Bertil Lennartsson

A study of children with unilateral posterior crossbite, treated and untreated, in the deciduous dentition--occlusal and skeletal characteristics of significance in predicting the long-term outcome.

Abstract.Background and Aim: The generally recommended treatment in children with unilateral posterior crossbite is expansion of the maxillary dental arch. The reported treatment success rate varies between 50% and 96%. The aim of the prsent study was to analyse whether some occlusal and skeletal characteristics could be found in the deciduous dentition of children with treatment success (including self-correction) in contrast to those showing non-correction (including relapse) in the young permanent dentition. Patients and Method: Two groups of children with unilateral posterior crossbite were followed from the age of 5 years up to 13 years of age. The childrfen in one of the groups (n = 32) were treated in the deciduous dentition, while the children in the other group (n = 32) were to be treated in the late mixed or early permanent dentition. Another 25 children (5 years old) with excellent occlusion were included as controls. Results of clinical examination and biometric and cephalometric analyses, performed at the first examination (at 5 years of age), are presented for the three groups (“treated”“untreated” and controls). Results and Conclusions: Compared to the controls, asymmetry was registered in both dental arches. The crossbite side, measured to the midline, was narrower than the non-crossbite side in the upper jaw but broader in the lower jaw. Differences between upper/lower widths (at intercanine and intermolar level) seem to be of importance for correction or non-correction, both for “untreated” and “treated” children. A narrow crossbite side in the upper arch together with a broad crossbite side in the lower arch was found in non-corrected children in both groups, even among those treated with maxillary expansion, where the SNB angle was larger and the ANB angle smaller than in controls as well as in those with correction (including self-correction). Possibilities and limitations of treatemtn planning are discussed.Zusammenfassung.Hintergrund und Ziel: Bei Kindern mit unilateralem Kreuzbiss wird im Allgemeinen eine Dehnungstherapie des oberen Zahnbogens empfohlen. Die angegebene Erfolgsrate variiert dabei zwischen 50% und 96%. Zielsetzung der vorliegenden Studie war zu untersuchen, ob im Milchgebiss charakteristische okklusale und skelettale Parameter bei erfolgreich behandelten Kindern (Spontankorrekturen eingeschlossen) vorliegen im Gegensatz zu anderen, bei denen der Kreuzbiss im frühen bleibenden Gebiss noch bestand bzw. Rezidive aufgetreten waren. Patienten und Methode: Bei zwei Gruppen von Kindern mit unilateralem Kreuzbiss wurden zwischen dem 6. und 14. Lebensjahr fortlaufend Befunde dokumentiert. Die Kinder der ersten Gruppe (n = 32) wurden im Milchgebiss behandelt, die der zweiten (n = 32) hingegen im späten Wechselgebiss oder bleibenden Gebiss. Als Kontrollgruppe dienten 25 weitere 5-jährige Kinder mit einwandfreier Okklusion. Für die drei Gruppen (“behandelt”, “unbehandelt” sowie “Kontrollgruppe”) werden die Ergebnisse der Erstvorstellung im Alter von 5 Jahren, d. h. die Befunde der klinischen Untersuchung sowie der Modell- und röntgenkephalometrischen Analyse dargestellt. Ergebnisse und Schlussfolgerungen: Im Vergleich zur Kontrollgruppe waren Asymmetrien in beiden Zahnbögen festzustellen. Die Kreuzbissseite war gemessen von der Mittellinie aus im Oberkiefer schmaler als die Gegenseite, im Unterkiefer hingegen breiter. Unterschiede zwischen oberen/unteren Bogenbreiten (auf Höhe der Milcheckzähne und Milchmolaren) scheinen im Hinblick auf eine mögliche Korrektur sowohl bei behandelten als auch unbehandelten Kindern bedeutsam zu sein. Eine schmale Kreuzbissseite im oberen Zahnbogen in Kombination mit einer breiten Kreuzbissseite im unteren Zahnbogen wurde bei Kindern beider Gruppen mit persistierendem Kreuzbiss festgestellt, sogar bei einem Teil derjenigen, die mittels einer Erweiterung des Oberkiefers “behandelt” wurden. Bei diesen Kindern war der SNB-Winkel größer und der ANB-Winkel kleiner als in der Kontrollgruppe und in der Gruppe mit erfolgreich korrigiertem Kreuzbiss (Spontankorrekturen eingeschlossen). Möglichkeiten und Grenzen der Behandlungsplanung werden diskutiert.

Transalveolar transplantation of maxillary canines an alternative to orthodontic treatment in adult patients

Transalveolar transplantation of 31 maxillary canines in 26 patients was performed. Fixed orthodontic appliances were used for fixation for 6 to 8 weeks. All the transplanted teeth were firmly affixed in the new positions 3 to 6 months postoperatively. Complete bone regeneration and an attached gingiva with a stippled surface buccally and a normal pocket depth were observed 1 to 2 years postoperatively. These positive treatment results indicate that transalveolar transplantation is a useful alternative in the treatment of impacted maxillary canines in selected patients.

