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Biomedical subjects

B Prahl-Andersen

Publications and source records attributed to B Prahl-Andersen.

At least 19 recordsLinked to original sources
PubMed2006

[Attitudes towards orthodontic treatment. A comparison of treated and untreated adolescents].

Dutch adolescents' attitudes towards orthodontic treatment and the determinants of these attitudes are unknown. The aim of the present study was to evaluate treated and untreated adolescents' attitudes towards orthodontic treatment, and to examine possible determinants of these attitudes. Previously treated adolescents were found to have a more positive attitude towards orthodontic treatment than untreated adolescents. Age, but not gender, was found to be a significant predictor for their general attitude towards orthodontic treatment. Consequently, it was concluded that attitudes were not determined by one specific aspect, but by a combination of several determinants.

Adolescent↗
PubMed2005

The reliability and validity of the Index of Complexity, Outcome and Need for determining treatment need in Dutch orthodontic practice.

The Index of Complexity, Outcome and Need (ICON), based on international opinion, has been proposed as a multipurpose occlusal index. The aim of this study was to validate the ICON for treatment need in the Netherlands by relating it to Dutch orthodontic opinion. Furthermore, the reliability of this index was explored, for both a calibrated orthodontist and non-calibrated orthodontists. A sample of 102 patients was chosen which represented the actual distribution of severity of malocclusion experienced by orthodontists in every day practice. The ICON was scored, based on complete patients records of those 102 patients, by an examiner calibrated in the use of this index. The results were compared with the opinion about treatment need of seven Dutch orthodontists - the 'gold standard'. Nine non-calibrated orthodontists also scored the ICON for 49 patients. The intra-examiner agreement of both the non-calibrated and the calibrated orthodontists was moderate to high [0.52-0.86 and 0.89, respectively, measured with the Intraclass Correlation Coefficient (ICC)]. The inter-examiner agreement of the ICON score of the nine orthodontists was moderate measured with the single estimate of the ICC (0.60), and high measured with the average estimate (0.93). Spearman's correlation coefficient between the ICON score (calibrated) and the gold standard was sufficient: 0.78. The sensitivity and specificity were 1 and 0.36, respectively. The best compromise between sensitivity and specificity was at a cut-off point of 52, instead of the international ICON cut-off point of 43. There was a significant difference in ICON score between the non-calibrated orthodontists and the calibrated orthodontist, mainly based on the Aesthetic Component (AC) of the Index of Orthodontic Treatment Need (IOTN). It can be concluded that the ICON needs to be adjusted when used to determine treatment need in the Dutch orthodontic population.

Dental Health Surveys↗
PubMed2005

The influence of accelerating the setting rate by ultrasound or heat on the bond strength of glass ionomers used as orthodontic bracket cements.

Conventional glass ionomer cements (GICs) may be a viable option for bracket bonding when the major disadvantages of these materials, such as the slow setting reaction and the weak initial bond strength, are solved. The aim of this in vitro study was to investigate the influence of ultrasound and heat application on the setting reaction of GICs, and to determine the tensile force to debond the brackets from the enamel. A conventional fast-setting GIC, Fuji IX Fast, and two resin-modified glass ionomer cements (RMGICs), Fuji Ortho LC and Fuji Plus, were investigated. Three modes of curing were performed (n = 10): (1) according to the manufacturer's prescription, (2) with 60 seconds application of heat, or (3) with 60 seconds application of ultrasound. The tensile force required to debond the brackets was determined as the tension 15 minutes after the start of the bonding procedure. The mode of failure was scored according to the Adhesive Remnant Index (ARI) to establish the relative amount of cement remnants on the enamel surface. Curing with heat and ultrasound shortened the setting reaction and significantly (P < 0.05) increased the bond strength to enamel. The ARI scores showed an increase for all materials after heat and ultrasound compared with the standard curing method, most notably after heat application.

Acrylic Resins↗
PubMed2005

Surgically assisted rapid maxillary expansion (SARME): a review of the literature.

Transverse maxillary hypoplasia, in adolescents and adults, is frequently seen in non-syndromal and syndromal patients including cleft patients. In skeletally matured patients, the uni- or bilateral transverse hypoplasia can be corrected by means of a surgically assisted rapid maxillary expansion. The treatment is a combination of orthodontics and surgical procedures and provides dental arch space for alignment of teeth. The procedure also causes a substantial enlargement of the maxillary apical base and of the palatal vault, providing space for the tongue for correct swallowing and thus preventing relapse. In addition, a distinct subjective improvement in nasal breathing associated with enlargement of the nasal valve towards normal values is seen with an increase of nasal volume in all compartments. In this article we give a review on surgically assisted rapid maxillary expansion. We conclude that there is no consensus in the searched literature regarding either the surgical technique, the type of distractor used (tooth-borne or bone-borne), the existence, cause and amount of relapse and whether or not overcorrection is necessary. A proposal for a prospective randomized patient study in order to find answers to the lacunas in knowledge regarding this treatment is done.

