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Primary failure of tooth eruptionA unique case
Primary failure of tooth eruption A unique case Anne C. O’Connell, B Dent Sc, MS,a and Kevin R. Torske, DDS, LT, DC, USN,b Bethesda, Md NATIONAL INSTITUTE OF DENTAL RESEARCH AND NATIONAL NAVAL DENTAL CENTER
Primary failure of tooth eruption rarely occurs. This case represents a rare clinical situation and appears to reflect a generalized disturbance in the eruptive process, inasmuch as (1) deciduous and permanent dentition are affected, (2) incisors, molars, and premolars are involved in all quadrants, (3) skeletal and craniofacial growth are within normal limits, and (4) no systemic/genetic anomalies were detected. This is the first such case reported in the literature; diagnosis and management are discussed. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;87:714-20)
Tooth eruption has been defined as the movement of a tooth from its site of development within the alveolar process to its functional position in the oral cavity.1 It is a localized process in the jaws that exhibits precise timing and bilateral symmetry. The dental follicle is necessary for the coordinated resorption and deposition of bone on opposite sides of the erupting tooth during intraosseous tooth eruption.2 Absence of a tooth in the oral cavity may be the result of some interference with the process of tooth eruption. Most commonly, local factors causing mechanical obstruction to tooth movement into the oral cavity are responsible for the failure of tooth eruption (Table I). Impaction is defined as the cessation of eruption because of mechanical interference caused by a physical barrier such as supernumerary teeth or cysts. As soon as the barrier is removed, the teeth often will erupt normally. Generalized failure/delay in tooth eruption can occur in a number of syndromes—eg, cleidocranial dysplasia (CCD) and Gardner syndrome, in which disturbances are thought to occur because of physical interference by supernumerary teeth coincident with a reduced eruptive potential as yet unexplained.3-5 Eruption disturbances may also be associated with endocrine/hormonal disturbances or be the consequence of other systemic diseases (Table I). Ankylosis is a disturbance of tooth eruption that results from the fusion of cementum or dentin with the alveolar bone.6-8 The involved teeth may become fixed in place any time during or after eruption. Ankylosis is relatively more common in the primary dentition, most often involving the primary molars where interference aDirector, Clinical Research Core, National Institute of Dental Research, National Institutes of Health. bResident, Oral and Maxillofacial Pathology, Naval Dental School, National Naval Dental Center. Received for publication Aug 25, 1998; returned for revision Sept 22, 1998; accepted for publication Nov 17, 1998. Copyright © 1999 by Mosby, Inc. 1079-2104/99/$8.00 + 0 7/14/96028
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Table I. Differential diagnosis of delayed eruption Systemic causes
Local causes
CCD Ectodermal dysplasia Endocrine disorders: Hypothyroidism Hypopituitarism Hypoparathyroidism Vitamin D–resistant rickets Gardner syndrome Down syndrome Apert syndrome Mucopolysaccharidosis De Lange syndrome Prematurity/low birth weight Icthyosis Cherubism
Impaction Ankylosis Primary retention Trauma Cysts Neoplasms
with the eruptive process occurs after the teeth erupt into the oral cavity. Ankylosis has not been reported to interfere with the mucosal penetration of the primary dentition and has not been reported to occur concurrently in all tooth types. Many terms have been used to describe the clinical situation in which teeth have failed to erupt into the oral cavity without associated local or systemic factors, including ankylosis, primary retention, idiopathic failure of tooth eruption, and embedded teeth.9,10 These terms all describe failures of the eruptive process. Primary retention is defined as a cessation of tooth eruption before emergence that is not due to a physical barrier in the eruption path, does not result from an abnormal position, and has no systemic cause.11,12 A review of the literature suggests that primary retention of permanent teeth is rare, has not been reported in all 4 quadrants, and has not been associated with abnormalities of eruption of the primary teeth.9,11,13 This report describes a child with primary retention in the deciduous dentition and the entire permanent dentition.
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Fig 1. Panoramic radiograph taken when patient was 3 years 9 months of age shows presence of all primary teeth and age-appropriate development of permanent dentition.
