Biomedical subjects

H Tideman

Publications and source records attributed to H Tideman.

At least 19 recordsLinked to original sources

PubMed1998

Desmoplastic variant of ameloblastoma in Chinese patients.

Desmoplastic ameloblastoma is a rare tumour, and we know of only 43 previously reported cases. We report seven Chinese patients (five men and two women) with the desmoplastic variant of ameloblastoma, which makes up 9% of all ameloblastomas diagnosed during the years 1981-1995. The age ranged from 18 to 68 years (mean 43). Five of the tumours were in the maxilla and two were in the mandible. Five of them were situated anteriorly, the remaining two cases involving both anterior and posterior maxilla. The features of the 42 cases previously reported were reviewed and were compared with those in the present study. Our results differ in that we found a male predominance, wider age range and more tumours in the maxilla. Histologically, this variant of ameloblastoma is characterized by abundant collagenous stroma. Because the epithelial clusters may show prominent squamous metaplasia or may be compressed into thin strands in most areas, the appearance may mimic a squamous odontogenic tumour or odontogenic fibroma. The behaviour of this variant of ameloblastoma is likely to be the same as that of the classic ameloblastoma.

Adolescent↗

PubMed1998

Functional reconstruction of the mandible: a modified titanium mesh system.

This paper describes a method for mandibular reconstruction utilizing autogenous cancellous bone in a titanium mesh. The mesh is designed preoperatively based on a duplicate of the patient's mandible which is modified to simulate an anatomically correct edentulous segment in the region to be reconstructed. The duplicate mandible is articulated with a maxillary dental cast, and a locating splint is fabricated for intraoperative use to aid the positioning of the mesh in relation to the upper teeth. The method facilitates future rehabilitation with dental implants and results in a symmetric and highly functional reconstruction of the mandible.

Adult↗

PubMed1998

Ameloblastic carcinoma of the jaws. A report of two cases.

Two cases of ameloblastic carcinoma of the jaws are reported. Histopathologically, the lesions showed cytologic features of malignancy in addition to classical ameloblastoma patterns and were therefore documented as examples of ameloblastic carcinoma. The negative cytokeratin expression by the malignant cells on histochemical analysis is notably different from that normally observed in classical ameloblastomas.

Adult↗

PubMed1997

A bone graft condensing syringe system for maxillofacial reconstructive surgery.

A new system of metallic syringes and pluggers specifically designed for delivery and condensation of particulate bone graft is reported, and the clinical application in maxillofacial reconstructive surgery is described. This bone graft condensing system has advantages over the conventional plastic injection syringes in enabling much better bone graft condensation as well as easier bone delivery and insertion of the syringe to the depth of the reconstruction crib.

Bone Transplantation↗

PubMed1997

Temporalis myofascial flap in maxillofacial reconstruction: clinical and histological studies of the oral healing process.

OBJECTIVES: To report our experience with temporalis myofascial flaps (TMF), describe the healing process of uncovered flaps in the mouth, and the histology of the repaired mucosa in the long term. DESIGN: Prospective clinical and histological study. SUBJECTS: 36 patients who received a TMF over a 6.5 year period for serial assessment of the oral healing, 24 patients whose scars over the reconstructed area were assessed clinically, and 11 whose repaired mucosa was assessed histologically. MAIN OUTCOME MEASURES: To follow the clinical process of oral healing of the TMF and describe the repaired mucosa healed over the flap. RESULTS: The uncovered TMF in the mouth healed gradually starting with an acute inflammatory phase, going through chronic inflammatory and proliferative phases with eventual epithelialisation of the oral mucosa. There were no major complications. The healed mucosa showed mild scarring in 70% of cases and the repaired mucosa had characteristic histological features that were distinct from the normal mucosa. CONCLUSION: The TMF is an extremely reliable and versatile flap for maxillofacial reconstruction which heals gradually with eventual coverage by mildly scarred repaired mucosa.

