Porcelain Fillings (Inlay - Onlay) and Clinical Applications
The fundamental principle in dentistry is always to preserve the natural tooth structure as much as possible. This approach, called “Minimally Invasive Dentistry,” aims for minimal intervention to the remaining intact tooth structure while repairing caries or substance losses occurring in teeth. In traditional methods, the cavity formed after cleaning the decay in the tooth was closed with either composite (white) fillings or amalgam (metal) fillings. In cases where the substance loss was excessive, the tooth was reduced, and a crown (veneer) was made. However, developing technology today offers a perfect intermediate form between filling and crowning: Porcelain Fillings.
These restorations, prepared in a laboratory environment and designed like the missing part of the tooth, are the gold standard in cases where the substance loss is too large to be repaired with a filling but not large enough to require a crown. Following current treatment protocols in the Thrace region, Kırklareli Dental Clinic Atlas Sea Dental applies these tissue-friendly restorations according to the functional and aesthetic needs of patients.
What is a Porcelain Filling (Indirect Restoration)?
Classic fillings are “direct” applications shaped by the physician in the patient’s mouth and completed in a single session. Porcelain Fillings, on the other hand, fall into the class of “indirect” restorations. That is, after the decay is cleaned, an impression is taken from the mouth, and the filling is prepared in a laboratory environment or with CAD/CAM (Computer-Aided Design and Manufacturing) devices.
These restorations are divided into two main classes according to the area they cover and whether they cover the cusps (tubercles) of the tooth: Inlay Fillings and Onlay Fillings. Both are produced from aesthetic ceramics or reinforced composites and integrated into the tooth with special adhesives (resin cements).
Differences Between Inlay and Onlay
These two terms, frequently confused by patients, actually refer to the size and placement of the filling.
- Inlay Fillings: Restorations placed in the hollow area between the cusps (tubercles) on the chewing surface of the tooth. They fit into the cavity inside the tooth just like a puzzle piece. Inlay Fillings are preferred in cases where the cusps of the tooth are not damaged, and only the tissue in the center is lost. Their biggest advantage over standard fillings is that the contact point with neighboring teeth can be precisely adjusted in the laboratory. In this way, the problem of food impaction is minimized.
- Onlay Fillings: Restorations applied in cases where the substance loss is wider and one or more cusps of the tooth are also damaged. Onlay Fillings protect the tooth almost like a hat by partially or completely covering the chewing surface of the tooth. While it is necessary to cut from all sides of the tooth in the crowning process, in the onlay application, only the upper part is adjusted, and the side walls of the tooth are preserved. Kırklareli Dental Clinic Atlas Sea Dental physicians adopt the onlay method, which protects intact walls instead of cutting the tooth circumferentially, as a principle of biomimetic (nature-mimicking) dentistry.
Why Porcelain Fillings Instead of Classic Fillings?
Composite fillings are quite successful materials today, but they have a disadvantage called polymerization shrinkage (shrinking while hardening). In large fillings, this shrinkage can lead to microscopic gaps between the tooth and the filling and leakage/secondary caries over time. Since Porcelain Fillings harden in a laboratory environment, no shrinkage occurs in the mouth.
Also, in terms of wear resistance, Porcelain Fillings are the material closest to natural tooth enamel. In posterior molars where chewing pressure is high, while composites may wear down and collapse over time, porcelain inlays and onlays maintain their form for many years.
Treatment Process and Clinical Stages
The porcelain filling procedure applied within Kırklareli Dental Clinic Atlas Sea Dental is usually completed in two sessions and includes the following stages:
First Session: Preparation and Impression
- Anesthesia and Cleaning: The tooth to be treated is numbed with local anesthesia. Decayed tissue and, if any, old fillings are completely cleaned.
- Cavity Preparation: The internal structure of the tooth is prepared in a special geometry (without undercuts) where the porcelain filling can sit comfortably. A design is made concave for Inlay Fillings and covering the tubercles for Onlay Fillings.
- Impression Taking: A precise impression of the prepared tooth is taken. This process can be done with traditional silicone materials or by using intraoral digital scanners.
- Temporary Filling: A temporary filling is placed so that the tooth does not cause sensitivity while the laboratory process continues.
