British Journal of Orthodontics
ISSN: 0301-228X (Print) (Online) Journal homepage: http://www.tandfonline.com/loi/yjor19
Familial Primary Failure of Eruption of Permanent Teeth John Brady B.D.S., F.D.S., D.D.O., R.C.P.S., M.Orth, R.C.S. To cite this article: John Brady B.D.S., F.D.S., D.D.O., R.C.P.S., M.Orth, R.C.S. (1990) Familial Primary Failure of Eruption of Permanent Teeth, British Journal of Orthodontics, 17:2, 109-113, DOI: 10.1179/bjo.17.2.109 To link to this article: http://dx.doi.org/10.1179/bjo.17.2.109
Published online: 21 Jun 2016.
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Citing articles: 23 View citing articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=yjor19 Download by: [University of Tasmania]
Date: 13 March 2017, At: 20:12
British Journal of OrthodmttiCJ/Vol. 17/1990/109-IIJ
Familial Primary Failure of Eruption of Permanent Teeth BRADY, D.D.S., F.D.S., D.D.O., R.C.P.S., M.ORTH, R.C.S. Birmingham Dental Hospital, St. Chad's Queensway, Birmingham 84 6NN
JOHN
Received for publication January 1989
Abstract. A son and his mother presented with features consistent with a diagnosis of primary failure of eruption. 'l'he features of this condition are described together with some aspects of treatment. The impact of the condition on vertical facial growth is discussed. Index words: Eruption Failure, Posterior Open Bite, Vertical Jaw Growth.
Introduction The failure of teeth to erupt can be due either to mechanical interferance, before or after emergence, or to a failure of the eruptive mechanism, partially or totally. Ankylosis seems to be accepted as a major factor in the failure of eruption of deciduous teeth (Darling and Levers, 1973) and is probably responsible for the isolated eruption failure of single permanent teeth; though localised obstruction, in the form of cysts, supernumeraries or odontomes have first to be excluded (Mellor, 1981). Where numerous teeth are affected, mechanical obstruction may take the form of interposed soft tissues or of overlying dense fibrotic tissue and abnormally resorbing alveolar bone. The last two factors are typical of cleidocranial dysplasia (Hall and Hyland, 1978). Where there are no mechanical interferences with eruption Proffit and Vig (1981), have termed the condition, 'Primary Failure of Eruption', and have postulated that a disturbance of the eruption mechanism within the periodontal membrane may be responsible. Following examination of sixteen affected individuals they identified several typical characteristics. However, there have been few reported cases in the literature showing these features. Brenchley (1960) reported a case with occlusion only on the anterior teeth, bilateral eruption failure of premolar and molar teeth having produced lateral open bites. Cases reported by Kapoor eta/. (1981), Hall and Reade (1981), and the first of the cases reported by Oliver et a/. (1986), were similar, although in the last mentioned, the lateral open bites were asymmetrical, having premolar occlusion on one side and a lower canine affected on the opposite side. The two cases reported by Bosker et a!. (1978) seem to fit well the description of 030 1·228X/90/002000 + 00102.00
primary failure of eruption and they also identified a familial tendency from study of 193 affected members from nine families. The inheritance in these cases was autosomal dominant with a vertical transmission and no skipping of generations. Other cases reported, possibly representing less extensive examples of the condition, include that of Nadine (1935) and one of the cases reported by Kahan eta/. (1976). Failure of vertical adaptation, described by Ballard (1966), seems to be the same condition as that under discussion, and it's rarity is underlined by an occurence in only nine cases out of over 16 000 patients referred to the Department of Orthodontics at the Eastman Dental Hospital, a family history being present in only one case. Examples of single first molars which fail to erupt in the absence of mechanical obstruction, such as those reported by Oliver eta/. (1986), Mellor (1981), Kahan eta/. (1976), and Reid (1954}, may represent a partial expression of the full condition. Case reports A 9!-year-old Caucasion male (BM) was referred regarding partial eruption of the permanent first molars on the left side. The incisor occlusion was Class I with an average overjet and overbite, the latter being complete. The skeletal relationship was mildly Class II with a reduced maxillary/mandibular. planes angle, though with an average lower factal percentage and a slightly raised anterior lower facial height (Fig. 1, Table 1). There were no soft tissue abnormalities noted and the lips were competant at rest. A radiograph (Fig. 2) confirmed the presence of all developing permanent teeth, except © 1990 British Society ror the Study or Orthodontics
110 J. Brady
BJO Vol. /7 No.1
TABLE I MeasuremeniS of patient B.M. 's lower facial height and chin prominance
9t Years
Me-ANS(mm) Ar-Go(mm) S-N-Po (")
14 Years
64·5 (55·7)
70·0 (61·7)
39·5 (39·2)
47·5 (45·0)
79·0 (79·0)
80·5 (80·7)
Bolton standard means in parentheses.
