Biomedical subjects

S Isaksson

Publications and source records attributed to S Isaksson.

At least 19 recordsLinked to original sources

PubMed2000

Temporomandibular dysfunction in patients treated with orthodontics in combination with orthognathic surgery.

Fifty-two patients with malocclusions underwent orthodontic treatment in combination with orthognathic surgery involving a Le Fort I and/or sagittal split osteotomy. Approximately 5 years after surgery, the patients were examined for signs and symptoms of temporomandibular disorders (TMD). The frequencies were found to be low in comparison with epidemiological studies in this field. The aesthetic outcome and chewing ability were improved in most patients (about 80 per cent). Some of the patients had reported recurrent and daily headaches before treatment. At examination, only two patients had reported having a headache once or twice a week, while all the others suffered from headaches less often or had no headache at all. Eighty-three per cent of the patients reported that they would be prepared to undergo the orthodontic/surgical treatment again with their present knowledge of the procedure. This study shows that orthodontic/surgical treatment of malocclusions not only has a beneficial effect on the aesthetic appearance and chewing ability, but also results in an improvement in signs and symptoms of TMD, including headaches.

Adolescent↗

PubMed1999

Oral implants in combination with bone grafts. A 3-year retrospective multicenter study using the Brånemark implant system.

A retrospective, multicenter, Scandinavian study of bone grafting of alveolar processes of severely atrophic jaws in combination with implant insertion was conducted with 150 patients. Five different grafting techniques were assessed: local or full onlay; inlay; combination of onlay/inlay grafts; and LeFort I osteotomies. The majority of the patients were treated using a one-stage approach (n = 125) and all had autogenous bone grafts. A total of 781 Brånemark implants were inserted, of which 624 were placed in bone grafts and alveolar bone. Twenty-five patients (17%) dropped out during the follow-up period of three years. Within the remaining patients, 77% of the inserted implants (n = 516) were still in function at the end of the follow-up period. A further ten implants were kept mucosa-covered, resulting in an overall implant survival rate of around 80%. Onlays, inlays and LeFort I osteotomies showed almost the same success rates (76-84%), whereas the onlay/inlay technique gave rise to less favourable results (60%). Most of the observed losses (n = 131) took place during healing and the first year of loading. More implants were lost when they were inserted simultaneously with the grafting (23%) than when they were placed in a second stage (10%). The latter technique was used mainly in combination with local onlay grafting (16/25). The failure percentage for implants inserted in non-grafted bone (11%) was lower than for those inserted in bone grafts and alveolar bone (25%). The surviving implants of treated and followed patients served, in 88% of the cases (n = 110), to support fixed bridges or overdentures, albeit, in some instances (n = 23), after additional implant placement. In only 15 patients was it necessary to fall back on conventional removable prostheses or fixed partial bridges.

Adolescent↗

PubMed1998

Stability of Le Fort I osteotomy with advancement: a comparison of single maxillary surgery and a two-jaw procedure.

PURPOSE: This study compared single maxillary surgery and a two-jaw procedure in patients who underwent one-piece Le Fort I advancement without bone grafting. PATIENTS AND METHODS: Fifty-three patients had Le Fort I osteotomy performed using a standard technique. Twenty-two patients had maxillary surgery alone, and 31 patients additionally had a bilateral sagittal split ramus osteotomy performed. Both rigid and nonrigid fixation were used. The postoperative movement of the maxilla was investigated, comparing cephalograms taken preoperatively, 2 to 3 days postoperatively, and at least 6 months postoperatively. A computer program was used to superimpose the three radiographs. RESULTS: No difference in postoperative stability was found when the two surgical procedures were compared, and no correlation between magnitude of advancement and degree of relapse could be identified (P > .05). Nonrigid fixation in patients receiving only maxillary surgery resulted in greater postoperative forward movement of the maxilla (P = .022). CONCLUSION: This study indicates that postoperative stability of the maxilla in a two-jaw procedure is equivalent to that of single maxillary surgery. Nonrigid fixation in single maxillary surgery reduces the need for postoperative orthodontics.

Adolescent↗

PubMed1998

Importance of bone graft quality for implant integration after maxillary sinus reconstruction.

