Develop. Med. Child Neurol. 1967, 9, 299-302

Age of Teething in Retarded Children E. C. Donoghue R. Shakespeare

Introduction Developmental paediatrics is playing an increasingly important part in the manage- ment of children. Knowledge and experi- ence of development scales will tell one a great deal about the present and future development of a child. But the average parent remembers only a few milestones and among these is one of which authorities such as Gesell (1940), Griffiths (1954), Illingworth (1962) and Sheridan (1960) take no cognisance : teething. Nevertheless we have observed that a number of doctors as well as members of the general public include the date of the appearance of the first tooth when considering a child’s milestones. Does this traditional practice have any rationale or has it merely been perpetuated by the simplicity of its observation? This paper describes a study of the history of two small groups of children and attempts to relate the age of teething to other milestones and subsequent development.

Material The history of sixty children is reviewed.

Thirty were already long-term patients in hospital and known to be severely sub- normal mentally; all had IQS below 40. The other thirty children were part of a group whose mothers were interviewed during the course of another investigation. They

were assumed to be normal in intelligence as those of school age were all attending normal schools and none of the younger children had shown any evidence of mental backwardness.

Methods The past history of thirty mentally

subnormal children, recorded just before admission by one experienced social worker, was considered and the following information noted: age when the history was taken, birth-weight, age of eating solids, of teething, of using a spoon, of walking and of becoming clean in habits. ‘Time of teething’ was defined as the eruption of the first tooth visible above the gum margin.

The thirty normal children were selected so that the groups were matched with respect to the age of the child when the mother was questioned. The average age of the subnormal group at the time that the history was taken was 6 years 11 months (SD 3 years 1 month), and that of the normal group 7 years 1 month (SD 3 years 3 months). The mothers of the normal group were interviewed by one of us (ECD) and the same items were recorded for them as for the subnormal children.

Results The average time of teething for the

subnormal group was 8 - 6 months (SD 4 .0

Queen Mary’s Hospital for Children, Carshalton, Surrey.

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DEVELOPMENTAL MEDlClNE AND CHILD NEUROLOGY, 1967, 9

months) and for the normal group 6 . 9 months (SD 2 . 5 months). The higher mean and standard deviation for the subnormal group was due to the fact that this group contained two children who did not teethe until 18 months. The means, in fact, were not significantly different ( t = 0 . 16, p > 0.05).

Both groups contained ‘premature’ or low birth-weight children--i.e., with a birth-weight of under 5* Ib. The subnormal group had a mean birth-weight of 6 Ib. 7 oz. (SD 1 Ib. 12 oz.) and contained seven low birth-weight children, while the normal group had a mean birth-weight of 7 Ib. 6 oz. (SD 1 Ib. 8 oz.) and contained five low birth-weight children. These means are not significantly different (t = I .3, p > 0.05). As the average age of teething of these twelve low birth-weight children was 7.9 months and that of the forty-seven other children was 7 .5 months, it seems clear that birth-weight and time of teething are not related ( N ~ 59 here as one child was adopted and her birth-weight unknown).

The other milestones were recorded as ‘normal’ or ‘retai ded’. The average age for normal children to reach each milestone was assumed to be that agreed on by most child development scales. A rough estimate

of the normal range was computed by using the range which would be covered by two standard deviations above and below these means if quotients were computed on the ratio IQ principle for each milestone, and the standard deviation taken as 15 points.

Mean Ratige Hence :

(WOS.) ( / i l o S . )

Ate solids . . . . 6 4-8 Walking . . . . 15 11-20 Used spoon . . . . 15 1 1-20 Clean habits . . . . 36 25-47

The Table shows the distribution of the two groups of children between the two categories of normal or retarded for each milestone. The differences are very clear and for each milestone the differences are unlikely to have been due to chance (xp test in each case produces a figure signifi- cant well beyond the 1 per cent level). This seems to confirm that our two groups were in fact representative of the two popula- tions-normal and severely retarded.

Although no normal child teethed later than 12 months and two subnormal children did not teethe unt i l 18 months, the other twenty-eight subnormal children had all teethed by 12 months.

TABLE I Numbers of Children in ‘Normal’ and ‘Retarded’ Categories for Developmental Milestones

Metitally Nornial Meri1dly Sirhtiorinol

X 2 ‘Normal ‘ Retarded’ ‘ Nornrol ‘Retarded‘

Age- Range ’ A f e - Ratrge ’

Ate Solids

Talking .. , .

Walking . . . . I 30 I 0 I

* I not known. t I not clean yet and too young to be retarded in this respect.

300

ELAINE C. DONOGHUE ROSEMARY A. SHAKESPEARE

Discussion We have assumed that the mother’s

recall of the age of teething is reliable, since we found in a previous study that the standard error of the mother’s estimate of t h e r e c o r d e d d a t e was 1 . 1 m o n t h s (Donoghue and Shakespeare 1967).

