Fitting of PROSTHESES
Evaluation of the prosthesis on the surrogate type before fitting
It is very necessary for the doctor to check the fit between the crown and the type of prosthesis before evaluating the type of prosthesis on the generation. By examining the crown, the physician may discover possible problems with the crown's marginal fit, aesthetics, and occlusion. In general, common problems may include: too close contact between adjacent surfaces, small protrusions on the cast tissue surfaces, excessive crown edge extension, insufficient crown edge extension, and type replacement damage.
1, the adjacent surface contact is too tight generally for the generation type localization, is not accurate or the collar surface contact point has the attrition result.
Solution: Crown in the generation of the position, check generation whether displacement, and through the occlusal paper to determine the point of contact, grinding and polishing.
2. The small protrusion on the surface of casting is caused by the air bubble when it is embedded.
Solution: Remove the small round drill.
3. overstretching can be caused by poor impression quality, poor molding, and excess untrimmed wax or porcelain on the crown edges.
SOLUTION: fix the axis of the crown and Polish it, or consider returning the restoration to the shop and making it again.
4. The edges don't stretch enough because the impression quality is poor, generation finishing is not good, can not determine the finish line, etc. .
Solution: Make a new impression and repair body
5, generation type damage because the technician is not careful and lead to complete line damage, or there are bubbles on the casting on the generation type wear and tear generation type.
Solution: carefully examine the cause of the generational damage. If the restoration is not in place after removing bubbles or small protrusions and trimming too long of the edges, it should be returned to the shop to be remade.
Try a prosthesis on the mouth
After examination of the PROSTHESIS, the temporary prosthesis should be removed from the patient's mouth and the temporary adhesive left on the teeth should be thoroughly removed, especially the adhesive left in the retention groove or in the GINGIVAL groove. The cause of the failure can be gradually determined by a series of examinations:
1) to determine that there is no residual temporary adhesive or interference from the gingival tissue;
2) to examine and adjust excessive adjacent contact, also check for contact zone model damage
3)Check for obvious errors associated with the technician's fabrication, including bubbles, nodules, generation defects and edge defects, the needle can be used to remove the bubbles and small tumors of the casting.
4)For the overextended edges, the crown must be trimmed from the outside rather than from the inside. 5, all imperfections should be gently removed with a needle and re-worn.
Final evaluation of the placement of the prosthesis
The final evaluation of the prostheses should be carried out from four aspects:
the contact between adjacent surfaces, aesthetic appearance, marginal cohesion and occlusion.
An adjacent contact dentist uses dental floss to examine the adjacent surface contact. The appropriate adjacent surface contact is for the floss to pass through but with little resistance. If the contact is slightly tight, the crown adjacent to the contact area can be a small amount of attrition and polishing, when should be very careful, improper operation easy to make contact area open. Use a thin occlusal paper between the crowns (in the mouth or on the crown) before adjustment. This can also be helpful in checking jaw fit. Contact zone conditions are rare and, if they occur, can be improved by returning the crown to the shop and adding porcelain and alloy solder to the adjacent face. Untreated prostheses must not be worn and bonded to the patient's mouth, as this may cause food impaction.
Aesthetic adjustment of the color and shape of the crown, here to pay attention to is should be in order to make small adjustments, if necessary, in the metal layer add porcelain. If the color is too light, it can be improved by dyeing and re-sintering. In addition, all-ceramic crown and porcelain veneer color can also be fine-tuned with resin adhesives. Before bonding, patients should be allowed to evaluate the restoration. If they can not accept the color and shape of the crown, it is recommended that they speak up. The doctor must not risk the patient's dissatisfaction with the risk of bonding, and finally will repair body disassembly, and then repeat all the previous production process. Persuading a patient to accept a prosthetic that is disagreeable to him may be a temporary success, but it leaves a potential source of trouble later.
Marginal occlusal Crown occlusions range from very occlusal to open along the edge of the tooth, especially at the edge where only a probe can be used. During the operation, it is very important for the doctors to follow the high clinical standard to prolong the service life of the prosthesis. The failure of most clinical crown and bridge restorations is closely related to the marginal defect. Non-close-fitting edges can make cement easier to contact with saliva or water in the mouth and dissolve, resulting in poor crown retention, accumulation of marginal plaque and secondary caries. A defective subgingival margin can affect gum health through the action of local bacteria.
The final step is the evaluation of the bite. The dentist should remove the crown and select several adjacent teeth. In order to re-position the crown as a reference for evaluation, at this time the paper to determine the amount of adjustment.