OBJECTIVE: The aim of this study was to determine whether bone quality, as assessed by osteometry and histologic parameters, can be used to predict implant integration in conjunction with maxillary sinus reconstruction. STUDY DESIGN: Twelve patients with severely atrophied maxillary alveolar processes were treated through use of a two-stage surgical reconstructive strategy with implant placement 4 months after bone grafting. Bone biopsy specimens taken from the iliac crest peroperatively and from the sinus inlay sites 1, 2, 4, 6, or 12 months postoperatively were analyzed by light microscopy and osteomorphometry. Bone mineral content was measured by osteometry. RESULTS: Osteometric and osteomorphometric data (trabecular bone volume [%], assessment of chromatin staining, and an osteocyte index) registered for the biopsy specimens were not statistically correlated with implant failure. CONCLUSIONS: Prognostic evaluation of implant survival is difficult. The tested methods did not contribute to the improvement of guidelines for the clinical handling of these patients.

Adult↗

PubMed1998

Sensibility following sagittal split osteotomy in the mandible: a prospective clinical study.

Bilateral sagittal split osteotomy may be associated with postoperative sensory deficiency in the area innervated by the inferior alveolar nerve. The aim of this study was to assess the neurosensory response of the inferior alveolar nerve after such surgery. Fifty consecutive patients receiving mandibular setback or advancement were investigated. Four different neurosensory tests were used: light touch, pin prick, static two-point discrimination, and vibration thresholds. These tests were performed preoperatively, 2 days, as well as 3 months and 12 months postoperatively. The methodologic error was found negligible. The pin prick and light touch tests as well as vibratory thresholds often disclosed a short period of decreased local sensibility, whereas static two-point discrimination displayed a slightly more extended postoperative sensory reduction. The patients did not experience any practical problems or essential drawbacks postoperatively. The only variable significantly associated with neurosensory disturbance was age. In conclusion, bilateral sagittal split osteotomy, when properly performed, must be considered a safe and reliable surgical technique, even from a neurosensory point of view.

Adolescent↗

PubMed1997

Sinus inlay bone augmentation: comparison of implant positioning after one- or two-staged procedures.

PURPOSE: This study was undertaken to compare implant angulation and position after one- or two-stage sinus inlay bone augmentation. PATIENTS AND METHODS: Twenty patients were retrospectively selected; group 1 (n = 10) was operated on with a one-stage procedure, and group 2 (n = 10) with a two-stage operation. Casts processed for the final permanent or temporary bridgework were collected and photographed from an oblique anterior view paralleling the alveolar crest on the right and left sides, as well as from an occlusal view. The angle between impression pins inserted in the abutments relative to the true vertical was recorded. In the occlusal view, the midpoints of the abutments were related to an individual computerized superimposed parabola. RESULTS: The implants inserted during the one-stage procedure were generally placed more palatally (Wilcoxon rank sum test, P = .0101) and angled more palatally (P = .0009) compared with those placed with the two-stage operation. CONCLUSION: This study showed that the two methods of treating patients by sinus inlay bone augmentation differed significantly with regard to placement and angulation of the implants. A two-stage procedure seems to offer the surgeon more optimal conditions for positioning the implants.

Adult↗

PubMed1997

A comparison of skeletal stability after mandibular advancement and use of two rigid internal fixation techniques.