Adolescent↗
PubMed2005

The influence of force magnitude on intrusion of the maxillary segment.

The purpose of this study was to determine whether the magnitude of intrusive force to the maxillary incisors influences the rate of incisor intrusion or the axial inclination, extrusion, and narrowing of the buccal segments. Twenty patients between the ages of nine and 14 years who needed at least two mm of maxillary incisor intrusion were assigned to one of two equal groups. In group 1 patients, the teeth in the maxillary anterior segment were intruded using 40 g, whereas in group 2 patients, 80 g was used. Records were taken from each patient at the beginning and end of intrusion. There was no statistically significant difference between the 40- and 80-g groups in the rate of incisor intrusion, or the amount of axial inclination change, extrusion, and narrowing of the buccal segments.

Adolescent↗
PubMed2005

The relation between the point of force application and flaring of the anterior segment.

The purpose of this study was to determine whether application of an intrusive force by an intrusion arch at the distal wings of the lateral incisor brackets causes a change in the axial inclination of the anterior segment. Maxillary incisor intrusion was performed, and records were taken from 40 adolescent patients at the beginning and end of intrusion. Intrusion of the maxillary anterior segment caused a statistically significant mean increase in axial inclination of the central incisor of 8.74 degrees. The following correlations were investigated and found not statistically significant. The correlation between the (1) distance from the point of force application to the center of resistance at the start of intrusion and the change in axial inclination of the incisor, (2) distance from the point of force application to the center of resistance at the start of intrusion and the change in distance from the incisal edge to the distal side of the first molar, (3) distance from the point of intrusive force application to the center of resistance at the start of intrusion and at the end of intrusion, (4) distance from the point of intrusive force application to the center of resistance at the start of intrusion and the change in this distance between start and end of intrusion, and (5) amount of intrusion and the change in axial inclination.

Adolescent↗
PubMed2005

Dental age in Dutch children.

Dental age was studied in a sample of 451 Dutch children (226 boys and 225 girls) according to the method of Demirjian. They were born between 1972 and 1993 and were between 3 and 17 years of age at the time a dental pantomogram (DPT) was obtained. All children were placed in the age group closest to their chronological age. All 451 DPTs were scored by one examiner. A subset of 52 DPTs was scored by a second examiner and the intra-class correlation coefficient (ICC) and Cohen's kappa were calculated. The ICC was 0.99 and Cohen's kappa 0.68. Boys and girls were analysed separately.A significant difference was found between chronological age and dental age. On average, the Dutch boys were 0.4 years and the girls 0.6 years ahead of the French-Canadian children analysed by Demirjian. Therefore, the French-Canadian standards were not considered suitable for Dutch children. New graphs for the Dutch population were constructed using a logistic curve with the equation Y = 100*{1/(1 + e(-alpha(x - x0)))} as a basis. The 90 per cent confidence interval was calculated. To determine whether the logistic curve was correct, a residual analysis was carried out and scatter plots of the differences were made. The explained variance was 93.9 per cent for the boys and 94.8 per cent for the girls. Both the residual analysis and the scatter plots indicated that the logistic curve was appropriate for use with Dutch children. In addition to the graphs, tables were produced which transfer the maturity scores calculated by the method of Demirjian into Dutch dental age.

Adolescent↗
PubMed2005

[Care for children born with cleft lip, jaw and/or palate].

The number of children with cleft lip and/or palate needing care in and the possibilities of care delivering to these patients by muitidisciplinary teams are described. The data are compared with data from other European countries. The improvements in quality of care and patients are elucidated by research data.

Adolescent↗
PubMed2004

Outcome of treatment of Class II malocclusion by intraoral mandibular distraction.

Our aim was to find out long-term results of treatment in patients treated orthodontically and by mandibular distraction osteogenesis. Data on duration of treatment, costs, and results of 26 patients (13 girls and 13 boys) with a mean age of 15 years were analysed. The preoperative cephalograms were compared with those taken at the last follow-up visit. There was a significant reduction in duration of treatment when patients were treated without a first phase that included functional appliances. The differences in costs of orthodontic treatment were not significant. The costs of the operation for distraction were significantly higher compared to BSSO, mainly because of the costs of the distraction devices. Comparison of the cephalograms showed a significant increase in SNB angle, Wits value, ANB angle, overjet, and overbite. The Y-axis, MP/S, and SpP/MP angle increased. Orthodontic treatment and distraction of the mandible was a successful, but more expensive, treatment.

