Running title : Single Maxillary Central Incisor.

SOLITARY MAXILLARY CENTRAL INCISOR IN THE MIDLINE ASSOCIATED WITH SYSTEMIC ANOMALIES * Othman M. Yassin, DDS, MSC. ** Yaser M. El - Tal, MD, JMB. * Senior specialist in pediatric dentistry, Royal Medical Services and Part time Lecturer in the Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan. ** Pediatric specialist, Prince Rashed Ben Al-Hassan Hospital, Royal Medical Services, Irbid, Jordan. Running title : Single Maxillary Central Incisor. Correspondence : Dr. Othman M. Yassin P. O. Box 31, Al - Sareeh 21156 - Jordan. FAX-00962 2 295123 00962 2 277005

ABSTRACT Single maxillary central incisor in the midline is a rare developmental anomaly.the appearance of a single incisor in place of two teeth may occur as an isolated dental finding that can be related to fusion of two neighbouring tooth or to agenesis of a tooth germ. However, it has also been reported to occur in association with autosomal dominant holoprosencephaly, growth retardation, and midline developmental defects. This report added other systemic defects found in association with the single maxillary central incisor. 2 2

INTRODUCTION. Dental anomalies of number, form, size and structure are of interest to dentists, geneticists, and anthropologists. Developmental disturbances during the initiation and proliferation stages of tooth formation are known to produce aberration in both number and structure. Congenital absence of one or few teeth (hypodontia) is the most common anomalies in the permanent dentition, even considered to be a variant of normal. Agenesis of the primary teeth is rare and if it occurs it is seen in the incisor region and is normally associated with agensis of the succeeding permanent teeth. In the permanent dentition, hypodentia is most commonly seen in third molars followed in frequency by second premolars and maxillary lateral incisors 1-3. Congenital absence of teeth may arise from (1) physical obstruction or disruption of dental lamina, (2) space limitation in the dental arch, (3) functional abnormalities of the dental epithelium or (4) failure of induction of the underlying mesenchyme 1. When a patient exhibits multiple congenitally missing teeth (oligodontia), there is a likelihood that the patient may have a genetic disorder 2-5. A congenitally absence of maxillary central incisor is a rare developmental anomaly 4. Epidemiological data indicated that agenesis of central incisors was not observed in 10.000 Americans aged 6 to 15 years 1 nor among 12.500 American black population 2. Similar observation was reported in 7, 7.886 Canadian individuals 7. Rappaport et al, introduced the term monosuperocentroincisivodontic dwarfism to describe the association between 3

a single maxillary central incisor and growth hormone deficiency 8,9.This association was 3 later confirmed by Vanelli et al 10. Other cases had short stature but normal growth hormone level 9,11.A single maxillary central incisor has also been reported as an isolated finding in association with normal growth 11-14.. The exact etiology of congenitally missing central maxillary incisor is still unknown. According to Osborn and Ten Cate the formation of one tooth instead of two could be due to disturbances in mitotic potential of the incisor group 15, which could be under genetic and environmental determinants 1-5. This case report describes a child with a congenitally missing maxillary central incisor associated with systemic abnormalities. CASE HISTORY. A 9-year-old- Jordanian boy was referred to the Pediatric Dental Clinic at Prince Rashid Ben Al-Hassan Hospital for unerupted maxillary central incisor. Family history revealed that he was first among two siblings. His parents are consanguineous members of the family not affected by similar dental condition. Both the mother and father were of normal stature, and neither had clinical deformity. He was born after an uneventful full-term pregnancy. There was no history of orofacial trauma. Clinical examination revealed a single maxillary right central incisor positioned in the midline of the alveolar bone (Figure 1). The tooth appeared normal in color with no enamel defects. The mesiodistal crown diameter was 6.5mm. Radiographic examination showed that the tooth had a single root, and pulp canal with an open apex. The 4

primary and permanent lateral incisors could be seen on both sides of the tooth (Figure 2). 4 All permanent teeth are present except the maxillary third molars.physical examination revealed a short child height of 122 cm ( 3rd percentile ), skeletal age of 54 months (Figure 3). The patient had a small head (circumference 47 cm; 3rd percentile), deviated nasal septum and depressed nasal bridge. Genital examination revealed an undescended left testicle (cryptorchism). Provocative growth hormone assay revealed partial deficiency on two occasions. Thyroid function test was normal. The child`s intellectual assessment revealed slow learning abilities, with an intelligence quotient ( IQ ) of 86. Cardiovascular and respiratory systems were normal. Spinal radiography, brain computed tomography and renal ultrasound were within normal limits. DISCUSSION Agenesis of teeth may be an isolate trait or an integral manifestation of a syndrome. Some of these syndromes have specific patterns of hypodontia. 2,3 Congenitally missing central incisor is a rare developmental anomaly which has been found in certain types of dwarfism and growth hormone deficiency as well as an isolated phenomenon. Developmentally, the formation of one incisor instead of two could result from a disturbances in the mitotic potential of the incisor group. 10 Another possible cause is the primary tooth could be fused with one of the permanent successor. 16 Patients with hypodontial of anterior teeth often seek treatment because of appearance, impaired 5