CASE REPORT A 6-year-old girl appeared for evaluation and treatment at our clinic with a history of delayed eruption of her primary teeth. The patient’s medical history revealed that she was the product of an uneventful pregnancy and was delivered at 38 weeks by cesarean section. Birth weight was 7 lb 10 oz; Apgar scores were 8/9. At age 3 years 9 months, she had only 6 teeth erupted (all central incisors and the lower lateral incisors). A panoramic radiograph (Fig 1) revealed the presence of all primary teeth and appropriate development of the permanent teeth. At that time, an extensive evaluation showed no abnormalities in thyroid function, and calcium, phosphorus, and alkaline phosphatase levels were within the normal range for a growing child. Bone age corresponded to chronologic age at 4 years 2 months. The patient has continued to grow normally throughout childhood; for her age she is above the 95th percentile in height and above the 75th percentile in weight and head circumference. The general health of the patient has been excellent, with no allergies or hospitalizations; however, there is a history of recurrent otitis media. She has 1 older male sibling with no dental problems, and there is a negative family history of dental anomalies. Physical evaluation revealed her to be a well-proportioned child with no craniofacial, dermal, or skeletal dysmorphologies. She displayed age-appropriate development, and no abnormalities were noted in her hair, skin, or nails. On initial examination at 6 years of age, it was noted that 13 of her primary teeth had erupted; these teeth displayed normal size, shape, and quality of enamel (Fig 2). The only occlusal contact was on the primary incisors, and the overeruption of the upper primary canine and first molars was evident. Radiographically, all primary teeth were present, and the permanent tooth buds of all teeth except the upper second premolars were identified (Fig 3, A). The nonerupted teeth were covered with bone and had well-circumscribed follicles (Fig 3, B). The developing lower second premolar tooth buds were ectopically placed, being anterior to the primary second
molars. Root development or dental maturity, assessed by the method of Demirjian et al,14 revealed age-appropriate dental maturity; however, when clinical emergence was used to assess dental age there was a significant discrepancy because of the failure of eruption of the primary molars. Comparison of previous radiographs revealed that there had been little progress in tooth eruption (Fig 1 vs Fig 3). However, continued root development of the permanent teeth was noted, without progress toward the alveolar crest. The timing and sequence of tooth eruption is detailed in Table II. In addition to the significant delay, the sequence of eruption was inappropriate. The upper lateral incisors erupted more than 1 year apart and later than the cuspids and first molars. The patient was evaluated extensively at the initial visit and at subsequent visits. All laboratory values were within the normal range for a growing child, including parathyroid, thyroid, and growth hormone levels and calcium, phosphorus, and vitamin D levels. Bone age at 6 years 10 months corresponded to chronologic age. Genetic evaluation, including high-resolution karyotyping, was performed; no abnormalities were noted. In the absence of any other signs, the working diagnosis was primary retention of the primary and permanent teeth. Management The patient was re-evaluated after 6 months. Continued crown and root development was observed in the permanent teeth, but no progress toward emergence was evident. The initial treatment goal was to encourage eruption into the oral cavity by removing any physical barrier (soft tissue or bone) associated with the unerupted teeth. One possibility was to extract the erupted primary incisors and observe for eruption of the permanent incisors; these teeth were in the final stages of root development and should have erupted in a 7-year-old child. However, the parents and child expressed concern about removing the only existing teeth with unknown probability of eruption of the permanent teeth. In addition, the vertical dimension of
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Fig 2. Frontal and occlusal views of erupted teeth taken when patient was 6 years of age. Size, shape, and location of teeth are normal.
occlusion would no longer be maintained by tooth-to-tooth contact. A decision was made to leave the erupted teeth alone and use one quadrant as a “test site” for surgical exposure of the unerupted molars; the removal of any physical barrier might facilitate eruption of these teeth. Root development of the molars was age-appropriate for successful eruption. Surgical exposure of the lower right first permanent molar and second primary molar, with extraction of the primary canine and first primary molar, was completed with the patient under general anesthesia. The teeth were observed to move easily within the crypt, and no luxation was performed. Clinical and radiographical examination 6 months later showed that the crown of the mandibular right first permanent molar was partially visible in lingual orientation in the oral cavity. No progress toward emergence was evident in any other quadrant. The application of orthodontic forces was not possible because of the absence of erupted teeth; there was no appropriate anchorage to allow for controlled movement. Another operation was planned to expose the lower left first permanent molar and re-expose the right permanent molar. Anterior ectopic position of the second premolar tooth buds was confirmed, and extraction of the remaining unerupted primary mandibular teeth was also planned. An unerupted primary molar and the attached soft tissue were analyzed microscopically. The dental follicular tissue consisted primarily of variably dense fibrovascular connective tissue with focal areas of slight myxomatous change. Small odontogenic rests were noted, scattered within the connective tissue stroma. The outer periphery of 1 fragment was focally surfaced by nonkeratinizing epithelium consistent with reduced enamel epithelium (Fig 4, A). The decalcified left second primary molar consisted primarily of dentin and cementum. Also noted was a focal area of loosely intertwined collagen bundles displaying a
rim of palisaded columnar cells consistent with dental pulp and odontoblasts. The dentin displayed numerous normally formed dentinal tubules. The outer root surface displayed a longitudinal arrangement of Sharpy’s fibres embedded within acellular and cellular cementum (Fig 4, B). On re-evaluation, the clinical crown of the right mandibular first permanent molar was seen to be lingually placed and fully through the gingiva. The left mandibular first permanent molar was not visible in the oral cavity, and minimal eruptive progress was noted. The premolar tooth buds had moved distally, and the permanent molars tipped mesially into extraction sites. No progress toward emergence was noted in the upper arch. Eight months later, another operation was performed to expose the upper first permanent molars and reexpose the lower left permanent molar. Extraction of all remaining unerupted primary teeth was also performed, with the exception of the upper right second primary molar, which was retained because of the absence of the upper right second premolar. During surgery, the occlusal surface of the lower left permanent molar was observed to be tipped 90 degrees lingually, which explained the failure of emergence of this tooth after surgical exposure. Once again, all teeth could be moved easily within the crypt, and no luxation was performed. Continued evaluation 9 months later revealed absence of the upper right and lower left first permanent molars in the oral cavity. The maxillary left first permanent molar was present in good position on the alveolar ridge, and the lower right first permanent molar remained lingually inclined (Fig 5). At this time, the patient is increasingly conscious of her appearance and will not smile. The only occlusal contact is on the primary incisors, which have now begun to exhibit resorption and mobility. The patient remains on a regular recall schedule as she considers the option of an overdenture to establish posterior occlusal stability and improve the esthetics.
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Fig 3. A, Panoramic radiograph at age 6 years 9 months shows continued development of permanent dentition but little progress toward emergence in either primary or permanent dentition. B, Intraoral radiographs show mandibular teeth to have well-circumscribed follicle; they are still covered by bone.
