Osteopetrosis, (generic term)

Teething

Teething does not appear to cause diarrhea, fever, rashes, seizures or bronchitis. It may be associated with some daytime restlessness, thumb sucking, gum rubbing, drooling and temporary loss of appetite. It is not clear whether these signs are developmental in origin or are actually related to tooth eruption. Illness occurring with teething should be thoroughly evaluated so that a serious systemic disturbance is not overlooked. The eruption of primary teeth in infancy (deciduous dentition) is commonly referred to as "teething," but this term is not applied to the eruption of permanent teeth at six to eight years of age (permanent dentition). Throughout recorded history, a wide variety of symptoms and illnesses have been ascribed to teething. For example, Hippocrates[1] wrote that "teething children suffer from itching of the gums, fevers, convulsions [and] diarrhoea especially when they cut their eye teeth, and when they are very corpulent and costive." As late as the middle of the last century, the teething process was considered a potential cause of death. In 1839, for example, 5,016 deaths in England and Wales were attributed to teething.[2]

In 1975, Honig[3] wrote to 70 practicing pediatricians in Philadelphia, asking them to identify the signs and symptoms they ascribed to teething. Of the 64 pediatricians who replied, only five thought that teething did not cause symptoms. The others blamed teething for irritability, increased salivation, fever, increased mucus secretion, changes in bowel habits, anorexia, pain on chewing, wakefulness, increased mouthing and biting, skin rashes, ear pulling, thickening of the gums, colic, otitis media, cough, hemorrhage under the gums, eye blinking and maternal stress.

The literature on the subject of tooth eruption and its complications is contradictory, subjective and often unscientific. It is not clear whether the signs and symptoms observed in teething children are developmental in origin or are related to tooth eruption. It is clear, however, that illness in a teething child should be evaluated carefully so that a serious systemic disturbance is not overlooked. This article reviews the teething process and offers suggestions for management.

The Process of Teething

Normally, a primary tooth begins its upward movement about the time of crown completion. Until the tooth emerges into the oral cavity, its crown is covered by reduced dental epithelium. As the crown moves toward the surface, the connective tissue between dental epithelium and oral epithelium disappears.[4] When the tip of the cusp of the crown approaches the oral mucosa, the oral epithelium and reduced dental epithelium fuse. In the central area of fusion, the epithelium degenerates and the incisal edge or tip of a cusp emerges into the oral cavity.

The prime force of upward movement comes from the growth of the pulp tissue in a proliferating ring at its basal end. This causes the calcified crown to be lifted away from the base of its follicle. As the calcified crown moves upward, Hertwig's epithelial root sheath grows downward and controls root formation. Thus, root formation is a consequence of tooth movement and not the cause of it. An intermediate plexus between the developing root and the socket permits continual eruption of the tooth.

The upward movement is influenced by growth hormone, which stimulates the basic growth process, and thyroid hormone, which controls differentiation and maturation. Growth changes in the maxilla and mandible also influence upward movement of the tooth.

Time of Eruption

Intrauterine tooth growth begins during the second fetal month. The eruption of deciduous teeth usually begins by six months after birth. Further tooth eruption continues at a rate of approximately one new tooth for each month after six months of age, until the eruption of all deciduous teeth is completed by about 30 months of age. The average ages for deciduous tooth eruption are given in Table 1.[5,6]

Dental development is under strong genetic control, and environmental factors are only a minor influence.[7] In developing countries, where dates of birth may not be kept, the number of teeth is useful in assessing an infant's age. To determine the age in months, six is added to the number of teeth present. This method of calculating an infant's age is effective until 20 teeth are present. Premature infants get their first teeth at a later chronologic age but at the same postconceptual age as full-term infants.[8]

Generalized delay in eruption has been noted in hypopituitarism, hypothyroidism, infantile rickets, mongolism, cleidocranial dysostosis, osteopetrosis, Gardner's syndrome and achondroplastic dwarfism. Generalized premature eruption of the teeth is less common. Premature eruption may be familial, but an underlying endocrine disorder, such as hyperpituitarism, must also be considered.