Adolescent↗

PubMed1996

Blood loss and transfusion requirements in orthognatic surgery.

PURPOSE: This study quantified the blood loss and transfusion requirements in orthognathic surgery. PATIENTS AND METHODS: Three hundred sixty consecutive healthy orthognathic surgery patients were included in this retrospective study. The female:male ratio was 1.8:1, and the age range was 8 to 49 years (mean, 24). Estimated blood volume (EBV), estimated blood loss (EBL), and transfused blood were calculated. RESULTS: EBL ranged from 50 to 5,000 mL (mean, 600) representing up to 73% of EBV (mean, 16%). In total, 24% (84 patients) were transfused, 8.7% (6 patients) after single-jaw surgery and iliac bone harvest and 26.7% (78 patients) after bimaxillary osteotomies. Forty-seven patients received 1 unit of transfused blood, 25 patients had 2 units, and 12 patients had more than 2 units. Most transfused patients lost 11% to 40% of EBV. CONCLUSIONS: Transfusion is not necessary for single-jaw surgery unless a bicoronal flap or iliac bone harvest are required. Although only 27% of bimaxillary osteotomy patients required transfusion of 1 to 2 units, this group was not predictable based on the type of procedure involved, and a further subgroup (4% of the 291 patients) required a larger transfusion.

Adolescent↗

PubMed1996

Variations in costochondral grafting of the mandibular ramus.

This paper reviews the indications for, and the biological basis of, costochondral grafting for mandibular condyle replacement in adults and children. Our approach to costochondral grafting is described and illustrated, and known variations in techniques are reviewed and discussed. Data from our clinical series of 28 grafts is summarized.

Adolescent↗

PubMed1996

Functional reconstruction of the jaws: new concepts.

This paper describes the surgical reconstruction of the maxilla and mandible after ablative surgery. The methods described are original and recently developed with illustrative clinical data presented. Presurgical planning of the occlusion, titanium mesh design supporting the bone graft, and implant-borne prostheses are integral elements of the concepts described to achieve functional reconstruction of the jaws.

Adolescent↗

PubMed1996

[Combined surgical-orthodontic correction for mandibular protrusion].

Through the analysis of the treatment plans and the results of 159 patients with mandibular prognathism, the authors emphasized that orthodontic treatment plays an important role in the combined procedure in which the aims of orthodontic treatment include eliminating dental compensation, aligning the teeth, harmonizing arch compatibility, adjusting and maintaining occlusal relationship. The choice of surgical procedure used for setting back the mandible is closely related to the result of pre-operative orthodontic treatment. The body step osteotomy and vertical ramus osteotomy are the most commonly used procedure to set back the mandible after pre-operative orthodontic preparation.

Humans↗

PubMed1995

The stability of segmentalized Le Fort I osteotomies with miniplate fixation in patients with maxillary hypoplasia.

PURPOSE: This study evaluates the postsurgical stability of segmentalized Le Fort I osteotomies with miniplate fixation in patients with maxillary hypoplasia. MATERIALS AND METHODS: Eighteen adult patients who had undergone segmentalized Le Fort I osteotomy for anterior and inferior repositioning of their hypoplastic maxilla were studied radiographically. The positional change of five maxillary landmarks (PNS, ANS, A, U1, and UM) were measured on serial cephalometric radiographs according to a reference frame constructed by using the SN line for superimposition, sella as the origin of the coordinates, and a line parallel to Frankfort horizontal plane as the x-axis. The positional changes of all variables were measured twice, and the means were calculated for analysis. The paired t-test was used for statistical analysis. RESULTS: Statistically significant mean vertical change (P < .01) was found in the anterior maxilla, with U1 having moved up by 27.8% (1.5 mm) of its initial downward surgical movement by 1 year postoperatively. U1 and UM had moved forward 2.0 mm and 1.5 mm, respectively (P < .01) by 1 year postoperatively, but the bony landmarks had no statistically significant change in their horizontal positions. CONCLUSION: Although statistically significant postsurgical changes were found at 1 year postoperatively, overcorrection is not recommended because of the large individual variation observed and the relatively small magnitude of the relapse.