PURPOSE: Two different methods of rigid fixation were compared for postoperative stability 6 months after mandibular advancement for treatment of Class II malocclusion. MATERIAL AND METHODS: Sixty (30 + 30) patients from two different oral and maxillofacial units treated for a Class II malocclusion by bilateral saggital split osteotomy (BSSO), and two different methods of internal rigid fixation were prospectively investigated. Two groups (S1, n = 15; S2, n = 15) had bicortical noncompressive screws inserted in the gonial area through a transcutaneous approach, and the other two groups (P1, n = 15; P2, n = 15) had the bone segments fixed with unicortical screws and miniplates on the lateral surface of the mandibular body. Cephalograms were taken preoperatively, 2 days postoperatively and 6 months after the operation. A computer program was used to superimpose the three cephalograms and to register the mandibular advancement and postoperative change both sagittally and vertically. RESULTS: These were minor differences in the advancement and postoperative changes between the four groups, but statistically no significant difference was shown in either sagittal or vertical directions. However, statistically verified differences proved that increasing age was associated with a smaller amount of postsurgical relapse. Low-angle cases (ML/NSL < 25 degrees) had a bigger amount of surgical (P = .0008) and postsurgical (P = .0195) movement compared with the patients in the high-angle group (ML/NSL < 38 degrees). Using a multiple regression test, a positive correlation was also shown between the amount of surgical advancement and the amount of postsurgical instability (P = .018). CONCLUSIONS: This prospective dual-center study indicates that the two different methods of internal rigid fixation after surgical advancement of the mandible by BSSO did not significantly differ from each other, and it is up to the individual operator to choose the method for internal rigid fixation.

Adolescent↗

PubMed1997

Patients' assessment of surgical removal of mandibular third molars. An inquiry study.

The aim of this study was to find out patients' experience of pain and discomfort in connection with removal of lower third molars under local anaesthesia. Patients consecutively referred to the Oral and Maxillofacial Unit in Halmstad for removal of lower impacted third molars were the selection for this study. Three surgeons operated 294 lower third molars under local anaesthesia. The Visual Analogue Scale was used to register pain at several occasions during the surgical performance. The patients experienced the operation as an acceptable procedure and the most painful event during the operation was the injection of local anaesthetic solution. The study showed that the surgical procedure was very well tolerated by the patients with only a minor incident of inconvenience or excessive pain.

Adolescent↗

PubMed1996

A clinical follow-up study of 278 autotransplanted teeth.

This open study was undertaken to investigate the outcome of autotransplanted teeth over a 6-year period. The subjects were 296 patients who underwent autotransplantation in the 6-year period September 1986-August 1992 and outcome was measured by considering root formation, occlusion, endodontal and periodontal complications. 18 patients were excluded because of inadequate notes or radiographs (n = 3) or because they were lost to follow-up (n = 15). The groups were divided into open apex and closed apex, and duration of follow up was 6 months-5 years. Aplasia was the indication for operation in 158 (77 percent) of the open apex group but only 10 (14 percent) of the closed apex group, whereas caries and associated disease was the most common in the latter (n = 45, 61 percent compared with 20, 10 percent). There were 24 complete failures, 12 in each group (p <0.01). Only 7 teeth in total developed full roots, and 159 showed incomplete growth. In the open apex group 112 teeth were in occlusal contact and 4 were extracted for severe infraocclusion. In the closed apex group there were 10 cases of mild infraocclusion, none of which required treatment. There were 7 cases of pulp necrosis in the open apex group, 4 of which required extraction. Two teeth in the closed apex group were extracted for endodontic reasons. Only 1 tooth (in the closed apex group) had to be extracted for periodontal reasons. Autotransplantation is a reliable method with a good prognosis for donor teeth with both open and closed apexes. The technique is applicable whatever the aetiology of the agenesis, and is worthy of consideration should there be a suitable donor tooth.

Adolescent↗

PubMed1996

Factors in implant integration failure after bone grafting: an osteometric and endocrinologic matched analysis.

In a retrospective analysis of 49 patients who received bone graft augmentation to the maxillary sinuses in conjunction with implant insertion, 11 patients had a significantly reduced success rate. The aim of the present study was to determine whether bone quality, as assessed by osteometry and selected haematologic and urinary tests, influences the integration of implants, and whether such data can be prognostically useful. Relative bone mass density (BMD%) differed significantly among these patients as compared to age- and sex-matched control patients receiving the same reconstructive treatment (P=0.01). Other parameters tested did not demonstrate any significant differences. In addition to local complications, general disorders, such as osteoporosis, must be considered in cases of excessive implant loss.

Adult↗

PubMed1996

Thrombin inhibition by antithrombin III on the subendothelium is explained by the isoform AT beta.

