Dieter Riediger

Anatomy of the SMAS Revisited

Despite the relevance of the superficial musculoaponeurotic system (SMAS) in facial rejuvenation a clear anatomic definition of the SMAS is still lacking. Therefore, the morphology of the SMAS in 18 cadavers was investigated using different macroscopic and microscopic techniques. The region-specific anatomy of the SMAS is described in the forehead, parotid, zygomatic, and infraorbital regions, the nasolabial fold, and the lower lip. The SMAS is one continuous, organized fibrous network connecting the facial muscles with the dermis. It consists of a three-dimensional scaffold of collagen fibers, elastic fibers, and fat cells. Two different types of SMAS morphology were demonstrated: type 1 SMAS architecture is located lateral to the nasolabial fold with relatively small fibrous septa enclosing lobules of fat cells, whereas type 2 architecture is located medial to the nasolabial fold, where the SMAS consists of a dense collagen–muscle fiber meshwork. Overall, it was demonstrated that different facial regions show specific morphological characteristics, and thus region-specific surgical interventions may be necessary in facial rejuvenation.

The Use of Rapid Prototyping in the Preoperative Planning of Distraction Osteogenesis of the Cranio-Maxillofacial Skeleton

Objective: In cranio-maxillofacial surgery, the principle of distraction osteogenesis (DO) can be used for the reconstruction of the deformed skull, midface complex, mandible and alveolar ridge. Optimal results can only be obtained with accurate planning of the osteotomies and accurate positioning of the distraction device. In addition, the surgical planning must be transferred very precisely to the patient in the operating theater. The clinical accuracy and utility of stereolithographic models in cranio-maxillofacial distraction osteogenesis of the midface, mandible and alveolar ridge will be demonstrated. Materials and Methods: Thirteen patients were treated by DO in the cranio-maxillofacial skeleton. Five patients suffered from midface retrusion and were treated by a LeFort HI advancement. One patient suffered from an aseptic necrosis of the condylar process of the mandible and had a reconstruction of the condylar process by DO. Seven patients underwent an osteotomy of the alveolar ridge of the mandible with subsequent placement of distraction screws and implants because of advanced atrophy of the mandible. Following preoperative acquisition and conversion of the CT-scan data, a model was fabricated by stereolithography (SLA). Simulation of the osteotomies and placement of distraction devices was performed on these models, then surgical guides were used to transfer the surgical planning to the patient in the operating theater. Pre-and postoperative facial photographs and X-rays were compared to evaluate the accuracy of the transfer procedure. Results: In all cases, matching of pre-and postoperative facial photographs and X-rays showed reconstruction of the bony structures to be as accurate as planned on the SLA models. Transfer of the surgical plan by means of custom-made surgical guides was optimal in all cases. Conclusion: Preoperative planning of distraction osteogenesis of the cranio-maxillofacial skeleton and transfer to the operating theater by custom-made surgical guides remains the standard procedure for the planning of complex distraction cases. However, improvements in surgical simulation software and accurate virtual-reality surgery will probably make the use of these models redundant in the future.

A new biphasic osteoinductive calcium composite material with a negative Zeta potential for bone augmentation

The aim of the present study was to analyze the osteogenic potential of a biphasic calcium composite material (BCC) with a negative surface charge for maxillary sinus floor augmentation. In a 61 year old patient, the BCC material was used in a bilateral sinus floor augmentation procedure. Six months postoperative, a bone sample was taken from the augmented regions before two titanium implants were inserted at each side. We analyzed bone neoformation by histology, bone density by computed tomography, and measured the activity of voltage-activated calcium currents of osteoblasts and surface charge effects. Control orthopantomograms were carried out five months after implant insertion. The BCC was biocompatible and replaced by new mineralized bone after being resorbed completely. The material demonstrated a negative surface charge (negative Zeta potential) which was found to be favorable for bone regeneration and osseointegration of dental implants.

Evaluation of computer‐assisted jaw reconstruction with free vascularized fibular flap compared to conventional surgery: a clinical pilot study

The introduction of computer‐assisted surgery was a milestone in functional reconstructions of facial skeletal defects.

