Dental Anomalies – Dental News

This entire discussion would be seriously flawed were it not for at least a brief mention of the concept promoted by Angle, stating that only the entire, uncompromised complement of teeth can function properly. Such views fur- ther state that if the integrity of human dentition is compromised by extracting, for instance, premolars, then the entire stomatognathic system malfunctions. Modern dentistry largely abandoned these views. In the 1950s and 1960s, it was quite common and almost fashion- able to treat malocclusions with the help of extraction of the four first premolars. Among the notable proponents of such an approach were the most popular names of the time, including Drs. Tweed and Begg. However, in the 1980s and 1990s, the pendulum of the popular approach swung to the opposite direc- tion and it became rather unpopular to extract teeth. In the opinion of this writer, clinicians have gone too far in adopting either philosophy. The ubiquitous extractions of one generation ago, along with the hesitation and almost a fear of extractions during the more recent decades are both too extreme. The most rational approach to resolving the problems of dental crowding could and often should consider both approaches and decide on the one, or even the combination of the two, that offer the most desirable correction of this common problem.

While there are numerous anomalies in this broad category, this paper will elab- orate on the most common ones, namely impactions, congenitally missing teeth, the so-called ‘peg shaped’ maxil- lary lateral incisors and transposition of teeth. Conspicuously absent from this discussion will be various forms of developmental anomalies of the face and the mouth. This is because there are numerous comprehensive articles and dissertations on the topics through- out the dental literature. Similarly, because this author has published numerous papers on the subject of impactions, transposition and related anomalies, instead of repeating himself, he will summarize and then speculate on the future approaches and solutions in resolving many of these anomalies.

It is generally recognized that the most common positional anomaly of a tooth is rotation. Rotations are so prevalent that it is difficult to find a modern man or woman with an occlusion that does not exhibit some degree of this common anomaly. Because this anomaly is so ubiquitous, many clinicians do not even list them as a trait of malocclusion, except when rotations are severe, e.g. a Orthodontics tooth rotated more than 45 degrees.

From the clinical aspect, rotations are not overly difficult to correct, particular- ly with the use of fixed orthodontic appliances. It is important to keep in mind, however, that corrected rotations also represent the condition most likely to relapse. Various strategies have been developed to guard against, or to minimize, rotational relapse. One of the most effective ones is the procedure known as supra-crestal fiberotomy [SCF], a minor surgical procedure in which the supra-crestal gingival fibers are sev- ered.4

Ectopic position constitutes the second most common positional anomaly of the dentition. Within this category, the one that concerns clinicians the most is impaction. Even though any one tooth from either dental arch can be impacted, impaction of the maxillary permanent canine receives most attention. This is the case for numerous reasons, including the central role that the canine plays in the function of articulation and occlusion. A second, nearly equally important reason, is its role in facial esthetics.

There is an abundance of clinical reports on the management of impactions. The long list of related publications includes many contributions by this writer.5-9 Many years of managing treatments of the maxillary canine impaction, supplemented with information from the published work have yielded some interesting observations:

• Impactions affect approximately one out of ten individuals [based on the various reports, from 3 to 18% of population is affected];

• Excluding third molars, the maxillary canine is the most frequently impacted tooth in humans;

• There appears to be interesting gender and side differences. Females exhibit nearly twice as many maxillary canine impactions as males. Reportedly, the left side is significantly more often affected than the right side [based on the various reports, from about 2:1 up to 6:1];

• No racial predilection could be detected. Similarly, the global distribution of impactions seems to be quite similar. Practically no significant secular changes can be detected, even though some authors predict an increase in prevalence of impactions. This prediction is based on somewhat preliminary conclusions, stating that human teeth are increasing in size at the same time that the available bone appears to be shrinking. Note that the reader can relate this last statement to discussion on the etiology of the dental crowding.