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Duplication of the premolar dentition
Duplication
of the premolar dentition
Mel L. Kantor, D.D.S.,* c’. Stephen Bailey, D.D.S.,** and E. Jeflerson Burkes, Jr., D.D.S., M.S., *** Chapel Hill and Shelby. N.C LNIVERSITY
Of
UORI‘H
CAROLINA
Multiple supernumerary teeth, often dental anomaly. We present a case premolar dentition and premolarization (ORAL
SIJRG ORAL
MED
ORAL
PATHOI.
S:ctlOOl
OF DI:hTlS-IR\r
associated with various syndromes, of a g-year-old black male patient of the permanent canines.
is a relatively with complete
uncommon duplication
isolated of the
1988;66:62-41
S
upernumerary or supplemental teeth are a common dental anomaly found in 1% to 3% of the population.‘,’ They may occur as isolated dental *Section of Oral Radiology, University of North Carolina School of Dentistry. **In private practice. Shelby. N.C. ***Section of Oral Pathology, University of North Carolina School of Dentistry.
findings or as part of a syndrome; cleidocranial dysplasia is a well-known example. One of the largest studies was reported by Stafne3 in 1932. Among 48,550 patients, he found 441 patients with supernumerary teeth. Of thesepatients, 382 (87%) had a single supernumerary tooth, 54 (12%) had two extra teeth, and 5 (1%) had three supernumerary teeth. The ratio of supernumerary
Fig. 1. A, Panoramic view. B, Bitewing view. The radiographs show eight supernumerary teeth positioned in an orderly fashion that result in a duplication of the premolar dentition. Tn addition, premolarization of the permanent canines is evident. 62
Volume 66 Number 1
Duplication of premolar dentition
63
Fig. 3. Ground section of supernumerary tooth showing normal structure of premolar crown with regular formation of enamel and dentin with a scalloped dentinoenamel junction.
Fig. 2. Gross specimens of primary molar and supernumerary teeth positioned as they were in jaws with line drawing of normally developing premolar tooth.
teeth found in the maxilla to those found in the mandible was 8.2 to 1. Stafne did not report the distribution with respect to the gender in his sample population. Results from epidemiologic studies in Sweden,4,5India,6 France,’ Japan,” and Israel9 are in general agreement with Stafne’s results and, in addition, reveal a male-to-female ratio of approximately 2: 1. The studies were in general agreement in regard to the frequency of single and multiple supernumerary teeth. Single supernumerary teeth account for 76% to 87% of all findings, supernumerary teeth occurring in twos account for 12% to 23%, and multiple supernumerary teeth account for less than 1%. Casesof multiple mandibular supernumerary premolars have been published.‘0-‘2However, on the basis of epidemiologic studies, these are rare. CASE
REPORT
A 9-year-old black male patient was seen for a routine examination. Radiographs disclosed an unusual number of
developing permanent teeth (Fig. 1). Apical to each maxillary and mandibular primary molar, two developing premolars were seen. There was a very regular vertical pattern throughout. Immediately apical to the primary molar was a radiopacity that had the density and morphology of the enamel cap of the succedaneous premolar. Apical to this was a premolar tooth of normal form and in the normal stage of development for a patient of this age. In addition, the permanent canine teeth appeared to be tricuspid, approximating the shape of the premolars, a condition described as premolarization of the canine.’ No other morphologic abnormalities were noted. According to report, neither the patient’s parents nor his siblings have or had any unusual dental findings. However, the mother had sixth digits on each hand that were removed during infancy, and a 4-year-old brother has an extra nipple. The primary molars and the enamel caps were surgically removed, and a space maintenance appliance was placed to facilitate eruption of the premolars that were normal in appearance. The gross appearance of the enamel cusps (Fig. 2) was that of normally developing premolar teeth without root formation. Two of the teeth were decalcified, processed routinely, and stained with hematoxylin and eosin. These teeth had a scalloped dentinoenamel junction and S-shaped dentinal tubules. The dental papilla consisted of myxomatous connective tissue with vital odontoblasts regularly arranged at the interface with the uncalcified dentinal matrix. Two teeth were examined after ground section preparation (Fig. 3). Each had well-formed enamel rods in incrementally deposited layers and showed Hunter-Shrager bands. The dentinoenamel junction was scalloped, and the dentin formed in slight curves to the region of the dental papilla. All of the teeth examined histologically appeared to be vital developing premolars of normal size with no significant abnormalities.