Teeth may be present at birth (natal teeth), or they may erupt during the first month of life (neonatal teeth). The reported incidence of natal teeth varies from one in 2,000 live births to one in 6,000 live births. There is a strong predilection for the lower central incisors, and there is often a family history of natal or neonatal teeth. Some cases have been associated with Ellis-van Creveld syndrome (chondroectodermal dysplasia), Jadassohn-Lewandowsky syndrome (pachyonychia congenita), Hallermann-Streiff syndrome (oculoman-dibulofacial syndrome with hypotrichosis), steatocystoma multiplex, Pierre Robin syndrome and cleft lip or cleft palate.[9]

Signs and Symptoms of Teething

A review of the literature reveals many uncontrolled, subjective observations and few well-documented reports on the effects of teething. Opinions about local and systemic disturbances in the teething infant vary. Some investigators attribute the disturbances to the teething process itself (dentitio difficilis).[10,11] Others think that the disturbances are caused by a disease process.[12,13] Still others believe that the local and systemic disturbances observed in teething are caused by a normal physiologic mechanism.[14]

There are many reasons for the divergence of opinion. First and foremost, much of the information gathered about teething is based on subjective parental opinion that is influenced by the desire to explain behavioral changes with an anxiety-reducing diagnosis. Second, during the teething period (five to 30 months), it is difficult to separate signs and symptoms of teething from normal physiologic and psychologic changes, such as drooling at three to four months or wakefulness at six to nine months. Third, it is difficult to carry out controlled studies of teething. Finally, many past studies were based on highly selected populations.

Brewer and Akers[10] reported on 457 cases of disturbed dentition seen in private practice. Of these, 50 patients were sent for surgery. Fifteen patients had temperatures of 37.7 [degrees] to 38.9 [degrees] C (100 [degrees] to 102 [degrees] F) and mild symptoms of fretfulness, appetite loss and local ischemic bulging over the tooth. Twenty-eight patients had temperatures of up to 40 [degrees] C (104 [degrees] F), with acute diarrhea and severe symptoms of fretfulness, crying and finger gnawing; in these patients, the gums were red and inflamed over the unerupted or partially erupted teeth. Seven patients had temperatures higher than 40 [degrees] C, with mucus discharge from the nose and throat, severe head cold, frequent convulsions, poor appetite, weight loss, and swollen and engorged gingiva over the teeth.

Schwartzman[11] reported on teething patients seen in five years of private practice and seven years of hospital observation. He found that 98 of the 378 children of teething age seen in his private practice had dentition disturbances. Rhinitis was present in 75 patients, fever in 60, anorexia in 52 and vomiting in 41. Other frequently observed symptoms were cough, irritability, diarrhea and drooling. Twenty-one patients had otitis media, 33 had tonsillitis and two had seizures. Schwartzman found disturbed dentition in 55 of 14,950 hospitalized children of teething age. The symptoms were comparable to those he had seen in private practice, except that six of the 55 hospitalized children with disturbed dentition had seizures.

The mechanisms by which dentitio difficilis causes clinical symptoms have been the subjects of several hypotheses, including irritation of the trigeminal nerve,[15] infection of the dental sac, lowered local resistance to disease, and the release of toxin(s) during the eruption process.[11]

Some investigators claim that since the eruption of teeth is a normal process, disease or disturbances cannot be associated with this process. Thus, teething produces teeth and nothing else.[12,13] In 1861, Jacobi[16] reported teething to be as harmless a process as menstruation or menopause. In 1922, Heiman[17] compared teething with the growth of nails or hair.

It is perhaps going a bit too far to say that teething produces nothing but teeth. Prior to the eruption of teeth, the gums swell. Not infrequently, the irritated gums are painful, and infants may chew on fingers and demonstrate other evidence of discomfort. During teething, infants may drool excessively and become irritable and restless. These observations parallel those reported by authorities in veterinary medicine.[18] For example, dogs have increased salivation, loss of appetite and irritability when their teeth erupt. During teething, monkeys become hyperactive and irritable, and they exhibit increased biting activity.