Orthodontic fine adjustment after vertical callus distraction of an ankylosed incisor using the floating bone concept

The outcome of vertical callus distraction of a segment of tooth-supporting alveolar process might be functionally and esthetically unsatisfactory because of the unidirectional impact of intraoral distraction devices. In this case report, we describe how, with a shortened consolidation phase and application of the floating bone effect, the tooth-supporting osteotomy segment can be successfully aligned 3 dimensionally. We applied orthodontic force systems that went beyond the unidirectional vector preset by the mechanical properties of the distraction device.

Microsurgical Free Flap Reconstructions of Head and Neck Region in 406 Cases: A 13-Year Experience

PURPOSE The reconstruction of extended soft tissue and bony defects in the maxillofacial region with microsurgical flaps is considered to be the therapy of first choice. The aim of this retrospective study was to detect different influencing factors concerning flap survival. MATERIALS AND METHODS We examined the data of 406 patient cases (121 female and 285 male cases; mean age, 57 years) undergoing reconstruction with a microsurgical flap in our facility between 1998 and 2010. In these cases 326 soft tissue flaps (radial forearm flap, scapula flap, latissimus dorsi flap, anterolateral thigh flap, lateral arm flap, and jejunum flap) and 80 bony flaps (fibula flap and deep circumflex iliac artery flap) were examined. Evaluated parameters were, among others, the timing of reconstruction, defect localization, and recipient vessels used (external vs internal jugular system), as well as anticoagulative management. We statistically analyzed data by means of a χ(2) test, taking account of the odds ratio with P < .05, which was deemed significant. RESULTS The overall flap survival rate was approximately 92%, without any gender- or age-specific differences. Primary reconstructions proceeded distinctly more successfully than secondary reconstructions (P < .01). Likewise, the defect localization exerted a significant effect on the survival rate (P = .01), with a more caudal localization affecting flap survival positively. Finally, neither the anticoagulation regimen nor the choice of recipient vein system exercised an influence on the survival rate. CONCLUSIONS Microsurgical tissue transfer is a convenient and reliable method in maxillofacial surgery, provided that one is aware of the determining factors for success.

Comparison of donor-site engraftment after harvesting vascularized and nonvascularized iliac bone grafts.

PURPOSE The objective of this study is to characterize the donor-site morbidity after harvesting of nonvascularized and vascularized iliac bone grafts. PATIENTS AND METHODS Clinical data of 353 patients were collected for analysis. In addition, a questionnaire was sent to all patients asking about their perceptions of different parameters. In an individual age-matched layout, we compared 34 patients with nonvascularized iliac bone grafts with 34 patients with vascularized iliac bone grafts. RESULTS Transplantation of vascularized bone grafts has been increasingly performed at our institution. The mean age was 41.5 years in the nonvascularized group and 48.6 years in the vascularized group. The main reason for the bony defect in the vascularized group was malignancy. The majority of postoperative functional problems were observed in obese patients. No patient had serious or long-term complications at the donor site. The amount of bone graft taken affected postoperative sensitivity disturbance and caused postoperative functional problems and pain. CONCLUSIONS We conclude that the iliac crest is a suitable site for harvesting both vascularized and nonvascularized bone grafts measuring up to 10 x 3 cm. For larger defects that require a larger bone graft, a vascularized bone graft is more suitable with a better predictable healing capability. No significant differences in donor-site morbidity were found between the vascularized and nonvascularized bone grafts if a similar amount of bone was taken for transplant.