DISCUSSION Disorders of tooth eruption can be difficult to diagnose, given the lack of knowledge about the eruptive process. The diagnosis is based on clinical and radiographic characteristics and sometimes on the response to treatment. The treatment goals are to encourage the teeth to erupt into the oral cavity, usually through surgical exposure. This case, which is unique, represents a generalized failure/delay in tooth eruption involving all tooth types in both dentitions; there was minimal response to repeated surgical intervention. Delayed eruption is a feature of many diseases and syndromes. Our patient was growing at a normal rate, was within normal limits with respect to facial and skeletal growth, and was of normal intelligence. No underlying systemic abnormalities have been discovered on repeated examination over a number of years. Many possible syndromes were eliminated because of a lack of associated signs and the lack of any familial tendency. CCD is characterized by the presence of abnormal clavicles and supernumerary teeth, with delayed eruption of the permanent teeth3-5; however, the eruption of the primary dentition is not affected in CCD. Any abnor-
mality of the clavicles in this case was ruled out by physical examination and radiographic assessment of the clavicles. Gardner syndrome is another autosomal dominant disorder associated with failure of eruption of the permanent teeth.15,16 There was no family history of the disorder, and once again a defect in eruption of the primary dentition has not been reported in this syndrome. An invasive gastrointestinal investigation was not indicated at this time. Congenital hypertrophy of the retinal pigment epithelium is sometimes present in Gardner syndrome, but the presence of this ocular deformity was ruled out by ophthalmologic examination. Ankylosis can occur at any stage during eruption and can sometimes be diagnosed radiographically by the absence of the periodontal ligament space. The diagnosis of ankylosis may be confirmed when a tooth fails to move after the application of orthodontic forces.6,8,17 The diagnosis is usually based on clinical findings and can be difficult if the teeth have not penetrated the oral mucosa. Ankylosis occurs in the primary and permanent dentitions, most commonly in the primary molar region; it has been described in all 4 quadrants. Mancini et al8 have suggested that ankylosis may be due to a defect in the
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Fig 4. A, Photomicrograph shows normal appearance of dental follicular tissue. B, Root surface of decalcified primary molar shows presence of acellular and cellular cementum.
Table II. Clinical emergence of primary teeth
Tooth Lower left central Lower right central Upper right central Upper left central Lower left lateral Lower right lateral Upper left first molar Upper right first molar Upper left cuspid Upper right cuspid Upper right lateral Upper left lateral Lower left cuspid
Patient’s age at emergence 2y 2 y 1 mo 3 y 2 mo 3 y 4 mo 3 y 9 mo 3 y 9 mo 4y 4y 4 y 2 mo 4 y 3 mo 4 y 7 mo 5 y 7 mo 5 y 10 mo
Mean age at emergence (± 1 SD)* 8 mo (6-10 mo) 10 mo (8-12 mo) 13 mo (10-16 mo) 16 mo (14-18 mo) 19 mo (16-22 mo) 11 mo (9-13 mo) 20 mo (17-23 mo)
A total of 13 teeth had erupted into the mouth by age 5 years 10 months, with no further progress over the next 16 months. The upper left lateral incisor erupted 1 year later than its antimere. SD, Standard deviation. *Age suggested by Lunt and Law26 (1974).
periodontal ligament, whereas Pytlik and Alfter18 suggest a genetic predisposition to impairment of tooth eruption in some families. Generalized ankylosis, affecting all tooth types and in both dentitions, has not been reported previously. A diagnosis of primary retention, idiopathic failure of eruption, or embedded teeth is a diagnosis of exclusion and cannot be separated from ankylosis when there is no eruption of teeth into the oral cavity. There have been many reports of idiopathic failure of
permanent tooth eruption.9,11-13,19-21 In each case, there were no abnormalities in the eruption of the deciduous dentition and only single tooth types were affected, usually molars. There have been no reports in the literature of generalized primary retention of primary and permanent teeth in the same patient. Primary retention of primary and permanent teeth could be due to a defect in the dental follicle causing disturbed local metabolism and interference with the biological interactions necessary for the eruptive process. Research on mechanisms of tooth eruption have been reviewed by Marks et al.22,23 They define tooth eruption as a localized, symmetric process of bone resorption and deposition that is dependent on interaction with the dental follicle and is regulated by a number of biological mediators, such as epidermal growth factor, interleukin 1, nuclear matrix-intermediate filament, and matrix metalloproteinases.23,24 To date, however, the interactions of these mediators have been studied only in animal models. It has also been proposed that each tooth has a “window of opportunity” for successful eruption and that defects during this critical time will cause interference in the eruptive process. In our patient, 13 primary teeth erupted, which indicates a delayed but complete eruptive process at that time. The failure of subsequent teeth to erupt even after surgical intervention indicates progressive dysregulation in the process of tooth eruption. The presence of the upper left and lower right molars in the oral cavity may be a result of the surgical exposure rather than evidence of eruption.
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Fig 5. Panoramic radiograph at 10 years of age reveals that upper right and lower left permanent molars are not present but that both other first permanent molars are present in oral cavity.
The management of our patient involved a number of challenging decisions. Application of orthodontic forces on the surgically exposed teeth was not feasible because of the lack of anchorage. The teeth moved easily in the crypt during the operation, and a decision was made not to luxate the teeth because they did not appear ankylosed. Luxation after surgical exposure has been suggested as a way of promoting eruption by breaking the site of fusion while maintaining the apical blood supply6; however, Jacobs25 suggests that luxation may be unnecessary and may even cause ankylosis. In addition, aggressive removal of bone was avoided during surgery to preserve bony support; this was also the reason for not removing the upper right second primary molar. At this time, the patient has an adequate vertical dimension of occlusion, and her phonetics are within normal limits. However, the girl’s upper incisors are becoming mobile, and esthetics are becoming more important to her. The provision of an overdenture has been suggested. Construction of a prosthesis will be complicated by the fact that the upper first molars and canines are overerupted, there is decreased interarch space with contact in the tuberosity region, and the patient has a short upper lip. The option of an overdenture has not been accepted by the patient at this time.
