Panoramic Radiologic Appraisal of Anomalies of Dentition: Chapter 2

Volume 3, Issue 2 US $6.00 Editor: Panoramic radiologic appraisal of Allan G. Farman, BDS, PhD (odont.), DSc (odont.), anomalies of dentition: Chapter #2 Diplomate of the By Dr. Allan G. Farman entiated from compound odonto- American Board of Oral mas. Compound odontomas are and Maxillofacial The previous chapter Radiology, Professor of encapsulated discrete hamar- Radiology and Imaging higlighted the sequential nature of tomatous collections of den- Sciences, Department of developmental anomalies of the ticles. Surgical and Hospital dentition in general missing teeth Recognition of supernumerary Dentistry, The University of in particular. This chapter provides teeth is essential to determining Louisville School of discussion supernumerary teeth appropriate treatment [2]. Diag- Dentistry, Louisville, KY. and anomalies in tooth size. nosis and assessment of the Supernumeraries: mesiodens is critical in avoiding Featured Article: Supernumeraries are present when complications such as there is a greater than normal impedence in eruption of the Panoramic radiologic complement of teeth or tooth maxillary central incisors, cyst appraisal of anomalies of follicles. This condition is also formation, and dilaceration of the dentition: Chapter #2 termed hyperodontia. The fre- permanent incisors. Collecting quency of supernumerary teeth in data for diagnostic criteria, In The Recent Literature: a normal population is around 3 % utilizing diagnostic radiographs, [1]. Most supernumeraries are found and determining when to refer to Impacted canines in the anterior maxilla (mesiodens) a specialist are important steps in or occur as para- and distomolars the treatment of mesiodens [2]. Space assessment in that jaw (see Fig. 1). These are Early diagnosis and timely surgical followed in frequency by intervention can reduce or Age determination premolars in both jaws (Fig. 2, 3). eliminate the need for orthodon- Pre-, post- or para-dentition tic treatment and reduce compli- Hypodontia supernumeraries are possible cations to the regular dentition in depending on the timing of Apical root resorption such cases. As a good rule of development of the supernumer- thumb, if a permanent tooth is Third molar eruption ary teeth in relation to that of the erupted to half its crown height assessment regular teeth. Most supernumerar- and the contralateral equivalent ies are rudimentary or conical in tooth in the same arch is not seen shape; however, some are regular clinically, a radiograph should be FAQs: in shape and are then termed made to investigate the cause. supplemental teeth. Supernumer- Infection control In a series of 10 cases of ary premolars are frequently supernumerary premolars treated Reading films supplemental. Complications from in Barcelona only one case supernumerary teeth include altered the normal eruption of the impactions and displacement or regular premolars; two evidenced delayed eruption of regular teeth. follicular cyst development [3]. Most individual supernumerary This is consistent with the teeth are sporadic in occurance; supernumerary premolars com- however, multiple supernumeraries monly being post-dentition in can occur in association with onset and being impeded from cleidocranial dysplasia or eruption by the regular teeth. Gardner’s syndrome. Multiple Panoramic radiography is an supernumeraries should be differ- important step toward the identi- “ Cleidocranial dysplasia is an autosomally dominant condition characterized by defective ossification of cranial bones and clavicles.” fication, localization and surgical removal of these supernumerary teeth [4]. (a) Cleidocranial dysplasia: Cleidocranial dysplasia is an autosomally dominant condition characterized by defective ossification of cranial bones and clavicles. It is associated with multiple supernumerary teeth, especially anterior to the first permanent molars, retained primary teeth and unerupted permanent teeth (Fig. 4). There is also delayed fontanelle closure, and hypolasia or aplasia of the clavicles [5]. Fig. 1: Unerupted mesiodens McNamara et al. (1999) (arrowed on panoramic radiograph) reported the effectiveness of is causing displacement of the adjacent regular central incisors. dental panoramic radiography in Uncommonly (photograph) there is identifying features pathogno- room for the mesiodens to erupt monic for cleidocranial dysplasia and “function”. [6]. In addition to the established dental complications of failure of eruption of the permanent dentition and multiple supernumerary teeth, morphological abnormalities of the maxilla and mandible, particularly in the ascending ramus and coronoid process are present. While there often are numerous supernumerary teeth present in cleidocranial dysplasia this might not be apparent