Three-Dimensional Evaluation of Postoperative Swelling After Third Molar Surgery Using 2 Different Cooling Therapy Methods: A Randomized Observer-Blind Prospective Study

PURPOSE In most cases, the removal of third molars leads to a significant degree of tissue trauma, resulting in common postoperative symptoms and signs of pain, facial swelling, dysfunction, and limited mouth opening (trismus). The beneficial effects of cold treatment on postoperative swelling, edema, pain, and inflammation, as well as the reduction in bleeding and hematomas, have been described. The aim of the present study was to compare postoperative cooling therapy using cooling compresses with that using the water-circulating cooling face mask by Hilotherm. We recorded the beneficial effects on postoperative facial swelling, pain, trismus, and neurologic complaints. PATIENTS AND METHODS A total of 30 patients were scheduled to undergo third molar surgery and were divided randomly into 2 groups for treatment with either the Hilotherm or conventional cooling with cooling compresses. Cooling was performed one time for 45 minutes immediately after surgery. Facial swelling was quantified using a 3-dimensional optical scanning technique. The pain and neurologic scores and the degree of mouth opening were observed for each patient. RESULTS Patients receiving cooling therapy using Hilotherm demonstrated less facial swelling, less pain, a tendency toward fewer neurologic complaints, and were more satisfied than the patients who had received conventional cooling. CONCLUSION The results of our study have shown that the Hilotherm is more efficient for managing postoperative swelling and pain after the removal of third molars than conventional cooling using compresses.

Impact of rhBMP-2 on regeneration of buccal alveolar defects during the osseointegration of transgingival inserted implants

OBJECTIVE New approaches to enhance vertical bone regeneration in clinically relevant implant models are needed. Therefore, we analyzed the impact of recombinant human bone morphogenic protein 2 (rhBMP-2) on the healing of large buccal alveolar defects during osseointegration of transgingivally inserted implants. STUDY DESIGN Twenty-four dental implants were inserted transgingivally in the mandibles of 6 labrador/golden retriever cross-bred dogs. Before implantation, a standardized buccal bone defect was created and refilled with either calcium phosphate as a carrier containing rhBMP-2 or calcium phosphate alone. Either ceramic abutments that enabled immediate implant loading or healing distance collars to prevent loading were mounted. Sixteen weeks after intervention, bone implant units were analyzed by radiofrequency analysis and histomorphometry. RESULTS In total, 14 implants (58.3%) were available for further analysis. The mean depth of the bone defects, the gain of regenerated bone, the vertical osseointegration of the implants, and the bone-to-implant contact in the newly formed bone were slightly greater in the rhBMP-2-containing samples. In contrast, the osseointegration in the preexisting bone was even superior within the non-rhBMP-2-treated specimen. However no differences were statistically significant. CONCLUSIONS When rhBMP-2-conducted bone regeneration was compared with control samples, no significant differences of newly formed bone were found at the bone-implant interface. The amounts of rhBMP-2 applied do not seem suitable to enhance implant osseointegration in large buccal defects.

Quantitative computed tomography bone mineral density measurements in irradiated and non‐irradiated minipig alveolar bone: an experimental study

OBJECTIVE The objective of this study was to analyse the effect of irradiation on bone mineral density (BMD). MATERIALS AND METHODS All maxillary and mandibular pre-molars and molars of six minipigs were extracted. After a 3-month healing period, the maxilla and mandibles of three minipigs received three irradiation exposures at a total dose of 24 Gy. At 3 months after irradiation, quantitative computed tomography (QCT) was performed. As a reference, a calibration bone phantom with pre-determined BMD was attached to the head of the minipigs. The QCT data were imported into a software program to calculate the BMD of the alveolar bone and the calibration bone phantom. In order to compare BMD values of individual minipigs, the so-called bone mineral density quotient (BMDQ) was created, dividing the BMD value of the alveolar bone by the BMD value of the calibration bone phantom. RESULTS Mean BMDQ values appeared to be higher in irradiated than in non-irradiated minipigs. However, the difference was not significant. In both irradiated and non-irradiated minipigs, the average mandibular BMDQ values were statistically significantly higher than the average maxillary BMDQ values (P=0.003). The P-values of the Student t-test, determining the irradiation effect, were 0.11 for maxillary, 0.14 for mandibular, and 0.07 for overall peri-implant BMDQ. P-values of the non-parametric Mann-Whitney test were all 0.05. CONCLUSION It could be concluded that, 3 months after irradiation, the BMD of irradiated alveolar minipig bone was increased, when compared with non-irradiated alveolar minipig bone. However, the increase was not statistically significant.