SUMMARY The diagnosis of an eruption disorder can be difficult, given our limited knowledge of the eruptive process. Diagnosis is based on clinical and radiographic characteristics; however, the goal of treatment
is to encourage teeth to erupt into the oral cavity. Recent work indicates that disturbances of tooth eruption are due to the failure of the dental follicle to initiate essential metabolic events, which are still being defined. This case represents a unique clinical situation and appears to reflect a severe generalized disturbance in the eruptive process. This is the first report describing a case of generalized primary retention or idiopathic failure of tooth eruption. Such a conclusion is based on the following facts: on the one hand, all quadrants are involved, both the deciduous and permanent dentitions are affected, and the incisors, molars, and premolars are involved; on the other hand, the skeletal and craniofacial growth are within normal limits and no systemic abnormalities have been found. We thank everyone who helped with this case, especially Dr J. Brahim, CRC, NIDR; the faculty of the Department of Pediatric Dentistry, University of Maryland Dental School; and Drs J. Hellstein and D. Schafer, Oral and Maxillofacial Pathology, National Naval Dental Center, Bethesda, Md. REFERENCES 1. Massler M, Schour I. Studies in tooth development: theories of eruption. Am J Orthodont Oral Surg 1941;27:552-76. 2. Marks SC Jr, Cahill DR. Regional control by the dental follicle of alterations in alveolar bone metabolism during tooth eruption. J Oral Pathol 1987;16:164-9. 3. Jensen BL, Kreiborg S. Development of the dentition in cleidocranial dysplasia. J Oral Pathol Med 1990;19:89-93. 4. Becker A, Shteyer A, Bimstein E, Lustmann J. Cleidocranial dysplasia, 2: treatment protocol for the orthodontic and surgical modality. Am J Orthod Dentofac Orthop 1997;111:173-83. 5. Becker A, Lustmann J, Shteyer A. Cleidocranial dysplasia, 1: general principles of the orthodontic and surgical treatment modality. Am J Orthod Dentofac Orthop 1997;111:28-33.
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6. Biederman W. Etiology and treatment of tooth ankylosis. Am J Orthod 1962;48:670-84. 7. Brearley LJ, McKibben DH Jr. Ankylosis of primary molar teeth, I: prevalence and characteristics. ASDC J Dent Child 1973;40:54-63. 8. Mancini G, Francini E, Vichi M, Tollaro I, Romagnoli P. Primary tooth ankylosis: report of case with histological analysis. ASDC J Dent Child 1995;62:215-9. 9. Kaban LB, Needleman HL, Hertzberg J. Idiopathic failure of eruption of permanent molar teeth. Oral Surg Oral Med Oral Pathol 1976;42:155-63. 10. Wood N, Goaz P. Multiple separate radioopacities: differential diagnosis of oral and maxillofacial lesions. St Louis: MosbyYear Book, Inc; 1997. p. 505. 11. Proffit WR, Vig KW. Primary failure of eruption: a possible cause of posterior open-bite. Am J Orthod 1981;80:173-90. 12. Oliver RG, Richmond S, Hunter B. Submerged permanent molars: four case reports. Br Dent J 1986;160:128-30. 13. Mellor TK. Six cases of non-eruption of the first adult lower molar tooth. J Dent 1981;9:84-8. 14. Demirjian A, Goldstein H, Tanner JM. A new system of dental age assessment. Hum Biol 1973;45:211-27. 15. Lyons LA, Lewis RA, Strong LC, Zuckerbrod S, Ferrell RE. A genetic study of Gardner syndrome and congenital hypertrophy of the retinal pigment epithelium. Am J Hum Genet 1988;42:290-6. 16. Baker RH, Heinemann MH, Miller HH, DeCosse JJ. Hyperpigmented lesions of the retinal pigment epithelium in familial adenomatous polyposis. Am J Med Genet 1988;31:427-35. 17. Mitchell DL, West JD. Attempted orthodontic movement in the presence of suspected ankylosis. Am J Orthod 1975;68:404-11. 18. Pytlik W, Alfter G. Impairment of tooth eruption: pathogenetic aspects. J Orofac Orthop 1996;57:238-45.
19. Hall G, Reade P. Quadrilateral submersion of permanent teeth. Brief review and case report. Aust Dent J 1981;26:73-6. 20. Grover PS, Lorton L. The incidence of unerupted permanent teeth and related clinical cases. Oral Surg Oral Med Oral Pathol 1985;59:420-5. 21. Raghoebar GM, Boering G, Vissink A, Stegenga B. Eruption disturbances of permanent molars: a review. J Oral Pathol Med 1991;20:159-66. 22. Marks SC Jr. The basic and applied biology of tooth eruption. Connect Tissue Res 1995;32:149-57. 23. Marks SC Jr, Gorski JP, Wise GE. The mechanisms and mediators of tooth eruption: models for developmental biologists. Int J Dev Biol 1995;39:223-30. 24. Bidwell JP, Fey EG, Marks SC Jr. Nuclear matrix-intermediate filament proteins of the dental follicle/enamel epithelium and their changes during tooth eruption in dogs. Arch Oral Biol 1995;40:1047-51. 25. Jacobs SG. Ankylosis of permanent teeth: a case report and literature review. Australian Orthodontic Journal 1989;11:38-44. 26. Lunt RC, Law DB. A review of the chronology of eruption of deciduous teeth. J Am Dent Assoc 1974;89:872-9.