clinically. Failures in tooth eruption often results in apparent hypodontia. It is often necessary to fabricate overdentures for the prosthodontic treatment of such Fig. 2: Post-dentition supplemental patients. supernumerary premolars are illustrated Dentigerous cysts may form in the panoramic radiograph. The clinical photograph shows dental around the crowns of unerupted malocclusion occurring in a patient regular and supernumerary teeth having three such supplemental teeth weakening the structure of the that have erupted. The dried jaw jaw and predisposing it to patho- specimen is of an ancient Indian jaw logic fracture. Dental panoramic more than 1000 year old (Mississippian) radiography is a valuable adjunct showing an erupted supplemental in confirming the diagnosis of premolar tooth. 2 cleidocranial dysplasia and in subsequently checking for dentigerous cyst formation. (b) Gardner’s syndrome: Gardner’s syndrome (famial adenomatosis coli; intestinal polyposis type II ) is characterized by the occurrence of multiple impacted supernumerary teeth, osteomas of the long bones, skull and jaws, multiple polyposis of the large intestines and multiple epidermoid or dermoid cysts Significantly, the intestinal polyps are premalig- nant. Detection of osteomas in Fig. 3: Multiple unerupted supernumerary the jaws and multiple supernu- teeth in the mandible that are not merary teeth (Fig. 5) on pan- interfering with the regular dentition. In oramic radiology may lead to such cases a syndrome such as cleidoc- the early determination of the ranial dysplasia should be ruled out. syndrome and preventive management of a potentially fatal malignancy [7]. In a matched study 82 % of patients having this syndrome showed osteomatous changes compared to 10 % of controls. Super- numerary teeth, compound odontomas and impacted teeth were found in 30 % of patients having Gardner’s syndrome compared to 4 % of controls. Anomalies in Tooth Size (a) Macrodontia Macrodontia involves a tooth or teeth being larger than normal in size with proportional enlarge- ment of pulp chamber, crown and root (Fig 6). This condition Fig. 4: Cleidocranial dysplasia is may be general or localized. associated with multiple supernu- General true macrodontia can merary teeth (panoramic radio- be associated with pituitary graph). Affected patients often giantism. Unilateral relative have hypoplastic or absent clavicles and have the flexibility to macrodontia can occur in bring their shoulders close together hemifacial hypertrophy. Macro- in the midline (e.g. photograph). dontia is often sporadic, but can also be a feature of Ekman- Westborg-Julin syndrome [8, 9]. There is usually a normal 3 complement of teeth. Macro- Fig. 5: Gardner’s dontia needs to be differenti- syndrome: multiple ated from connation (gemina- osteomas are tion or fusion) and concres- present in both jaws cence. In germination there is and there are also division of a tooth with an retained primary attempt to make an additional teeth and multiple tooth. In fusion there is combina- impacted perma- tion of two or more teeth with a nent teeth. Such patients are also reduction in number. For fusion, prone to develop this number count presupposes intestinal cancer. that the combination does not involve a supernumerary tooth or teeth. Concrescence is the joining of adjacent teeth through cementum. Early detection of macrodontia is of importance for orthodontic planning of space and cosmetic intervention. Certainly if space is not avail- able for eruption of all of the teeth due to macrodontia, impaction or malocclusion is likely to ensue. Panoramic radiology can help in early diagnosis. Caution needs to be applied; however, as the crown of a tooth that is lingually or palatally displaced will appear magnified horizontally on stan- dard panoramic views. Moreover care needs to be made to ensure the patient was posi- tioned symmetrically in the cephalostat. Rotation or lateral displacement of the head during panoramic radiology can cause Fig. 6: Sporadic macro- one side of the jaws and teeth dontia results in a to be minified, while the other disproportionately large side is magnified. tooth crown in compari- (b) Microdontia son with the contralateral counterpart tooth Microdontia implies the abnor- (radiograph). The mal smallness of a single or photograph illustrates a case of multiple teeth. This is most macrodont lateral incisior in which the commonly an isolated anomaly tooth was similar in size to a maxillary such as a peg lateral or diminu- central incisor tooth. tive third molar tooth (Fig. 7). The 4 “ Microdontia implies the abnormal smallness of a single or multiple teeth. This is most commonly an isolated anomaly such as a peg lateral or diminutive third molar tooth.” Fig. 7: Bilateral microdont

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