Adolescent↗
PubMed2004

The role of a high pull headgear in counteracting side effects from intrusion of the maxillary anterior segment.

Intrusion of incisors is often the preferred treatment of a deep overbite. This study focuses on deep overbite correction by intrusion of maxillary incisors. The purpose of this study is to determine whether high-pull headgear wear can prevent steepening of the buccal segment, extrusion of the buccal segment, maintain arch width, and increase the rate of incisor intrusion. The number of patients needed for this study was calculated to be 20. Patients were between nine and 14 years of age and assigned to one of two groups. In each group, intrusion of maxillary incisors was performed. Patients in one group wore a high-pull headgear at night, and patients in the other group did not. For each patient, a lateral head film, impressions with a wax bite in centric occlusion, and intraoral photographs were taken at the beginning and end of intrusion. This study demonstrated that high-pull headgear had no effect on steepening and extrusion of the buccal segments or on the rate of intrusion but did have an effect on narrowing of the buccal segments. By performing intrusion as described in this study, no statistically significant side effects were observed in the buccal segments, whereas a statistically significant amount of incisor intrusion of 2.24 mm in the no-headgear group and 2.37 mm in the headgear group was observed.

Adolescent↗
PubMed2004

Human jaw muscle strength and size in relation to limb muscle strength and size.

The aim of the present study was to investigate to what extent general factors (e.g. genotype, hormones) and factors at the craniofacial level (e.g. craniofacial size, jaw muscle architecture) contribute to the size and strength of the jaw muscles. A strong relationship of jaw muscle size and strength with that of other muscles would argue for general influences, whereas a weak relationship would argue for craniofacial influences. In 121 adult individuals, moments of maximal bite force, arm flexion force and leg extension force were measured. In addition, thicknesses of jaw muscles, arm flexor muscles and leg extensor muscles were measured using ultrasound. Relationships were assessed by using a principal component analysis. In females, one component was found in which all force moments were represented. Bite force moment, however, loaded very low. In males, two components were found. One component loaded for arm flexion and leg extension moments, the other loaded for bite force moments. In both females and males, only one component was found for the muscle thicknesses in which all muscle groups loaded similarly. It was concluded that the size of the jaw muscles was significantly related to the size of the limb muscles, suggesting that they were both subject to the same general influences. Maximal voluntary bite force moments were not significantly related to the moments of the arm flexion and leg extension forces, suggesting that besides the general influence on the muscle size, variation in bite force moment was also influenced by local variables, such as craniofacial morphology.

Adolescent↗
PubMed2004

Precision and accuracy of CT-based measurements of masticatory muscles in patients with hemifacial microsomia.

OBJECTIVE: The objective of this study was to quantitatively assess masticatory muscle volumes in patients with hemifacial microsomia. Until recently, this congenital malformation was only studied in terms of restoring bony and skin morphologies. Study of the masticatory muscles, however, adds a new dimension. MATERIALS AND METHODS: Contiguous 1.5 mm CT scans were made using a Philips Tomoscan 350 in six patients with hemifacial microsomia and in one patient without asymmetry. These CT scans were processed by a Cemax 1500X 3D workstation. The volume of the masseter, temporal, and medial and lateral pterygoid muscles was measured from CT scans using three-dimensional (3D) segmentation followed by 3D imaging. The precision and accuracy of measurements of masticatory muscle volumes were investigated. The precision of 3D imaging was assessed by carrying out repeated measurements by two observers. The accuracy of the volume determination technique was assessed by scanning a piece of porcine muscle tissue with a known volume. RESULTS: Intraobserver repeatability was near perfect, with the lowest alpha being 0.96 (for the medial pterygoid muscle). All interobserver correlations were high (>0.99). The accuracy of the method of measurement demonstrated differences ranging from 2.3% to 4.4%. CONCLUSION: Craniofacial soft tissue measurements obtained from CT scans in patients with hemifacial microsomia were accurate and reproducible but time consuming.

Adolescent↗
PubMed2004

[Ectopic eruption of the maxillary first permanent molar].

Ectopic eruption of the maxillary first permanent molar is an eruption disturbance. This article discusses current literature views on diagnosis, prevalence, aetiology and treatment of this disturbance. It is a relatively uncommon disturbance and its aetiology remains unclear. A combination of extraction of the maxillary second primary molar and cervical headgear treatment seems the treatment of choice, although this treatment option is successful in only 70% of cases. More research has to be conducted to compare the effectiveness of treatment options.

Humans↗
PubMed2003

Outcome of bone grafting in relation to cleft width in unilateral cleft lip and palate patients.