Reprint requests: Anne O’Connell, B Dent Sc, MS Director, Clinical Research Core Bldg 10, Rm 1N113 NIDR, NIH Bethesda, MD 20892
Primary failure of tooth eruption rarely occurs. This case represents a rare clinical situation and appears to reflect a generalized disturbance in the eruptive process, inasmuch as (1) deciduous and permanent dentition are affected, (2) incisors, molars, and premolars are involved in all quadrants, (3) skeletal and craniofacial growth are within normal limits, and (4) no systemic/genetic anomalies were detected. This is the first such case reported in the literature; diagnosis and management are discussed. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;87:714-20)
Tooth eruption has been defined as the movement of a tooth from its site of development within the alveolar process to its functional position in the oral cavity.1 It is a localized process in the jaws that exhibits precise timing and bilateral symmetry. The dental follicle is necessary for the coordinated resorption and deposition of bone on opposite sides of the erupting tooth during intraosseous tooth eruption.2 Absence of a tooth in the oral cavity may be the result of some interference with the process of tooth eruption. Most commonly, local factors causing mechanical obstruction to tooth movement into the oral cavity are responsible for the failure of tooth eruption (Table I). Impaction is defined as the cessation of eruption because of mechanical interference caused by a physical barrier such as supernumerary teeth or cysts. As soon as the barrier is removed, the teeth often will erupt normally. Generalized failure/delay in tooth eruption can occur in a number of syndromes—eg, cleidocranial dysplasia (CCD) and Gardner syndrome, in which disturbances are thought to occur because of physical interference by supernumerary teeth coincident with a reduced eruptive potential as yet unexplained.3-5 Eruption disturbances may also be associated with endocrine/hormonal disturbances or be the consequence of other systemic diseases (Table I). Ankylosis is a disturbance of tooth eruption that results from the fusion of cementum or dentin with the alveolar bone.6-8 The involved teeth may become fixed in place any time during or after eruption. Ankylosis is relatively more common in the primary dentition, most often involving the primary molars where interference aDirector, Clinical Research Core, National Institute of Dental Research, National Institutes of Health. bResident, Oral and Maxillofacial Pathology, Naval Dental School, National Naval Dental Center. Received for publication Aug 25, 1998; returned for revision Sept 22, 1998; accepted for publication Nov 17, 1998. Copyright © 1999 by Mosby, Inc. 1079-2104/99/$8.00 + 0 7/14/96028
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Table I. Differential diagnosis of delayed eruption Systemic causes
Local causes
CCD Ectodermal dysplasia Endocrine disorders: Hypothyroidism Hypopituitarism Hypoparathyroidism Vitamin D–resistant rickets Gardner syndrome Down syndrome Apert syndrome Mucopolysaccharidosis De Lange syndrome Prematurity/low birth weight Icthyosis Cherubism
Impaction Ankylosis Primary retention Trauma Cysts Neoplasms
with the eruptive process occurs after the teeth erupt into the oral cavity. Ankylosis has not been reported to interfere with the mucosal penetration of the primary dentition and has not been reported to occur concurrently in all tooth types. Many terms have been used to describe the clinical situation in which teeth have failed to erupt into the oral cavity without associated local or systemic factors, including ankylosis, primary retention, idiopathic failure of tooth eruption, and embedded teeth.9,10 These terms all describe failures of the eruptive process. Primary retention is defined as a cessation of tooth eruption before emergence that is not due to a physical barrier in the eruption path, does not result from an abnormal position, and has no systemic cause.11,12 A review of the literature suggests that primary retention of permanent teeth is rare, has not been reported in all 4 quadrants, and has not been associated with abnormalities of eruption of the primary teeth.9,11,13 This report describes a child with primary retention in the deciduous dentition and the entire permanent dentition.
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Fig 1. Panoramic radiograph taken when patient was 3 years 9 months of age shows presence of all primary teeth and age-appropriate development of permanent dentition.
CASE REPORT A 6-year-old girl appeared for evaluation and treatment at our clinic with a history of delayed eruption of her primary teeth. The patient’s medical history revealed that she was the product of an uneventful pregnancy and was delivered at 38 weeks by cesarean section. Birth weight was 7 lb 10 oz; Apgar scores were 8/9. At age 3 years 9 months, she had only 6 teeth erupted (all central incisors and the lower lateral incisors). A panoramic radiograph (Fig 1) revealed the presence of all primary teeth and appropriate development of the permanent teeth. At that time, an extensive evaluation showed no abnormalities in thyroid function, and calcium, phosphorus, and alkaline phosphatase levels were within the normal range for a growing child. Bone age corresponded to chronologic age at 4 years 2 months. The patient has continued to grow normally throughout childhood; for her age she is above the 95th percentile in height and above the 75th percentile in weight and head circumference. The general health of the patient has been excellent, with no allergies or hospitalizations; however, there is a history of recurrent otitis media. She has 1 older male sibling with no dental problems, and there is a negative family history of dental anomalies. Physical evaluation revealed her to be a well-proportioned child with no craniofacial, dermal, or skeletal dysmorphologies. She displayed age-appropriate development, and no abnormalities were noted in her hair, skin, or nails. On initial examination at 6 years of age, it was noted that 13 of her primary teeth had erupted; these teeth displayed normal size, shape, and quality of enamel (Fig 2). The only occlusal contact was on the primary incisors, and the overeruption of the upper primary canine and first molars was evident. Radiographically, all primary teeth were present, and the permanent tooth buds of all teeth except the upper second premolars were identified (Fig 3, A). The nonerupted teeth were covered with bone and had well-circumscribed follicles (Fig 3, B). The developing lower second premolar tooth buds were ectopically placed, being anterior to the primary second
