A ceramic inlay is a dental filling made of ceramic, and it is fabricated in a dental lab. These inlays are generally used to treat the consequences of dental caries. Here is the upper jaw of a patient; he has two leaking plastic fillings in the posterior teeth. The leak can be clearly identified as the black gap around the filling margin. The patient now wants to replace the leaking fillings in the other two teeth with ceramic inlays.
First, the old fillings are removed; cooling with water irrigation prevents overheating of the tooth. Filling removal and further cutting are performed with medical magnifying glasses because the dentist wants to conserve as much healthy tooth structure as possible. The dark discolorations underneath the fillings are partly the result of previous amalgam fillings and partly the result of caries.
Thus, tooth discolorations do not always have to be removed unless they indicate caries. After removal of the old fillings, the caries detector is applied and rinsed off. This process verifies if all carious dental material has been eliminated. Now the final cutting for inlay fabrication is performed. The edges are smoothed with novaculite.
A sealant is applied prior to taking the impression. After a specific contact time is achieved, it is rinsed off and the impression is taken. The impression is also examined with magnifying glasses; the tooth and preparation margins must be clearly visible. Finally the tooth will be given a provisional crown which protects it from hot and cold.
A week after cutting, the ceramic inlays are glued into the prepared cavities. The temporary dentures are removed and the fit of the ceramic inlays is checked. A precise fit is verified with medical magnifying glasses. Then the teeth are protected against saliva, the tongue, and consequently, moisture, with a rubber dam (the violet membrane) because the ceramic glue is extremely sensitive to moisture during the hardening process.
Ceramic inlays must be glued by a process called bonding, which is discussed further in the video titled “What is dental bonding”. Then, the tooth core is cleaned with special polishing compounds and dried, following which the blue etching gel is applied. This gel is initially only applied to the enamel. After a certain time period has elapsed, the gel is also applied to the dentin, where it is kept for a short period of time before rinsing off.
Now the tooth is treated with numerous chemicals. After a specific contact time, the tooth is intermittently dried with air. Here, precise workmanship is particularly important; contact times specified by the manufacturer are strictly observed, this is why dentists uses a stop watch during the gluing procedure.
Finally, the cementing compound is applied; two-phase glue is ideally used. The two phases should be mixed prior to the bonding process, following which they start hardening by themselves. The lamp only accelerates the hardening process after the two phases have been mixed. Although the use of two-phase glue is more cumbersome, it has an added advantage.
The glue continues to harden after the lamp has been turned off if it has not already hardened during the lamp application phase. Glues that only harden when a lamp is used always carry a risk of incomplete hardening, which is harmful to the tooth; toothaches and/or subsequent root canal treatments are possible consequences.
Only now is the ceramic inlay placed. A short prehardening process is initiated with the lamp, after which all the residual or excess materials are immediately removed. Finally, a glycerin gel is applied so that the glue can harden thoroughly, even at the edges, because this is only possible in the absence of oxygen.
After hardening, the teeth are polished. Smooth surfaces do not allow caries-causing bacteria to colonize. In the best case, even the dentist will not be able to recognize the glue joint. Ceramic inlays offer a unique option for tooth restoration, provided the elaborate gluing guidelines are followed.
Alternatives to inlays include well-known filling materials, such as amalgam, cements, glass ionomer cements, etc. However, these materials are not long lasting and must be replaced every couple of years.
This process always results in the loss of healthy tooth structure. After a number of years, a root canal treatment becomes necessary. This is why high-quality materials should always be used, especially in young individuals, and improved brushing techniques should be encouraged. Although high-quality fillings are initially associated with higher costs, the patient will save money, suffering, and time in the long-term.
The risks of inlay preparation are negligible when performed by an experienced dentist; nevertheless, complications may occur in individual cases, possibly requiring additional measures. Each additional measure may in turn lead to complications that may eventually lead to tooth loss. At this point, we will discuss the specific complications associated with inlay preparation.
These include injury to the surrounding structures, such as the tongue, cheeks, nerves, blood vessels, neighboring teeth, and neighboring roots, which in turn lead to the following consequences: dental nerve (pulp) infection requiring root canal treatment and/or a leaking inlay resulting in secondary caries.
In principle, all dental work is associated with the risk of a pulp infection. This is why patients should use materials that will form a tight seal for a long period of time with proper care.