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Hereditary opalescent dentine (Dentinogenesis imperfecta)
Department
of Oral Surgery and Pathology Edited STERLING
V.
MEAD
Articles on oral surgery, radiography, V. Mead, 1149 Sixteenth Street Northwest, should be submitted to Dr. Kurt H. Thoma,
HEREDITARY
OPALESCENT
by
AND
KURT
and anesthesia Washington, 53 Bay State
DENTINE
H.
THOYA
should be submitted D. C. Articles on Road, Boston, Mass.
to Dr. Sterling oral pathology
(DENTINOGENESIS
IMPERFECTA) E.
ROBERTS,*
URBASA,
ILL.,
ASD
I. SCHoUR,t
CHICAGO,
ILL.
IXTRODUCTION
M
ANY cases of hereditary abnormalities of human teeth have been reported. Some of these which involve the dentine and enamel are listed in the references. Among the more recent reports, those of Noyes, Hodge and co-workers,11 and Skillen” show that dentine is primarily affected. Roberts” reported a family in which the teeth of certain members were soft and wore away rapidly, a condition common to both the deciduous and the permanent teeth. The case was, in gross appearance, very similar to that reported by Clark and Clark,” and for this reason it was thought t,hat the enamel was primarily affected. The purpose of this paper is to present in detail the histologic and genetic studies of this condition. NoyeP summarized his observations of this anomalous condition in both deciduous and permanent teeth as follows: peculiar bluish brown color of the teeth; normal enamel; complete obliteration of the pulp, and atypical dentinc showing increased dentine matrix and irregular arrangement of tubules. Hodgel’ in 1936 confirmed the findings of Noyes and in addition found in the dent,ine a very low microhardness, an abnormally high perccntagc water content, and a low inorganic cont.ent. Hodge suggested the term hereditary opalescent dentine. MATERIAL
ASD
FIXDIKGS
Our findings are based chiefly on bhe radiographic studies of the teeth of three members (V-18, VI-6, VI-8, Fig. 1) of the family and on the histologic studies of the teeth of V-18, Fig. 1, which were extracted prior to the preparation of full dentures. Our findings confirm those reported in the literature and throw additional light on this interesting condition. Gross Analysis.-The teeth appeared normal in size and form but showed a marked abrasion, and the enamel was lost except near the gingival level (Figs. 2 and 3). The enamel chipped and fractured readily. Function could be *From TFrom
the the
Division of Animal Genetics, College of Agriculture. University of Illinois. Department of Dental Histology, College of Dentistry, University of Illinois, 267
268
E. Ro’berts und I. &hour
maintained, and further abrasion was prevented only after the insertion of gold inlays which covered the entire ocelusal surfaces (Figs. 4 and 5). Another dentist, who has had experience wibh this type of defect, places inlays on the crowns of the teeth soon after eruption to prevent abrasion, which proWe expected to find much pain in these ceeds rapidly without protection. teeth, incident to the marked abrasion, but the patients had experienced no pain, and the teeth were not very sensitive. The teeth, especially the exposed denbine, showed an amberlike translucency or opalescence. Caries was not apparent. Radiographic Anulysis.-The loss of enamel and dentine through abrasion was marked. The pulp showed prominent recession and a very marked progressive decrease in the size of the pulp chamber and pulp canal. I
x
x
.
x
a
q = MALE
0 = FEMALE
q E DIEDIN ,NFANCY Fig.
l.-Pedigree and
will
of a family not show
in
m
= ““SSANDANDWIFE
m=
q = ,NFORMAT,ON NOTOSTAlNED
with an inherited defect of dentine. the children unless possessed by
BROTHER ANDSISTER n = DEFECTWE TEETH
This character one of the’parents.
is dominant
The fact that the x-ray films (Fi g, 6) of a younger member of the family, who is 7 years old, show in the unerupted teeth a normal contour of the crown, a normal thickness of the enamel, and a normal outline of the pulp indicates that the clinical changes are chiefly a posteruptive phenomenon. Fig. 7 shows (Compare with normal changes which have taken place in a 14-year-old girl. teeth in Fig. 8.) The roots appear to be shorter than normal. Histologic Analysis.-The followin g changes were observed in ground and decalcified sections : I. Enamel : The ground sections showed a normal structure in the enamel. II. Dentine: A. The dentine nearest to the enamel (mantle dentine) appeared normal. B. The remaining (circumpulpar) dentine showed an atypical structure characterized by : 1. Irregular tubular arrangement.
Hereditary
Fig.
Opalescent Dentine
3.
