Carl O. Henrikson

Root resorption during Begg treatment: A longitudinal roentgenologic study

Abstract Forty-two patients consecutively treated by the Begg method, all of whose first premolars had been extracted before orthodontic treatment, were examined roentgenologically by an intraoral technique on three to four occasions. The examinations were made before treatment, during treatment (before uprighting of tipped teeth), after completion of treatment, and 6 months after completion of treatment. In order to determine the occurrence and degree of root resorptions during the treatment period, a root resorption index was constructed. The reproducibility of the resorption index was studied by two observers. For assessment of the incidence and degree of root resorptions, the series of roentgenograms from each patient were examined simultaneously. The reproducibility of the simultaneous evaluation was also studied. In all of the forty-two cases treated, root resorption was recorded in the last roentgenologic examination. Before treatment small resorptions were found in 4 per cent of the teeth. Already, before uprighting of the tipped teeth, irregular root contours (score 1), probably caused by resorptions, and resorptions At the completion of treatment resorption When analyzing the percentage distribution of different degrees of root resorption in the teeth examined, we found that the relatively high frequency of root resorption before uprighting of tipped teeth increased slightly at completion of treatment. The resorption increased more for the upper central incisors, which were subjected to root torque, than for the upper lateral incisors. The incidence of root resorption 6 months after completion of treatment was highest at the lower central incisors (95 per cent). The upper central and lateral incisors showed an incidence of 90 and 87 per cent, respectively, and the lower and upper canines showed an incidence of 79 and 72 per cent, respectively. The lower premolars showed the lowest incidence of root resorption (53 per cent). The teeth that exhibited root resorption prior to treatment developed more resorption than the average during orthodontic treatment. This was especially marked for the upper incisors.

Effect of fractionated radiotherapy on salivary gland function.

The effect of fractionated radiotherapy on salivary gland function was studied by sialography and sialometry of parotid glands in four patients irradiated with 4000 or 6400 rads for malignant tumors of the head and neck region. Sialography was performed at the beginning and end of the irradiation period and 8 months later. By sialometry, the salivary secretion rate was determined after each irradiation treatment (a daily dose of 200 rads) during the whole treatment period and again 8 months later. The size of the glands was found to be unchanged at the end of the irradiation period despite the pronounced disturbance of the salivary secretion rate at this time. Thus it can be stated that the size of irradiated parotid glands is not a criterion of their function as in the case of normal glands. It was not possible to identify a critical dose level giving a pathologically low salivary secretion. Even after high doses in fractionated radiotherapy, a recovery of the parotid gland function has been found. Parotid glands on the “non‐tumor” side were irradiated with a dose of between 400 and 600 rads, and these small doses did not cause a reduction of salivary secretion rate below normal variation.

Mineralization in the midpalatal suture after orthodontic expansion.

A new method is described for an objective measurement of the mineralization in the anterior part of the midpalatal suture after its orthodontic expansion. The radioisotope 125I is used as radiation source and is placed intraorally in the same position on each measurement occasion. The extraoral part of the apparatus consisted of a scintillation crystal and a pulse-height analyzer to determine the number of roentgen quanta transmitted. The measurements showed that the mineral content within the suture rose rapidly during the first month after the completion of suture opening. In the bone beside the suture, the mineral content decreased sharply during the first month of measurement; later it returned to the initial level.

Proximal alveolar bone loss in a longitudinal radiographic investigation: IV. Smoking and some other factors influencing the progress in individuals with at least 20 remaining teeth

In Sweden people in all age groups now have more remaining teeth than previously. An investigation has been made to identify some predictors of alveolar bone loss in a 10-year period in subjects with at least 20 remaining teeth. The material consisted of 349 individuals, examined radiographically, clinically, and by interview in 1970 and in 1980. These subjects, born in 1904-1952, constituted a subgroup, with regard to remaining teeth, of an unselected sample of the population of the old county of Stockholm. In the unselected sample statistically significant predictors of alveolar bone loss found in a stepwise multiple regression analysis were alveolar bone loss in 1970, age, number of lost teeth, and Russells Periodontal Index (PI). In the subgroup the predictors were in the order Russells PI and smoking. The prediction values (R2) of further variables were marginal. The analyses showed that there was an interaction between PI and smoking, implying that the effect of smoking on alveolar bone loss was increased in individuals with high PI values. Furthermore, a tendency was found for a dose-response effect of tobacco consumption. This tendency almost disappeared when controlling for PI.

