Biomedical subjects

L L Habets

Publications and source records attributed to L L Habets.

At least 19 recordsLinked to original sources

PubMed1997

Interposed bone grafts to accommodate endosteal implants for retaining mandibular overdentures. A 1-7 year follow-up study.

The results are reported on 34 edentulous patients, who underwent interposed autogenous bone graft augmentation in the symphysis of the mandible, combined with bone-hydroxylapatite onlay augmentation of the area posterior to the mental foramina. Two to four implants were placed in the grafted symphysis after 3-5 months. An overdenture was constructed three months later. The follow-up period ranged from one to seven years. An average loss of mandibular bone height of 10-13% was observed. The data provided no evidence of a further time-dependent resorption from two-and-half to seven years.

Adult↗

PubMed1997

[Dental research in the Netherlands. Citations in publications].

This study examines the citation frequency (via the Science Citation Index) of publications by Dutch dental scientists that have appeared in the international literature since World War II. It was found that most citations were obtained by a relatively small group of researchers, many of them working in the fields of cariology and periodontology. High scores were particularly found among scientists who had their academic training in disciplines other than dentistry. Out of 109 frequently cited papers over 25% was microbiology-oriented and most of them could be characterized as original basic dental research.

Dental Research↗

PubMed1996

Quantification of facial morphology using stereophotogrammetry--demonstration of a new concept.

OBJECTIVES: The purpose of this study was to introduce stereophotogrammetry as a three-dimensional registration method for quantifying facial morphology and detecting changes in facial morphology during growth and development. METHODS: Using stereophotogrammetry, three-dimensional (3-D) co-ordinates for the bilateral landmarks Exocanthion and Cheilion and the midsagittal landmark Pronasale were determined in 10 subjects to ascertain the reproducibility of the method, and in 59 children to detect changes in facial morphology due to growth and development. Linear and angular measurements were calculated by means of the 3-D co-ordinates in order to quantify facial morphology. Significant differences were determined by means of analyses of variance (MANOVA). RESULTS: During the observation period, significant (P < 0.01) changes in facial morphology were determined for the linear measurements. Advantages and disadvantages of current registration methods are discussed. CONCLUSION: It is concluded that stereophotogrammetry is a suitable 3-D registration method for quantifying and detecting developmental changes in facial morphology.

Analysis of Variance↗

PubMed1996

[Dental research in the Netherlands: Ph.D theses 1956-1994].

The number of PhD-theses by Dutch scientists shows a continuous increase over the last four decades, resulting in about 20 theses per year during the early nineties. They cover a wide range of subjects in all major disciplines of dental research and nowadays are usually written in English (in 80% of the cases). A substantial proportion (23%) of all dental theses comes from scientists not trained as dentist but in other disciplines like biochemistry and psychology. So far, the drastic decline in the number of Dental Schools in the Netherlands during the eighties has had little influence on the overall outcome of PhD-theses. The international impact of Dutch dental research seems to increase over the years as shown by the declining fraction of Dutch dental scientists who are never cited in the international dental literature.

Academic Dissertations as Topic↗

PubMed1995

Method for quantifying facial asymmetry in three dimensions using stereophotogrammetry.

A three-dimensional method to quantify facial asymmetry is introduced. Stereophotogrammetry was applied to determine three-dimensional (3-D) coordinates for eight pairs of surface landmarks of 106 individuals, including 16 with an operated complete unilateral cleft lip and palate. Facial asymmetry was quantified from four different reference planes that were defined perpendicular to and bisecting lines between pairs of bilateral landmarks related to the eyes, nose and mouth. Significant differences (P < 0.01) between these four planes were determined using multivariate analyses of variance (MANOVA). It is concluded that the best reference plane to select in studies of facial asymmetry is formed by the one which is perpendicular to and bisects the line that connects the landmarks Exocanthion. Reproducibility and validity of the method is demonstrated.

Child↗

PubMed1995

Spatial and morphologic aspects of temporomandibular joints with sounds.

Various spatial and morphological aspects of the temporomandibular joint may be involved in the development of TMJ sounds. The present study examines their contribution to the prediction of sounds. A non-patient sample was studied using sensitive sound measurement and panoramic radiography. It was found that temporomandibular joint sounds are common in asymptomatic subjects showing substantial variation in several spatial and morphological parameters. An autonomous contribution of spatial relationships, asymmetries or morphology of bony structures to the prediction of joint sounds could not be detected. When unilateral sounds were present, they were more likely to be found on the side with the less steep condylar movement path. Joint imaging is not indicated in the detection of relationships between bony structures and their eventual asymmetries and joint sounds.

Auscultation↗

PubMed1995

Longitudinal study on three-dimensional changes of facial asymmetry in children between 4 to 12 years of age with unilateral cleft lip and palate.