I
Fig. 2.-Casts of teeth 1). Right: From girl clearly the amount of Fig. 3.-Casts of teeth show amount of wear. Fig. 4.-Cast of teeth partially protected by gold Fig. more
with defective dentine. 14 years old (VI-6, Fig. wear. from same boy and girl of father crowns.
of boy
and
girl
Left: 1).
From boy Teeth have
in Fig.
2.
Teeth
in Figs.
2 and
3.
7 years of age (W-8. been darkened to show have These
been teeth
darkened have
to been
E. Roberts and I. Schour
Fig.
Fig:
5.-Radiograph
of teeth
B.-Radiograph of teeth m pulp and enamel have
of father
(Y-18. Fig. 1) by gold crowns.
of boy 7 years not progressed
with
defective
of age (VI-a, Fig. 1) with so far as in sister (Fig.
dentine.
Teeth
protected
defective dentine. Changes 1) or father (Fig. 1).
IJereditnry
Fig.
‘I.-Radiograph
of
teeth
of
Dentine
Opalescent
14-year-old
girl
(VI-6,
Fig.
1)
with
defective
dentine.
272
E. Roberts and I. S&our 2. Smaller number
of tubuli
decreasing toward
the pulp.
3. Occasional larger diameter of tubuli and cellular inclusions. 4. Numerous branchings of the tubuli. 5. Markedly accentuated incremental stratification of the dentine matrix. 6. Poor calcification. It required only half the normal time to decalcify these teeth. The circumpulpar dentine picture resembles irregular secondary dentine formation (Figs. 9 and 10).
Fig. 9.-A, Diagram of a ground section of a normal human premolar. Note the thickness and distribution of the enamel, the regular course of the dentinal tubules and the extent of the pulpal cavity; B, Diagram of a ground section of a premolar of the patient. Note the marked abrasion which has resulted in the loss of most of the enamel except at the gingival portion. Note the irregular course and scant amount of the dentinal tubules and the almost complete obliteration of the pulpal cavity.
III.
Pulp:
The pulp cavity was markedly diminished in size and filled in with the atypical circumpulpar dentine described above. The pulps begin to disappeas as early as 7 years (Fig. 6) and are practically obliterated in the case of the 14-year-old (Fig. 7). The cellular picture was indistinct because of the marked obliteration of the pulp (Fig. 9). DISCUSSION
OF
DENTAL
CHANGES
We recently have had the opportunity of studying several additional cases In each case histologic in which the teeth had a typical opalescent appearance. analysis revealed the typical disturbance in dentine formation (dentinogenesis imperf ecta) . In two of these additional cases the patient was suffering from osteogenesis imperfecta. It is our impression, and a careful review of the literature tends to support this ( Preiswerk,21 Haubach,l“ Bauer,2 Vanderveer
Here&my
Opalescent Dentine
273
and IXckinson,“o Naito,l” Adloff,’ Becks,3 Jeckeln,14 and others), that an intimate relationship may exist between osteogencsis impcrfecta and hereditary opalescent dentine. This possibility merits further investigation. It appears that both the dentinification of the pulp and the opalescence are postformative and posteruptive phenomena. The pulp outline is normal in the unerupted tooth, and the opalescence is less marked in the newly erupted tooth. The essential nature of hereditary opalescent dentine is the imperfect dentine formation rather than the poor calcification, which is probably a secondary effect. Therefore while t,he term ’ ‘ hereditary opalescent dentine ” employed by Hodge is useful from the point of view of clinical description, the term ’ ‘dentinogenesis imperfecta” is also useful from the point of view of microscopic and embryologic descriptiou. The term, dentinogcnesis imperfect,a, also has the advantage of bringing the dental changes in osteogenesis imperfecta a.nd hereditary opalescent dentine under a common denominator. Beck? has suggested parenthetically the term “ odontogenesis imperfecta. ’ ’ Since the defective formation applies entirely to the dcntine, and does not, therefore, involve the entire tooth’ (odont), “dentinogenesis imperfects” is preferable.
Fig. 10.-A (left). Photomicrograph of a ground section of the mandibular first molar of the patient. Most of the enamel has chipped off during the grinding process. The dentine nearest to the enamel shows a normal texture; the remainingportion resembles secondarv dentine. Compare with Fig. 9. B (right), Photomicrograph of fleld indicated in A, and magnified. The dentine nearest to the enamel (mantle dentine) shows a normal pattern but soon shows a twist in the direction of the dentinal tubules at t. The dentine below is abnormal in texture and contains only a few tubules. Their branches are very delicate and resemble nerve endings at m.