Prevalence and change of malocclusions from primary to early permanent dentition: a longitudinal study.

OBJECTIVE To follow a group of children from primary to early permanent dentition and determine the prevalence, self-correction, and new development of malocclusions; the need for orthodontic treatment; and the possible influences of habits, breathing disturbances, and allergies. MATERIALS AND METHODS Two hundred and seventy-seven children were followed at 3, 7, and 11.5 years of age. Malocclusions and orthodontic treatment need were determined by clinical examinations. Data on sucking habits, breathing disturbances, allergies, dental trauma, and orthodontic treatments were collected from a questionnaire and dental records. RESULTS Malocclusions were found in 71% of participants at 3 years of age, 56% at 7 years of age, and 71% at 11.5 years of age. Self-correction was noted for anterior open bite, sagittal malocclusions, and posterior crossbite, while deep bite developed. A high number of contact point displacements and spacings contributed to the prevalence of malocclusion rate of 71% at 11.5 years. Severe or extreme orthodontic treatment need was apparent in 22%. Habits, allergies, or breathing disturbances found at 3 years of age had no associations with malocclusions at 11.5 years of age. CONCLUSIONS This sample revealed a significant percentage of malocclusions and orthodontic treatment need. A substantial number of self-corrections and establishment of new malocclusions occurred during the transition from primary to early permanent dentition.

Malocclusions in children at 3 and 7 years of age: a longitudinal study

The aim of this longitudinal study was to compare the prevalence of malocclusion at ages 3 and 7 years in a sample of children, exploring the hypothesis that prevalence of malocclusion is higher at 3 than at 7 years of age and may be influenced by sucking habits. The study sample comprised 386 children (199 girls and 187 boys), aged 3 years at study start, sourced from three Public Dental Service clinics in Sweden. Malocclusion was diagnosed by clinical examination, using a specific protocol. Data on allergy, traumatic injuries, sucking habits, and breathing pattern including nocturnal breathing disturbances were obtained by means of a questionnaire answered by child and parent in conjunction with the initial and final clinical examination. The overall prevalence of malocclusion decreased significantly, from 70 to 58% (P < 0.0001): predominantly anterior open bite, excessive overjet, and Class III malocclusion. Although high rates of spontaneous correction were also noted for deep bite, Class II malocclusion and posterior and anterior crossbites, new cases developed at almost the same rate; thus, the prevalence was unchanged at the end of the observation period. Anterior open bite and posterior crossbite were the only conditions showing significant associations with sucking habits. The results confirm the hypothesis of higher prevalence of malocclusion at 3 years of age and clearly support the strategy of deferring orthodontic correction of malocclusion until the mixed dentition stage.

Muscle spindles in the human anterior digastric muscle.

The occurrence of muscle spindles in the anterior digastric muscle in man was investigated and the fibre calibre spectrum of the corresponding nerve was determined. After removal at autopsy from five individuals of both sexes (aged 23--73), the muscles were stained with Weigerts iron hematoxylin-van Gieson stain and the nerves according to the Alzheimer - Mann - Häggqvist method. Altogether 12 spindles were found in five out of ten muscles. Only muscles from one individual were devoid of spindles. This sparsity or absence was supported by analyses of fibre calibre spectra. The small number of spindles and the fact that they do not occur in all muscles or in all individuals, suggest that they are not an essential source of sensory information.

Jaw muscle activity during chin-tapping

Electromyographic (EMG) activity was recorded from the masseter, the anterior temporal and the anterior digastric muscle on the right side of ten dental students when taps were administered upwards or downwards to the chin. The experiment was performed both with relaxed jaw muscles and with contracting depressor muscles. Pairs of intracutaneous platinum hook electrodes were used for the masseter and temporal muscles while concentric needle electrodes were inserted into the anterior digastric muscles. The mean latency of the jaw-jerk elicited in the relaxed masseter muscle when tapping downwards on the chin was 7.8 msec and in the temporal muscle 8.4 msec. The corresponding values of the latency during jaw opening against resistance from the investigators finger was 8.2 msec and 9.0 msec. During upward tapping on the chin recordings from the anterior digastric muscle showed obvious changes in EMG activity, the latency ranging from 13 to 34 msec. Thus, compared to the latency of the jaw-jerk in the masseter and temporal muscles, which contain numerous muscle spindles, recordings from the anterior digastric muscle, where muscle spindles are thought to be either lacking or few in number, showed no signs of a monosynaptic reflex.