mastication and speech difficulties. Hypodontia is linked to a complex of dental changes including the size and form of remaining teeth, malocclusion and the overall rate of dental development. In this case, history taking did not confirm an extraction 5 or avulsion of maxillary incisors whether the patient had single or two maxillary primary central incisors. The evidence presented indicates that this is an instance of agenesis of a central incisor where the remaining central incisor erupted in the midline. Comparison of the measurement with that reported by Hattab et al. 17 on Jordanian individuals revealed that the size of the central incisor in the present case was 2.4mm (27%) smaller than its counterpart in normal population. A single maxillary central incisor in association with other anomalies has been reported. Short stature with or without growth hormone deficiency has been previously reported with a single maxillary central incisor. 8,18-21 The child in this report had short stature associated with deficiency in growth hormone. Midline disorders associated with a single maxillary central incisor have been reported which varied in severity from a broad nasal groove to vertebral, anal, tracheoesophageal and renal defects. (Table). In our patient the single maxillary central incisor was associated with, microcephaly, cryptorchism, growth hormone deficiency, depressed nasal bridge and deviated nasal septum in addition to the slow learning abilities. 6

We can conclude that any patient who presents with a single maxillary central incisor should be referred for a detailed medical examination to exclude other associated systemic abnormalities. The labeling of an association of anatomical abnormalities is used to alert the Clinician to the possible existence of other problems which may require specialist care 6 Table: Systemic abnormalities reported in patients with a single incisor Endocrine Short stature 9,18.19.20,21.* Growth hormone deficiency,9,10, * Graves disease 9 Precocious puberty 23 Central nervous system Microcephaly 18,24,* J - shape sella turcica 9 Hypothalamic hamartoma 23 Spina bifida 19 Holoprosencephaly 21,22,25 Cardiovascular system Congenital heart disease 18 Patent ductus arteriosus 19 Cyanotic attacks 19 Right bundle branch block 12 Ventricular septal defect 22 Gastrointestinal tract Tracheoesophageal fistula 12 Oesophageal atresia 12 Anal atresia 12 Congenital ectopic anus 19 Renal Absent left kidney 12 Renal defects 12 Eyes Visual defects 19 Hypotelorism9,10,25 Slanting palpebral fissures 20 Staphylomas 21 Micropthalmia 28 Iris coloboma 21,24,28 Nose Nasal obstruction 19 Depressed nasal bridge 9,20,24,* Anteverted nostrils 9,12 Nasal groove 9,12 Deviated nasal septum * Broad nose 9 small nose 26 Ears Thick pinae and small pit 26 Reriauricular skin tag 28 Oral cavity Torus palatinus 20,24 Narrow high arch palate 9,10,25 Prominent philtrum 12,26 Skin Incontinentia pigmenti achromians 24 Cafe an lait spots 26 Fine axillary hair 26 maxillary central 7

Bilateral fifth finger clinodoctyly 26 Bilateral single transverse palmar creases 26 Genitalia Undescended testis 12,* Skeletal Scoliosis 12,18 Partial syndactyly toes 3-4 9,26 Hemivertebral T12 12,22 Absence of 2 sacral vertebrae 12 Klippel - Feil deformity 2 Chromosomal abnormality Chromosome 18 short arm deletion 20,26 XXX-syndrome 27 Mental status Slow learning abilities * * In the present case 7 REFERENCES 1.Stewart RE. Witkop CJ, Bixler D. The dentition chapter 3 in Pediatric Dentistry: scientific foundations and clinical practice. R.E. Stewart; Barber TK, K.C. Troutman; S.H.Y. Wei. (eds) St Louis: The C.V Mosby Co, 1982, pp 87-134. 2.Winter GB, Brook AH. Tooth Abnormalities. In A companian to Dental Studies: Vol. 4. Clinical Dentistry. Ed. Rowe AHR. Chapter3, Oxford, Blackwell Scientific Publications. 1986, pp 55-103. 3.Jorgenson RJ. Clinician s view of hypodontia. J Am Dent Assoc 1980; 101: 283-286. 4.Silverman NE, Ackerman JL. Oligadonta a study of its prevalence and variation in 4032 children. J Dent Child 1979; 46:38-45. 5-Hattab FN, Angmar-Mansson B. Oligodontia of the permanent dentition in two sisters with polycystic ovarian syndrome. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997, 84: (In press). 6.Hattab FN, Al-Khateeb T, Mansour M. Oral manifestations of severe short-limb dwarfism resembling Grebe chondrodysplasia. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1996, 81: 550-555. 7.Shah RM, Boyd MA, Vakil TF. Studies of permanent tooth anomalies in 7,886 Canadian individuals. J Canad Dent Assn 1978; 446: 265-276. 8.Rappaport EB, Ulstrom RA. Monosuperoincisivodontic dwarfism. Birth Defect 1976; 7: 243-245. 8