Balloon injury of the rabbit aorta results in thrombin coagulant activity on the injured vessel wall that causes fibrin formation. The anticoagulant activity of both the intact and injured vessel wall has been partly explained by glycosaminoglycans with heparin-like activity that augment that activity of antithrombin III (AT). AT exists in two isoforms, alpha and beta, AT beta, which constitutes only 5% to 10% of AT in plasma, lacks one carbohydrate side chain, has higher affinity for glycosaminoglycans, and associates more readily with the subendothelium. This study evaluated whether AT can inhibit thrombin on the injured vessel wall and, if so, whether one of the isoforms is more effective then the other. The two isoforms were isolated from human plasma by heparin-Sepharose chromatography, and the purity was investigated by isoelectric focusing and crossed immunoelectrophoresis. Rabbits were subjected to balloon injury of the aorta; 3 hours after injury the aorta was excised. Thrombin coagulant activity on the aorta was measured by exposure to fibrinogen and thereafter by measuring the generation of fibrinopeptide A. Injured animals were treated with AT, AT alpha, or AT beta and were compared with control animals. AT was demonstrated on the injured vessel wall by using an immunohistochemical method. Animals receiving crude AT had significantly lower amounts of thrombin coagulant activity on the injured aortic wall than control animals, but AT alpha at a comparable dose had no effect. AT beta was given in the same dose as crude AT and also at a dose (10%) proportional to its presence in plasma. Animals receiving AT beta had significantly lower values of thrombin on the injured aortic wall than control animals. We conclude that the inhibitory effect of AT on thrombin coagulant activity on the injured vessel wall in explained by its AT beta content.

Animals↗

PubMed1994

Skeletal stability after mandibular advancement: a comparison of two rigid internal fixation techniques.

OBJECTIVE: To compare two different methods of rigid fixation for any difference in postoperative stability after mandibular advancement. MATERIAL AND METHODS: Thirty-eight patients with Class II malocclusion treated by bilateral sagittal split osteotomy (BSSO) and mandibular advancement were selected for this retrospective study. Group A (n = 16) had noncompressive bicortical screws inserted in the gonial area through a transcutaneous approach and Group B (n = 22) had the bone segments fixed with unicortical screws and miniplates on the lateral surface of the mandibular body. Cephalograms were taken preoperatively, 2 days postoperatively, and 6 months after the operation, and a computer program was used to superimpose the three cephalograms and register the advancement and postoperative instability. RESULTS: There was a minimal difference in advancement of the mandible in the two groups. Statistical analysis showed no significant difference in postsurgical stability. However, positive correlation between the amount of advancement and the amount of postsurgical instability was demonstrated using a linear multiple regression test (P = .0002). CONCLUSION: This study indicates that the two different methods of internal rigid fixation of the segments after surgical advancement of the mandible give equal stability postoperatively and their use is a matter of surgical choice.

Adult↗

PubMed1993

Early results from reconstruction of severely atrophic (Class VI) maxillas by immediate endosseous implants in conjunction with bone grafting and Le Fort I osteotomy.

This report presents our experience with 12 consecutive patients treated by the method of SAILER19, comprising bone grafting to the floor of the nose and the maxillary sinus after a Le Fort I inferior repositioning of the maxilla followed by immediate implantation of endosseous implants. The corticocancellous grafts were harvested from the iliac crest. Fifty-nine implants were inserted in the bone grafts and eight in the adjacent nongrafted bone. Fourteen implants (21%) had to be removed because of nonintegration, of which 10 had been placed in two patients. The follow-up ranged from 11 to 24 months. No implants have been lost after loading. Six patients received fixed prostheses, and four overdentures. The importance of complete preoperative positional stability of the bone grafts and implants is emphasized.

Adult↗

PubMed1993

Influence of three alloplastic materials on calvarial bone healing. An experimental evaluation of HTR-polymer, lactomer beads, and a carrier gel.

This study evaluated experimentally three alloplastic materials (HTR-polymer, lactomer beads, and a resorbable gel substance). A bioassay performed in a critical size defect rat model disclosed no osteoinductive capacity of any material. A total of 72 trephine calvarial 5-mm defects were created in 18 rabbits. The inlays were tested relative to control (empty) defects in a varied pattern, and the results were assessed by light microscopy and contact radiography after 4 and 15 weeks. The HTR-polymer alone or combined with bone chips displayed the most rapid early bone regeneration and more mature bone marrow redevelopment. The present form of the gel material seems to be less suitable for use as a carrier substance because of the intense inflammatory response produced.