molars. Root development or dental maturity, assessed by the method of Demirjian et al,14 revealed age-appropriate dental maturity; however, when clinical emergence was used to assess dental age there was a significant discrepancy because of the failure of eruption of the primary molars. Comparison of previous radiographs revealed that there had been little progress in tooth eruption (Fig 1 vs Fig 3). However, continued root development of the permanent teeth was noted, without progress toward the alveolar crest. The timing and sequence of tooth eruption is detailed in Table II. In addition to the significant delay, the sequence of eruption was inappropriate. The upper lateral incisors erupted more than 1 year apart and later than the cuspids and first molars. The patient was evaluated extensively at the initial visit and at subsequent visits. All laboratory values were within the normal range for a growing child, including parathyroid, thyroid, and growth hormone levels and calcium, phosphorus, and vitamin D levels. Bone age at 6 years 10 months corresponded to chronologic age. Genetic evaluation, including high-resolution karyotyping, was performed; no abnormalities were noted. In the absence of any other signs, the working diagnosis was primary retention of the primary and permanent teeth. Management The patient was re-evaluated after 6 months. Continued crown and root development was observed in the permanent teeth, but no progress toward emergence was evident. The initial treatment goal was to encourage eruption into the oral cavity by removing any physical barrier (soft tissue or bone) associated with the unerupted teeth. One possibility was to extract the erupted primary incisors and observe for eruption of the permanent incisors; these teeth were in the final stages of root development and should have erupted in a 7-year-old child. However, the parents and child expressed concern about removing the only existing teeth with unknown probability of eruption of the permanent teeth. In addition, the vertical dimension of
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Fig 2. Frontal and occlusal views of erupted teeth taken when patient was 6 years of age. Size, shape, and location of teeth are normal.
occlusion would no longer be maintained by tooth-to-tooth contact. A decision was made to leave the erupted teeth alone and use one quadrant as a “test site” for surgical exposure of the unerupted molars; the removal of any physical barrier might facilitate eruption of these teeth. Root development of the molars was age-appropriate for successful eruption. Surgical exposure of the lower right first permanent molar and second primary molar, with extraction of the primary canine and first primary molar, was completed with the patient under general anesthesia. The teeth were observed to move easily within the crypt, and no luxation was performed. Clinical and radiographical examination 6 months later showed that the crown of the mandibular right first permanent molar was partially visible in lingual orientation in the oral cavity. No progress toward emergence was evident in any other quadrant. The application of orthodontic forces was not possible because of the absence of erupted teeth; there was no appropriate anchorage to allow for controlled movement. Another operation was planned to expose the lower left first permanent molar and re-expose the right permanent molar. Anterior ectopic position of the second premolar tooth buds was confirmed, and extraction of the remaining unerupted primary mandibular teeth was also planned. An unerupted primary molar and the attached soft tissue were analyzed microscopically. The dental follicular tissue consisted primarily of variably dense fibrovascular connective tissue with focal areas of slight myxomatous change. Small odontogenic rests were noted, scattered within the connective tissue stroma. The outer periphery of 1 fragment was focally surfaced by nonkeratinizing epithelium consistent with reduced enamel epithelium (Fig 4, A). The decalcified left second primary molar consisted primarily of dentin and cementum. Also noted was a focal area of loosely intertwined collagen bundles displaying a
rim of palisaded columnar cells consistent with dental pulp and odontoblasts. The dentin displayed numerous normally formed dentinal tubules. The outer root surface displayed a longitudinal arrangement of Sharpy’s fibres embedded within acellular and cellular cementum (Fig 4, B). On re-evaluation, the clinical crown of the right mandibular first permanent molar was seen to be lingually placed and fully through the gingiva. The left mandibular first permanent molar was not visible in the oral cavity, and minimal eruptive progress was noted. The premolar tooth buds had moved distally, and the permanent molars tipped mesially into extraction sites. No progress toward emergence was noted in the upper arch. Eight months later, another operation was performed to expose the upper first permanent molars and reexpose the lower left permanent molar. Extraction of all remaining unerupted primary teeth was also performed, with the exception of the upper right second primary molar, which was retained because of the absence of the upper right second premolar. During surgery, the occlusal surface of the lower left permanent molar was observed to be tipped 90 degrees lingually, which explained the failure of emergence of this tooth after surgical exposure. Once again, all teeth could be moved easily within the crypt, and no luxation was performed. Continued evaluation 9 months later revealed absence of the upper right and lower left first permanent molars in the oral cavity. The maxillary left first permanent molar was present in good position on the alveolar ridge, and the lower right first permanent molar remained lingually inclined (Fig 5). At this time, the patient is increasingly conscious of her appearance and will not smile. The only occlusal contact is on the primary incisors, which have now begun to exhibit resorption and mobility. The patient remains on a regular recall schedule as she considers the option of an overdenture to establish posterior occlusal stability and improve the esthetics.
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Fig 3. A, Panoramic radiograph at age 6 years 9 months shows continued development of permanent dentition but little progress toward emergence in either primary or permanent dentition. B, Intraoral radiographs show mandibular teeth to have well-circumscribed follicle; they are still covered by bone.
