Expression of transforming growth factor beta 1-related signaling proteins in irradiated vessels.

AIM: Microvascular free tissue transfer is a standard method in head and neck reconstructive surgery. However, previous radiotherapy of the operative region is associated with an increased incidence in postoperative flap-related complications and complete flap loss. As transforming growth factor beta (TGF-ß) 1 and galectin-3 are well known markers in the context of fibrosis and lectin-like oxidized low-density lipoprotein 1 (LOX-1) supports vascular atherosclerosis, the aim of this study was to evaluate the expression of TGF-ß1 and related markers as well as LOX-1 in irradiated vessels. MATERIALS AND METHODS: To evaluate the expression of galectin-3, Smad 2/3, TGF-ß1, and LOX-1, 20 irradiated and 20 nonirradiated arterial vessels were used for immunohistochemical staining. We semiquantitatively assessed the ratio of stained cells/total number of cells (labeling index). RESULTS: Expression of galectin-3, Smad 2/3, and TGF-ß1 was significantly increased in previously irradiated vessels compared with nonirradiated controls. Furthermore, LOX-1 was expressed significantly higher in irradiated compared with nonirradiated vessels. CONCLUSION: Fibrosis-related proteins like galectin-3, Smad 2/3, and TGF-ß1 are upregulated after radiotherapy and support histopathological changes leading to vasculopathy of the irradiated vessels. Furthermore, postoperative complications in irradiated patients can be explained by increased endothelial dysfunction caused by LOX-1 in previously irradiated patients. Consequently, not only TGF-ß1 but also galectin-3 inhibitors may decrease complications after microsurgical tissue transfer.

Regenerative treatment of peri-implantitis bone defects with a combination of autologous bone and a demineralized xenogenic bone graft: a series of 36 defects.

AIM: As the treatment of peri-implantitis-induced bone loss is still a problem, we studied the regenerative treatment of these defects with a mix of autologous bone and a new type of bone graft substitute (demineralized xenogenic bone graft) including growth factors. MATERIAL AND METHODS: In a prospective manner, 36 cases of peri-implantitis-induced bone loss (depth >4 mm) in 22 patients were followed for 1 year. After resolving the acute infection by local rinsing, granulation tissue was removed. The implants were decontaminated with etching gel and the defects were filled with autologous bone mixed 1:1 with a xenogenic bone graft. The prosthetic reconstructions did not have to be removed. Values of probing depths as well as bone defects were analyzed. RESULTS: The radiologic evaluation of the bone defects after regenerative treatment revealed a mean reduction of 3.5 mm comparing the values from 5.1 mm prior to surgery to 1.6 mm 1 year after treatment. Average reduction of the probing depth was 4 mm. The remaining bone defects were larger than 3 mm in 4 out of 36 implants 1 year after treatment. Probing depths of more than 4 mm were present in seven implants. CONCLUSION: Within the limits of the study, we conclude that for bone defects larger than 4 mm in case of peri-implantitis, this single surgical intervention provided a reliable method to reduce bone defects.

Three-dimensional analysis of changes of the malar-midfacial region after LeFort I osteotomy and maxillary advancement.