Animals↗

PubMed1992

Osseous response to implanted natural bone mineral and synthetic hydroxylapatite ceramic in the repair of experimental skull bone defects.

The purpose of this study was to assess and compare the osseous responses to implanted particles of resorbable anorganic xenograft bone mineral and non-resorbable dense synthetic hydroxylapatite of two different granule sizes. Four trephine calvarial defects were produced in each of 13 adult rabbits. The experimental materials were subsequently implanted in three defects, leaving the fourth defect for control purposes. Six animals were killed 4 weeks after surgery and seven at 14 weeks. The tissue responses were assessed by contact radiography, light microscopy, and histometry. The biocompatibility of the implants was confirmed. All defects healed uneventfully, although the resorbable hydroxylapatite seemed to promote initial bone regeneration. The importance to orthognathic surgery of early and effective healing of bone gaps, as well as of the advantage of implant resorbability to bone remodeling, are discussed.

Absorption↗

PubMed1992

Maxillary alveolar ridge augmentation with onlay bone-grafts and immediate endosseous implants.

Management of the atrophic maxilla can be a taxing surgical problems. One treatment alternative is to use autogenous bone transplants and immediate titanium fixture implantation. Despite the extensive literature on routine implant treatment of the edentulous jaws, only very few reports have dealt with the outcome of bone graft reconstructive surgery as part of the dental implant restoration. This study presents the treatment and healing results of 8 consecutive patients, who, over a period of 2 years and 8 months, were treated using onlay iliac bone grafts to atrophic maxillary alveolar ridges with immediate implant insertion. The patients were followed for 32-64 months. 83% of the fixtures (n = 46) were well-integrated. Two fixtures in each of 2 patients were lost due to traumatic bone-graft fractures. Palpatory bone-graft volume and prosthetic function were, with the exception of 1 patient, good. Radiological examination demonstrated preservation of the major part of the vertical dimension of the grafted bone. Patient's assessment was of good aesthetics and intraoral function; 2 patients had minor phonetic problems. In conclusion, similar success to routine maxillary implant treatment can be achieved in the event of extreme maxillary bone deficiency, by bone grafting and immediate fixture insertion.

Adult↗

PubMed1992

Contribution of autogeneic membranous bone chips and bone paste to healing of rabbit skull defects.

In skeletal surgery, bone chips and bone paste are often used to facilitate bony repair. However, no comparative investigation between these forms of bone graft implantation has been undertaken. In this study four trephine skull defects were produced in each of 14 adult rabbits and inlays of bone paste and two separate amounts of bone chips were then implanted in each animal. The results were compared relative to a control defect and assessed by gross inspection, light microscopy, and contact radiography after periods of 4 and 15 wk. Bone chips offered only minor advantages over controls in the defects investigated and differences in bony regeneration between the diversified amounts of bone chips were negligible. After bone paste implantation, a cellular and mature bone was rapidly produced. The clinical significance of these findings is discussed.

Animals↗

PubMed1992

Regenerative response to membranous and enchondral lyophilized allogeneic bone in rabbit skull defects.

The regenerative responses of inlays of lyophilized allogeneic bone of membranous (skull) and enchondral (tibia) origin were studied in an experimental cranioplasty model in rabbits. The lyophilized bone particles were also bioassayed for inductive bone production in an orthotopic critical size defect rat model. Three trephined calvarial defects were evaluated in each of 14 adult rabbits. The experimental materials were implanted into two of the defects and the third was left empty for control purposes. The implants disclosed no major structural divergences as assessed by scanning electron microscopy. Healing was evaluated by light microscopy and contact radiography after periods of four and 15 weeks. The lyophilized bone allografts of both embryonic origins displayed a similar fashion of bone regeneration, bone marrow reappearance, and volumetric density of trabecular bone substance and displayed no obvious differences between experimental groups or intervals. The two materials exhibited low osteoinductive potential.

Animals↗