DISCUSSION Disorders of tooth eruption can be difficult to diagnose, given the lack of knowledge about the eruptive process. The diagnosis is based on clinical and radiographic characteristics and sometimes on the response to treatment. The treatment goals are to encourage the teeth to erupt into the oral cavity, usually through surgical exposure. This case, which is unique, represents a generalized failure/delay in tooth eruption involving all tooth types in both dentitions; there was minimal response to repeated surgical intervention. Delayed eruption is a feature of many diseases and syndromes. Our patient was growing at a normal rate, was within normal limits with respect to facial and skeletal growth, and was of normal intelligence. No underlying systemic abnormalities have been discovered on repeated examination over a number of years. Many possible syndromes were eliminated because of a lack of associated signs and the lack of any familial tendency. CCD is characterized by the presence of abnormal clavicles and supernumerary teeth, with delayed eruption of the permanent teeth3-5; however, the eruption of the primary dentition is not affected in CCD. Any abnor-
mality of the clavicles in this case was ruled out by physical examination and radiographic assessment of the clavicles. Gardner syndrome is another autosomal dominant disorder associated with failure of eruption of the permanent teeth.15,16 There was no family history of the disorder, and once again a defect in eruption of the primary dentition has not been reported in this syndrome. An invasive gastrointestinal investigation was not indicated at this time. Congenital hypertrophy of the retinal pigment epithelium is sometimes present in Gardner syndrome, but the presence of this ocular deformity was ruled out by ophthalmologic examination. Ankylosis can occur at any stage during eruption and can sometimes be diagnosed radiographically by the absence of the periodontal ligament space. The diagnosis of ankylosis may be confirmed when a tooth fails to move after the application of orthodontic forces.6,8,17 The diagnosis is usually based on clinical findings and can be difficult if the teeth have not penetrated the oral mucosa. Ankylosis occurs in the primary and permanent dentitions, most commonly in the primary molar region; it has been described in all 4 quadrants. Mancini et al8 have suggested that ankylosis may be due to a defect in the
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Fig 4. A, Photomicrograph shows normal appearance of dental follicular tissue. B, Root surface of decalcified primary molar shows presence of acellular and cellular cementum.
Table II. Clinical emergence of primary teeth
Tooth Lower left central Lower right central Upper right central Upper left central Lower left lateral Lower right lateral Upper left first molar Upper right first molar Upper left cuspid Upper right cuspid Upper right lateral Upper left lateral Lower left cuspid
Patient’s age at emergence 2y 2 y 1 mo 3 y 2 mo 3 y 4 mo 3 y 9 mo 3 y 9 mo 4y 4y 4 y 2 mo 4 y 3 mo 4 y 7 mo 5 y 7 mo 5 y 10 mo
Mean age at emergence (± 1 SD)* 8 mo (6-10 mo) 10 mo (8-12 mo) 13 mo (10-16 mo) 16 mo (14-18 mo) 19 mo (16-22 mo) 11 mo (9-13 mo) 20 mo (17-23 mo)
A total of 13 teeth had erupted into the mouth by age 5 years 10 months, with no further progress over the next 16 months. The upper left lateral incisor erupted 1 year later than its antimere. SD, Standard deviation. *Age suggested by Lunt and Law26 (1974).
periodontal ligament, whereas Pytlik and Alfter18 suggest a genetic predisposition to impairment of tooth eruption in some families. Generalized ankylosis, affecting all tooth types and in both dentitions, has not been reported previously. A diagnosis of primary retention, idiopathic failure of eruption, or embedded teeth is a diagnosis of exclusion and cannot be separated from ankylosis when there is no eruption of teeth into the oral cavity. There have been many reports of idiopathic failure of
permanent tooth eruption.9,11-13,19-21 In each case, there were no abnormalities in the eruption of the deciduous dentition and only single tooth types were affected, usually molars. There have been no reports in the literature of generalized primary retention of primary and permanent teeth in the same patient. Primary retention of primary and permanent teeth could be due to a defect in the dental follicle causing disturbed local metabolism and interference with the biological interactions necessary for the eruptive process. Research on mechanisms of tooth eruption have been reviewed by Marks et al.22,23 They define tooth eruption as a localized, symmetric process of bone resorption and deposition that is dependent on interaction with the dental follicle and is regulated by a number of biological mediators, such as epidermal growth factor, interleukin 1, nuclear matrix-intermediate filament, and matrix metalloproteinases.23,24 To date, however, the interactions of these mediators have been studied only in animal models. It has also been proposed that each tooth has a “window of opportunity” for successful eruption and that defects during this critical time will cause interference in the eruptive process. In our patient, 13 primary teeth erupted, which indicates a delayed but complete eruptive process at that time. The failure of subsequent teeth to erupt even after surgical intervention indicates progressive dysregulation in the process of tooth eruption. The presence of the upper left and lower right molars in the oral cavity may be a result of the surgical exposure rather than evidence of eruption.
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Fig 5. Panoramic radiograph at 10 years of age reveals that upper right and lower left permanent molars are not present but that both other first permanent molars are present in oral cavity.
The management of our patient involved a number of challenging decisions. Application of orthodontic forces on the surgically exposed teeth was not feasible because of the lack of anchorage. The teeth moved easily in the crypt during the operation, and a decision was made not to luxate the teeth because they did not appear ankylosed. Luxation after surgical exposure has been suggested as a way of promoting eruption by breaking the site of fusion while maintaining the apical blood supply6; however, Jacobs25 suggests that luxation may be unnecessary and may even cause ankylosis. In addition, aggressive removal of bone was avoided during surgery to preserve bony support; this was also the reason for not removing the upper right second primary molar. At this time, the patient has an adequate vertical dimension of occlusion, and her phonetics are within normal limits. However, the girl’s upper incisors are becoming mobile, and esthetics are becoming more important to her. The provision of an overdenture has been suggested. Construction of a prosthesis will be complicated by the fact that the upper first molars and canines are overerupted, there is decreased interarch space with contact in the tuberosity region, and the patient has a short upper lip. The option of an overdenture has not been accepted by the patient at this time.
