What are the reasons for longitudinal root fractures??
There are two complexes of risk factors:
1. Risk factors that can be controlled by dentists
Risk factors for longitudinal fractures that can generally be controlled by dentists concern fillings, crowns and dentures.
- Tooth loss without dentures because the remaining teeth are subjected to higher loads,
- not exactly adjusted occlusal surfaces on fillings, crowns and dentures
- improper exposure to dentures
- super hard functional surfaces made of ceramic or non-precious metal on dentures
Longitudinal root fractures were preceded by root canal treatment in around 90% of cases. Risk factors for root canal treatments and the subsequent treatment of root canal teeth:
(according to Tang W, et al as before)
- unnecessary loss of substance and weakening of the tooth when opening the canal access.
- inadequate exploration of the fine structures of the channel anatomy.
- Ignorance, negligence and haste when preparing the root canal (type of instrument, degree of wear and tear of instruments, exact determination of the preparation length, precision and caution when guiding the instruments, avoiding unnecessary pressure on the canal wall, inadequate removal of drilling chips during preparation and much more.).
- Collateral damage when flushing the root canal.
- Collateral damage during root filling.
- Tilting and jamming of all kinds of instruments in the root canal
- many criteria for the selection of pens.
- Precision and dimension of the pen preparation.
- Material selection and procedure for gluing or cementing root posts.
- Planning and precision of the implementation of abutments (anchoring, resilience, bond with the tooth structure).
- insufficient coverage of the fragile root by the artificial crown.
- Missing a necessary crown extension.
- Failure to protect the tooth at risk of breakage in time with a crown.
- inadequate static and caudal dynamic planning of the crown preparation.
- lack of accuracy of fit of the crown on the edge and on the occlusal surface.
- insufficient cleanliness, tightness and stability of the cementation.
2. Despite all care, uncontrollable risk factors remain:
- Regionally different chewing and eating habits
- Grinding teeth and clenching
How stable is a tooth after root canal treatment??
The stability depends on the size of the defect and the type of care after root canal treatment. Stress tests on removed teeth give the following values - provided that they are handled properly.
|Resilience in percent|
|Only filling, no root canal treatment|
|a) made of plastic or ceramic in adhesive technology|
|b) made of amalgam, gold or provisional|
|Root canal treatment and then|
|a) Plastic or ceramic in adhesive technology|
|b) Amalgam filling, gold inlay or temporary filling|
|c) Crown in optimal design with glued structure|
|medium substance defect||100-200|
|large substance defect with root canal||80-120|
|d) Crown with root pin in faulty execution||5-50|
Improper handling can result in an immediate fracture or extremely reduced stability.
Which teeth are affected?
The large molars in the lower jaw and the small molars in the upper jaw are particularly at risk of fracture. Anatomical weak points and the distribution of chewing force play a role here. About 50% of all fractures affect these teeth.
What types of cracks are there?
enamel cracks range from the surface to the surface of the dentin, where the crack growth is almost always stopped by the structure of the dentin. They are painless and require no treatment.
cusp fractures arise with the loss of a tooth bump. They run through the enamel and dentine, deep fractures also through the dental pulp. There is sensitivity to hot-cold-sweet on the fracture surface. Depending on the size and load, a glued filling, a partial crown or a crown may be required.
Dentin and enamel cracks (also "Infractures" or "Cracks" called) extend from the surface deep into the dentine. When chewing, the parts on the fracture surface move minimally against each other, causing pain. Enamel dentin cracks are often difficult to see. After a while, germs enter the oral cavity. If left untreated, enamel dentin cracks lead to inflammation of the tooth pulp and to tooth breakage, i.e. tooth loss. A quickly made crown protects the tooth from it. More: see download longitudinal cracks / enamel dentine cracks
Crown-root fractures start at the occlusal surface and end more or less deep in the root. The fragment hangs on the gums. The affected tooth hurts when chewing and cold. Deep fractures mean tooth loss. In the case of less deep fractures, a crown can be used after the fracture surface has been exposed with a crown extension or orthodontically by lengthening the tooth. More see download / longitudinal cracks / crown root fractures
Split teeth are completely broken along. They hurt when chewing and sometimes cold.
Root longitudinal fracture
1. Partial cracks start at the root canal wall and end somewhere within the root wall. They can grow to complete cracks under stress. Very little is known about the details of crack growth.
2. Complete cracks run through the entire wall of the root. They are usually only manifested by symptoms after several weeks or even months.
(after Tang W, Wu Y, Smales RJ. Identifying and reducing risks for potential fractures in endodontically treated teeth. J Endod. 2010; 36 (4): 609-17)
(See Ferrari M1, Cagidiaco MC, Grandini S, De Sanctis M, Goracci C. Post placement affects survival of endodontically treated premolars. J Dent Res. 2007 Aug; 86 (8): 729-34.
Mancebo JC, Jiménez-Castellanos E, Cañadas D .: Effect of tooth type and ferrule on the survival of pulpless teeth restored with fiber posts: a 3-year clinical study. On J Dent. 2010 Dec; 23 (6): 351-6.)
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