The purpose of the present study was to describe three-dimensional developmental changes of facial asymmetry in children with an operated complete unilateral cleft lip and palate (UCLP) and in children without craniofacial anomalies (controls). Using stereophotogrammetry, three-dimensional coordinates for 16 bilateral and 10 midsagittal facial landmarks were determined for the UCLP group (n = 33) and the control group (n = 63) on two occasions. In this mixed-longitudinal study, the children were 4 to 12 years of age. Facial asymmetry and left-right dominance was measured and resolved for transverse, vertical, and sagittal components. Significant effects were analyzed with multivariate analyses of variance (MANOVA). We concluded that individuals with complete unilateral cleft lip and palate, as well as individuals without craniofacial anomalies, show an increase, during growth, in the amount of facial asymmetry in the basal region of the nose. In the region that is related to the cleft, children with complete unilateral cleft lip and palate do not show changes in the amount of facial asymmetry between the occasions. Regarding facial left-right dominance and variation in dominance, no demonstrable growth changes take place in individuals with complete cleft lip and palate, nor in individuals without craniofacial anomalies.

Case-Control Studies↗

PubMed1995

[Dental research in the Netherlands: an international orientation].

Analysis of dental scientific literature (section Dentistry & Odontology of the Science Citation Index) has revealed that the majority of the contributions to dental science come from the USA, the UK and Japan. Also Dutch scientists showed up as active contributors, especially when viewed against the distribution of IADR-members and dental practitioners over the world. The scientific output in the Netherlands is evenly spread over the various dental subdisciplines, although some emphasis is seen on the fields of cariology and social dentistry.

Dentistry↗

PubMed1994

Three-dimensional evaluation of facial asymmetry in cleft lip and palate.

The purpose of the present study was to describe facial asymmetry in three dimensions in individuals with an operated complete unilateral cleft lip and palate (UCLP) and in individuals without craniofacial anomalies (controls). Three-dimensional coordinates for 16 bilateral and 10 midsagittal facial landmarks were determined for the UCLP group (N = 49) and the control group (N = 80) by means of stereophotogrammetry. The total asymmetry was measured and resolved for transverse, vertical, and sagittal components. It can be concluded that all three components are important in studies on facial asymmetry. Individuals with UCLP show more facial asymmetry in the vertical direction than controls. They demonstrate more facial asymmetry in the region related to the cleft than controls. And, males in general demonstrate more asymmetry of the nose than females.

Cephalometry↗

PubMed1994

Facial left-right dominance in cleft lip and palate: three-dimension evaluation.

Studies on facial left-right dominance in individuals without craniofacial anomalies have demonstrated controversial results. This is probably due to the frequent use of two-dimensional methods, yet left-right dominance consists of transverse, vertical, and sagittal components. The aim of the present study was to describe three-dimensionally facial left-right dominance in individuals with an operated complete unilateral cleft lip and palate on the left side (LUCLP), on the right side (RUCLP), and in individuals without craniofacial anomalies (controls). Using stereophotogrammetry, three-dimensional coordinates for 16 bilateral and 10 midsagittal facial landmarks were determined for the LUCLP group (N = 32), the RUCLP group (N = 17), and the control group (N = 80). Left-right dominance was measured in three directions. Individuals without craniofacial anomalies showed a facial left sided dominance in the transverse direction, a facial right sided dominance in the sagittal direction, and no particular dominated side in the vertical direction. Individuals with a unilateral cleft lip and palate demonstrated a facial dominance of the nonaffected side in the vertical direction as well as in the sagittal direction, with no particular side dominant in the transverse direction. Generally, there was more variation in left-right dominance within the face in the vertical and sagittal directions.

Cephalometry↗

PubMed1992

The relation between periodontitis and systemic bone mass in women between 46 and 55 years of age.

It has been suggested that periodontitis and systemic bone mass might be related. In order to evaluate this possible relationship, we performed an intra-oral examination and measured lumbar bone mineral density (lumbar BMD) and metacarpal cortical thickness (MCT) in 286 female volunteers between 46 and 55 years of age. In addition, the alveolar bone height was measured on bite wing radiographs of the dentate subjects. Of the subject, n = 60 (21%) were edentulous. Compared to the dentate subjects, the lumbar BMD and MCT of the edentulous women were not significantly different. In the dentate subjects, no significant correlation was observed between the clinical parameters of periodontitis (mean probing depth, occurrence of bleeding after probing and number of missing teeth) and the bone mass parameters (lumbar BMD and MCT); nor was a significant relation observed between the bone mass measurements and alveolar bone height. We therefore suggest that systemic bone mass is not an important factor in the pathogenesis of periodontitis.

Absorptiometry, Photon↗

PubMed1990

Craniomandibular asymmetry in headache patients.

The stomatognathic system was examined in 100 chronic recurrent headache patients, and the asymmetry in clinical and radiographic findings was studied. A clinically recorded facial asymmetry was found more frequently in patients with a definite CMD pain (P less than 0.001), in patients with mainly a unilateral headache (P less than 0.01), and in patients with a head injury in the history (P less than 0.05). The radiographically determined asymmetry in condylar height in these headache patients was high. More condylar asymmetry was found in migraine patients than in patients with tension headache (P less than 0.05). Asymmetric findings in the hard-tissue condition of the temporomandibular joint were more prevalent in patients with a definite CMD pain and in those with mainly bilateral headaches.