The study of this peculiar condition is of more than passing interest as a case report. The fact that the ectodermal tissue (enamel) is unaffected, while the mesenchymal tissue (dentine) is very much disturbed, marks this condition as a mesenchymal dysplasia. We have thus a dissection experiment. In addition, the odontoblastic processes (the dentinal fibrils within the dentinal tubuli)
274
E. Roberts and I. Schour
are markedly hypoplastic, while the dentine matrix is hyperplastic. A careful study of the mechanism of this and other experimentally induced dentine dysplasias may well serve to further our knowledge of the cells responsible for dentine apposition. Genetic Ancclysis.-This condition is hereditary and has been traced in the family represented in Fig. 1 for seven generations. The first individual in the pedigree was born in 1763, beyond which time information was not available. From a study of the pedigree, it is obvious that the condition does not This show in the children unless it is visibly possessed by one of the parents. means that it is dominant in expression. Also, it is apparently due to a single gene difference from the normal condition. If this is true, a theoretical ratio of 1 :l would be expected among children, one parent of whom possessed the deThe observed ratio of 23 normal to fect, if it is in the heterozygous condition. 22 defective in the pedigree (Fig. 1) is as good a fit as is possible with fortyfive cases. DISCUSSION
OF
GENETIC
ANALYSIS
Through the kindness of Dr. R. M. Stephan, College of Dentistry, University of Illinois, another family with this condition was reported to us. He made the following observations : 1. Both the deciduous and permanent teeth are affected. 2. The teeth are much smaller than normal, about one-half or one-eighth the volume.
the dimensions
3. Enamel appears as a very thin layer, which is not always evident in radiographs, and is apparently quickly worn away in the mouth. 4. Pulp chambers and canals show in the radiographs of deciduous teeth during formation, but are almost completely obliterated in erupted teeth of the permanent set. 5. The teeth are not sensitive to grinding, indicating that the dentine does not contain vital fibrils. 6. All other oral structures appear normal. A pedigree of this family is given in Fig. 11. The mode of inheritance is apparently the same as that in the other families discussed in this paper. Among seven individuals in three generations, five have defective teeth. If these are added to those of the family in Fig. 1, the ratio becomes 25 normal : 27 defective, when the theoretical expectation is l:l, if the affected parent in each case is heterozygous. This is an extremely good fit. The deviation from the expected is 1, and the probable error ~~2.43. To be homozygous the gene for the No such case was defect would have to be obtained from each of the parents. found. All the children of an individual homozygous for the defect would show it. In every case an individual with the defect married a normal person with resulting heterozygosity of progeny showing the defect. If D = defect and d = normal condition, the heterozygous individual will be represented by Dd. Such an individual marries a normal dd. Dd produces two kinds of repro-
Hereditary ductive cells, D and d. duced by dd individuals of 1 Dd : 1 dd.
275
Opalescent Dentine
The random fertilization of these by the d type proresults in Dd and dd progeny in the theoretical ratio
The mode of inheritance in the families reported by Clark and Clark6 is in complete agreement with those discussed in this paper. From correspondence with Dr. F. H. Clark, one of the family names found in his study was also present in ours. Since this character is so rare, the occurrence of the same name in both families, together with the fact that they originally lived in the same region of the country, suggests the possibility that the two families are related. In Clark’s family twenty-three normal and thirty-seven defective individuals were found. The departure of this ratio from the theoretical is not statistically significant, yet it is not nearly so close as the one which exists in our data. The authors suggest the possibility of not having all the normal children included. In the two pedigrees presented in this paper reasonable assurance is felt that all children were reported.
Fig.
Il.-Family
with
defective
dentine
reported
by
Dr.
R. M.
Stephan.
In the summary by Finn,’ 220 matings produced 740 offspring, 357 of The deviation of thirteen whom were normal and 383 with opalescent dentine. from a theoretical ratio of 1 :l, with a probable error of k9.17, indicates a good fit of the observed to the theoretical expectation. This tooth defect is in no way the result of faulty nutrition, though conceivably it might be accentuated by it. While this condition cannot be controlled by the diet, it can be prevented from appearing in future generations. A dominant character of this kind can be permanently eliminated if the afflicted If it were a recessive character, the difficulty individuals do not bear children. of eliminating it from the germ plasm would be much greater. SUMMARY
Several cases of hereditary opalescent dentine are described and analyzed histologically and genetically. The similarity in the dental changes in hereditary opalescent dentine and osteogenesis imperfecta is pointed out, and the characteristic effects are grouped under the general term “dentinogenesis imperfecta.”
276
E. flobrts
und 1. Schou:,
REFERENCES 1. Adloff 2. Bauer, 3. 4. 5. 6. 7. 8. 9. 10. 11. lla. 12.