m. It was also noted that, although the right first permanent molars were clinically well erupted, they were not in occlusion, neither was ~· The patient was initially reluctant to undergo surgery, but after some delay, at the age of I 0 years 9 months, the E] roots were removed and the semierupted left first permanent molars were exposed. The occlusal surfaces of these teeth were reported free from obvious obstruction and Whitehead's Varnish packs were inserted. Although [6 remained clinically visible, gingival regrowth occurred and obscured ~rapidly. At II years 4 months (Fig. 3) this upper molar was re-exposed and again packed, which had continued to be in infra whilst occlusion, was extracted. Although ~ remained clinically well exposed, there was no improvement in the general eruptive level of the cheek teeth. Observations continued over the next 33 months and the various treatment options considered during this period included the provision of soft tissue deflectors and orthodontic extrusion of the affected teeth following further surgical exposure. However, as the diagnosis of primary failure of eruption was arrived at, and since it has been reported by Proffit and Vig (1981) that such measures are ineffective in this condition, these were not persued.
rn
FIG. I
Lateral skull radiograph at age 9t years.
5321112345 By age 14 years 4 3 2 1 1 1 2 3 4 5 7 were pre6 4 I 7 were erupted sent clinically (Fig. 4a, b), 7 and 87 86 5 1678 6 8 were unerupted. There were occlusal contacts present only on the incisors and canines with a bilateral posterior open bite. The first molars and 5], all of which had communication with the oral cavity were extracted at 14 years 6 months. A year later little further improvement in the posterior open bite had occurred. Restorative options to be considered in the future include over-
F1o. 2 Panoramic radiograph at age 9t years.
Primary Failure of Eruption
BJOMay /990
FIG.
3 Panoramic radiograph at age II years 4 months.
FIG. 4 (a) Panoramic and lateral skull radiographs at age 14 years. (b)
Ill
112 J. Brady
HJV Vol. 17 No.:!
FIG.