Proximal alveolar bone loss in a longitudinal radiographic investigation: II. A 10-year follow-up study of an epidemiologic material

Four hundred and six individuals from an unselected sample from the County of Stockholm aged 18-65 years in 1970 were examined radiographically in 1970 and 1980. The differences in proximal alveolar bone height were recorded, attention being paid to the divergences in projection between the two investigations. The mean of the alveolar bone difference was 5.5% of the mean root length, which corresponds to an average annual bone loss of 0.09 mm. Ninety per cent of the individuals had a difference in alveolar bone height of less than 10% of the root length--that is, an average bone loss of 1.6 mm or less during 10 years. By linear regression analysis it was shown that the difference in alveolar bone height is a function of the initial bone loss; that is, the greater the initial bone loss, the greater the alveolar bone loss during the 10-year period. The result of the regression analysis may facilitate predictions of alveolar bone loss.

The Effect of Irradiation in High Doses on Parotid Glands

On radiation therapy of malignant tumours in the head and neck region, the salivary glands are often situated in the radiation field. Ten patients undergoing radiation therapy with high doses for tumours in the region of nasopharynx, lingua and bucca have been examined with respect to the function of the parotid glands. The glands received doses of 4 400-7 200 rad, and the function has been investigated by sialographic and sialometric methods. The sialograms show that one year or more after irradiation the parotid glands have a significantly smaller projected area than the non-irradiated glands. The irradiated glands had a sparser duct system than the non-irradiated ones. The sialometric examinations showed that all the irradiated glands stimulated with 1 % citric acid produced very little saliva. The secretion was in all cases remarkably lower than in a normal material, and in most cases only a few drops were collected during 10 min. In spite of a marked decrease in secretion at the end of the irradiatio...

Pre-irradiation qualities of a parotid gland predicting the grade of functional disturbance by radiotherapy

In the irradiation of head and neck tumours, often more than one of the major salivary glands and also many of the minor salivary glands are located within the therapy beams. This might then explain any functional disturbance of the salivary gland tissue causing xerostomia with difficulties in swallowing, a high incidence of caries, etc., after radiotherapy in this region. As the grade of these complications shows a great interindividual variation, it is questioned whether there is an individual sensitivity to irradiation therapy of the salivary gland tissue. To ascertain whether it is possible to predict in which patients radiotherapy will be more liable to cause a functional disturbance, a study has been made of 15 parotid glands located within the therapy beams at radiotherapy of malignant head and neck tumours to find whether any correlation exists between the pre-irradiation quality of the glands and their reaction to irradiation at different doses. The pre-irradiation quality of the parotid glands h...

Substitution of sucrose by lycasin in candy "the roslagen study".

The aim of the study was to ascertain whether substitution of sucrose in candy by Lycasin can influence the incidence of dental caries in a group of children. The caries increment in the primary dentition in three to six year old children using Lycasin candy as a substitute for conventional candy was observed for 1½ to 2½ years. Initially 225 children took part in the study, which started with a 6-month observation period. For various reasons many of the children dropped out, especially in the Lycasin group. Of the children, 173 were observed for one year and 113 for two years. A coupon system showed that the substitution in the Lycasin group had been only partial. Statistical analysis of the findings, which included the ordinary t-test between the Lycasin group and the contrast group as well as an intraindividual comparison between the observation period and the substitution period, showed a tendency towards a difference in caries increment between the Lycasin group and the control group and the presubst...

Proximal alveolar bone loss in a longitudinal radiographic investigation I. Methods of measurement and partial recording

A longitudinal radiographic investigation was made of the progression of the proximal alveolar bone loss over a 10-year period (1970-1980). The material was unselected and consisted of 669 individuals in the county of Stockholm. Sixty-one individuals were randomly selected for evaluation of a recording system using alternative methods of measurement, and 90% of the measurement sites could then be assessed. The correlations between some of the methods were high, such as between measurement of alveolar bone height and root length and between alveolar bone height and tooth length. To reduce the number of measurements, a partial recording was made, giving a high correlation coefficient between the partial recording and total recording. When five measurement sites (12 m, 11 m, 33 d, 31 d, 41 m) were were used, the correlation coefficient was 0.96, and a slight increase of the coefficient was obtained when using additional sites.

The Speed and Contrast of Dental Films

The film commonly used in dental roentgenology is of the no-screen type. There are numerous kinds on the market each with different characteristics. The film employed in diagnostic work must be of a type that permits roentgenograms of good contrast and definition to be obtained with minimum radiation dosage to the patient. The purpose of this work was to investigate the speed and contrast of ten dental films by an analysis of their characteristic curves according to the American standard method for the sensitometry of medical roentgen films, A.S.A. PH 2.9.1956. Comparison of speed and contrast was also made with various developers and different filtration of the incident radiation. The characteristic curve of a film is a graphic representation of the density after development plotted against the exposure which is expressed as the radiation dose in r units given to the film; the density (D) after exposure and development is the loglo of the relationship of the intensity of the visible light before and after passage of the latter through the film.