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Biomedical subjects

B Rosenquist

Publications and source records attributed to B Rosenquist.

At least 19 recordsLinked to original sources
PubMed2001

Radiographic stereophotogrammetric evaluation of intersegmental stability after mandibular sagittal split osteotomy and rigid fixation.

PURPOSE: The purpose of this study was to determine if rigid fixation with bicortical screws and/or miniplates with monocortical screws prevent mobility at the osteotomy site after bilateral mandibular sagittal split osteotomy. PATIENTS AND METHODS: Three metal bone markers were inserted in the proximal and the distal segments of the mandible during the sagittal split operation in 10 patients. These served as measurement points in postoperative follow-up by radiographic stereophotogrammetry. The patients were examined at intervals during the first postoperative year. At each examination, 2 sets of radiographic stereograms were obtained: 1 in rest position and 1 with stress applied to the osteotomy sites. The difference in the position of the proximal segment in relation to the distal segment between the 2 sets of stereograms was recorded. Findings greater than 0.4 degrees and 0.2 mm change indicated true displacement of the bone segments. RESULTS: Immediately after surgery, mobility at of the osteotomy site(s) was found in 8 of 10 patients, and after 1 year it was still present in 4 patients. CONCLUSIONS: Fixation with bicortical screws or miniplates and monocortical screws does not prevent mobility at the osteotomy site after sagittal split osteotomies. This mobility may remain as long as 1 year after surgery. The term "rigid fixation" is thus not a proper term for this kind of fixation.

Adolescent↗
PubMed2001

Postoperative migration at the individual osteotomy site following sagittal split ramus osteotomy: a stereometric radiographic study.

The aim of the present study was to evaluate whether migration occurs at individual osteotomy sites following sagittal split osteotomy of the mandible stabilized with rigid internal fixation, and if it occurs, how long it lasts. In 10 consecutive patients operated with bilateral sagittal split osteotomies, postoperative migration, defined as displacement of the proximal segments in relation to the distal over time, was studied 3-dimensionally by means of stereometric radiography. Follow-up was performed with stereometric radiographs obtained at intervals from 2 days until 1 year after surgery. During the 1-year observation period, migration at one or both of the osteotomy sites was found at some stage in all of the patients and in as many as 4 patients during the final 6 months. It is concluded that rigid internal fixation, as performed in the present study, does not prevent postoperative migration at the osteotomy. Furthermore, stable bone union at the osteotomy site appears to be a slower process than previously expected, thus emphasizing the importance of follow-up procedures to prevent relapse.

Adolescent↗
PubMed2000

The immediate replacement of teeth by dental implants using homologous bone membranes to seal the sockets: clinical and radiographic findings.

Placement of dental implants into fresh extraction sockets has several advantages compared to the original protocol. However, the soft-tissue handling is often complicated and the aesthetic results less rewarding. A method to use a homologous bone membrane as the sole sealer of the extraction socket after immediate implant placement is introduced and the outcome of 34 cases is presented. In 4 cases early losses of the membranes occurred (2 of these iatrogenic damage) in all other cases the homologous membranes were covered by proliferation of the surrounding mucosa within 2-4 weeks. In 2 of the 4 cases where the membranes were lost, the implants did not integrate, in the other 2 cases the implants did integrate but the sockets did not fill completely with bone and the aesthetic results were not acceptable. In all other cases bone filling of the socket occurred, the implants were stable at 180 days after insertion (functional success rate 94.1%) and the aesthetic results were excellent. The method thus seems very promising but the healing process is delicate and the operation site highly vulnerable during the first postoperative weeks. It should also be stressed that the present study offers conclusions neither about the quality of the newly formed bone nor about the quality of osseointegration offered by this bone.

Adolescent↗
PubMed1998

Postoperative migration of the osteotomy segment stabilized by titanium miniplate osteosynthesis following Le Fort I osteotomy: an x-ray stereometric study.

The aim of the present study was to evaluate whether titanium miniplate fixation prevents postoperative migration of the osteotomy segment following Le Fort I osteotomy and, if not, to evaluate whether postoperative migration varies with the direction and amount of surgical repositioning. In 10 consecutive patients who received Le Fort I osteotomies, postoperative migration of the osteotomy segment was studied in a three-dimensional system by means of x-ray stereometry. Surgical repositioning was recorded by cephalometry in lateral head films obtained before surgery and at 2 days postoperatively. X-ray stereograms were obtained at intervals from 2 days to 1 year after surgery. During the 1-year observation period, significant postoperative migration of the osteotomy segment was found at some stage in nine patients. No correlation between the amount of surgical repositioning and postoperative migration was found. However, a tendency toward superiorly directed postoperative migration of the osteotomy segment, independent of the direction of surgical repositioning, was observed. It is thus concluded that titanium miniplates do not prevent postoperative migration of the osteotomy segment. The weak correlation between the amount of surgical repositioning and postoperative migration of the osteotomy segment indicates that predictions of individual outcomes of surgical corrections are uncertain.