SUMMARY The diagnosis of an eruption disorder can be difficult, given our limited knowledge of the eruptive process. Diagnosis is based on clinical and radiographic characteristics; however, the goal of treatment
is to encourage teeth to erupt into the oral cavity. Recent work indicates that disturbances of tooth eruption are due to the failure of the dental follicle to initiate essential metabolic events, which are still being defined. This case represents a unique clinical situation and appears to reflect a severe generalized disturbance in the eruptive process. This is the first report describing a case of generalized primary retention or idiopathic failure of tooth eruption. Such a conclusion is based on the following facts: on the one hand, all quadrants are involved, both the deciduous and permanent dentitions are affected, and the incisors, molars, and premolars are involved; on the other hand, the skeletal and craniofacial growth are within normal limits and no systemic abnormalities have been found. We thank everyone who helped with this case, especially Dr J. Brahim, CRC, NIDR; the faculty of the Department of Pediatric Dentistry, University of Maryland Dental School; and Drs J. Hellstein and D. Schafer, Oral and Maxillofacial Pathology, National Naval Dental Center, Bethesda, Md. REFERENCES 1. Massler M, Schour I. Studies in tooth development: theories of eruption. Am J Orthodont Oral Surg 1941;27:552-76. 2. Marks SC Jr, Cahill DR. Regional control by the dental follicle of alterations in alveolar bone metabolism during tooth eruption. J Oral Pathol 1987;16:164-9. 3. Jensen BL, Kreiborg S. Development of the dentition in cleidocranial dysplasia. J Oral Pathol Med 1990;19:89-93. 4. Becker A, Shteyer A, Bimstein E, Lustmann J. Cleidocranial dysplasia, 2: treatment protocol for the orthodontic and surgical modality. Am J Orthod Dentofac Orthop 1997;111:173-83. 5. Becker A, Lustmann J, Shteyer A. Cleidocranial dysplasia, 1: general principles of the orthodontic and surgical treatment modality. Am J Orthod Dentofac Orthop 1997;111:28-33.
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6. Biederman W. Etiology and treatment of tooth ankylosis. Am J Orthod 1962;48:670-84. 7. Brearley LJ, McKibben DH Jr. Ankylosis of primary molar teeth, I: prevalence and characteristics. ASDC J Dent Child 1973;40:54-63. 8. Mancini G, Francini E, Vichi M, Tollaro I, Romagnoli P. Primary tooth ankylosis: report of case with histological analysis. ASDC J Dent Child 1995;62:215-9. 9. Kaban LB, Needleman HL, Hertzberg J. Idiopathic failure of eruption of permanent molar teeth. Oral Surg Oral Med Oral Pathol 1976;42:155-63. 10. Wood N, Goaz P. Multiple separate radioopacities: differential diagnosis of oral and maxillofacial lesions. St Louis: MosbyYear Book, Inc; 1997. p. 505. 11. Proffit WR, Vig KW. Primary failure of eruption: a possible cause of posterior open-bite. Am J Orthod 1981;80:173-90. 12. Oliver RG, Richmond S, Hunter B. Submerged permanent molars: four case reports. Br Dent J 1986;160:128-30. 13. Mellor TK. Six cases of non-eruption of the first adult lower molar tooth. J Dent 1981;9:84-8. 14. Demirjian A, Goldstein H, Tanner JM. A new system of dental age assessment. Hum Biol 1973;45:211-27. 15. Lyons LA, Lewis RA, Strong LC, Zuckerbrod S, Ferrell RE. A genetic study of Gardner syndrome and congenital hypertrophy of the retinal pigment epithelium. Am J Hum Genet 1988;42:290-6. 16. Baker RH, Heinemann MH, Miller HH, DeCosse JJ. Hyperpigmented lesions of the retinal pigment epithelium in familial adenomatous polyposis. Am J Med Genet 1988;31:427-35. 17. Mitchell DL, West JD. Attempted orthodontic movement in the presence of suspected ankylosis. Am J Orthod 1975;68:404-11. 18. Pytlik W, Alfter G. Impairment of tooth eruption: pathogenetic aspects. J Orofac Orthop 1996;57:238-45.
19. Hall G, Reade P. Quadrilateral submersion of permanent teeth. Brief review and case report. Aust Dent J 1981;26:73-6. 20. Grover PS, Lorton L. The incidence of unerupted permanent teeth and related clinical cases. Oral Surg Oral Med Oral Pathol 1985;59:420-5. 21. Raghoebar GM, Boering G, Vissink A, Stegenga B. Eruption disturbances of permanent molars: a review. J Oral Pathol Med 1991;20:159-66. 22. Marks SC Jr. The basic and applied biology of tooth eruption. Connect Tissue Res 1995;32:149-57. 23. Marks SC Jr, Gorski JP, Wise GE. The mechanisms and mediators of tooth eruption: models for developmental biologists. Int J Dev Biol 1995;39:223-30. 24. Bidwell JP, Fey EG, Marks SC Jr. Nuclear matrix-intermediate filament proteins of the dental follicle/enamel epithelium and their changes during tooth eruption in dogs. Arch Oral Biol 1995;40:1047-51. 25. Jacobs SG. Ankylosis of permanent teeth: a case report and literature review. Australian Orthodontic Journal 1989;11:38-44. 26. Lunt RC, Law DB. A review of the chronology of eruption of deciduous teeth. J Am Dent Assoc 1974;89:872-9.
Reprint requests: Anne O’Connell, B Dent Sc, MS Director, Clinical Research Core Bldg 10, Rm 1N113 NIDR, NIH Bethesda, MD 20892