Analysis of Various Reasons for Denture Remakes

Remaking dentures is the last thing both dentists and dental laboratories want to see, as it concerns the reputation of both doctors and enterprises, as well as cost accounting.

How to control the remaking of dentures and improve production output and credibility is an issue that cannot be ignored and must be addressed by every prosthodontist and dental laboratory. This problem requires the cooperation of both doctors and dental labs to effectively solve. It cannot be thoroughly resolved by relying solely on either party.

Below is a brief description of the potential issues that may arise from both the dentist’s and the dental lab’s perspectives. Causes of denture remakes from the dentist’s side include poor tooth preparation, inadequate impression taking, or inadequate scanning. This can lead to an inaccurate and unclear original impression or digital model, and even technicians with strong abilities can only do their best. Conversely, if the technician’s skills or internal management in the lab are inadequate, even with a good impression or scan file, it can still lead to many remake issues.

Next, let’s analyze the specific causes in detail. Even if you are not a professional, I hope you can gain a general understanding of the reasons after reading. Based on the information from HINNO Dental Lab and the industry, remaking is an objective issue. Because everyone has a different opinion on the same tooth, some may find it beautiful, while others may not. This is a subjective feeling and cannot be judged by completely quantifiable standards.

Common External Causes of Remakes:

1. The dental bridge cannot be seated properly.
   • The die cutting is deformed, the die Reduction is inaccurate, or the undercut of the die is not handled correctly.
   • The impression taken by the doctor has unclear edges, and the technician misjudges the edges, resulting in an overlong edge of the denture that cannot be seated properly.
   • The doctor removes the impression too early, causing the model to deform. When using two types of plaster for pouring the mold, due to their inconsistent expansion coefficients, and the impression does not have a suspended fulcrum at the back when pouring, causing the model to deform.
   • The denture is not polished properly, with long edges and tight proximal contacts.
   • The doctor’s preparation of the abutment teeth is rough, with unpolished surfaces and small fulcrums. The patient does not wear a temporary crown after tooth preparation, causing physiological displacement of the abutment teeth.
2. The occlusal surface is raised or lowered.
   • The plaster nodule affecting occlusion is not removed by the technician.
   • The occlusion is inaccurate, such as in cases of free-end edentulism where wax is used to record jaw position, and the wax is prone to deformation.
   • The technician wears down the opposing teeth when adjusting the occlusion.
   • The patient does not wear a temporary crown after tooth preparation, causing the abutment teeth to rise naturally.
3. The tooth shape is not aesthetically pleasing.
   • The patient has specific needs.
   • The aesthetic views of the technician and the doctor do not align.
   • The technician’s skills are poor, and the denture does not coordinate with the patient’s adjacent teeth.
4. Black line exposure at the cervical margin.
   • The technician operates irregularly, and the opacifying layer is not applied in a droplet shape at the edge of the base crown.
   • The mobile phone used for grinding rotates too fast, causing the porcelain at the edge of the denture to crack.
5. Incorrect color.
   • The doctor has an error in shade matching, resulting in a color difference between the denture and adjacent teeth.
   • Insufficient tooth preparation, revealing the underlying color.
   • The technician makes an operational error, reads the wrong prescription, and uses the wrong porcelain powder.
   • The color of the porcelain powder differs from the doctor’s shade guide.
6. The cervical margin is not tight.
   • The impression taken by the doctor has unclear edges, and the technician misjudges the edges.
   • The technician’s grinding is inaccurate, and the edge is shortened.
7. Porcelain fracture.
   • There are occlusion interferences in the patient’s mouth, which the doctor fails to adjust.
   • The occlusion space is too small, and the porcelain layer is too thin.
   • The denture design is unreasonable, with the porcelain layer being too thick and the metal-porcelain junction located at the occlusion point.
   • The doctor’s design is unreasonable, with the bridge being too long, causing excessive internal stress when the patient chews.
8. Other reasons.
   • Doctors may also have unreasonable returns or remakes due to various reasons to transfer economic risks and losses.

Common Internal Causes of Denture Remakes:

1. The tooth shape is not aesthetically pleasing.
   • The technician lacks scientific training in tooth carving.
   • Poor aesthetic awareness.
   • Lack of experience in tooth shape and space.
2. The cast inner crown has shrinkage pores or sand holes.
   • The inner crown is too thick without a reservoir.
   • Impurities are mixed in during investment.
   • The crucible is not clean.
   • The casting spout is not clean during casting.
3. The bridge body rocks.
   • Related to wax pattern making, investment, and casting.
   • For long bridges, wax stress relief treatment is not performed before investment.
   • Unreasonable casting spout design.
   • Artificial deformation occurs during investment.
   • The expansion coefficient of the investment material is not properly controlled.
   • The casting timing is not properly controlled.
   • The die is loose.
4. Does not meet the doctor’s requirements.
   • Misreading the production order.
   • The technician lacks professional knowledge and cannot understand the doctor’s production requirements.
   • Ambiguous instructions from the doctor.
5. Incomplete casting.
   • The wax pattern is too thin.
   • The casting timing is too early.
   • No vents are placed in thin areas.
   • Incorrect casting spout design.
6. Black line exposure at the cervical margin.
   • The technician operates irregularly, and the opacifying layer is not applied in a droplet shape at the edge of the base crown.
   • The mobile phone used for grinding rotates too fast, causing the porcelain at the edge of the denture to crack.

The causes of remakes come from both doctors and dental laboratories or technicians. It is never too late to mend. Doctors, dental laboratories, and technicians can learn from each other and make progress together. Especially when they first start cooperating, there may be more remakes as there is often no rapport between newly cooperating doctors, dental laboratories, and technicians, and there may be differences in aesthetics, process requirements, etc., leading to a period of adjustment. However, as long as they communicate patiently with each other, their rapport will gradually increase, and the number of remakes will decrease.