5 Panoramic radiograph of the patient's mother at age 40 years.
dentures, or the provision of bridges once facial growth is completed. On questioning, it became apparent that the patient's mother had possessed a similar condition and her microfilmed records taken some 30 years previously, were obtained. The mother had been seen initially at the age of 10 years, because of a delay in the eruption of much of the permanent dentition. She had been seen earlier at a Dental Hospital where a provisional diagnosis of cleidocranial dysostosis had been made. However, the only abnormalities seen on examination were limited to the dentition and involved ~. which was unerupted although it had an oral communication via a sinus and was carious. In the mother's case, it seems that there was incisor involvement, since 1 ~ 1 were exposed and§] extracted at age 12 years. There was little sign of movement of the buried teeth and l! was removed shortly afterwards whilst 21 J12~
3
were extracted at 17 years and l§ at 19 years. A recent radiograph (Fig. 5) at age 40 years shows 87 345 ~ to be still unerupted. J
7
Discussion The case of the son fits well with the criteria of primary failure of eruption, as described by Proffit and Vig (1981). Posterior teeth are mainly affected, with varying degrees of abnormality in the segment distal to the first involved tooth. Three permanent molars had shown some eruptive capacity, since they all possessed occlusal restorations. However, they subsequently became infra-occluded, whilst other affected teeth did not erupt at all. Exposure of the involved teeth, with removal of the overlying bone and mucosa, did not affect their eruptive
pos1t10ns though
~ were not found to be
ankylosed when they were extracted since they were easily removed by forceps and elevators without the need for bone removal. There was some involvement of deciduous teeth, with q E showing infraocclusion. Although Proffit and Vig (1981) found that their patients generally did not have similarly affected close relatives, the involvement of a mother and son in this report agrees with the inheritance pattern found by Bosker et a/. (1978). In addition, a first cousin was also reported to have the condition. The involvement of upper incisors in the case of the mother is unusual, although it seems likely that she too suffers from primary failure of eruption. An interesting aspect of primary eruption failure is the effect that lack of eruption of posterior teeth has on vertical facial growth. Bjork and Skeiller ( 1972), found that where there was forward rotation of the mandible during growth, the centre of this rotation was located in the anterior part of the dental arch. This indicated that the eruption of the molars was greater than of the incisors and that remodelling of the lower border masked the differential eruption. Solow ( 1980) linked alveolar growth with condylar growth as did Mills ( 1983 ), who felt that in cases of forward rotation, growth of the vertical ramus was greater than the combined vertical growth of upper and lower alveolar processes. In backward rotation, the opposite was thought to occur. Mills did not suggest whether or not differential growth caused the rotation, although a cause and effect relationship has been proposed by authors. Schudy (1968) felt that vertical relationships of the incisor teeth depended largely upon the amount of vertical growth of molars. Growth of the maxillary posterior process
Primary Failure of Eruption
BJO May /9'JO
was suggested as the primary cause of increase in facial height and he postulated that alveolar bone may have a growth potential independent of basal bone growth. Proffit ( 1978) has also linked the vertical position of the jaws to the eruption of the teeth, suggesting that individuals with primary failure of eruption have, as a consequence, a short lower face height, and that hyperactivity of the eruptive mechanism could result in an increased vertical dimension. The tracings of lateral skull radiographs of B.M. taken at 9i years and 14 years were examined at each age, particularly the measurements of the anterior lower face height (menton-anterior nasal spine) and the posterior lower face height (articulare-gonion) and the chin prominence (sellanasion-pogonion). These were all found to lie within one standard deviation of the published norms of the University of Michigan Growth Measurements and the Bolton Study ( 1975), and most are close to the mean values (Table I). The increase in facial heights in this case are quite normal through the growth spurt. Conclusions
Two cases of primary failure of eruption are presented, those of a son and his mother. Both seem similar in many ways to previously reported cases although the incisor involvement in the mother's case, is rare. In neither case did surgical exposure aid eruption of the involved teeth, indicating the futility of this procedure in such cases. In the son's case the lack of a buccal segment occlusion and associated alveolar growth does not appear to have affected vertical facial development, implying that basal jaw growth is the primary determinant of facial height in this individual. Acknowledgements
I wish to thank Mr J. G. Heyes, Consultant Orthodontist, Wrexham, for permission to report these cases, and Dr W. P. Rock, Consultant Orthodontist, Birmingham, for his helpful advice. References Ballard, C. F. (1966) The adaptive alveolar process, Annals of' the Royal College of' Surgeons
of' England. 39,299-311.
Bjork, A. and Skeiller, V. (1972) Facial development and tooth eruption, American Journal of' Orthodontics, 62, 339- 383.
