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What are the causes of failure of eruption of the deciduous molars?
WHAT ARE THE CAUSES OF FAILURE OF ERUPTION OF THE DECIDUOUS MOLARS Y· FLOYD ARNOLD, D.D.S., DEARBORN,
MICH.
M
y EXPERIENCE has been that the dental literature has nothing to offer on this subject. Most of my information came from Dr. Geo. R. Moore, who wrote a case history of partially erupted deciduous molars. I contacted no one who could give me any satisfactory explanation of the partial eruption of permanent teeth. However, the same factors may be present as with deciduous teeth. I shall attempt to outline this information and divide the cause into two classes: First, the remote causes: 1. The possibility of a circulatory disturbance in the region. 2. The possibility of disorder in the nervous system. 3. Lack of physiologic impulse. Second, the proximate causes: 1. The possibility of a feebleness of maxillary or mandibular growth in the region. This may very easily be associated with lack of bone cell development. 2. The normal tendency of the first permanent molars to assume a more anterior relation due to mastication. 3. Physical force of the permanent molars causing an intrusion of the deciduous molars. From the above outline we assume that normal bone growth has resulted on both sides of the partially erupted teeth. In the case Dr. Moore experienced in his own practice the patient presents a history of at one time having normal occlusion of deciduous molars. Report of the case follows: "The patient, a girl of six and one-half years, called for examination on October 27, 1928. The father and mother, and, according to their account, all relatives of whom they had any knowledge, exhibited normal dentitions with only minor irregularities, if any. The mother reported for the girl a normal prenatal period, normal birth, and normal early infancy. The child was breast fed for three months only, but the mother has been conscientious in matters of nutrition and rest, and has been careful to give her the very best of attention by placing her in the hands of a competent pediatrician. She has suffered only two of the ordinary children's diseases, measles and chickenpox, and until recently she had never been subject to colds. She presented at that time evi-From the Section on Children's Dentistry of the Detroit Clinic Club.
1023
1024
Floyd Arnold
dence of hypertrophy of adenoid and tonsil tissue and was referred for a tonsillectomy and adenoidectomy, which were done within two weeks after our original consultation. The child was of a somewhat nervous temperament, possessing at that time the last evidences of a thumb-sucking habit, a lip-biting habit of some severity, and a nail-biting habit." ATTRIBUTED ETIOLOGY
Unfortunately, my observation of the case began after the complete eruption of the permanent first molrrrs, The mother reported that deciduous molars had once been in occlusion. I can therefore account for open-bite shown in the lateral views only very inadequately by referring to a possible circulatory or nervous disorder in that region of the developing maxilla and mandible. This might be attributed to a temporary feebleness of growth with the result that the normal tendency of the first permanent molars to assume more anterior positions in the head delivered stresses which actually caused the intrusion of the molars lying between them and the canines which were supported by more healthy bone. This is only a subjective opinion not at all sustained by scientific evidence, and I am hoping some day to hear the real cause of intrusion of deciduous molars.
MICH.
M
y EXPERIENCE has been that the dental literature has nothing to offer on this subject. Most of my information came from Dr. Geo. R. Moore, who wrote a case history of partially erupted deciduous molars. I contacted no one who could give me any satisfactory explanation of the partial eruption of permanent teeth. However, the same factors may be present as with deciduous teeth. I shall attempt to outline this information and divide the cause into two classes: First, the remote causes: 1. The possibility of a circulatory disturbance in the region. 2. The possibility of disorder in the nervous system. 3. Lack of physiologic impulse. Second, the proximate causes: 1. The possibility of a feebleness of maxillary or mandibular growth in the region. This may very easily be associated with lack of bone cell development. 2. The normal tendency of the first permanent molars to assume a more anterior relation due to mastication. 3. Physical force of the permanent molars causing an intrusion of the deciduous molars. From the above outline we assume that normal bone growth has resulted on both sides of the partially erupted teeth. In the case Dr. Moore experienced in his own practice the patient presents a history of at one time having normal occlusion of deciduous molars. Report of the case follows: "The patient, a girl of six and one-half years, called for examination on October 27, 1928. The father and mother, and, according to their account, all relatives of whom they had any knowledge, exhibited normal dentitions with only minor irregularities, if any. The mother reported for the girl a normal prenatal period, normal birth, and normal early infancy. The child was breast fed for three months only, but the mother has been conscientious in matters of nutrition and rest, and has been careful to give her the very best of attention by placing her in the hands of a competent pediatrician. She has suffered only two of the ordinary children's diseases, measles and chickenpox, and until recently she had never been subject to colds. She presented at that time evi-From the Section on Children's Dentistry of the Detroit Clinic Club.
1023
1024
Floyd Arnold
dence of hypertrophy of adenoid and tonsil tissue and was referred for a tonsillectomy and adenoidectomy, which were done within two weeks after our original consultation. The child was of a somewhat nervous temperament, possessing at that time the last evidences of a thumb-sucking habit, a lip-biting habit of some severity, and a nail-biting habit." ATTRIBUTED ETIOLOGY
Unfortunately, my observation of the case began after the complete eruption of the permanent first molrrrs, The mother reported that deciduous molars had once been in occlusion. I can therefore account for open-bite shown in the lateral views only very inadequately by referring to a possible circulatory or nervous disorder in that region of the developing maxilla and mandible. This might be attributed to a temporary feebleness of growth with the result that the normal tendency of the first permanent molars to assume more anterior positions in the head delivered stresses which actually caused the intrusion of the molars lying between them and the canines which were supported by more healthy bone. This is only a subjective opinion not at all sustained by scientific evidence, and I am hoping some day to hear the real cause of intrusion of deciduous molars.