Adult↗

PubMed1995

Contamination of titanium castings by aluminium oxide blasting.

OBJECTIVES: It is desirable that the surfaces of surgical implants be uncontaminated by foreign materials to avoid untoward tissue reactions, and grit blasting is widely assumed to leave clean metal surfaces. SEM examination and X-ray microanalysis of a recovered 'pure' titanium implant casting that was associated with tissue breakdown revealed embedded particles of alumina. The casting had been cleaned of investment by blasting with alumina grit. METHODS: A variety of treatments of cast titanium plates was used: (a) to establish that the observed aluminium was due to the blasting grit, and (b) to determine whether removal of investment could be achieved effectively by other means. SEM examination and X-ray microanalysis were used. RESULTS: The detected aluminium was associated with embedded fragments identified as coming from the blasting grit. Acid-pickling and mechanical (rotary instrument) trimming produced minimally contaminated surfaces. CONCLUSIONS: Whilst unproven, the presence of the alumina is viewed with great concern as a possible causative agent in the observed tissue breakdown and procedures avoiding alumina blasting are recommended as a precautionary measure.

Aluminum Oxide↗

PubMed1995

Titanium miniplate fixation for osteotomies in facial fibrous dysplasia--a histologic study of the screw/bone interface.

In four patients who had osteotomies of the jaws affected by fibrous dysplasia (FD), screws embedded in bone blocks were removed at a re-entry operation 20 months postoperatively. Morphometric measurement of the bone density and calculation of the bone contact percentage were performed. Both normal and dysplastic bone were found to have some direct bone contact with the titanium screws. Although the bone contact percentage was higher in the normal bone when compared with FD, statistics failed to show any significant difference (P < 0.05). The dysplastic bone healed well around the titanium screws without inflammatory reaction and direct dysplastic bone/screw contact was noted. Longer screws should be used in facial FD in order to compensate for the reduced bone contact percentage.

Adult↗

PubMed1995

Overgrowth of a costochondral graft in an adult male.

This paper is the first report of overgrowth of a costochondral graft in an adult male. The case supports the notion that this graft partly exhibits features of a primary growth center with inherent potential for growth.

Adult↗

PubMed1995

Orthognathic surgery in osteogenesis imperfecta: a case report with management considerations.

Osteogenesis imperfecta is a disease of connective tissues with additional metabolic defects. It is associated with recognisable facial disproportion and sometimes warrants surgical intervention for aesthetic, functional and psychological reasons. A severe case of osteogenesis imperfecta type 3 is presented to illustrate the feasibility of bimaxillary surgery using a mandibular body step osteotomy and maxillary down grafting at the Le Fort I level. The medical, anaesthetic, surgical and specific maxillofacial implications of surgery in these patients are discussed.

Adult↗

PubMed1995

[Evaluation of presurgical orthodontic correction of the mandibular prognathism].

The aim of this study was to evaluate the effects of presurgical orthodontic correction of the mandibular prognathism. The sample consisted of two groups of surgical cases. The cases of the mandibular prognathism in group I with lower anterior dental compensation received presurgical orthodontic decompensation, and the cases in group II without lower anterior dental compensation did not receive presurgical orthodontic decompensation. The results showed that before presurgical orthodontic treatment, significantly differences existed between the two groups variable ILi/OL and ANB. After presurgical orthodontic correction lower incisors position in group I was very close to that in the group II, this means that the presurgical orthodontic treatment significantly changed the position of the lower incisors.

Adolescent↗

PubMed1995

Presurgical orthodontic decompensation of mandibular incisors.