113
Bosker, H., Tenkate, L. P. and Nijenhuis, L. E. (1978) Familial reinclusion of permanent molars, Clinical Genetics, 13, 314-320. Brenchley, M. L. (1960) Submerged first permanent molars, The Dental Practitioner, ll, 105-107. Broadbent, B. H. and Golden, W. H. (1975) Bolton standards of dentofacial developmental growth, C.V. Mosby Co., St. Louis. Darling, A. and Levers, B. G. H. (1973) Submerged human deciduous molars and ankylosis, Archir•es of Oral Biology, 18.8, 1021-1040. Hall, G. M. and Reade, P. C. (1981) Quadrilateral submersion of permanent teeth, Australian Dental Journal, 26, 73--76. Hall, R. K. and Hyland, A. L. (1978) Combined surgical and orthodontic management of the oral abnormalities in children with cleido-cranial dysplasia, International Journal of Oral Surgery, 7, 267-273. Kaban, L. B., Needleman, H. L. and Hertzberg, J. (1976) Idiopathic failure of eruption of permanent molar teeth, Oral Surgery, 42, 155-163. Kapoor, A. K., Srivastavia, A. B. and Singh, B. P. (1981) Bilateral posterior open bite, Oral Surgery, 51, 2-22. Mellor, T. K. (1981) Six cases of non-eruption of the first adult molar tooth, Journal of Dentistry, 9, 84-88. Mills, J. R. E. (1983) A clinician looks at facial growth, British Journal ()f' Orthodontics, 10, 58-72. Nadine, A. M. (1935) Case of ten unerupted and impacted teeth in a man twenty one years of age, Dental Cosmos, 77, 304-306. Oliver, R. G., Richmond, S. and Hunter, B. (1986) Submerged permanent molars: four case reports, British Dental Journal, 160, 128-130. Proffit, W. R. (1978) Equilibrium theory revisited: Factors influencing position of the teeth, Angle Orthodontist, 48, 175-186. Proffit, W. R. and Vlg, K. W. L. (1981) Primary failure of eruption: A possible cause of posterior open bite, American Journal of Orthodontics, 80, 173-190. Reid, D. J. (1954) Incomplete eruption of the first permanent molar in two generations of the same family, British Dental Journal, 96, 272-273. Schudy, F. F. (1968) The control of vertical overbite in clinical orthodontics, Angle Orthodontist, 38, 19-39. Solow, B. (1980) The dento-alveolar compensatory mechanism: background and clinical implications, British Journal of' Orthodontics, 1, 145 161.
ISSN: 0301-228X (Print) (Online) Journal homepage: http://www.tandfonline.com/loi/yjor19
Familial Primary Failure of Eruption of Permanent Teeth John Brady B.D.S., F.D.S., D.D.O., R.C.P.S., M.Orth, R.C.S. To cite this article: John Brady B.D.S., F.D.S., D.D.O., R.C.P.S., M.Orth, R.C.S. (1990) Familial Primary Failure of Eruption of Permanent Teeth, British Journal of Orthodontics, 17:2, 109-113, DOI: 10.1179/bjo.17.2.109 To link to this article: http://dx.doi.org/10.1179/bjo.17.2.109
Published online: 21 Jun 2016.
Submit your article to this journal
Article views: 2
View related articles
Citing articles: 23 View citing articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=yjor19 Download by: [University of Tasmania]
Date: 13 March 2017, At: 20:12
British Journal of OrthodmttiCJ/Vol. 17/1990/109-IIJ
Familial Primary Failure of Eruption of Permanent Teeth BRADY, D.D.S., F.D.S., D.D.O., R.C.P.S., M.ORTH, R.C.S. Birmingham Dental Hospital, St. Chad's Queensway, Birmingham 84 6NN
JOHN
Received for publication January 1989
Abstract. A son and his mother presented with features consistent with a diagnosis of primary failure of eruption. 'l'he features of this condition are described together with some aspects of treatment. The impact of the condition on vertical facial growth is discussed. Index words: Eruption Failure, Posterior Open Bite, Vertical Jaw Growth.