: Dentinstruktur bei Osteogenesis Imperfecta, Vrtlj. f. Zahnheilkunde 44: 478, 1928. R. H.: ijber Osteogenesis Imperfecta, zugleich ein Beitrag zur Frage einer allgemeinen Erkrankung samtlicher Stiitzgewebe, Deutsche Ztschr. f. Chir. 154: 166, 1920. Becks, Hermann : Histologic Study of Tooth Structure in Osteogenesis Imperfecta, Dental Cosmos 73: 437. 1931. Bennett, N. C.: Teeth Devoid of Enamel, Dental Cosmos 48: 788, 1906. Cautly, R. L.: Abnormalities of Human Dentition, Brit. Dent. J. 49: 669, 1928. Clark, F. H. and Clark, C. S.: Absence of Tooth Enamel, J. Hered. 24: 425, 1933. Finn, S. B.: Hereditary Opalescent Dentin. I. An Analysis of the Literature on Hereditary Anomalies of Tooth Color, J. A. D. A. and Dental Cosmos 25: 1240, 1938. Gruneberg, H. : Two Independent Inherited Tooth Anomalies in One F’amily, J. Hered. 27: 225, 1936. Guilford, S. H.: Anomalies of the Teeth and Maxillae, Am. System of Dentistry 3: 415, 1887. Haubach : fiber Anormale und Normale Dentinbildung bei Osteogenesis Imperfecta, Vrtljsschr. f. Za.hnh. 45: 268, 1929. Hodge, H. C. et al.: Correlated Clinical and Structural Study of Hereditary Opalescent Dentin, J. Dent. Research 15: 316, 1936. Hodge, H. C. and Finn, S. B.: Hereditary Opalescent Dentin, J. Hered. 29: 359, 1938. Hope;;liSmith, A.: Some Studies of Jaws in Health and Disease, Dental Cosmos 55: 765,
13. Idem: 14. Jeckeln, 15. 16. 17. 18. 19.
20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32.
Case of Partial Dental Aplasia, Dental Cosmos 63: 465, 1921. Ernst: Systemgebundene mesenchymale Erschijpfung. Eine neue Begriffsfassung der Osteogenesis Imperfecta, Virchows Arch. f. path. Anat. 280: 351, 1931. Eeller, C. E.: Review of Hereditary Factors in Dentistry, Dental Cosmos 77: 1147, 1935. Macklin, Madge T.: Absent Tooth Enamel, Eugenical News 23: 28, 1938. Moody, E. and Montgomery, L. B. : Hereditary Tendencies in Tooth Formation, J. A. D. A. 21: 1774, 1934. Moore, G. R.: Case of Agenesia of Enamel, Dental Cosmos 66: 582, 1924. Naito, S.: Klinische und Histologische Untersuchungen des Zahngewebes bei Osteogenesis Imperfecta, nebst Studien iiber die sog. Korff ‘schen Fasern und einem Beitrag zur Dentinbildung, Mitt. aus d. med. Fakultltd. Kaiserl. Univ. Kyushu 9: 97, Cited from Zilkens, Fortschr. d. Zahnhlk. 3: 284, 1924. Noyes, F. B.: Hereditary Anqmaly in Structure of Dentin, J. Dent. Research 15: 154, 1935. Preiswerk : Ein Beitrag zur Kenntnis der Osteogenesis Imperfecta (Vrolik), Jahrb. f. Kinderheilk. 76: 5, 1912. Roberts, E.: Effect of Heredity on Human Enamel, J. Dent. Research 15: 221, 1935. Roberts, J. S.: Case of Deficiency of Enamel, Brit. Dent. J. 49: 1203, 1928. Skillen, W. G.: Histologic and Clinical Study of Hereditary Opalescent Dentin, J. A. D. A. and Dental Cosmos 24: 1426, 1937. Spokes, Sidney: A Case of Faulty Enamel (Brown Teeth), Brit. J. Dent. SC. 33: 750, 1890. Idem: Notes on the Hypoplasia of Enamel, Brit. Dent. Assoc. J. 18: 31, 1897. Stainton, C. W.: Crownless Teeth, Dental Cosmos 34: 978, 1892. Talbot, E. S.: Arrests of Development and Decalcification of Enamel and Dentin, J. A. M. A. 20: 29, 1893. Turner, J. G.: Hereditary Hypoplasia of Enamel, Trans. Odont. Sot. 39: 137, 1907. Vanderveer. E. A. and Dickinson. A. M.: Fraa-ilatas Ossium. Ann. Surg. 74: 629. 1921. Willett, R. ‘C. : Unusual Diet and’ Its Questionaoble Effect Upon Dentitiog, INT. J: ~RTHO. 20: 432, 1934. Wilson, G. W. and Steinbrecher, M.: Hereditary Hypoplasia of Dentin, J. A. D. A. 16: 866, 1929.
of Oral Surgery and Pathology Edited STERLING
V.