Adolescent↗
PubMed1996

Is there an anterior loop of the inferior alveolar nerve?

The inferior alveolar nerve has an anterior ramification with two terminal branches, the mental nerve and the anterior plexus (or "incisor nerve"). The mental nerve is described to have a superior, lateral, and posterior course formed as a loop. The length of the loop is reported to be between 3 and 7 mm. In the present study, dissection of the ramification of the inferior alveolar neurovascular bundle was performed unilaterally in 58 patients. In 43 cases the loop was 1.0 mm long. In addition, the anatomy of the ramification with the mental and incisor canals frequently diverged in other respects from prevalent descriptions in the literature.

Adult↗
PubMed1996

Accuracy of cephalometry in measurements of postoperative migration of the maxilla after Le Fort I osteotomy.

The aim of the study was to evaluate the accuracy of cephalometry when point A is used to assess the migration of the maxilla following Le Fort I osteotomy. In 10 consecutive patients, postoperative migration of the maxilla was studied by means of cephalometry and x-ray stereometry. Because the precision and accuracy of the x-ray stereometric method are known to be high, this method was used as a norm against which the results obtained by cephalometry were compared. The values of postoperative migration obtained by cephalometric analysis exceeded the corresponding values obtained by x-ray stereometry in all but four recordings. In 16 of 40 recordings, migration in opposite directions was found. The differences were statistically significant. Cephalometric analysis may be an inaccurate tool for postoperative follow-up of minor segment migration such as that usually found after osteotomies.

Cephalometry↗
PubMed1995

Mobility of the osteotomy site following Le Fort I osteotomy stabilized by titanium plate osteosynthesis.

PURPOSE: This study analyzed whether titanium plate osteosynthesis prevents mobility after Le Fort I osteotomy and, if not, how long the osteotomized segment is mobile. PATIENTS AND METHODS: In 10 patients aged 17 to 49 years, three metal bone markers were inserted below and three above the osteotomy during the Le Fort I procedure, each set forming a triangle. The patients were examined at intervals until 1 year postoperatively. At each examination two sets of x-ray stereograms were obtained; one in rest and one with pressure applied to the anterior part of the maxilla. The difference in position of the maxillary segment in relation to the reference segment between the two sets of stereograms, ie, the mobility, could thus be recorded. Findings of 0.4 degrees and 0.2 mm are considered significant. RESULTS: Immediately after surgery mobility in the osteotomy site was found in 7 of the 10 patients. One year postoperatively mobility in the osteotomy site was still found in four patients. CONCLUSION: Titanium plate osteosynthesis does not prevent mobility between the osteotomy segments after Le Fort I osteotomies. The osteotomized segment may remain mobile at least until 12 months after surgery. During this period the impact of the functional matrix may cause migration of the segment.

Adolescent↗
PubMed1993

Anterior segmental maxillary osteotomy. A 24-month follow-up.

Anterior segmental maxillary osteotomies were performed in 14 patients. Both the downfracture and the Wunderer methods were used. The patients were examined regularly until 24 months after surgery. No major complications occurred. Long-term stability of the osteotomy was found to be acceptable except when used to correct deep overbites. In these cases, other methods should be considered.

Adult↗
PubMed1992

Fixture placement posterior to the mental foramen with transpositioning of the inferior alveolar nerve.

The results of 10 fixture placement operations with transpositioning of the inferior alveolar nerve are presented. Nerve transpositioning increased the operating time, but with experience this time should be reduced. Neurosensory dysfunction of the inferior alveolar nerve was found in 7 of 10 operated sites 1 week after surgery. Six months postoperatively, altered sensation was still present in 2 patients. Nerve function was normal in all patients 1 year postoperatively. The stability of fixtures was satisfactory throughout the examination period and the procedure should prove useful in treatment of the resorbed mandible posterior to the mental foramina.

Alveolar Bone Loss↗
PubMed1991

Median lip fissure: etiology and suggested treatment.