Chronic Disease↗

PubMed1989

The recognition of craniomandibular disorders; condylar symmetry in relation to myogenous and arthrogenous origin of pain.

Sixty-seven per cent of the forty-three patients suffering from craniomandibular disorders (CMD) had a vertical condylar asymmetry greater than 3%. After division into two different groups, myogenous and arthrogenous origin of pain, it was found that myogenous patients were younger and showed significantly bigger asymmetry between the vertical heights of the left and right condyles, evaluated on an Orthopantomogram, than the patients with arthrogenous origin of pain (P less than 0.05). The mean vertical condylar asymmetry was 9.10% and 4.83%, respectively. It is suggested that the possible triggering morphological condylar asymmetry on the pathogenesis of a CMD should be recognized at an early stage of the disorders development. The use of a screening protocol and an Orthopantomogram could be of preventive importance in daily practice.

Adolescent↗

PubMed1989

The OPG: an aid in TMJ diagnostics. III. A comparison between lateral tomography and dental rotational panoramic radiography (Orthopantomography).

In the comparison of radiographical findings (flattening, irregular surface and osteophyte formation) between lateral tomography and Orthopantomography in thirty-one female patients with craniomandibular disorders, a 76% similarity was found. A trend in the findings was seen: with an increase in radiographical findings visible in the tomograms there is a decrease in the amount of condylar asymmetry visible in the Orthopantomograms and a decrease in the age of the patients.

Adolescent↗

PubMed1988

Mandibular atrophy and metabolic bone loss. Histomorphometry of iliac crest biopsies in 74 patients.

Histomorphometry of iliac crest biopsies of 74 edentulous patients with severe atrophy of the mandible submitted for ridge augmentation, showed a minority of the patients (14%) to have a significant decrease of trabecular bone volume, indicating osteoporosis. On the other hand, osteoid volume, osteoid seam thickness and active resorption surface, parameters for disturbances in mineralization, lack of calcium and hyperfunction of parathyroid glands, were significantly increased by 38%, 88% and 65% of the patients, respectively. These findings were more pronounced in the patients with radiological evidence of metabolic bone loss (38%, Gonion less than 1). It may be concluded that metabolic bone loss, due to a lack of calcium and a subsequent hyperfunction of the parathyroid glands, plays a role in the etiology of severe atrophy of the edentulous mandible. which therefore might be prevented by supplementing with calcium with or without vitamin D.

Adult↗

PubMed1988

Mandibular atrophy and metabolic bone loss. Endocrinology, radiology and histomorphometry.

In 11 edentulous patients with a severe atrophy of the mandible and submitted for ridge augmentation, endocrinological, radiological and histomorphometrical studies were carried out. The results showed that metabolic bone loss, histologically in nearly all patients characterized as a disturbance in mineralization and endocrinologically in 55-73% of the patients as a secondary hyperfunction of the parathyroid glands, plays a rôle in the etiology of mandibular atrophy.

Atrophy↗

PubMed1988

The recognition of craniomandibular disorders--a comparison between clinical and radiographic findings in eighty-nine subjects.

A comparison has been made between clinical and radiographical findings in a study of eighty-nine patients suffering from craniomandibular disorders. In general it was found that condylar changes were more common in these patients than in earlier studies concerning the severe problems of craniomandibular disorders. A statistically significant correlation between clinical and radiographical findings was found for crepitation with osteophyte formation of the condyle (P less than 0.01). After clinical separation of the patients into two groups based upon the origin of pain, myogenous versus arthrogenous, no radiographical correlation could be made except for condylar osteophytes. With the clinical method used for separation of patients it was found that the clicking of the temporomandibular joint (TMJ) was more common among myogenous patients (P less than 0.05); crepitation was more common among arthrogenous patients (P less than 0.01), as was limited mouth opening (P less than 0.05) and deviation on opening (P less than 0.05). Radiographically, the only statistical difference between the two groups was found for osteophyte formation of the condyle, this was more common among arthrogenous patients (P less than 0.05). As the clinical method has been tested earlier, the results of this study lends support to the idea that conventional radiographical examination is of limited use in the initial diagnostics of craniomandibular disorders. Therefore new alternatives have to be developed.

Facial Pain↗

PubMed1988

The Orthopantomogram, an aid in diagnosis of temporomandibular joint problems. II. The vertical symmetry.

Vertical measurements of the Orthopantomograms of 152 patients were made for condylar and rami heights. The symmetry between the right (R) and the left (L) side was calculated with the formula: [(R-L)/(R + L)]. A statistically significant difference between the patients of a routine dental group and the patients treated for craniomandibular disorders was found regarding condylar height symmetry.

Adult↗