Introduction The failure of teeth to erupt can be due either to mechanical interferance, before or after emergence, or to a failure of the eruptive mechanism, partially or totally. Ankylosis seems to be accepted as a major factor in the failure of eruption of deciduous teeth (Darling and Levers, 1973) and is probably responsible for the isolated eruption failure of single permanent teeth; though localised obstruction, in the form of cysts, supernumeraries or odontomes have first to be excluded (Mellor, 1981). Where numerous teeth are affected, mechanical obstruction may take the form of interposed soft tissues or of overlying dense fibrotic tissue and abnormally resorbing alveolar bone. The last two factors are typical of cleidocranial dysplasia (Hall and Hyland, 1978). Where there are no mechanical interferences with eruption Proffit and Vig (1981), have termed the condition, 'Primary Failure of Eruption', and have postulated that a disturbance of the eruption mechanism within the periodontal membrane may be responsible. Following examination of sixteen affected individuals they identified several typical characteristics. However, there have been few reported cases in the literature showing these features. Brenchley (1960) reported a case with occlusion only on the anterior teeth, bilateral eruption failure of premolar and molar teeth having produced lateral open bites. Cases reported by Kapoor eta/. (1981), Hall and Reade (1981), and the first of the cases reported by Oliver et a/. (1986), were similar, although in the last mentioned, the lateral open bites were asymmetrical, having premolar occlusion on one side and a lower canine affected on the opposite side. The two cases reported by Bosker et a!. (1978) seem to fit well the description of 030 1·228X/90/002000 + 00102.00
primary failure of eruption and they also identified a familial tendency from study of 193 affected members from nine families. The inheritance in these cases was autosomal dominant with a vertical transmission and no skipping of generations. Other cases reported, possibly representing less extensive examples of the condition, include that of Nadine (1935) and one of the cases reported by Kahan eta/. (1976). Failure of vertical adaptation, described by Ballard (1966), seems to be the same condition as that under discussion, and it's rarity is underlined by an occurence in only nine cases out of over 16 000 patients referred to the Department of Orthodontics at the Eastman Dental Hospital, a family history being present in only one case. Examples of single first molars which fail to erupt in the absence of mechanical obstruction, such as those reported by Oliver eta/. (1986), Mellor (1981), Kahan eta/. (1976), and Reid (1954}, may represent a partial expression of the full condition. Case reports A 9!-year-old Caucasion male (BM) was referred regarding partial eruption of the permanent first molars on the left side. The incisor occlusion was Class I with an average overjet and overbite, the latter being complete. The skeletal relationship was mildly Class II with a reduced maxillary/mandibular. planes angle, though with an average lower factal percentage and a slightly raised anterior lower facial height (Fig. 1, Table 1). There were no soft tissue abnormalities noted and the lips were competant at rest. A radiograph (Fig. 2) confirmed the presence of all developing permanent teeth, except © 1990 British Society ror the Study or Orthodontics
110 J. Brady
BJO Vol. /7 No.1
TABLE I MeasuremeniS of patient B.M. 's lower facial height and chin prominance
9t Years
Me-ANS(mm) Ar-Go(mm) S-N-Po (")
14 Years
64·5 (55·7)
70·0 (61·7)
39·5 (39·2)
47·5 (45·0)
79·0 (79·0)
80·5 (80·7)
Bolton standard means in parentheses.
m. It was also noted that, although the right first permanent molars were clinically well erupted, they were not in occlusion, neither was ~· The patient was initially reluctant to undergo surgery, but after some delay, at the age of I 0 years 9 months, the E] roots were removed and the semierupted left first permanent molars were exposed. The occlusal surfaces of these teeth were reported free from obvious obstruction and Whitehead's Varnish packs were inserted. Although [6 remained clinically visible, gingival regrowth occurred and obscured ~rapidly. At II years 4 months (Fig. 3) this upper molar was re-exposed and again packed, which had continued to be in infra whilst occlusion, was extracted. Although ~ remained clinically well exposed, there was no improvement in the general eruptive level of the cheek teeth. Observations continued over the next 33 months and the various treatment options considered during this period included the provision of soft tissue deflectors and orthodontic extrusion of the affected teeth following further surgical exposure. However, as the diagnosis of primary failure of eruption was arrived at, and since it has been reported by Proffit and Vig (1981) that such measures are ineffective in this condition, these were not persued.
rn
FIG. I
Lateral skull radiograph at age 9t years.
