Biomedical subjects

Heiner Wehrbein

Publications and source records attributed to Heiner Wehrbein.

6 recordsLinked to original sources

PubMed2006

The unilateral chewing phenomenon, occlusion, and TMD.

The aim of this study was to evaluate the role of occlusal factors to determine the extent of their role in temporomandibular disorders (TMD). Two groups were selected: a patient group (I) of 100 patients with TMD problems (pain and clicking) and a control group (II) of 100. Each individual had to have 28 permanent teeth. A clinical evaluation was conducted and the models were evaluated according to the criteria of the Angle Classes and the Reinhardt Index, with the number of permanent teeth (A), the number of the correctly (R) and the number of incorrectly (F) related antagonist pairs of teeth. The individuals had to observe the preference of their chewing side. The results of this investigation revealed: the number of F can be used as an occlusal indicator for possible functional disorders (p=0.041). Individuals with one chewing side have more signs and symptoms of TMD (p<6.22x10(-9)).

Adolescent↗

PubMed2005

Molar distalization with a modified pendulum appliance--in vitro analysis of the force systems and in vivo study in children and adolescents.

The standard pendulum appliance was modified by integrating a distal screw into its base and by special preactivation of the pendulum springs. The suitability of this Pendulum K for the translatory distalization of maxillary molars was investigated in an in vitro analysis and in an in vivo study in children and adolescents. The in vitro measurement of the resulting force systems revealed that all forces and moments remained virtually constant over a three-mm simulated distalization increment. The transverse force, Fx, increased from two to 11 cN and the weakly intrusively acting force, Fy, from six to eight cN, but these increases were not statistically significant. The distalization force, Fz, initially 201 cN, was still 199 cN after a three-mm distalization increment. The mesially acting moment, My, rose from 1654 to 1834 cN mm, whereas the palatally acting moment, Mz, declined slightly from 229 to 164 cN mm. The slight, consistent distoinclinatory moment, Mx, initially 306 cN mm, was 310 cN mm after three mm. In parallel, the in vivo study with its collective of 66 patients confirmed that the Pendulum K allows a virtually translatory molar distalization with slight tippings of 4.75 degrees to the palatal plane and 4.25 degrees to the anterior basal plane. Palatal movements of the first molars were avoided. The proportion of molar distalization in the total movement was 73.53%.

Adolescent↗

PubMed2005

Orthodontic anchorage implants inserted in the median palatal suture and normal transverse maxillary growth in growing dogs: a biometric and radiographic study.

Small osseointegrated implants inserted in the palate provide a reliable anchorage control during orthodontic treatment. When these implants are inserted in the median palatal suture in growing individuals, the possible effects on normal transverse maxillary growth are still unknown. Therefore, the aim of this study was to evaluate the influence of orthodontic anchorage implants on transverse maxillary growth when inserted in the median palatal suture of growing dogs. Five growing dogs were used, one of them randomly selected as a control dog. The test dogs each received two implants in the median palatal suture. Impressions and occlusal radiographs of the upper jaws were taken at baseline (TO), after 84 days (T1), and at the end of the study after 168 days (T2). Measurements to compare increases in maxillary width between test dogs and control dog were performed on study casts and occlusal radiographs at TO, T1, and T2. Restricted transverse growth was observed in the test dogs in the canine region. Transverse growth in the region of second and fourth premolars was similar for the test dogs and the control dog. These results may be of some clinical relevance when orthodontic anchorage implants are to be inserted in growing individuals. An alternative insertion site, for example the parasagittal region, should be considered in these cases, to avoid possible negative effects on normal transverse maxillary development.

Animals↗

PubMed2005

Root repair after injury from mini-screw.

Mini-implants and mini-screws are commonly used in orthodontics to provide extra anchorage. One potential insertion site is between the roots in the alveolar process, which results in a risk of damaging the roots of neighbouring teeth. In an animal-experimental study, 20 mini-screws (bracket screw bone anchors, BSBAs) were inserted into the mandible of five beagle dogs. Each dog received two BSBAs in each lower quadrant, between the roots of the second and third, and third and fourth premolars. Sequential point labelling was performed every 6 weeks with vital stains, and apical X-rays were taken every 6 weeks. Radiographic examination demonstrated damage at three roots because of insertion of the BSBAs. Histological examination at these three roots demonstrated an almost complete repair of the periodontal structure (e.g. cementum, periodontal ligament and bone) in a period of 12 weeks, following removal of the screws.

Animals↗

PubMed2004

Load-deflection behavior of transpalatal bars supported on orthodontic palatal implants. An in vitro study.

Within the scope of indirect orthodontic implant anchorage, the transpalatal bar (TPB) transmits the forces applied at the anchorage teeth to an implant inserted into the palate. It is thus the connecting element between teeth and palatal implant. The aim of the present study was to analyze the extent of sagittal deflection of TPBs of different dimensions attached to an implant abutment. For this purpose, commercially available stainless steel wires measuring 1.2 mm x 1.2 mm (n = 25) and 0.8 mm x 0.8 mm (n = 25) respectively were bent to comply with a representative bend specified with respect to casts, fixed with clamp caps to the implant abutment, and exposed for forces of 50, 100, 150, 200 and 300 cN. The mean deflection of the 1.2 mm x 1.2 mm TPB was lower by a factor of 4.5 than that of the 0.8 mm x 0.8 mm TPB. With a clinically relevant load of 200 cN, for example, the mean deflection of the 1.2 mm x 1.2 mm (0.051" x 0.051") TPB was 301 microm, whereas that of the 0.8 mm x 0.8 mm (0.032" x 0.032") TPB was 1337 microm. When maximum anchorage is required, 1.2 mm x 1.2 mm (0.051" x 0.051") TPBs should be used as a matter of principle.

Compressive Strength↗

PubMed2004

Age-related changes in the midpalatal suture. A histomorphometric study.

AIM: The issue of the present study was to register age-related morphological differences with reference to the mean sutural width (MSW) and the degree of obliteration (O) in the region of the human midpalatal suture. MATERIAL AND METHODS: 22 human palate specimens from subjects of different ages (18-63 years) were available for this purpose. Three sections (anterior, median and posterior) from each specimen underwent histological preparation and staining with toluidine blue before being subjected to histological and histomorphometric analysis. Two age groups (< or = 25 years and > or = 26 years) were formed. RESULTS: The findings showed that the median sutural width in the younger group (< or = 25 years) was 211.20 microm versus only 161.16 microm in the older group. This difference was statistically significant (p = 0.05). The proportion of ossified tissue in the entire suture (obliteration) was low in all subjects. At 13.10%, the maximum obliteration measured was found in a 44-year-old man in the older age group. The median value of the ossification was 0% in the younger age group and 3.11% in the group > or = 26 years. This difference was statistically significant (p = 0.036). The earliest ossification was registered in a 21-year-old man. The oldest subject without ossification was a 54-year-old man. In terms of local topography, no statistically significant differences between anterior, median and posterior palatal region were observed with respect to the two investigated parameters (MSW, O). CONCLUSION: These findings confirm that ossification of the midpalatal suture is not a valid reason for the increased transversal resistance encountered during rapid palatal expansion in younger subjects (< or = 25 years) as well as in many older persons.

Adolescent↗