The effects of presurgical orthodontic decompensation on lower incisor inclination and angle ANB were studied using a modified Pancherz method of cephalometric analysis. Two groups of patients with mandibular hyperplasia were studied: one group (Group 1) of nineteen cases which required orthodontic decompensation and another (Group 2) of twenty-one cases which did not. The cephalometric changes which occurred in Group 1 were compared with the significant cephalometric differences existing between the two groups with respect to incisor inclination (ILi/OL; P < .001) and the sagittal relation (ANB; P < 0.05). After orthodontic treatment the average lower incisal angulation of the treated group was the same as that in the untreated group; the variations (S.D) being 3.6 degrees and 7.4 degrees respectively indicating that the clinical assessment of the orthodontic treatment effect was quite high.

Adaptation, Physiological↗

PubMed1994

The 3-dimensional stability of maxillary osteotomies in cleft palate patients with residual alveolar clefts.

OBJECTIVES: To evaluate the stability of maxillary osteotomies in cleft palate patients using miniplate fixation. DESIGN: A prospective clinical study. SUBJECTS: 46 consecutive cleft palate patients with residual alveolar clefts and maxillary hypoplasia in one or more dimensions. These patients underwent standardised maxillary osteotomies and simultaneous bone grafting of the alveolar cleft over 44 months during 1988-1992. Titanium mini-plate fixation was used for the maxilla in all patients. Follow-up ranged from 6 to 51 months with a mean of 28 months. MAIN OUTCOME MEASURES: The 3-dimensional stability of maxillary osteotomies in cleft palate patients in the long term. RESULTS: In the unilateral clefts, relapse in the horizontal plane was 22% and in the vertical plane 22.5%; in bilateral clefts, the relapse was 17.5% and 7% respectively, with no statistically significant difference between the two groups. Longitudinal analysis of the repositioned maxilla over a 3-year period showed that most of the relapse occurred in the first 6 months and stabilised at 2 years postoperatively. Relapse in the transverse plane, based on analysis of the study models of 26 cases, ranged from 13.4% to 33.6%. A clockwise rotational relapse of the maxilla was noted in bilateral cases. Postoperative orthodontics compensated for the horizontal relapse by increasing incisor proclination to maintain positive overjet. There was no significant difference between the relapse of bimaxillary cases and that of maxillary osteotomies alone. CONCLUSION: The long-term 3-dimensional surgical stability, using miniplate fixation, has decreased the relapse of cleft maxillary osteotomies with simultaneous alveolar bone grafting to a level comparable to that of maxillary osteotomies in non-cleft patients.

Adult↗

PubMed1994

Mandibular reconstruction with the Dacron urethane tray: a radiologic assessment of bone remodeling.

A retrospective study was made of 22 consecutive patients who underwent mandibular reconstruction with a Dacron (Osteo-mesh, Xomed Inc, Jacksonville, FL) tray technique from September 1988 to April 1992. Free autogenous iliac bone, in the form of particulate cancellous chips and marrow, was densely packed into the Dacron tray, that was adapted to bridge the mandibular segmental defect. Sixteen cases underwent uneventful healing with the formation of a continuous bony bridge and union with the remaining mandible. The pattern of bone remodeling and rate of resorption in these cases were assessed by sequential panoramic radiographs taken up to 3 years postoperatively. The mean horizontal dimension of the mandibular defects was 75 mm and the mean vertical reconstructed height was 25 mm. When the grafted bone was radiographically of uniform density, it progressed into a mature trabecular pattern matching that of the normal mandible. However, when there were areas of radiolucency, most likely from inadequate condensation of the graft, such areas were not replaced by bone in the long term. The bony height at both ends and the middle of the reconstructed segment underwent reasonably even resorption and retained about 80% of the bony height over a 3-year period. The rate of resorption was highest in the first 6 months and stabilized at about 2 years. There were six failures, all showing significant irregular bony resorption prior to tray removal.

Adolescent↗