5321112345 By age 14 years 4 3 2 1 1 1 2 3 4 5 7 were pre6 4 I 7 were erupted sent clinically (Fig. 4a, b), 7 and 87 86 5 1678 6 8 were unerupted. There were occlusal contacts present only on the incisors and canines with a bilateral posterior open bite. The first molars and 5], all of which had communication with the oral cavity were extracted at 14 years 6 months. A year later little further improvement in the posterior open bite had occurred. Restorative options to be considered in the future include over-
F1o. 2 Panoramic radiograph at age 9t years.
Primary Failure of Eruption
BJOMay /990
FIG.
3 Panoramic radiograph at age II years 4 months.
FIG. 4 (a) Panoramic and lateral skull radiographs at age 14 years. (b)
Ill
112 J. Brady
HJV Vol. 17 No.:!
FIG.
5 Panoramic radiograph of the patient's mother at age 40 years.
dentures, or the provision of bridges once facial growth is completed. On questioning, it became apparent that the patient's mother had possessed a similar condition and her microfilmed records taken some 30 years previously, were obtained. The mother had been seen initially at the age of 10 years, because of a delay in the eruption of much of the permanent dentition. She had been seen earlier at a Dental Hospital where a provisional diagnosis of cleidocranial dysostosis had been made. However, the only abnormalities seen on examination were limited to the dentition and involved ~. which was unerupted although it had an oral communication via a sinus and was carious. In the mother's case, it seems that there was incisor involvement, since 1 ~ 1 were exposed and§] extracted at age 12 years. There was little sign of movement of the buried teeth and l! was removed shortly afterwards whilst 21 J12~
3
were extracted at 17 years and l§ at 19 years. A recent radiograph (Fig. 5) at age 40 years shows 87 345 ~ to be still unerupted. J
7
Discussion The case of the son fits well with the criteria of primary failure of eruption, as described by Proffit and Vig (1981). Posterior teeth are mainly affected, with varying degrees of abnormality in the segment distal to the first involved tooth. Three permanent molars had shown some eruptive capacity, since they all possessed occlusal restorations. However, they subsequently became infra-occluded, whilst other affected teeth did not erupt at all. Exposure of the involved teeth, with removal of the overlying bone and mucosa, did not affect their eruptive
pos1t10ns though
~ were not found to be
ankylosed when they were extracted since they were easily removed by forceps and elevators without the need for bone removal. There was some involvement of deciduous teeth, with q E showing infraocclusion. Although Proffit and Vig (1981) found that their patients generally did not have similarly affected close relatives, the involvement of a mother and son in this report agrees with the inheritance pattern found by Bosker et a/. (1978). In addition, a first cousin was also reported to have the condition. The involvement of upper incisors in the case of the mother is unusual, although it seems likely that she too suffers from primary failure of eruption. An interesting aspect of primary eruption failure is the effect that lack of eruption of posterior teeth has on vertical facial growth. Bjork and Skeiller ( 1972), found that where there was forward rotation of the mandible during growth, the centre of this rotation was located in the anterior part of the dental arch. This indicated that the eruption of the molars was greater than of the incisors and that remodelling of the lower border masked the differential eruption. Solow ( 1980) linked alveolar growth with condylar growth as did Mills ( 1983 ), who felt that in cases of forward rotation, growth of the vertical ramus was greater than the combined vertical growth of upper and lower alveolar processes. In backward rotation, the opposite was thought to occur. Mills did not suggest whether or not differential growth caused the rotation, although a cause and effect relationship has been proposed by authors. Schudy (1968) felt that vertical relationships of the incisor teeth depended largely upon the amount of vertical growth of molars. Growth of the maxillary posterior process
Primary Failure of Eruption
BJO May /9'JO
