Resin filling technology of wedge-shaped defect is a part of the theory of dental prosthetics, which is a combination of art and technology, aiming at restoring the normal shape, function and beauty of restored teeth and maintaining the stability of dental arch. A normal tooth is a combination of morphology, function and beauty, which is formed by long-term evolution of human beings. The reduction of shape in wedge filling is the mastery of tooth anatomy, and aesthetics is the understanding of color and art, and its function is to grasp the direction of food.
Selection of materials
Wedge-shaped defect filling materials have also experienced several generations of replacement, from early amalgam materials to glass ions in the 1990s, to later composite materials (which are still in use now) and to present resin materials.
Figure 1 amalgam filling (my filling case nine years ago)
Not all resin filling materials are suitable for filling wedge-shaped defects. Clinically, many doctors choose superhard resin for posterior teeth, thinking that the harder the resin is, the better (such as P60 resin), which is a big misunderstanding and also a factor leading to the failure of filling.
Fig. 2 the case of filling resin with superhard resin
How to choose the filling resin for wedge-shaped defects is the key to analyze the dynamic motion trajectory of teeth (combined transportation cycle).
Take maxillary canine when alveolar bone is unabsorbed as an example. The bite force will cause tooth deviation and increase the marginal pressure of the filling body. For example, if the composite resin with extremely high rigidity is selected, the maximum deformation will occur at the place with the lowest elastic modulus, and cracks will occur at the resin-rubber interface. Therefore, according to the tooth position and alveolar bone absorption, it is better to choose low elastic modulus and low filling composite resin, such as cola, which will disperse the pressure and tension on the whole filling body. But the technical level of the operator is more critical than the material selection.
Fig. 3 Tooth stress
Preparation of double-hole type
Whether it is necessary to prepare holes for resin repair of wedge-shaped defects is a concern of many doctors. The modern resin adhesive has developed to the seventh generation, and it has strong adhesion. Do we want the hole type? No, you need to prepare a wedge-shaped resin repair hole.
First of all, adhesion is a theoretical test, the data obtained in the laboratory and the necessary reference for clinical operation. In practice, the humidity in the mouth is a difficult problem for us to control. Rubber barrier technology is very practical, but it is not used in many clinics and hospitals.
Fig. 4 Filling completed under rubber barrier
Secondly, the stress is concentrated in the position where the tooth lacks wedge.
Fig. 5 Internal fragmentation of stress concentration
Fig. 6 Bionic restoration of bicuspid teeth with nano-resin
Third, the bonding foundation is built on the fresh dentin surface, and the wedge-shaped defects are mostly old, hardened and decayed, which must be removed to expose the fresh dentin surface.
How to prepare the cavity repaired by wedge-shaped defect resin? It is suggested to use a retainer with a small internal angle concave. The instrument uses small balls of emery to form a smooth inner angle, which conforms to the radian of the tooth neck. Appropriate mechanical retention form+effective bonding of resin+assurance of matching details = no falling off.
The textbook describes the preparation of the inclined plane of the combined wall cavity, aiming at the transition between resin and teeth, so as to make the colors more harmonious. Is it necessary to do this in clinic?
Pass diagram
I improved this two years ago, without preparing the inclined plane of the wall hole, and the filling was as perfect as before, which was later confirmed in a foreign document. On the other hand, after the preparation of the cave slope, the pigmentation area appears with the passage of time, because millions of chewing cycles every year lead to cracks and pigmentation at the weak interface of the resin binder on the cave slope.
Fig. 7 Pigmented area of wedge-shaped defect of second premolar.
In this case, I filled it out three years ago and prepared the empty inclined plane. Now I find that there is a pigmentation area in the middle-after millions of chewing cycles, the interface is partially detached.
Resin is confined in tooth tissue, which is the key point for wedge filling not to fall off.
Bionic treatment of wedge notch color
1 Prevention of "white line" in bionic therapy. The causes of edge white line can be summarized as too thick adhesive edge, incomplete bonding between material and teeth, excessive polishing pressure in reverse polishing direction, incorrect illumination direction and so on.
2 bionic imitation color, color comparison in wet environment, you can choose resin depth gradient color guide or curing small pieces of resin prior color.
Fig. 8 resin gradient shade guide
When there is no resin with very similar color, choose similar resin, and then complete color matching through external dyeing technology and internal dyeing technology. The following case is a combination of internal dyeing and external dyeing technology to complete bionics.
