This article mainly talks about training on the maxillary model combined with oral mirrors, visual field selection and motor skills. At the beginning, it is recommended to practice at a low magnification to train the eye-hand coordination ability. The low-power field of view is conducive to learning, and the direct or indirect field of view can be used to observe the model. Note that the rapid growth of the enlarged field of view has the opposite effect. You can also choose the right magnification to balance your skills and abilities according to the job at hand.
Basic skills of maxillary anterior mouth mirror
Materials to be prepared:
Tooth model (28 teeth)
Crown Preparation Emery Bur
Ergonomic doctor chair
Goals to be achieved by the exercise:
Further practice the skills of oral mirrors under the field of view of 2x-12x magnification
Working position of maxillary anterior teeth
Dental chair: Elevate at a 45° angle and place the operation area under the operating microscope.
Doctor: 12 o’clock position.
Nurse: From 2 o’clock to 4 o’clock, hold a strong straw in the left hand and extend it into the entrance at the right corner of the patient’s mouth.
Microscope: Reduce the angle between the microscope and the axial plane of the root canal.
Patient: Lying on his back, looking forward, the upper jaw plane is at a 45° angle to the ground.
The above picture shows the recommended positions of physicians, nurses and patients during microscopic root canal treatment of upper anterior teeth (pictures are demonstrations of positions, and rubber dams are recommended in actual treatment)
Basic operation of mouth mirror
The dental arch of the upper jaw in the mouth mirror
Observe the upper jaw dental arch in the mouth mirror with a microscope. At the beginning, place the mouth mirror in the middle area of the upper palate, and use the smallest magnification. The tongue surface of the entire upper jaw dental arch is very clear under the microscope. Observe the depth of field. When using a periodontal probe to explore the tongue surface of the upper collar teeth, observe the probe and teeth in the mouth mirror, you can still directly observe the tongue surface of the maxillary anterior teeth and maxillary teeth under the low power lens. When the magnification reaches 10 times, recheck the tooth number and observe the depth of field under the high magnification lens, making it more difficult to focus. Under high magnification, even a small movement of the mouth lens will change the focus surface, and attention should be paid to how the field of view is reduced under high magnification.
The mouth mirror is placed in the mid-sagittal plane
Place the mouth mirror close to the buccal cut edge
Maxillary anterior teeth
Proper ergonomics research can make it easier to explore the maxillary anterior area. Obviously, the surface of the teeth can be treated under direct vision, and the lingual and adjacent surfaces of the teeth between the two canines can also be observed indirectly at the midline.
Preparation of the veneer under the microscope
After completing a simple inspection of the entire dental arch, the next thing to do is to prepare the veneer of the maxillary anterior teeth. Use the same low-magnification field of view as the dental arch, and use 20 minutes to observe the two or three maxillary anterior teeth prepared for veneer preparation on the maxillary model. When you are near the junction of the incisal end and the lingual side, you need to use an oral mirror, please Put the mouth mirror in place a few minutes in advance.
Select veneer preparation bur according to personal preference
Preparation of the overlapping part of the lingual cut edge Fine gravel at the tip of the bur
Extending preparation for veneer
After finishing the veneer preparation, the next step is to prepare the full crown on the same tooth. This process requires a mouth mirror to observe the mesio-distal and lingual surface preparation. The proper position of the mouth mirror is slightly deviated from the sagittal plane between the canines.
Direct or indirect observation-to obtain a suitable view
The buccal side of the anterior area is the only one that can be directly observed. Even on the buccal surface, indirect observation often plays an important role in measuring the relationship between the bur-tooth and the gums, especially when it involves previous materials, soft tissue inflammation, subgingival deposits, or grooves on the lingual surface. . Indirect observation is also very helpful for preparing the gingival margin. It is important to understand the two observations: longitudinal observation of the long axis of the bur and lateral observation of the relationship between the bur and surrounding teeth.
Three ways to adjust focus
The focal length can be adjusted by moving the mouth mirror, the patient or the microscope.
1. The microscope can be adjusted left and right by gently lifting the head. This method is very useful in some cases. However, lateral movement cannot adjust the depth of field.
2. The easiest way to adjust the focal length is to move the lens, as long as you move it slightly by 5mm or less.
3. Under high magnification, you can adjust the focus by adjusting the patient’s head close to or away from the microscope with the knee under the dental chair.
In most cases, these movements are very small, or even imperceptible to the patient. However, you will immediately notice these obvious focal changes. This adjustment of the focal length completes the transformation of the focal plane from one surface to another without interrupting the diagnosis and treatment process. Moving the microscope to adjust the focus is the last method of choice because it interrupts the treatment.
The references for this article are taken from:
Rick Schmidt, Martin Boudro, “The Dental Microscope”