Laboratory Process
Taken impressions are sent to the laboratory or scanned with devices inside the clinic. Technicians or the physician design Porcelain Fillings that exactly match the color, form, and occlusion with the opposing tooth. The material used is usually reinforced glass ceramics (E.max) or hybrid ceramics. Since these materials have high light translucency, they are indistinguishable from natural teeth.
Second Session: Cementation (Bonding)
- Try-in: The temporary filling is removed, and the prepared Inlay Fillings or Onlay Fillings are rehearsed on the tooth. Marginal fit and height checks are performed.
- Surface Preparation: The inner surfaces of the porcelain and the tooth are prepared with special acids and bonding agents.
Bonding: The filling is bonded to the tooth with special resin cements cured by light or chemically. This process ensures the chemical integration of the filling with the tooth and strengthens the tooth against fractures.
Biocompatibility and Aesthetic Advantages
In the Atlas Sea Dental clinical approach, the compatibility of the used material with the gum and oral tissues is a priority. Porcelain surfaces are extremely polished and smooth. This feature makes it difficult for bacterial plaque and food residues to adhere. Therefore, in terms of gum health, Onlay Fillings and inlays are more hygienic than standard fillings.
Aesthetically, Porcelain Fillings show a “chameleon effect.” Thanks to their light reflecting and transmitting properties, they adapt perfectly by taking the color of the surrounding tooth tissue. Especially in posterior teeth visible in the smile line (premolars), the gray shadow created by metal fillings or the problem of color change of composites over time is not experienced with porcelain fillings.
Inlay/Onlay Indications: In Which Situation Is It Done?
Porcelain filling is not done on every tooth. As a result of the physician’s examination, the following criteria are evaluated:
- Amount of Substance Loss: If more than 50% of the tooth is lost, but there is not enough destruction to require a crown.
- Root Canal Treated Teeth: Teeth become fragile after root canal treatment. To protect these teeth, covering only the top with Onlay Fillings instead of completely cutting the tooth extends the life of the tooth.
- Teeth Grinding (Bruxism): Composite fillings can frequently break in patients who clench their teeth. The durability of porcelain provides an advantage in these cases.
- Neighboring Tooth Contact: In cases where the contact point with the adjacent tooth is lost, Inlay Fillings, whose anatomical form is given in the laboratory, are the best solution to prevent food accumulation.
Maintenance and Lifespan
Scientific studies show that porcelain fillings can be used for 10-15 years or even longer with good oral care. Kırklareli Dental Clinic Atlas Sea Dental recommends regular tooth brushing, flossing, and 6-month routine check-ups to its patients for the success of the treatment. Porcelain material does not decay, but a new decay can start at the border where the filling ends (in the tooth tissue). Therefore, hygiene rules are as important as for natural teeth.
Inlay Fillings and onlays are also resistant to staining. Yellowing and discoloration seen in composite fillings as a result of tea, coffee, or cigarette use do not occur on porcelain surfaces.
Aesthetic Dentistry in Kırklareli Region
Demand for aesthetic dentistry practices is increasing in the Thrace region. Well-equipped centers like Kırklareli Dental Clinic Atlas Sea Dental provide services with technological infrastructure at Istanbul standards. With the possibilities provided by digital dentistry, the problem of gag reflex during the impression stage is eliminated, and restorations can be produced with micron precision.
Patients in the region can keep their own tooth tissues in the mouth for a longer time by choosing Onlay Fillings, a protective treatment, instead of having their teeth completely cut and crowned. Atlas Sea Dental acts with a vision aimed at spreading this awareness and developing community oral health on the axis of preventive dentistry.
Porcelain Fillings are the point where modern dentistry combines art and engineering. While the internal structure of the tooth is strengthened with Inlay Fillings, the chewing surface of the tooth is protected with Onlay Fillings. Far from the unaesthetic appearance of metal fillings and the durability problems of composite fillings, these restorations restore the biomechanical and aesthetic integrity to the tooth.
Porcelain fillings made with correct indication and precise application are the treatment option closest to the natural tooth. Kırklareli Dental Clinic Atlas Sea Dental physicians create the most protective and longest-lasting treatment plan for their patients by evaluating the unique requirements of each case. For a healthy smile and fully functional chewing, these modern methods respectful to tooth tissue represent the future of dentistry.