MEAD
Articles on oral surgery, radiography, V. Mead, 1149 Sixteenth Street Northwest, should be submitted to Dr. Kurt H. Thoma,
HEREDITARY
OPALESCENT
by
AND
KURT
and anesthesia Washington, 53 Bay State
DENTINE
H.
THOYA
should be submitted D. C. Articles on Road, Boston, Mass.
to Dr. Sterling oral pathology
(DENTINOGENESIS
IMPERFECTA) E.
ROBERTS,*
URBASA,
ILL.,
ASD
I. SCHoUR,t
CHICAGO,
ILL.
IXTRODUCTION
M
ANY cases of hereditary abnormalities of human teeth have been reported. Some of these which involve the dentine and enamel are listed in the references. Among the more recent reports, those of Noyes, Hodge and co-workers,11 and Skillen” show that dentine is primarily affected. Roberts” reported a family in which the teeth of certain members were soft and wore away rapidly, a condition common to both the deciduous and the permanent teeth. The case was, in gross appearance, very similar to that reported by Clark and Clark,” and for this reason it was thought t,hat the enamel was primarily affected. The purpose of this paper is to present in detail the histologic and genetic studies of this condition. NoyeP summarized his observations of this anomalous condition in both deciduous and permanent teeth as follows: peculiar bluish brown color of the teeth; normal enamel; complete obliteration of the pulp, and atypical dentinc showing increased dentine matrix and irregular arrangement of tubules. Hodgel’ in 1936 confirmed the findings of Noyes and in addition found in the dent,ine a very low microhardness, an abnormally high perccntagc water content, and a low inorganic cont.ent. Hodge suggested the term hereditary opalescent dentine. MATERIAL
ASD
FIXDIKGS
Our findings are based chiefly on bhe radiographic studies of the teeth of three members (V-18, VI-6, VI-8, Fig. 1) of the family and on the histologic studies of the teeth of V-18, Fig. 1, which were extracted prior to the preparation of full dentures. Our findings confirm those reported in the literature and throw additional light on this interesting condition. Gross Analysis.-The teeth appeared normal in size and form but showed a marked abrasion, and the enamel was lost except near the gingival level (Figs. 2 and 3). The enamel chipped and fractured readily. Function could be *From TFrom
the the
Division of Animal Genetics, College of Agriculture. University of Illinois. Department of Dental Histology, College of Dentistry, University of Illinois, 267
268
E. Ro’berts und I. &hour
maintained, and further abrasion was prevented only after the insertion of gold inlays which covered the entire ocelusal surfaces (Figs. 4 and 5). Another dentist, who has had experience wibh this type of defect, places inlays on the crowns of the teeth soon after eruption to prevent abrasion, which proWe expected to find much pain in these ceeds rapidly without protection. teeth, incident to the marked abrasion, but the patients had experienced no pain, and the teeth were not very sensitive. The teeth, especially the exposed denbine, showed an amberlike translucency or opalescence. Caries was not apparent. Radiographic Anulysis.-The loss of enamel and dentine through abrasion was marked. The pulp showed prominent recession and a very marked progressive decrease in the size of the pulp chamber and pulp canal. I
x
x
.
x
a
q = MALE
0 = FEMALE
q E DIEDIN ,NFANCY Fig.
l.-Pedigree and
will
of a family not show
in
m
= ““SSANDANDWIFE
m=
q = ,NFORMAT,ON NOTOSTAlNED
with an inherited defect of dentine. the children unless possessed by
BROTHER ANDSISTER n = DEFECTWE TEETH
This character one of the’parents.
is dominant
The fact that the x-ray films (Fi g, 6) of a younger member of the family, who is 7 years old, show in the unerupted teeth a normal contour of the crown, a normal thickness of the enamel, and a normal outline of the pulp indicates that the clinical changes are chiefly a posteruptive phenomenon. Fig. 7 shows (Compare with normal changes which have taken place in a 14-year-old girl. teeth in Fig. 8.) The roots appear to be shorter than normal. Histologic Analysis.-The followin g changes were observed in ground and decalcified sections : I. Enamel : The ground sections showed a normal structure in the enamel. II. Dentine: A. The dentine nearest to the enamel (mantle dentine) appeared normal. B. The remaining (circumpulpar) dentine showed an atypical structure characterized by : 1. Irregular tubular arrangement.
Hereditary
Fig.
Opalescent Dentine
3.
I
Fig. 2.-Casts of teeth 1). Right: From girl clearly the amount of Fig. 3.-Casts of teeth show amount of wear. Fig. 4.-Cast of teeth partially protected by gold Fig. more
with defective dentine. 14 years old (VI-6, Fig. wear. from same boy and girl of father crowns.
of boy
and
girl
Left: 1).