OBJECTIVE: The purpose of this study was to determine the relationship between cleft width and the residual amount of bone after bone grafting in 53 unilateral cleft lip and palate patients. STUDY DESIGN: The fate of the bone graft was determined by the residual amount of bone calculated from computed tomography scans taken immediately after surgery and 1 year postoperatively. Initial cleft width was measured on the computed tomography scans taken immediately after bone grafting. RESULTS: An average cleft width of 6.4 mm (range 3.0-12.2 mm) was found. The average amount of residual bone in the cleft area after 1 year was 64% of the initial bone graft. Linear regression analysis showed that a significant correlation (r = -0.29, P =.04) was found for cleft width in relation to the percentage of residual bone after 1 year. CONCLUSION: The regression analysis indicates that a relation between cleft width and the fate of the bone graft exists. Bone grafts in wider clefts are more prone to resorption than those in more narrow ones.

Adolescent↗
PubMed2003

[A dentist and the orthodontist. A perspective].

The Advisory Committee on the future of dentistry in the Netherlands recommends to deliver dental care through oral health care teams consisting of dental hygienists, dental assistants and other oral health care workers with extended qualifications with a new dental professional, the oral physician, as the director of those teams. What does this mean for the orthodontist? As modern orthodontics is far more multidisciplinary than in the past a structured collaboration between the orthodontist and the oral physician under one roof will be the future, probably supported by a management service organisation. Furthermore a quality system for orthodontic professionals such as the one that was developed though the EURO-QUAI-network needs to be established. And finally, orthodontists should change their clinical behaviour by applying evidence-based treatment strategies. It is clear that these developments need to be tailored in a European context.

Delivery of Health Care↗
PubMed2001

A randomised prospective clinical trial into the effect of infant orthopaedics on maxillary arch dimensions in unilateral cleft lip and palate (Dutchcleft).

Aim of the study was to evaluate the effect of infant orthopaedics (IO) on maxillary dimensions in infants with unilateral cleft lip and palate (UCLP). The study design was a prospective two-arm randomised controlled trial in parallel with three participating academic Cleft Palate Centres. Treatment was assigned by means of a computerised balanced allocation method. One group (IO+) wore passive maxillary plates during the first year of life, the other group (IO-) did not. Maxillary casts, made at birth, and at 15, 24, 48, 78 wk were digitised three-dimensionally. Before lip closure alveolar, midpalatal and posterior cleft width reduced significantly more in IO(+) than in IO(-). After lip closure, the alveolar cleft width reduced significantly more in IO(-). Until soft palate closure the slope of the palatal vault flattened significantly by IO. It is concluded that IO only has a temporary effect on maxillary arch dimensions that does not last beyond surgical soft palate closure. Therefore, infant orthopaedics as a tool to improve maxillary arch form could be abandoned. However, other outcome variables like facial and dental appearance, speech outcome, and cost-effectiveness need to be investigated further in order to assess the comprehensive effect of infant orthopaedics.

Alveolar Process↗
PubMed2001

The Eurocleft project 1996-2000: overview.

INTRODUCTION: The original Eurocleft project, a European intercentre comparison study, revealed dramatic differences in outcome, which were a powerful stimulus for improvement in the services of respective teams. The study developed a preliminary methodology to compare practices and the potential for wider European collaboration including opportunities for the promotion of clinical trials and intercentre comparison was recognized by the European Commission. Therefore, the project: 'Standards of Care for Cleft Lip and Palate in Europe: Eurocleft' ran between 1996 and 2000 and aimed to promote a broad uplift in the quality of care and research in the area of cleft lip and palate. RESULTS: The results of the 1996-2000 project include: a register of services in Europe, with details of professionals and teams involved in cleft care, service organization, clinical protocols and special facilities for research; a set of common Policy Statements governing clinical practice for European cleft teams, Practice Guidelines describing minimum recommendations for care that all European children with clefts should be entitled to and recommendations for Documentation governing minimum records that cleft teams should maintain; encouraging initial efforts to compare outcomes (results) of care between centres. A survey showed a wide diversity in models of care and national policies as well as clinical practices in Europe. Of the 201 centres that registered with the network, the survey showed 194 different protocols being followed for only unilateral clefts. CONCLUSION: Cleft services, treatment and research have undoubtedly suffered from haphazard development across Europe. Attainment of even minimum standards of care remains a major challenge in some communities and both the will to reform and a basic strategy to follow are overdue. It is hoped that the Eurocleft Consensus Recommendations reached during the present project will assist in improving the opportunities for tomorrow's patients. It is also hoped that the collaborative research now beginning under the European Commission's Framework V Programme will provide a focus for European researchers wishing to improve understanding, treatment and prevention of clefts of the lip, alveolus and palate in the years ahead.

Child↗