64
Kantor, Bailey, and Burkes
Oral
Surg
July
1988
DISCUSSION
REFERENCES
Multiple supernumerary teeth associated with cleidocranial dysplasia are inherited as an autosomal dominant trait. However, the cause of supernumerary teeth as an isolated dental finding is essentially unknown; they are assumed to be polygenic in most instances.‘j The lack of a confirmed pedigree for this family prevents us from addressing the issue of inheritance. The pathogenesis of supernumerary teeth is not well understood but it is assumed to be the development of an extra or third tooth bud arising from the dental lamina or the splitting of a single permanent tooth bud during the initiation or proliferation stages of tooth development.13,‘4 The unique features in this case include the symmetry and the involvement of all four quadrants, the vertical orderly arrangement of the supernumerary and succedaneous premolar teeth, and the position of the normally developing premolars apical to the arrested supernumerary teeth. These findings support the theory of pathogenesis that assumes that two premolar anlagen arise from the dental lamina of the primary tooth since, if the supernumerary tooth was the result of a splitting of a single tooth bud, one would expect that the developmental stage of the supernumerary tooth and the premolar tooth would be approximately the same, and it would be unlikely that the vertical orderly arrangement would occur in all eight sites. This, in addition to the premolarization of the canines, suggests an unusually strong expression of the genetic mechanism for the production of premolars. This case represents an extreme example of a relatively common dental anomaly.
I. Pindborg JJ. Pathology of the dental hard tissues. Philadeiphia: WB Saunders Company, 1970:26-33, 39. 2. Dixon GH, Stewart RE. Genetic aspects of anomalous tooth development. In: Steward RE, Prescott GH, eds. Oral facial genetics. St. Louis: The CV Mosby Company, 1976:13x140. 3. Stafne EC. Supernumerary teeth. Dent Cosmos 1932:74. 653-9. 4. Lind V. Medfijdda antalsvariationer i permanenta dentitionen. Odont Revy 1959;10:176-89. 5. Grahnin H, Lindahl B. Supernumerary teeth in the permanent dentition. Odont Revy 1961;12:290-4. 6. Parry RR, Iyer VS. Supernumerary teeth amongst orthodontic patients in India. Br Dent J 1961;111:257-8. 7. Lacoste L, Hirsch C, Frank R. Les inclusions dentaires surnumdraires chez 1’ enfant. Rev Franc Odontostomat 1962;9:967-83. 8. Niswander JD, Sujako C. Congenital anomalies of teeth in Japanese children. Am J Phys Anthropol 1963;21:569-74. 9. Rosenzweig KA, Garbarski D. Numerical aberrations in the permanent teeth of grade school children in Jerusalem. Am J Phys Anthropol 1965;23:277-84. 10. Isokawa S, Ozaki T. Supernumerary teeth. ORAL SURG ORAL MED
ORAL
PATHOL
11. Ruhlman DC, supernumerary
1959;12:730-1.
Neely AR. Multiple impacted teeth. ORAL SURG ORAL
and erupted MED
ORAL
PATHOL1964;17:199-202.
12. Poyton merary PATHOL
GH, Morgan GA, Crouch SA. Recurring supernumandibular premolars. ORAL SURG ORAL MED ORAL 1960;13:964-6.