From boy Teeth have
in Fig.
2.
Teeth
in Figs.
2 and
3.
7 years of age (W-8. been darkened to show have These
been teeth
darkened have
to been
E. Roberts and I. Schour
Fig.
Fig:
5.-Radiograph
of teeth
B.-Radiograph of teeth m pulp and enamel have
of father
(Y-18. Fig. 1) by gold crowns.
of boy 7 years not progressed
with
defective
of age (VI-a, Fig. 1) with so far as in sister (Fig.
dentine.
Teeth
protected
defective dentine. Changes 1) or father (Fig. 1).
IJereditnry
Fig.
‘I.-Radiograph
of
teeth
of
Dentine
Opalescent
14-year-old
girl
(VI-6,
Fig.
1)
with
defective
dentine.
272
E. Roberts and I. S&our 2. Smaller number
of tubuli
decreasing toward
the pulp.
3. Occasional larger diameter of tubuli and cellular inclusions. 4. Numerous branchings of the tubuli. 5. Markedly accentuated incremental stratification of the dentine matrix. 6. Poor calcification. It required only half the normal time to decalcify these teeth. The circumpulpar dentine picture resembles irregular secondary dentine formation (Figs. 9 and 10).
Fig. 9.-A, Diagram of a ground section of a normal human premolar. Note the thickness and distribution of the enamel, the regular course of the dentinal tubules and the extent of the pulpal cavity; B, Diagram of a ground section of a premolar of the patient. Note the marked abrasion which has resulted in the loss of most of the enamel except at the gingival portion. Note the irregular course and scant amount of the dentinal tubules and the almost complete obliteration of the pulpal cavity.
III.
Pulp:
The pulp cavity was markedly diminished in size and filled in with the atypical circumpulpar dentine described above. The pulps begin to disappeas as early as 7 years (Fig. 6) and are practically obliterated in the case of the 14-year-old (Fig. 7). The cellular picture was indistinct because of the marked obliteration of the pulp (Fig. 9). DISCUSSION
OF
DENTAL
CHANGES
We recently have had the opportunity of studying several additional cases In each case histologic in which the teeth had a typical opalescent appearance. analysis revealed the typical disturbance in dentine formation (dentinogenesis imperf ecta) . In two of these additional cases the patient was suffering from osteogenesis imperfecta. It is our impression, and a careful review of the literature tends to support this ( Preiswerk,21 Haubach,l“ Bauer,2 Vanderveer
Here&my
Opalescent Dentine
273
and IXckinson,“o Naito,l” Adloff,’ Becks,3 Jeckeln,14 and others), that an intimate relationship may exist between osteogencsis impcrfecta and hereditary opalescent dentine. This possibility merits further investigation. It appears that both the dentinification of the pulp and the opalescence are postformative and posteruptive phenomena. The pulp outline is normal in the unerupted tooth, and the opalescence is less marked in the newly erupted tooth. The essential nature of hereditary opalescent dentine is the imperfect dentine formation rather than the poor calcification, which is probably a secondary effect. Therefore while t,he term ’ ‘ hereditary opalescent dentine ” employed by Hodge is useful from the point of view of clinical description, the term ’ ‘dentinogenesis imperfecta” is also useful from the point of view of microscopic and embryologic descriptiou. The term, dentinogcnesis imperfect,a, also has the advantage of bringing the dental changes in osteogenesis imperfecta a.nd hereditary opalescent dentine under a common denominator. Beck? has suggested parenthetically the term “ odontogenesis imperfecta. ’ ’ Since the defective formation applies entirely to the dcntine, and does not, therefore, involve the entire tooth’ (odont), “dentinogenesis imperfects” is preferable.
Fig. 10.-A (left). Photomicrograph of a ground section of the mandibular first molar of the patient. Most of the enamel has chipped off during the grinding process. The dentine nearest to the enamel shows a normal texture; the remainingportion resembles secondarv dentine. Compare with Fig. 9. B (right), Photomicrograph of fleld indicated in A, and magnified. The dentine nearest to the enamel (mantle dentine) shows a normal pattern but soon shows a twist in the direction of the dentinal tubules at t. The dentine below is abnormal in texture and contains only a few tubules. Their branches are very delicate and resemble nerve endings at m.