Seward[19,20] employed a retrospective questionnaire to collect data on 18 disturbances associated with the eruption of deciduous teeth in 224 normal infants. Irritability, night crying, drooling, poor appetite, circumoral rash and inflammation of the gums were common findings.

Tasanen[21] studied 192 tooth eruptions in 126 normal institutionalized infants four to 30 months of age and 107 control infants, with daily recordings of body temperature, appearance of gums, presence of infections and disturbances in behavior. He showed conclusively that the eruption of a tooth bore no relation whatsover to the incidence of infection, diarrhea, fever, rash, convulsions, sleep disturbance, cough or rubbing of the ear or cheek. Teething was, however, associated with some daytime restlessness, thumb sucking, gum rubbing, drooling and possibly some loss of appetite.

Kravitz and colleagues[18] studied 110 normal infants in a suburban pediatric clinic during routine monthly visits in the first year of life. At each visit, the parent was asked about the presence or absence of 17 specific signs and symptoms commonly ascribed to teething. They found that at the time of eruption, six signs were present in more than two-thirds of the subjects: hand biting, object biting, lip biting, drooling, restlessness and night crying. Drooling, object biting and hand biting were found to occur more frequently in early teethers (infants three to five months of age) than in normal and late teethers. Therefore, these six signs may be developmental in origin rather than related to tooth eruption.

The drooling that is commonly associated with teething may actually reflect normal onset of salivary gland activity. Wakefulness at six to nine months may be the result of separation anxiety and/or decreased need for sleep rather than teething.[3] Illingworth[14] suggests that in six- to 12-month-old infants, much of the evening and nocturnal crying that is ascribed to teething may in fact be due to bad habit formation and parental mismanagement. Infants of this age have discovered that as soon as they cry at night, they are picked up, played with and given a thoroughly enjoyable time.

The association between teething and infection is entirely coincidental, since infants in the teething months are susceptible to a wide variety of infections because of low antibody levels. Investigations are needed to support or refute the association between teething and the various physical and emotional ailments that may occur during the teething months.

Management

Various treatments have been advocated for relief of the discomfort or pain associated with teething. Parental reassurance is essential, but therapeutic measures should be employed if the eruption of teeth causes discomfort to the infant. Objects such as teething rings, rusks and biscuits have been used to satisfy the natural desire of teething infants to chew on something hard. Only reputable brands of teething devices should be used, because some of the less expensive imported devices contain dye with a high lead content. Teething powders are useless and, in the past, have led to mercury poisoning.[22] Lancing of the gums is contraindicated.

Seward[23] conducted a double-blind trial of the effectiveness of a topical preparation containing lignocaine (lidocaine in the United States), benzyl alcohol, tincture of myrrh, menthol, honey, sorbic acid and 90 percent alcohol. The preparation was compared with another preparation containing the same ingredients except lignocaine, benzyl alcohol and myrrh. A questionnaire was used to gather information on 291 children aged five to 31 months. In all cases, neither the mother nor the physician knew whether the child had had the active or the inactive topical preparation. The results of the questionnaire indicated that the lignocaine mixture had no untoward side effects and was much more effective than the inert substance.

Parents should be cautioned that illness occurring with teething should be thoroughly evaluated by the physician. Swann[24] observed 50 children who were hospitalized with symptoms attributed, by the parent or the physician, to the teething process. After a full investigation, an organic cause of illness was identified in all but two of these children. One child had meningitis, and 11 children had febrile convulsions. There were 15 cases of upper respiratory tract infection alone, 12 cases of upper respiratory infection with pharyngitis, tonsillitis and otitis media, and six cases of wheezy bronchitis. Three children were found to have infantile eczema, and 16 had miscellaneous infections, including ammoniacal dermatitis, infected scabies, balanitis and submandibular abscess.