13. Bergsma D, ed. Birth defects compendium. 2nd ed. New York: Alan R Liss Inc. 1979:lOlO. 14. Shafer WG, Hine MK, Levy BM. A textbook of oral pathology. 4th ed. Philadelphia: WB Saunders Company, 1983:917. Reprint requests to: Dr. Mel L. Kantor Section of Oral Radiology University of North Carolina School of Dentistry, CB no. 7450 Chapel Hill, NC 27599
of the premolar dentition
Mel L. Kantor, D.D.S.,* c’. Stephen Bailey, D.D.S.,** and E. Jeflerson Burkes, Jr., D.D.S., M.S., *** Chapel Hill and Shelby. N.C LNIVERSITY
Of
UORI‘H
CAROLINA
Multiple supernumerary teeth, often dental anomaly. We present a case premolar dentition and premolarization (ORAL
SIJRG ORAL
MED
ORAL
PATHOI.
S:ctlOOl
OF DI:hTlS-IR\r
associated with various syndromes, of a g-year-old black male patient of the permanent canines.
is a relatively with complete
uncommon duplication
isolated of the
1988;66:62-41
S
upernumerary or supplemental teeth are a common dental anomaly found in 1% to 3% of the population.‘,’ They may occur as isolated dental *Section of Oral Radiology, University of North Carolina School of Dentistry. **In private practice. Shelby. N.C. ***Section of Oral Pathology, University of North Carolina School of Dentistry.
findings or as part of a syndrome; cleidocranial dysplasia is a well-known example. One of the largest studies was reported by Stafne3 in 1932. Among 48,550 patients, he found 441 patients with supernumerary teeth. Of thesepatients, 382 (87%) had a single supernumerary tooth, 54 (12%) had two extra teeth, and 5 (1%) had three supernumerary teeth. The ratio of supernumerary
Fig. 1. A, Panoramic view. B, Bitewing view. The radiographs show eight supernumerary teeth positioned in an orderly fashion that result in a duplication of the premolar dentition. Tn addition, premolarization of the permanent canines is evident. 62
Volume 66 Number 1
Duplication of premolar dentition
63
Fig. 3. Ground section of supernumerary tooth showing normal structure of premolar crown with regular formation of enamel and dentin with a scalloped dentinoenamel junction.
Fig. 2. Gross specimens of primary molar and supernumerary teeth positioned as they were in jaws with line drawing of normally developing premolar tooth.
teeth found in the maxilla to those found in the mandible was 8.2 to 1. Stafne did not report the distribution with respect to the gender in his sample population. Results from epidemiologic studies in Sweden,4,5India,6 France,’ Japan,” and Israel9 are in general agreement with Stafne’s results and, in addition, reveal a male-to-female ratio of approximately 2: 1. The studies were in general agreement in regard to the frequency of single and multiple supernumerary teeth. Single supernumerary teeth account for 76% to 87% of all findings, supernumerary teeth occurring in twos account for 12% to 23%, and multiple supernumerary teeth account for less than 1%. Casesof multiple mandibular supernumerary premolars have been published.‘0-‘2However, on the basis of epidemiologic studies, these are rare. CASE
REPORT
A 9-year-old black male patient was seen for a routine examination. Radiographs disclosed an unusual number of
developing permanent teeth (Fig. 1). Apical to each maxillary and mandibular primary molar, two developing premolars were seen. There was a very regular vertical pattern throughout. Immediately apical to the primary molar was a radiopacity that had the density and morphology of the enamel cap of the succedaneous premolar. Apical to this was a premolar tooth of normal form and in the normal stage of development for a patient of this age. In addition, the permanent canine teeth appeared to be tricuspid, approximating the shape of the premolars, a condition described as premolarization of the canine.’ No other morphologic abnormalities were noted. According to report, neither the patient’s parents nor his siblings have or had any unusual dental findings. However, the mother had sixth digits on each hand that were removed during infancy, and a 4-year-old brother has an extra nipple. The primary molars and the enamel caps were surgically removed, and a space maintenance appliance was placed to facilitate eruption of the premolars that were normal in appearance. The gross appearance of the enamel cusps (Fig. 2) was that of normally developing premolar teeth without root formation. Two of the teeth were decalcified, processed routinely, and stained with hematoxylin and eosin. These teeth had a scalloped dentinoenamel junction and S-shaped dentinal tubules. The dental papilla consisted of myxomatous connective tissue with vital odontoblasts regularly arranged at the interface with the uncalcified dentinal matrix. Two teeth were examined after ground section preparation (Fig. 3). Each had well-formed enamel rods in incrementally deposited layers and showed Hunter-Shrager bands. The dentinoenamel junction was scalloped, and the dentin formed in slight curves to the region of the dental papilla. All of the teeth examined histologically appeared to be vital developing premolars of normal size with no significant abnormalities.