The study of this peculiar condition is of more than passing interest as a case report. The fact that the ectodermal tissue (enamel) is unaffected, while the mesenchymal tissue (dentine) is very much disturbed, marks this condition as a mesenchymal dysplasia. We have thus a dissection experiment. In addition, the odontoblastic processes (the dentinal fibrils within the dentinal tubuli)
274
E. Roberts and I. Schour
are markedly hypoplastic, while the dentine matrix is hyperplastic. A careful study of the mechanism of this and other experimentally induced dentine dysplasias may well serve to further our knowledge of the cells responsible for dentine apposition. Genetic Ancclysis.-This condition is hereditary and has been traced in the family represented in Fig. 1 for seven generations. The first individual in the pedigree was born in 1763, beyond which time information was not available. From a study of the pedigree, it is obvious that the condition does not This show in the children unless it is visibly possessed by one of the parents. means that it is dominant in expression. Also, it is apparently due to a single gene difference from the normal condition. If this is true, a theoretical ratio of 1 :l would be expected among children, one parent of whom possessed the deThe observed ratio of 23 normal to fect, if it is in the heterozygous condition. 22 defective in the pedigree (Fig. 1) is as good a fit as is possible with fortyfive cases. DISCUSSION
OF
GENETIC
ANALYSIS
Through the kindness of Dr. R. M. Stephan, College of Dentistry, University of Illinois, another family with this condition was reported to us. He made the following observations : 1. Both the deciduous and permanent teeth are affected. 2. The teeth are much smaller than normal, about one-half or one-eighth the volume.
the dimensions
3. Enamel appears as a very thin layer, which is not always evident in radiographs, and is apparently quickly worn away in the mouth. 4. Pulp chambers and canals show in the radiographs of deciduous teeth during formation, but are almost completely obliterated in erupted teeth of the permanent set. 5. The teeth are not sensitive to grinding, indicating that the dentine does not contain vital fibrils. 6. All other oral structures appear normal. A pedigree of this family is given in Fig. 11. The mode of inheritance is apparently the same as that in the other families discussed in this paper. Among seven individuals in three generations, five have defective teeth. If these are added to those of the family in Fig. 1, the ratio becomes 25 normal : 27 defective, when the theoretical expectation is l:l, if the affected parent in each case is heterozygous. This is an extremely good fit. The deviation from the expected is 1, and the probable error ~~2.43. To be homozygous the gene for the No such case was defect would have to be obtained from each of the parents. found. All the children of an individual homozygous for the defect would show it. In every case an individual with the defect married a normal person with resulting heterozygosity of progeny showing the defect. If D = defect and d = normal condition, the heterozygous individual will be represented by Dd. Such an individual marries a normal dd. Dd produces two kinds of repro-
Hereditary ductive cells, D and d. duced by dd individuals of 1 Dd : 1 dd.
275
Opalescent Dentine
The random fertilization of these by the d type proresults in Dd and dd progeny in the theoretical ratio
The mode of inheritance in the families reported by Clark and Clark6 is in complete agreement with those discussed in this paper. From correspondence with Dr. F. H. Clark, one of the family names found in his study was also present in ours. Since this character is so rare, the occurrence of the same name in both families, together with the fact that they originally lived in the same region of the country, suggests the possibility that the two families are related. In Clark’s family twenty-three normal and thirty-seven defective individuals were found. The departure of this ratio from the theoretical is not statistically significant, yet it is not nearly so close as the one which exists in our data. The authors suggest the possibility of not having all the normal children included. In the two pedigrees presented in this paper reasonable assurance is felt that all children were reported.
Fig.
Il.-Family
with
defective
dentine
reported
by
Dr.
R. M.
Stephan.
In the summary by Finn,’ 220 matings produced 740 offspring, 357 of The deviation of thirteen whom were normal and 383 with opalescent dentine. from a theoretical ratio of 1 :l, with a probable error of k9.17, indicates a good fit of the observed to the theoretical expectation. This tooth defect is in no way the result of faulty nutrition, though conceivably it might be accentuated by it. While this condition cannot be controlled by the diet, it can be prevented from appearing in future generations. A dominant character of this kind can be permanently eliminated if the afflicted If it were a recessive character, the difficulty individuals do not bear children. of eliminating it from the germ plasm would be much greater. SUMMARY
Several cases of hereditary opalescent dentine are described and analyzed histologically and genetically. The similarity in the dental changes in hereditary opalescent dentine and osteogenesis imperfecta is pointed out, and the characteristic effects are grouped under the general term “dentinogenesis imperfecta.”
276
E. flobrts
und 1. Schou:,
REFERENCES 1. Adloff 2. Bauer, 3. 4. 5. 6. 7. 8. 9. 10. 11. lla. 12.
