Many people who have a bad tooth, with only half of the crown or even just the root remaining, believe that there is no therapeutic value and should simply be extracted. This method of extraction can give a complete eradication of dental disease, but it can also bring some inconvenience to people. With the progress of society and the increase of people’s awareness of oral health care, “tooth extraction” is no longer the first choice for treating dental diseases. Due to the development of root canal treatment technology and pile core technology, more and more residual roots and crowns can be preserved for a long time, and some original molar residual roots and crowns that need to be extracted can be preserved and restored by pile core crown restoration after perfect root canal treatment.
I. Residual roots and crowns still have value
The residual roots and crowns are common clinical defects of large areas of dental tissue, but they are not worthless.
1, the residual root and crown can still withstand a certain amount of chewing pressure. Although the hard tissue of the residual root and crown is extensively damaged, the periodontal membrane tissue still exists and can play its normal role.
2.The tactile sensation of the residual root and crown is basically normal. Most of the nerves in the periodontium tissue are proprioceptive nerves, and the main function is tactile and deep pressure sensation, and preserving the residual root and crown can delay the alveolar bone resorption.
3, maintain the stability of the dental row, help patients’ psychological health, the human body is a complex organism, preserving the residual roots and crowns to restore the natural form and function is very important to prevent periodontal tissue lesions, coordinate the function of the oral and jaw system, improve the patient’s quality of life, and promote physical and mental health.
Therefore, regardless of the cause of tooth loss, it should be treated promptly instead of being extracted. Of course, not all residual roots and crowns can be preserved, and there is a strict adaptation range whether they can be preserved or not.
Secondly, the root and crown of the tooth caused by caries and trauma should be restored by pile crown
The residual roots and crowns caused by decay and trauma cannot be restored by full crown directly. After perfect root canal treatment and no clinical symptoms after 1-2 weeks of observation, pile crown restoration can be carried out and satisfactory results can be obtained.
Residual roots and crowns should undergo thorough periodontal treatment and perfect root canal treatment before retaining the restoration. Every aspect of root canal treatment directly affects the restoration. The practitioner is required to understand each step of root canal treatment and have a before and after filling radiograph for comparison. Root filling should ideally be within 0.5-2.0 mm of the root tip. If the root filling is more than 3.0 mm from the root tip, a dead cavity can form and become a source of secondary infection. For residual roots without apical inflammation, observation is required for one week after root canal treatment, and for teeth with obvious apical lesions, observation is required for more than 2 weeks after healing. Root canal preparation should be performed with maximum preservation of healthy tooth tissue, trimming the unsupported tooth structure and preserving and incorporating the remaining structure into the nucleus, making the preserved healthy tooth tissue a part of the nucleus.
Due to the small amount of hard tissue remaining in the crown, good retention cannot be achieved with a full crown restoration alone, so the root canal structure is utilized to first pile the core restoration.
Depending on the material, the piles can be divided into.
1. metal piles: with good mechanical properties.
2. porcelain piles: good aesthetic properties
3. fiber-reinforced resin piles: with a modulus of elasticity similar to that of dentin, which reduces the risk of root fracture after pile restoration.
According to the manufacturing method, pile cores can be classified as
1, preformed pile cores: are preformed semi-finished piles with different morphology and sizes, which are clinically selected for use according to the thickness of the root canal.
2.Cast pile cores: firstly, the tooth is prepared, then the mold is taken and embedded, de-waxed and cast outside the mouth. Casting pile cores include cast metal pile cores and cast all-ceramic pile cores.
The clinical situation of the residual root and crown varies widely, so it should be used flexibly according to different situations, and the appropriate pile core should be correctly selected for restoration under the guidance of the dentist in order to achieve good treatment results.
There are several options for full-crown restorations.
After the completion of the intraoral restoration of the pile core, full crown restoration of the tooth should be implemented. The following are common in clinical practice.
1, porcelain fused to metal full crown: commonly known as “porcelain teeth”, is a porcelain powder after high-temperature sintering fused to the surface of the metal inner crown to form a full crown restoration, both the mechanical strength of the metal inner crown and the advantages of porcelain surface aesthetics;.
2, all-ceramic crowns.
3, cast metal crowns: commonly used in the posterior teeth, with strong retention and good mechanical strength, but because of its exposed metal and obviously affect the aesthetics.
Porcelain fused to metal crowns and cast metal crowns, the metal composition of these two crowns have precious metals and non-precious metals. The former is chemically stable and biocompatible, which is beneficial to the health of gingival tissue; non-precious metals are prone to precipitate metal ions, which may lead to gray staining of the gums, and some metals are also allergenic.