64
Kantor, Bailey, and Burkes
Oral
Surg
July
1988
DISCUSSION
REFERENCES
Multiple supernumerary teeth associated with cleidocranial dysplasia are inherited as an autosomal dominant trait. However, the cause of supernumerary teeth as an isolated dental finding is essentially unknown; they are assumed to be polygenic in most instances.‘j The lack of a confirmed pedigree for this family prevents us from addressing the issue of inheritance. The pathogenesis of supernumerary teeth is not well understood but it is assumed to be the development of an extra or third tooth bud arising from the dental lamina or the splitting of a single permanent tooth bud during the initiation or proliferation stages of tooth development.13,‘4 The unique features in this case include the symmetry and the involvement of all four quadrants, the vertical orderly arrangement of the supernumerary and succedaneous premolar teeth, and the position of the normally developing premolars apical to the arrested supernumerary teeth. These findings support the theory of pathogenesis that assumes that two premolar anlagen arise from the dental lamina of the primary tooth since, if the supernumerary tooth was the result of a splitting of a single tooth bud, one would expect that the developmental stage of the supernumerary tooth and the premolar tooth would be approximately the same, and it would be unlikely that the vertical orderly arrangement would occur in all eight sites. This, in addition to the premolarization of the canines, suggests an unusually strong expression of the genetic mechanism for the production of premolars. This case represents an extreme example of a relatively common dental anomaly.
I. Pindborg JJ. Pathology of the dental hard tissues. Philadeiphia: WB Saunders Company, 1970:26-33, 39. 2. Dixon GH, Stewart RE. Genetic aspects of anomalous tooth development. In: Steward RE, Prescott GH, eds. Oral facial genetics. St. Louis: The CV Mosby Company, 1976:13x140. 3. Stafne EC. Supernumerary teeth. Dent Cosmos 1932:74. 653-9. 4. Lind V. Medfijdda antalsvariationer i permanenta dentitionen. Odont Revy 1959;10:176-89. 5. Grahnin H, Lindahl B. Supernumerary teeth in the permanent dentition. Odont Revy 1961;12:290-4. 6. Parry RR, Iyer VS. Supernumerary teeth amongst orthodontic patients in India. Br Dent J 1961;111:257-8. 7. Lacoste L, Hirsch C, Frank R. Les inclusions dentaires surnumdraires chez 1’ enfant. Rev Franc Odontostomat 1962;9:967-83. 8. Niswander JD, Sujako C. Congenital anomalies of teeth in Japanese children. Am J Phys Anthropol 1963;21:569-74. 9. Rosenzweig KA, Garbarski D. Numerical aberrations in the permanent teeth of grade school children in Jerusalem. Am J Phys Anthropol 1965;23:277-84. 10. Isokawa S, Ozaki T. Supernumerary teeth. ORAL SURG ORAL MED
ORAL
PATHOL
11. Ruhlman DC, supernumerary
1959;12:730-1.
Neely AR. Multiple impacted teeth. ORAL SURG ORAL
and erupted MED
ORAL
PATHOL1964;17:199-202.
12. Poyton merary PATHOL
GH, Morgan GA, Crouch SA. Recurring supernumandibular premolars. ORAL SURG ORAL MED ORAL 1960;13:964-6.
13. Bergsma D, ed. Birth defects compendium. 2nd ed. New York: Alan R Liss Inc. 1979:lOlO. 14. Shafer WG, Hine MK, Levy BM. A textbook of oral pathology. 4th ed. Philadelphia: WB Saunders Company, 1983:917. Reprint requests to: Dr. Mel L. Kantor Section of Oral Radiology University of North Carolina School of Dentistry, CB no. 7450 Chapel Hill, NC 27599