AIM: It has been the objective of the present prospective study to assess visible volume changes of the facial soft tissue after LeFort I osteotomy with advancement and to determine the soft-tissue-to-hard-tissue ratios of advancement. PATIENTS AND METHODS: Twenty adult patients (ten female, ten male, mean age 33.9 +/- 14.9 years) received a LeFort I osteotomy with advancement because of a maxillary protrusion. Lateral skull radiographs and optical three-dimensional (3D) scans of the facial surface were assessed preoperatively and 12 months after surgery. The lateral skull radiographs were used to carry out standard linear and angular cephalometric measurements. The pre- and postoperative optical 3D surface scans were registered. A well-defined area in the malar region was used to determine the visible volume changes for each side separately. The mean accommodation vector that transforms the preoperative into the postoperative surface was assessed for each facial half separately. The soft-tissue-to-hard-tissue ratios between the incision superius and the labrale superius, the maximal parasagittal advancement of soft tissue, and the accommodation vectors were calculated. RESULTS: A mean advancement of the incision superius of 5.3 +/- 2.1 mm was accompanied by a volume increase of 5.2 +/- 4.1 cm(3) in the right malar-midfacial region and 4.6 +/- 4.7 cm(3) on the left side, respectively, revealing a symmetrical volume change (p = 0.370). The soft-tissue-to-hard-tissue ratios were 80 +/- 94% for labrale superius and incision superius, 56 +/- 79% (right) and 51 +/- 56% (left) for accommodation vector and incision superius and 97 +/- 79% (right) and 98 +/- 89% (left) for maximal parasagittal advancement of soft tissue and incision superius. DISCUSSION: The determination of volume changes and accompanying accommodation vectors complete the cephalometric analysis during the follow-up of patients undergoing LeFort I osteotomy. The data show that maxillary advancement leads to a more pronounced shifting of the soft tissues in the malar-midfacial area than of the upper lip. The new parameters will help to assess normative soft tissue data based on 3D imaging with a view to an improved three-dimensional prediction of the operative outcome of orthognathic surgery away from the midline.

Comparative study on interactive computer-aided-learning and computer-aided-testing in patient-based dental training in maxillofacial surgery.

AIM: The objective of this comparative study was to validate, through empirical data, the use of interactive, problem-oriented computer-aided-learning (CAL) and computer-aided-testing (CAT) in dental studies by directly comparing these methods with conventional teaching. METHOD: A total of 95 students from the third and fourth clinical semesters participated in an interdisciplinary seminar on oral maxillofacial implantology; 47 of these were taught using conventional teaching methods, while the remaining 48 students were taught using mobiTED, a CAL/CAT-based interactive communication system that can be used patient- and problem-oriented. An examination was given at the end of the course to evaluate student learning. A student's interest/attentiveness, involvement, knowledge gain, and the course attractiveness and quality were evaluated with visual analogue scales (VAS) in a subjective experience protocol. RESULTS: The study group taught using the CAL/CAT-based interactive communication system showed statistically significant better results in the examination, with a median score of 89.2%, while the conventional teaching study group achieved a median score of 76.0%. A VAS-based analysis of subjective experiences also revealed statistically significant differences between the two study groups. CONCLUSION: Use of the CAL/CAT system for interactive, problem-oriented learning in patient-based dental training led to increased levels of attentiveness, of student acceptance and of the perceived attractiveness of the seminar. CAL/CAT-mediated instruction also led to increased communication, with a subsequent improvement in the qualitative and quantitative parameters of knowledge transfer and cognitive knowledge assimilation. Use of CAL/CAT also facilitated the acquisition, appraisal, and understanding of complex medical data.

Dynamic periosteal elevation.

The osteoinductive potential of the periosteum can be stimulated by raising the periosteum using a type of distraction. This was tested and confirmed in an animal experiment in 6 Goettingen minipigs. A titanium mesh was implanted beneath the periosteum and then raised. Bone formed underneath the mesh, with rows of micro-pillars similar to those found after osteodistraction. The main advantages of dynamic periosteal elevation are that invasion and morbidity are minimal. Clinically it might be applicable in craniomaxillofacial surgery, in augmentation before implantation, and in reconstruction of the skull.

Sensor-based laser ablation for tissue specific cutting: an experimental study.

The interaction of laser light and tissue causes measurable phenomenons. These phenomenons can be quantified and used to control the laser drilling within a feedback system. Ten halves of dissected minipig jaws were treated with an Er:YAG laser system controlled via a feedback system. Sensor outputs were recorded and analyzed while osteotomy was done. The relative depth of laser ablation was calculated by 3D computed tomography and evaluated histologically. The detected signals caused by the laser-tissue interaction changed their character in a dramatic way after passing the cortical bone layer. The radiological evaluation of 98 laser-ablated holes in the ten halves showed no deeper ablation beyond the cortical layer (mean values: 97.8%). Histologically, no physical damage to the alveolar nerve bundle was proved. The feedback system to control the laser drilling was working exactly for cortical ablation of the bone based on the evaluation of detected and quantified phenomenon related to the laser-tissue interaction.