was suggested as the primary cause of increase in facial height and he postulated that alveolar bone may have a growth potential independent of basal bone growth. Proffit ( 1978) has also linked the vertical position of the jaws to the eruption of the teeth, suggesting that individuals with primary failure of eruption have, as a consequence, a short lower face height, and that hyperactivity of the eruptive mechanism could result in an increased vertical dimension. The tracings of lateral skull radiographs of B.M. taken at 9i years and 14 years were examined at each age, particularly the measurements of the anterior lower face height (menton-anterior nasal spine) and the posterior lower face height (articulare-gonion) and the chin prominence (sellanasion-pogonion). These were all found to lie within one standard deviation of the published norms of the University of Michigan Growth Measurements and the Bolton Study ( 1975), and most are close to the mean values (Table I). The increase in facial heights in this case are quite normal through the growth spurt. Conclusions
Two cases of primary failure of eruption are presented, those of a son and his mother. Both seem similar in many ways to previously reported cases although the incisor involvement in the mother's case, is rare. In neither case did surgical exposure aid eruption of the involved teeth, indicating the futility of this procedure in such cases. In the son's case the lack of a buccal segment occlusion and associated alveolar growth does not appear to have affected vertical facial development, implying that basal jaw growth is the primary determinant of facial height in this individual. Acknowledgements
I wish to thank Mr J. G. Heyes, Consultant Orthodontist, Wrexham, for permission to report these cases, and Dr W. P. Rock, Consultant Orthodontist, Birmingham, for his helpful advice. References Ballard, C. F. (1966) The adaptive alveolar process, Annals of' the Royal College of' Surgeons
of' England. 39,299-311.
Bjork, A. and Skeiller, V. (1972) Facial development and tooth eruption, American Journal of' Orthodontics, 62, 339- 383.
113
Bosker, H., Tenkate, L. P. and Nijenhuis, L. E. (1978) Familial reinclusion of permanent molars, Clinical Genetics, 13, 314-320. Brenchley, M. L. (1960) Submerged first permanent molars, The Dental Practitioner, ll, 105-107. Broadbent, B. H. and Golden, W. H. (1975) Bolton standards of dentofacial developmental growth, C.V. Mosby Co., St. Louis. Darling, A. and Levers, B. G. H. (1973) Submerged human deciduous molars and ankylosis, Archir•es of Oral Biology, 18.8, 1021-1040. Hall, G. M. and Reade, P. C. (1981) Quadrilateral submersion of permanent teeth, Australian Dental Journal, 26, 73--76. Hall, R. K. and Hyland, A. L. (1978) Combined surgical and orthodontic management of the oral abnormalities in children with cleido-cranial dysplasia, International Journal of Oral Surgery, 7, 267-273. Kaban, L. B., Needleman, H. L. and Hertzberg, J. (1976) Idiopathic failure of eruption of permanent molar teeth, Oral Surgery, 42, 155-163. Kapoor, A. K., Srivastavia, A. B. and Singh, B. P. (1981) Bilateral posterior open bite, Oral Surgery, 51, 2-22. Mellor, T. K. (1981) Six cases of non-eruption of the first adult molar tooth, Journal of Dentistry, 9, 84-88. Mills, J. R. E. (1983) A clinician looks at facial growth, British Journal ()f' Orthodontics, 10, 58-72. Nadine, A. M. (1935) Case of ten unerupted and impacted teeth in a man twenty one years of age, Dental Cosmos, 77, 304-306. Oliver, R. G., Richmond, S. and Hunter, B. (1986) Submerged permanent molars: four case reports, British Dental Journal, 160, 128-130. Proffit, W. R. (1978) Equilibrium theory revisited: Factors influencing position of the teeth, Angle Orthodontist, 48, 175-186. Proffit, W. R. and Vlg, K. W. L. (1981) Primary failure of eruption: A possible cause of posterior open bite, American Journal of Orthodontics, 80, 173-190. Reid, D. J. (1954) Incomplete eruption of the first permanent molar in two generations of the same family, British Dental Journal, 96, 272-273. Schudy, F. F. (1968) The control of vertical overbite in clinical orthodontics, Angle Orthodontist, 38, 19-39. Solow, B. (1980) The dento-alveolar compensatory mechanism: background and clinical implications, British Journal of' Orthodontics, 1, 145 161.
