Dental Problems

Dental Crowding – Extraction of Teeth

What are the Reasons for Early Orthodontic Interventions?Dental crowding is one of the common problems that can be intercepted. Crowding is a common problem encountered at various stages of development and in varying degrees of severity. Crowding in the mandibular region may be seen in the early mixed dentition and is a finding of importance for the pedodontist. Read on to know more about dental crowding -extraction of teeth.

Extraction of teeth:

The extraction of teeth in order to create space is a well established procedure. The most recognized of these include the so-called serial extraction, timely extraction and Wilkinson’s extraction.

    • Serial extraction:

      Though the concept was initiated way back by Bunon (1743) the catchy term serial extraction was coined by Kjellgren (1929) and was popularized by Nance (1940), who has been called the ‘father of serial extraction’philosophy in the US. The extraction of teeth is often carried out without proper diagnostic aids or further comprehensive orthodontic correction is not taken into consideration. Thus the term ‘Guidance of eruption'(Hotz, 1970) would sound more appropriate.

      Definition:

      Serial extraction can be defined as the correctly times, planned removal of certain deciduous and permanent teeth in mixed dentition cases with dento alveolar disproportion i.e., teeth to supporting bone imbalance in order to:

      • a. Alleviate crowding of the incisor teeth for example to provide space for spontaneous alignment of incisors, when the lateral incisors are erupted at 7-8 years, deciduous canines may be extracted.
      • b. Allow unerupted teeth to guide themselves into improved positions. For example, deciduous first molar is extracted to speed eruption of first premolar, when root development of the first premolar is halfway.
      • c. Lessen the period of active appliance therapy or eliminate it.

      Indications for serial extraction:

      1. Class I with anterior crowding (space discrepancy 10mm or more)
      2. Lingual eruption of the lateral incisors.
      3. Midline shift potential due to unilateral canine loss.
      4. Crowded arches accompanied with extreme proclination.
      5. Abnormal primary canine root resorption.
    • Lack of developmental spacing
    • Anomalies such as ankylosis, ectopic eruption.

Contraindications:

      1. Mild to moderate crowding (about 8mm or less)
      2. Congenital absence of teeth providing space
      3. Where extensive caries of permanent first molars requires their removal.
      4. Accompanying deep or open bites without correction
      5. Severe class II, III of dental or skeletal origin
      6. Cleft lip and palate cases.

Assessment:

It includes

      • Clinical examination
      • Occlusion study (models)
      • X-rays -IOPA, OPG, cephalograms with cephalometric tracings
      • Mixed dentition analysis
      • Facial photographs

Rules to be followed:

      1. There must be class I molar relationship bilaterally
      2. The facial-skeletal relation must be balanced anterior-posteriorly, vertically and mesio distally.
      3. Discrepancy should be at least 5 mm in all quadrants
      4. Dental midline should coincide
      5. There must be neither open bite nor deep bite

Procedure and rationale:

Several sequences of treatment have been advocated with the most common ones being those of Dewel and Tweed.

    • Dewel (1978):

      The sequence proposed by Dewel is the extraction of CD4.

      • A.

        Extraction of deciduous canines:

        the deciduous canine space is utilized for aligning the crowded incisors. The resorption of the canine by a lateral incisor can provide an indication to the same. (Age 8.5 years).

      • B. Extraction of the first deciduous molars:

        At the age of 8.5 years, the unerupted permanent premolar will not have reached ½ root length. Once this happens (at about 9 ½ years), the deciduous first molar may be extracted to promote the eruption of the first premolar.

        At this stage, it would do well to note that the incisor crowding may have got resolved. Should the eruption sequence be unfavorable, with the canine erupting before the premolar, enucleation can be carried out. The extraction of the second deciduous molar with the placement of a lingual arch is another alternative, wherein the first premolar is encourage to shift distally. At a later date, once the canines erupt the first premolars are removed.

      It is most important that before extracting the first premolar, a reassessment of the existing problem is made.

    • Tweed (1966) proposed the extraction sequence as DC4:
      • a. At 8 year of age, all the deciduous first molars are extracted. The deciduous canines are maintained to hamper the eruption of permanent canines.
      • b. After the premolars (crowns) are through the alveolar bone, the premolars along with the deciduous canines are extracted.
    • Dale (1985) has proposed the same technique in cases of alveolodental protrusion. Here after extraction of the premolar and canine, no effort is made to prevent the lingual movement of teeth.

      Advantages of serial extraction procedure:

      The key advantage in serial extraction lies in the fact that by timely extraction of the teeth, further appliance therapy is minimized or eliminated. It will also reduce the complexity of treatment need.

      Disadvantages of serial extraction procedure:

      1. Unfortunately, quite too often the serial extraction procedure will have to be followed by fixed appliance therapy. This is particularly so in cases of Class I with crowding, where the procedure is accompanied by the following:
        • a. Relatively deep overbite
        • Distoaxial inclination of the canines and mesioaxial inclination of the second premolars. This has been termed as ditching. Thus mechanotherapy and retention may be unavoidable.
      2. It may be used only selectively in Class II malocclusions.
      3. Psychological trauma and lack of the patient co-operation may affect the future dental treatment.
      4. Caries may affect the second premolars, necessitation their removal.
      5. Impacted canines -even after removal or premolar, the canine may remain impacted.
  • Timely extraction:

    This is similar to serial extractions where in sequential removal of deciduous teeth is carried out, but differs in that no permanent teeth are removed. The term Timely extraction has been recommended by Stemm (1973).

    Timed extractions have been advocated in cases where:

    • a.There is a gingival recession due to labial positioning of the lower incisors, coupled with an inadequacy of dental arch length.
    • b.There is ectopic eruption of the lateral incisors or the first permanent molars. Apart from the locking of the tooth below the deciduous counterpart (especially in maxillary molar), space loss may also be present.

    The plain removal of the canine swill cause lateral and lingual shift of the mandibular incisors. Though this will help in repositioning, it may create arch length deficiency where none existed before and this should be accompanied by space maintenance to preserve the alignment. The best indication to use the so called times extractions of primary teeth would be when the crowding is 4-9 mm. this is because the alignment of the incisors after the permanent canines have erupted is a difficult task.

  • Incisor extraction:
    Occasionally, extraction of an incisor tooth may give a good result. This can be done in cases where the jaws are narrow and the teeth are fanned out laterally. Any pathology of the lateral incisors, where it cannot be saved or if it is excluded from the arch, may favor its extraction.
  • Wilkinson’s extractions:
    While serial extractions are primarily indicated in cases where the crowding exists in the anterior region for relief of crowding in the posterior teeth segments, the first molar extractions can be carried out.The criteria to be evaluated would thus be quite similar to serial extractions. The dental age of an individual needs to be assessed. For the second molar to assume a normal relationship, the first molar should be extracted preferably before eruption of the second molar (especially in the mandibular arch). Before extracting the first molars, the inclination of the second premolar should be evaluated, as it may incline further distally and get impacted below the second molar.

The above article discusses briefly about the

dental crowding – extraction of teeth

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