Analysis of bone resorption after secondary alveolar cleft bone grafts before and after canine eruption in connection with orthodontic gap closure or prosthodontic treatment.

PURPOSE: We sought to analyze the success rate of secondary alveolar cleft bone grafts before and after canine eruption in connection with orthodontic gap closure or gap opening. PATIENTS AND METHODS: Sixty-eight secondary alveolar cleft bone grafts with iliac crest spongiosa were carried out in 57 patients (mean age, 9 years; age range, 8 to 11 years) with 11 bilateral and 46 unilateral clefts of the lip, alveolus, or palate. Gap closures were carried out after 53 bone grafts (78%), and gap openings with subsequent dental implants were carried out with 15 bone grafts (22%). The parameters acquired radiologically (orthopantomograms) at the time of the surgery and the follow-up examination (mean age, 3 years; age range, 7 months to 9 years) were 1) bone resorption in relation to the interdental height of the alveolar process in the vicinity of the cleft and 2) root growth of the teeth in the vicinity of the cleft. The statistically significant differences (P <.05) were monitored with a software program. Resorption grades I and II (>50% of the interalveolar bone height) were considered to be a success. RESULTS: Resorption was grade I in 69%, grade II in 19%, grade III in 10%, and grade IV in 1% of cases. Thus, the overall success rate was 88%. At the time of the osteoplasty, the root growth of the tooth in the immediate vicinity of the cleft was fully completed in 27 teeth (39%), three-quarters completed in 23 teeth (26.5%), and semicompleted in 18 teeth (33.8%). Twelve teeth (18%) in the vicinity of the cleft (lateral incisors/canine) remained unerupted and displaced after the surgery. It was necessary to expose unerupted teeth surgically to reposition them orthodontically. The resorption losses were significantly lower with gap closures than with gap openings (P <.001). However, bone grafts performed before canine eruption were largely carried out with the objective of orthodontic gap closure, in contrast to the bone grafts that were carried out after canine eruption (P <.02). CONCLUSION: Gap closures provide more favorable results than do gap openings in regard to resorption. Controlled dental eruptions or orthodontic gap closures reduce the graft resorption. The exact timing of surgery proved to be only a secondary consideration.

The endoscopically controlled osteotome sinus floor elevation: a preliminary prospective study.

PURPOSE: It was the aim of the present prospective study to quantify the gain in height of implant sites by endoscopically controlled osteotome sinus floor elevations (ECOSFE) with simultaneous implant placement and to report the number of sinus membrane perforations. MATERIALS AND METHODS: From October 1999 to December 2000, of 92 sinus floor elevations, 18 were carried out endoscopically controlled with an osteotome technique. As augmentation material, beta-tricalcium phosphate (beta-TCP) or autogenous bone was used; 22 implants were placed. RESULTS: The residual height of the alveolar crest in the posterior maxilla was 6.8 +/- 1.6 mm on average. The implant lengths ranged from 10 to 16 mm (mean implant length 12.2 +/- 1.4 mm). They were significantly larger than the residual height of the alveolar crests (P < .0005). Elevation of the sinus floor with an osteotome had to be supported by conventional sinus floor elevation instruments after a mean elevation of 3.0 +/- 0.8 mm to prevent perforation of the sinus membrane. However, 1 perforation occurred, which was repaired with a periosteal patch. At stage 2 surgery, 2 implants were removed because of mobility. Endoscopic control revealed one case in which beta-TCP could be found within the sinus; another case showed areas of polypoid mucosa on the sinus floor. DISCUSSION: With the ECOSFE, perforations of the sinus membrane can be visualized; however, they cannot be avoided. Although this technique is less invasive than the lateral window technique, it cannot be recommended as a standard procedure in the posterior maxilla because of the large amount of additional equipment needed and the technically demanding procedure. CONCLUSION: The use of the ECOSFE should be confined to scientific trials.