: Dentinstruktur bei Osteogenesis Imperfecta, Vrtlj. f. Zahnheilkunde 44: 478, 1928. R. H.: ijber Osteogenesis Imperfecta, zugleich ein Beitrag zur Frage einer allgemeinen Erkrankung samtlicher Stiitzgewebe, Deutsche Ztschr. f. Chir. 154: 166, 1920. Becks, Hermann : Histologic Study of Tooth Structure in Osteogenesis Imperfecta, Dental Cosmos 73: 437. 1931. Bennett, N. C.: Teeth Devoid of Enamel, Dental Cosmos 48: 788, 1906. Cautly, R. L.: Abnormalities of Human Dentition, Brit. Dent. J. 49: 669, 1928. Clark, F. H. and Clark, C. S.: Absence of Tooth Enamel, J. Hered. 24: 425, 1933. Finn, S. B.: Hereditary Opalescent Dentin. I. An Analysis of the Literature on Hereditary Anomalies of Tooth Color, J. A. D. A. and Dental Cosmos 25: 1240, 1938. Gruneberg, H. : Two Independent Inherited Tooth Anomalies in One F’amily, J. Hered. 27: 225, 1936. Guilford, S. H.: Anomalies of the Teeth and Maxillae, Am. System of Dentistry 3: 415, 1887. Haubach : fiber Anormale und Normale Dentinbildung bei Osteogenesis Imperfecta, Vrtljsschr. f. Za.hnh. 45: 268, 1929. Hodge, H. C. et al.: Correlated Clinical and Structural Study of Hereditary Opalescent Dentin, J. Dent. Research 15: 316, 1936. Hodge, H. C. and Finn, S. B.: Hereditary Opalescent Dentin, J. Hered. 29: 359, 1938. Hope;;liSmith, A.: Some Studies of Jaws in Health and Disease, Dental Cosmos 55: 765,
13. Idem: 14. Jeckeln, 15. 16. 17. 18. 19.
20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32.
Case of Partial Dental Aplasia, Dental Cosmos 63: 465, 1921. Ernst: Systemgebundene mesenchymale Erschijpfung. Eine neue Begriffsfassung der Osteogenesis Imperfecta, Virchows Arch. f. path. Anat. 280: 351, 1931. Eeller, C. E.: Review of Hereditary Factors in Dentistry, Dental Cosmos 77: 1147, 1935. Macklin, Madge T.: Absent Tooth Enamel, Eugenical News 23: 28, 1938. Moody, E. and Montgomery, L. B. : Hereditary Tendencies in Tooth Formation, J. A. D. A. 21: 1774, 1934. Moore, G. R.: Case of Agenesia of Enamel, Dental Cosmos 66: 582, 1924. Naito, S.: Klinische und Histologische Untersuchungen des Zahngewebes bei Osteogenesis Imperfecta, nebst Studien iiber die sog. Korff ‘schen Fasern und einem Beitrag zur Dentinbildung, Mitt. aus d. med. Fakultltd. Kaiserl. Univ. Kyushu 9: 97, Cited from Zilkens, Fortschr. d. Zahnhlk. 3: 284, 1924. Noyes, F. B.: Hereditary Anqmaly in Structure of Dentin, J. Dent. Research 15: 154, 1935. Preiswerk : Ein Beitrag zur Kenntnis der Osteogenesis Imperfecta (Vrolik), Jahrb. f. Kinderheilk. 76: 5, 1912. Roberts, E.: Effect of Heredity on Human Enamel, J. Dent. Research 15: 221, 1935. Roberts, J. S.: Case of Deficiency of Enamel, Brit. Dent. J. 49: 1203, 1928. Skillen, W. G.: Histologic and Clinical Study of Hereditary Opalescent Dentin, J. A. D. A. and Dental Cosmos 24: 1426, 1937. Spokes, Sidney: A Case of Faulty Enamel (Brown Teeth), Brit. J. Dent. SC. 33: 750, 1890. Idem: Notes on the Hypoplasia of Enamel, Brit. Dent. Assoc. J. 18: 31, 1897. Stainton, C. W.: Crownless Teeth, Dental Cosmos 34: 978, 1892. Talbot, E. S.: Arrests of Development and Decalcification of Enamel and Dentin, J. A. M. A. 20: 29, 1893. Turner, J. G.: Hereditary Hypoplasia of Enamel, Trans. Odont. Sot. 39: 137, 1907. Vanderveer. E. A. and Dickinson. A. M.: Fraa-ilatas Ossium. Ann. Surg. 74: 629. 1921. Willett, R. ‘C. : Unusual Diet and’ Its Questionaoble Effect Upon Dentitiog, INT. J: ~RTHO. 20: 432, 1934. Wilson, G. W. and Steinbrecher, M.: Hereditary Hypoplasia of Dentin, J. A. D. A. 16: 866, 1929.