In a prospective study of 20 patients with median lip fissure, pedigrees were obtained. A hereditary predisposition for weakness in the first branchial arch fusion seems to exist. In some persons, more often in males than in females, this weakness eventually leads to development of a median lip fissure. The fissure becomes symptomatic when it is infected. In 10 patients the fissure was excised; in the other 10 patients excision was done in combination with a Z-plasty of the center of the lesion. The prognosis with the latter operation was superior to that with the former.

Adult↗
PubMed1990

Medial displacement of proximal segments. A complication to oblique sliding osteotomy of the mandibular rami.

In a retrospective study of 125 patients operated by oblique sliding osteotomy of the mandibular rami, unilateral medial displacement of the proximal segment was found in 10 patients. In 8 of these retropositioning of the distal segment during surgery was combined with lateral rotation and the amount of retropositioning was small. Medial displacement of the proximal segment had no influence on postoperative stability. In 6 of the 10 patients transient anesthesia for the inferior alveolar nerve was found on the side where the proximal segment was medially displaced.

Adult↗
PubMed1988

Accuracy of the oblique lateral transcranial projection, lateral tomography, and x-ray stereometry in evaluation of mandibular condyle displacement.

Condylar displacement similar to that occurring during and after mandibular ramus osteotomies was simulated in an in vitro study. Three different radiographic methods were used to measure the displacement, and the accuracy of the methods was compared. The stereometric method was more accurate than the plain radiographic methods and permitted measurements in all three dimensions. The oblique lateral transcranial projection was more accurate than lateral tomography, possibly because identification of measurement points in lateral tomography was complicated by the substantial displacement of the condyle.

Craniotomy↗
PubMed1988

Condylar displacement after oblique sliding osteotomy of the mandibular rami. A stereometric and plain radiographic study.

Condylar displacement after oblique sliding osteotomy was examined in 8 patients by X-ray stereometry and plain radiography. During the first 8 postoperative weeks the displacement was in a medial/superior/posterior direction. After removal of the intermaxillary fixation a continuous lateral translation was found together with an initial inferior and a minor anterior translation which after 6 months postoperatively changed to a posterior translation. At 12 months postoperatively a difference in findings of condylar position was found between the X-ray stereometric and plain radiographic analyses. We regard this difference as due to the sum of remodelling and method errors.

Adult↗
PubMed1987

Stability of the osteotomy site after oblique sliding osteotomy of the mandibular rami. A stereometric and plain radiographic study.

Displacement of the mandible 2-2 1/2 years after oblique sliding osteotomy of the mandibular rami is reported. Stability of the osteotomy site has been assumed to be complete much earlier, however. In the present stereo radiographic study mobility at the osteotomy site was recorded as late as 2 years after surgery. No sign of delayed healing was recorded in the plain radiographic examination. It seems possible that relapse after oblique sliding osteotomy continues as long as the functional matrix can influence an unstable osteotomy site. As plain radiography does not give full information on the quality of bone, the stability of the osteotomy site can not be assessed by this method.

Adolescent↗
PubMed1986

Displacement of the mandible after removal of the intermaxillary fixation following oblique sliding osteotomy.

In an earlier study (Rosenquist et al., 1985) on oblique sliding osteotomy in 14 patients, operative repositioning and postoperative displacement of the mandible during intermaxillary fixation were presented. In the present stereometric study on the same patients displacement of the mandible after removal of the intermaxillary fixation is presented. A continuous anterior and a minor initial cranial translation and an anterior rotation of the mandible were found. Proclination of both upper and lower incisors was recorded. Correlations were found between operative repositioning and postoperative displacement of the mandible after removal of the intermaxillary fixation. Possible relapse mechanisms are discussed.

Cephalometry↗
PubMed1985

Displacement of the mandible during intermaxillary fixation after oblique sliding osteotomy. A stereometric and cephalometric radiographic study.

The X-ray stereometric method was applied for the first time to a series of consecutive patients to record operative repositioning of the mandible during oblique sliding osteotomy and postoperative displacement of the mandible during intermaxillary fixation. Comparison with cephalometric measurements was presented. The operative repositioning pattern was presented. Postoperatively a posterior displacement pattern was found with incisor extrusion in both jaws. Correlation between operative repositioning and postoperative displacement and between the two measurement methods was assessed. The stereometric method offers information on displacement on all three planes and a higher degree of accuracy. To avoid incisor extrusion, besides intermaxillary dental fiscation also skeletal fixation is recommended.

Adolescent↗