Fig. 9 Color of large wedge-shaped defect of neck before operation.
Figure 10 intraoperative
Photo 1 1 color of upper right side cutting neck (no hole inclined plane)
Figure 12 color bionic completion
Fourthly, the bionic treatment of wedge shape.
In the study of prosthodontics, morphology and function complement each other. Wedge defects are mostly located in enamel cementum, which is the morphological transition from crown to root. Anatomical mark is the protrusion of the cervical crest, and it is also the key part to control the food flow. Excessive squeezing will cause useless atrophy of gums, and excessive squeezing will cause trauma. It is difficult to imitate the transition between crown and root in bionic wedge.
Figure 13 loss of neck convexity figure 14 neck reconstruction.
Figure 15 loss of neck convexity figure 16 neck reconstruction.
Five kinds of special effects imitation
Pigment line imitation, it is best to choose internal dyeing.
Figure 17 canine teeth have pigment lines.
Figure 18 fangs after imitation. Slight coloring of premolars combined with canine tooth transition to increase visual effect
Sixth, postoperative sensitive control.
It is a common problem for doctors to have allergic symptoms such as cold and hot stimulation and pain after wedge filling. Some of them have also caused medical disputes. There was no discomfort when I saw the doctor, but the doctor showed allergic symptoms after filling it out, which is difficult for us to explain. Therefore, how to avoid the sensitivity after the filling operation is the key to master this skill.
The main reason for the sensitivity of wedge-missing resin filling is the doctor's intraoperative control. Carefully grasping every detail of the filling process can completely avoid postoperative sensitivity.
Several sensitive factors after operation.
The etching depth of 1 is greater than the bonding depth, which is one of the main reasons for immediate postoperative sensitivity. This problem can be solved by using self-etching technology.
Figure 19 Good self-etching system
The control of two lines of defense inside and outside dentin is considered to be the most effective and advanced method to prevent dentin pulp injury.
The internal defense line is the formation of mixed layer-controlling the dentin permeability and the exudation rate of pulp tissue at night (it is suggested to contract blood vessels under local anesthesia of Bilan to reduce the exudation rate). The diameter of dentinal tubule near the pulp increases accordingly, and the tube pressure also increases accordingly. After the treatment liquid is coated with adhesive, the phenomenon of solar wind tunnel will appear-local dentinal tubule liquid will bubble, as shown in the following figure. Sensitive symptoms will appear after direct filling, which can be relieved by secondary adhesive coating. Poor internal care control is the main reason for immediate postoperative sensitivity.
Fig. 20 solar wind tunnel-very similar to adhesive foaming.
Figure 2 1
It is easy to understand that external protection-preventing edge change and destruction and reducing secondary caries are the most important factors to prevent postoperative delay sensitivity. There is no sensitivity in the short term after filling, but the damage of external protection can be considered when sensitivity occurs in a few months.
Whether effective adhesion is formed is also one of the sensitive factors after operation.
In the case of deep wedge-shaped space, many doctors need to perform bottom surgery, and the choice of bottom material is controversial. Some people argue that calcium hydroxide is helpful to dentin calcification, but the existing data prove that it is basically useless. Resin glass ion is a good choice or fluid resin, chemical curing fluid will be better (chemical curing fluid will shrink towards high temperature pulp). As long as an effective mixed layer is formed, there is no need to fill the bottom, my current filling method.
The premise of effective bonding is fresh dentin, so the decayed and old hardened dentin should be removed before filling, and the chelation between glass ions and dentin is also based on fresh dentin. This is consistent with the fact that there are no holes in the filling wedge.
Resin should be built in the cavity of teeth.
Resin filling requires gum wall, joint wall, proximal wall and distal wall.
There are also some operational details, such as preoperative gums, not supersaturating the treatment solution to prevent it from entering the gingival sulcus, and the method of applying adhesive. Tool selection for postoperative polishing, edge sealing and polishing control after polishing.
In short, the details determine success or failure. Doing one thing repeatedly to the extreme is success. In the last issue, we talked about dental preparation. In this issue, it is wedge filling. There will be detailed operations such as inlay preparation and bonding in the future to share with you. It is the direction of every dentist to make every step to the extreme. I don't envy how much others can do, but how much others can do.