Palatally displaced maxillary canines: factors influencing duration and cost of treatment

The purpose of this retrospective study was to assess the relationship between the initial position of palatally displaced canines (PDCs) on panoramic radiographs and the duration of the orthodontic treatment and further to estimate the costs of the treatment. Data from panoramic radiographs and patient records of 66 consecutive patients (mean age 14.9 ± 1.7 years) with PDC were analysed. The initial position of the canine, the distance between the canine cusp tip and the occlusal plane, and the inclination of the canine were significantly associated with treatment duration both unadjusted and adjusted for background characteristics. The average estimated cost of the treatment of PDC was €3200 per case. The total annual cost for treatment of PDC in Sweden may therefore be estimated at €600,0000. In this study, duration of treatment averaged 17 months for canines displaced in impaction zone 1 or 2, 2.6 [95% confidence interval (CI) -1.0 to 6.2] months longer for those in impaction zone 3, and 7.6 (95% CI 4.1-11.1) months longer for canines displaced in impaction zone 4 or 5. This information makes it easier, through study of the panoramic radiograph, to estimate the duration of treatment and to give patients more precise information about the expected length of their treatment.

Effect of interceptive extraction of deciduous canine on palatally displaced maxillary canine: A prospective randomized controlled study

OBJECTIVE To evaluate the effect of the extraction of deciduous canines on palatally displaced canines (PDCs), to analyze the impact of the age of the patient on this interceptive treatment, and to assess the outcome of one-sided extraction of a maxillary primary canine on the midline of the maxilla. MATERIALS AND METHODS This study included 48 PDCs in 24 consecutive patients with bilateral PDCs. The mean age of the patients at diagnosis was 11.6 years (standard deviation 1.2 years). After randomization, one deciduous canine of each patient was assigned to extraction, and the contralateral side served as control. The patients were then followed at 6-month intervals for 18 months with panoramic and intraoral occlusal radiographs. RESULTS The rates of successful eruption of the PDCs at extraction and control sites were 67% and 42%, respectively, at 18 months. The difference between the sites was statistically significant, and the effect was significantly more pronounced in the younger participants. A significant decrease in arch perimeter occurred at extraction sites compared to control sites during the observation period. No midline shift toward the extraction side was observed in any patient. CONCLUSIONS The extraction of the deciduous canine is an effective measure in PDC cases, but it must be done in younger patients in combination with early diagnosis, at the age of 10-11 years. Maintenance of the perimeter of the upper arch is an important step during the observation period, and a palatal arch as a space-holding device is recommended.

Oral health-related quality-of-life among children in Swedish dental care: The impact from malocclusions or orthodontic treatment need.

Abstract Objectives. To describe oral health-related quality-of-life (OHRQoL) and the impact of malocclusions or orthodontic treatment need in a cohort of children in Swedish dental care, using the Swedish version of the Child Perceptions Questionnaire–Impact Short Form (CPQ11–14–ISF:16). Subjects and methods. Two hundred and fifty-seven children (mean age = 11.5 years, SD = 0.8, range = 9.8–13.5 years) completed the CPQ11–14–ISF:16 in conjunction with a clinical examination. In addition to malocclusions and orthodontic treatment need (based on the Index of Orthodontic Treatment Need–Dental Health Component), possible confounders (caries, enamel defects, dental trauma, headache and socio-economic markers) were recorded. Children also rated their own dental fear on the Children’s Fear Survey Schedule–Dental Sub-scale (CFSS-DS). Results. The mean total CPQ11–14–ISF:16 score was 9.31. The logistic regression analyses revealed an impact of orthodontic treatment need on OHRQoL (CPQ), but no clear association between higher severity and higher impact on OHRQoL was seen. Dental fear and headache appeared to discriminate for poorer OHRQoL. No impact from caries, enamel defects, dental trauma, or socio-economic markers was revealed. Conclusions. This cohort of children reported good self-perceived OHRQoL. Effects on OHRQoL from malocclusions or orthodontic treatment need were limited and inconsistent. Dental fear and headache were found to be more distinct impact factors on OHRQoL than were malocclusions or orthodontic treatment need.

Effect of Post-Surgical Jaw-Orthopaedic Treatment in Unilateral Cleft Lip and Palate Patients

Reduction of the contraction of maxillary segments in newborn infants with unilateral cleft lip and palate by means of post-operative maxillary orthopaedic treatment was evaluated in 32 consecutive patients. Early surgery was performed in three stages and jaw-orthopaedic treatment with an acrylic plate was started one week after the first and again after the second operation. Between the first and second operation, between the second and third operation and during the period from the first operation to the age of three years there were no significant differences in changes of maxillary width dimensions between half of the children using the plates most frequently and the other half, with one exception. This difference was probably due to differences in initial values between the two groups of children. Thus, the influence on maxillary dimensions and dental occlusion of jaw-orthopaedic treatment, carried out according to our routines, was very limited. On the other hand, other treatment objectives might have been facilitated.