straw is extended into the patient’s left mouth corner, and the head of the straw is placed on the maxillofacial surface of the lower posterior teeth. The little finger of the left hand is fixed on the patient’s chin.
Microscope: Reduce the angle between the microscope and the axial plane of the root canal.
Patients: Lie on your back with your head tilted back; when treating the right upper molars, the patient’s head should be slightly to the left; when treating the right upper molars, the patient’s head should face completely to the left so that the doctor can operate in the right upper jaw posterior area, the chin Stretch to the right.
The above picture shows the recommended positions of doctors, nurses and patients during micro-root canal treatment in the upper right posterior area (pictures are demonstrations of positions, and rubber dams are recommended in actual treatment)
9 o’clock position of tooth 3
Dentists who operate with the right hand found that the left upper jaw area is the easiest position to operate, followed by the right upper jaw area. So choose the right side as the area for the next half of the exercise, we choose the 3rd tooth. Use 20 minutes to refine the crown edge of the left upper jaw 3 tooth. Here, the image reflected by the mouth mirror at 9 o’clock is similar to the No. 14 tooth viewed at 9 o’clock.
Figure (1) Observe No. 3 tooth at 9 o’clock
Figure (2) Observe the No. 3 tooth at 9 o’clock. Note the similarities with the No. 14 tooth at the 9 o’clock position.
Figure (3) Observe No. 3 tooth at 9 o’clock with microscope
11 o’clock position of tooth 3
Note the image in Figure 4, the mouth mirror moves around the target tooth along a continuous track. In this chapter, all areas of the teeth are observed in the same way. When observing any maxillary posterior teeth, the left side of the target tooth can be observed at 11 o’clock.
Picture (4) This picture shows the 11 o’clock position of the mouth mirror when observing the left side of tooth 3.
Figure (5) Observed at 11 o’clock position of No. 3 tooth, similar to observing No. 14 tooth at 11 o’clock position.
Picture (6) The 11 o’clock position of No. 3 tooth is observed. This picture is a complete picture in the mouth mirror.
Figure (7) 9 o’clock position of the mouth mirror of tooth 3
Figure (8) Microscope observation of the 9 o’clock position of No. 3 tooth
Figure (9) 11 o’clock position of the mouth mirror of tooth 3
Figure (10) Microscope observation of the 11 o’clock position of No. 3 tooth
3 o’clock position of tooth 3
Use the last 20 minutes to trim the right edge of tooth 3. The mobile phone will interfere with the line of sight on the right side of tooth 3. Prepare tooth 3 like tooth 14. Tooth 3 has a new challenge, it has no convenient fulcrum. If you use a physician chair with elbow support, this problem can be easily solved. At 3 o’clock and 1 o’clock on the right side of the tooth, the problem of lack of support points will also exist.
Figure (11) highlights the 3 o’clock position image of tooth 3.
Figure (12) 3 o’clock position of the mouth mirror of tooth 3
Picture (13) The 3 o’clock position of No. 3 tooth is observed under a microscope. There is an image of the edge of the mouth mirror at the far left of the picture, and an image of the phone handle at the top of the picture.
1 o’clock position of tooth 3
The image in Figure 14 shows that the mouth mirror surrounds the target tooth in a continuous track. When looking at any maxillary posterior teeth, the 1 o’clock position can show the right side of the target tooth.
Figure (14) highlights the 1 o’clock position of No. 3 dental mirror
Figure (15) Observe the right side of No. 3 tooth at 1 point
Figure (16) Microscopic observation of No. 3 tooth at the position of 1 point mouth mirror. The interesting thing about this picture is that the direct and indirect images of the mobile phone can be observed at the same time.
Figure (17) 3 o’clock position of the mouth mirror of tooth 3
Figure (18) Microscopic observation of 3 points of tooth 3
Figure (19) 1 o’clock position of the mouth mirror of tooth 3
Figure (20) Microscopic observation of the 1 point position of No. 3 tooth
What is the best magnification
Under different magnifications, the images seen in the mouth mirror are different. Under high magnification vision, the ability to obtain the visual relationship between the target tooth, the bur, and the adjacent teeth is reduced. The most effective way to solve this problem is to reduce the magnification and perform rough preparation. The problem of visual relationship is actually a problem of magnification selection. When making a rough preparation of the crown, establishing a certain line angle, maxillofacial shape, or preparing a curve with the long axis of the tooth, a low-magnification field of view should be used. Cut 90% of the tooth tissue under a low-power microscope, leaving enough material for the gingival margin to be refined under a microscope at high power. Our goal is to select the most suitable magnification while adapting to the depth of field and positioning ability lost under high magnification.
Avoid iatrogenic injury
Iatrogenic injuries to adjacent teeth are rare. This kind of damage should be avoided when operating in confined spaces. This type of iatrogenic injury can be avoided by focusing on the teeth to be avoided during the operation instead of the prepared teeth. The range of keen visual cognition is limited to an arc of approximately 2 degrees at the center of the visual range. It becomes approximately three-quarters of a millimeter of the central axis of the visual field under 10 times the visual field. Coupled with the lack of perspective ability under high magnification lenses, these are the reasons why low magnification is required for tooth preparation. however. Visual operations under high magnification still require some perspective and positioning capabilities.
Ideas and techniques for the early use of oral mirrors
The mouth mirror surrounds the teeth in a semicircular orbit, from the buccal side to the tongue side or from the tongue side to the buccal side. The tooth is located in the center of the semicircle. If you cannot see the image you want to see, move your mouth mirror. Do not stop the mouth mirror at a fixed position, move your mouth mirror until you see the image you want to see. Do not fix your sight on the bur. The position of the mouth mirror you adapt to when looking for an image is called the “most effective point”. One of the main goals of the third part of the exercise is to find and perfect the “most effective point” in different positions of the mouth mirror. Initially, the most effective point is obtained through experimentation, and then it will be found through intuition.
The references for this article are taken from:
Rick Schmidt, Martin Boudro, “The Dental Microscope”