9.Rappaport EB, Ulstrom RA, Gorlin RJ, Lucky AW, Colle E, Miser J. Solitary maxillary central incisor and short stature. J Pediatr 1977;91:924-928. 10.Vanelli M, Bernasconi S, Balestrazzi P. Incisive superieure unique et deficit en STH. Arch Fr1980;37:321-322. 11.Parker PR, Vann WFJr. Solitary maxillary central incisor : clinical report. Pediatr Dent 1985: 7: 134-136 8 12.Wesly RK, Hoffman WH, Perrin J, Delaney JR. Solitary maxillary central incisor and normal stature. Oral surg 1978; 46 : 837-842. 13.Santoro FP, Wesley RK. Clinical evaluation of two patients with a single maxillary central incisor. J Dent child 1983; 50;379-381. 14.Mass E, Sarnat H. Single maxillary central incisors in the midline. J Dent Child 1991; 58: 413-416. 15.Osborn JW, Ten Cate AR. Advanced dental histology, 4th edition. Bristol, London, Boston : Wright PSG, 1983, pp 35-45. 16.Grahnen H, Granath LE. Numerical variation in primary dentition and their correlation with the permanent dentition. Odontol Revy 1961; 12: 348-373. 17.Hattab FN, Al-Khateeb S, Sultan I. Mesiodistal Crown diameters of permanent teeth in Jordanians. Archs Oral Biol 1996; 41: 641-645. 18.Fulstow ED. The congenital absence of upper central incisor : report of a case. Br Dent J 1968; 124: 186-188. 19.Ellisdon PS, Marshal KF. Connation of maxillary incisors. Br Dent J 1970; 129 : 16-21. 20.Dolan JLM, Willson WG, Willson WG. 18p-syndrome with a single maxillary incisor. J Med Genet 1981; 18 :396-398. 21.Liberfarb RM, Abdo OP, Pruett RC. Ocular coloma associated with solitary maxillary central incisor and growth failure : manifestations of holoprosencephaly. Ann Ophthalmol 1977; 19 : 226-227. 9

22.Fleming P, Nelson J, Gorlin RJ. Single maxillary central incisor in association with midline anomalies. Br Dent J 1990; 168: 476-479. 23.Winter WE, Rosenbloom AL, Maclaren NK, Mickle JP. Solitary central maxillary incisor ssociated with precocious puberty and hypothalmic hamartoma. J Pediat 1982; 101: 965-967 9 24.Bartholonew DW, Jabs EW, Levin LS, Ribovich R. Single maxillary central incisor and coloboma in hypomelanosis of Ito. Clin Genet 1987; 32: 370-373. 25.Kocsis SG. A single central maxillary incisor in the midline as a mild form of holoprosencephaly. Fogorv Sz (Hungary) Mar. 1994; 87 (3) 63-70. 26.Aughton DJ, ALSaadi AA, Transue DJ. Single maxillary central incisor in a girl with del (18p) syndrome. J Med Genet Aug. 1991; 28(8) 530-532. 27.Miura M, Kato N, Kojima H, Ogichi. Triple-X syndrome accompanied by single maxillary central incisor. Ped Dent 1993;15:214-217. 28.Harrison M, Calvert ML, Longhurst P. Solitary maxillary central incisor as a new finding in CHARGE association : a report of two cases. Int. J Ped Dent 1997;7:185 189. 01

10 Legand to Figure. Figure 1. Intra-oral photograph showing the single maxillary central incisor in the midline. Figure 2. periapical radiograph of the single maxillary permanent central incisor. Figure 3. Radiograph of the hand wrist. 00

11 Dr. Othman M Yassin. P. O. Box 31 Al- Sareeh 21156 Jordan OCT 27, 1997 Dr. Jed. J. Jacobson University Of Michigan School Of Dentistry, Room G 306 Ann Arboi,Mi 481098 U.S.A Re: J-0216-P Dear Dr Jacobson, Thank you for your letter of march 30,1997 and the attached comments of two reviewers of my revised manuscript entitled (SOLITARY MAXILLARY CENTRAL INCISOR IN THE MIDLINE ASSOCIATED WITH SYSTEMIC ANOMALIES ), We are sorry for the delay because we missed the patient to get photo for the face and to do karyotype. I carefully read your comments and those raised by reviewers and the manuscript has been rewritten with a complete review of the literature. Enclosed please find the original and three copies of the corrected manuscript. Hopping that the manuscript is now in a better form for publication. 02

Thank you once again for your valuable suggestions and comments. With best regards Yours Sincerely Dr. Othman M. Yassin DDS, MSc 03