Davies and King (1961) quoted Broad- bent (1937) as having established that the first tooth normally to erupt is the lower central incisor and they suggest 4-8 months as the approximate age of eruption. They emphasize the wide range of erupted time and sequence and continue: ‘The reasons for this large but normal variability in eruption times are completely unknown . . . Eruption times are generally more advanced in girls than boys and there is an apparent relationship between eruption times and physical types.’

Falkner (1957) gives a detailed account of the pattern of total deciduous tooth eruption; in his data, the most usual age of eruption of the first tooth was between 26 and 39 weeks but the range was from 13 weeks to 18 months.

Massler and Savara ( I 950) considered generalised delay in eruption to be a feature of ‘cretinism, mongolism and infantile rickets’, but they state that ‘failure of any deciduous teeth to erupt before the

average age for eruption of the first deciduous tooth. He mentions mongolism in a chapter on the effects of endocrine disorders, but makes no mention of any associated dental abnormalities; hypoth- roidism is said to be associated with considerable delay in dental eruption. (Our thirty mentally subnormal children in- cluded two with Down’s syndrome, one of whom teethed at one year and one at 18 months. One child who was not a mongo1 also teethed at 18 months.)

As Tizard (1965) emphasized, ‘The usefulness of intelligence tests has been exaggerated by psychologists and under- rated by physicians.’ One reason for this under-rating may have been confusion between facts relating to physical and to psychological mental development. Both are necessary but the value of considering physical development is not enhanced by the inclusion of age of teething.

Conclusion The present study suggests that as a

group subnormal children do not teethe later than normal children do. There is no reason to include age of teething in a developmental history designed to assist in the recognition of mental subnormality.

first birthday is comparatively common and should OCCaSiOn no Concern’. LeViIlSOn e / a/. (1955), in a series of fifty mongols, reported that twelve teethed at one Year, and nine between 14 and 24 months.

Stones (1962) accepts 6 months as the

Acknowledgements: We wish to thank Dr. Soutar, D ~ , ~ ~ ~ ~ ~ ~ d , and the Health Visitors of the Surrey Public Health Service and Mrs. Frankel, Social Worker at Queen Mary’s Hospital, Car- shalton, without whose help this work would not have been possible. We would also like to acknow- ledge the helpful advice given by Dr. B. H . Kirman and ~i~~ Elspeth Stephen.

SUMMARY

The recorded date of teething--i.e., the eruption of the first deciduous tooth-is noted for matched groups of thirty severely subnormal and thirty normal children. The average date, between the seventh and eighth months, was the same for both groups. It was not influenced by birth-weight. Maternal recall is not considered significantly inaccurate. Other milestones were all significantly retarded in the severely subnormal group. The age of teething cannot be considered to have any value in predicting mental subnormality.

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DEVELOPMENTAL MEDICINE AND CHILD NEUROLOGY. 1967, 9

RESUME L’age de la premiere dent chez les enfants retard&

La date donnte comme le debut de la dentition, c’est-A-dire I’apparition de la premiere dent de lait, a ete notee chez deux groupes tquivalents de 30 enfants normaux et 30 enfants gravement subnormaux. La date moyenne, entre le septieme et le huitieme mois, ttait la m&me dans les deux groupes. La prematuritt n’avait aucune influence. Les souvenirs de la mtre ne sont pas considtris comme vraiment inexacts. D’autres etapes Ctaient retardies de facon significative dans le groupe des severement subnormaux. L‘iige de la premitre dent ne peut avoir, pense-t-on, aucune valeur de prediction de la subnormalite mentale.

ZUSA M M ENFASSUNG

Alter des Zahnens bei zuruckgebliebenen Kindern Das Datum des Zahnens d. h. das Durchstossen des ersten Milchzahnes ist bei vergleich-

baren Gruppen von 30 schwer zuruckgebliebenen und 30 normalen Kindern verzeichnet worden. Das durchschnittliche Datum zwischen dem 7. und 8. Monat war fur beide Gruppen dasselbe. Es war von Fruhreife nicht beeinflusst. Das Gedachtnis der Mutter unterscheidet sich nicht bedeutsam von dem verzeichneten Datum. Andere ‘Meilensteine’ waren in der schwer unterentwickelten Gruppe bedeutsam verzogert. Das Alter des Zahnens kann nicht als Hilfe zur Ermittlung geistiger Zuruckgebliebenheit betrachtet werden.

RESUMEN La edad de denticidn en nizos retrasados

Se not6 la fecha registrada de denticibn, es decir, de la salida del primer diente deciduo, para dos grupos parecidos de 30 niiios afectos de u n retraso grave y 30 niiios sanos. La fecha media, entre el stptimo y el octavo mes, era la misma para 10s dos grupos, incluso para 10s niiios prematuros. N o se considera que 10s recuerdos de las madres Sean inexactos hasta u n grado significante. En 10s niiios gravemente subnormales 10s otros aspectos del desarrollo eran todos retardados. N o hay que creer que la edad de dentici6n tenga valor en la prediccion de una subnormalidad mental.

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