Conservative Versus Conventional Restorative Approach for Endodontically Treated Posterior Teeth

This research protocol explores two different ways of restoring posterior teeth after root canal treatment. Teeth that have had root canal treatment often become weaker because part of their natural structure is removed, and the dentin itself becomes more fragile. As a result, these teeth are more likely to break. Dentists have usually treated this problem by placing a fiber post inside the root canal and then covering the tooth with a full coverage crown. This method has worked well, but it involves drilling inside the root canal, which can make the tooth weaker on the long run.

With advances in modern dentistry, new techniques aim to be more conservative; they try to save as much of the natural tooth as possible. One of these approaches is the overlay, a type of partial coverage restoration that seats on top of the tooth but does not require as much removal of healthy structure as a full coverage crown. Recent studies suggest that overlays can perform just as well as crowns, but there is still not enough strong clinical evidence to confirm this for all cases, especially for posterior teeth that face heavy biting forces. This trial will help fill that gap in the literature.

The study will take place at the Faculty of Dentistry, Cairo University, and will include fifty patients aged between 20 and 50 years. All patients must have had root canal treatment on a restorable posterior tooth. Those with poorly treated canals, cracked teeth, gum disease, or bruxism will not be included. Patients who join the trial will be divided randomly into two groups. One group will receive the conservative approach: the cavity will be filled with fiber-reinforced composite, and the tooth will be prepared for a lithium disilicate overlay. The other group will follow the conventional method: a fiber post will be placed, a composite build-up added, and finally the tooth will be covered with a full coverage lithium disilicate crown.

The main goal is to see how well each method keeps the tooth intact after six months, using a standard set of criteria to judge success. Other factors will also be checked, such as how well the margins fit, whether there is discoloration or secondary decay, and whether the color matches the surrounding teeth. Importantly, patients will also be asked how satisfied they are with the treatment, using a simple scale to record their feelings.

To make sure the study is fair, patients will be randomly assigned to one of the two groups using a computer program. The operator performing the treatment will know which method is being used, but the patients and the statistician analyzing the results will not, which helps reduce bias. Data will be collected carefully and stored securely. Standard statistical methods will be used to analyze the results, with differences considered significant if the probability of chance is 5% or less.

All patients will sign a consent before joining. Any possible side effects, such as minor discomfort, will be noted. After the six-month follow-up, results will be published in scientific journals and conferences.

By comparing these two approaches, the study hopes to show whether the conservative overlay technique can be a reliable alternative to the traditional crown. If proven successful, this method could help dentists save more of the natural tooth structure, reduce treatment time, and still provide durable, esthetic, and satisfying results for patients.