Serious mistakes have been made because various symptoms were ascribed to teething and a thorough evaluation was not performed. Therefore, great care must be taken to exclude other causes of disorders, both local and general, in teething infants. [Tabular Data Omitted]

REFERENCES [1]Hippocrates: aforisms. Section III/25. Translated by F. Adams. The genuine works of Hippocrates. Vol 2. London: Sydenham Society, 1849:721. [2]Morris D. Disorders associated with weaning and teething. Dent Abstr 1959;4:46. [3]Honig PJ. Teething--are today's pediatricians using yesterday's notions? J Pediatr 1975;87:415-7. [4]Barrancos RJ. Infancy teething: its relation to other physical ailments. J Mich State Dent Assoc 1965;47:241-4. [5]Turner EP. Growth and development of the teeth. In: Davis JA, Dobbing J, eds. Scientific foundations of paediatrics. 2d ed. London: Heinemann Medical, 1981:644-59. [6]Whipple DV. Dynamics of development: euthenic pediatrics. New York: McGraw-Hill, 1966:188-93. [7]Malcolm L. Protein-energy malnutrition and growth. In: Falkner F, Tanner JM, eds. Human growth. Vol 3. New York: Plenum, 1979:361-72. [8]Golden NL, Takieddine F, Hirsch VJ. Teething age in prematurely born infants. Am J Dis Child 1981;135:903-4. [9]Leung AK. Natal teeth. Am J Dis Child 1986;140:249-51. [10]Brewer H, Akers L. Surgical dentition: symptomatology, diagnosis, and treatment; its probable influence upon infant mortality. Tri-State Med J 1939;11:2302-3. [11]Schwartzman J. Derangements of deciduous dentition. Arch Pediatr 1942;59:188-97. [12]Feer E. The diagnosis of children's diseases. 2d ed rev. Philadelphia: Lippincott, 1928:182. [13]Janssen E. Teething patterns in infancy as initial manifestations of patient morbidities. S Afr Med J 1955;29:258-60. [14]Illingworth RS. The normal child: some problems of the early years and their treatment. 9th ed. New York: Churchill Livingstone, 1987:94-101. [15]Brebner E. Problems associated with teething. NZ Med J 1947;43:205-13. [16]Jacobi A. Errors respecting dentition. Br J Dent Sci 1861;4:3-4. [17]Heiman H. Dentition as a normal physiologic process. Int J Orthod Oral Surg 1922;8:432-40. [18]Kravitz H, Emanuel B, Kasper J, Neyhus A. Teething in infancy. A part of normal development. IMJ 1977;151:261-6. [19]Seward MH. General disturbances attributed to eruption of the human primary dentition. J Dent Child 1972;39:178-83. [20]Seward MH. Local disturbances attributed to eruption of the human primary dentition. A survey. Br Dent J 1971;130:72-7. [21]Tasanen A. General and local effects of the eruption of deciduous teeth. Ann Pediatr Fenn 1968;14(Suppl 29):1-41. [22]Ingram CS. Teething: myth and reality; a review of the literature. J NZ Soc Periodontol 1981;(52):13-4. [23]Seward MH. The effectiveness of a teething lotion in infants. A clinical study. Br Dent J 1969;127:457-61. [24]Swann IL. Teething complications, a persisting misconception. Postgrad Med J 1979;55(639):24-5.

ALEXANDER K.C. LEUNG, M.B.B.S. is clinical assistant professor of pediatrics at the University of Calgary and pediatric consultant at the Foothills Provincial Hospital and the Alberta Children's Hospital, all in Alberta. He is an honorary pediatric consultant at the Guangzhov Children's Hospital in the People's Republic of China. Dr. Leung graduated from the University of Hong Kong and completed internships at the Queen Mary Hospital, Hong Kong. He served a pediatric residency at the Foothills Hospital and trained in pediatric endocrinology at the University of Calgary. Dr. Leung is board-certified in pediatrics and pediatric endocrinology.

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