A laboratory study comparing the effect of ridge exposure using tissue punch versus mucoperiosteal flap on the formation of the implant-epithelial junction.

OBJECTIVE: The objective of the present study was to clarify the influence of the incision design at the time of implant placement on the consolidation of the implanto-epithelial junction. STUDY DESIGN: Twelve minipigs were chosen for the study. Four weeks after premolar extraction in the maxilla, 4 BEGO Semados RI implants were inserted in each quadrant. Using a split-mouth design, the alveolar crest was exposed by a punch ("flapless surgery") on one side and by a crestal incision ("flap surgery") on the other side. Biopsies were obtained from the peri-implant soft tissue at weeks 1, 2, 4, and 12 postinsertion, respectively, and analyzed for the expression of integrin α(6)ß(4) chain ß(4) (ITGB4) and laminin 5 γ(2) chain (lamc2), 2 important marker molecules for the formation of the implanto-epithelial junction. RESULTS: Following exposure of the alveolar crest by the punch technique, a significantly higher expression of ITGB4 was found at the 2- (P = .009), 4- (P = .001), and 12-week (P = .005) follow-up. Furthermore, the expression of lamc2 was significantly higher following punch exposure after 1 (P = .033), 2 (P = .041), 3 (P = .004), and 12 weeks (P = .002) of transmucosal implant healing. CONCLUSIONS: The data of the present study indicate that flapless placement improved the formation of a sufficient implanto-epithelial junction.

Correlation between clinical findings and CT-measured displacement in patients with fractures of the zygomaticomaxillary complex.

BACKGROUND: This prospective clinical study aimed to analyse the influence of displacement on duration and severity of symptoms of fractures of the zygomaticomaxillary complex. METHODS: 47 patients, who received surgical treatment of zygomaticomaxillary complex fractures at the Department of Oral and Maxillofacial Surgery/Plastic Surgery, University Hospital Jena were examined preoperatively, 1, 3 and 10 days as well as 6 months post-operation for ophthalmologic, occlusal and neurosensory changes. RESULTS: Preoperatively, periorbital haematoma and ooedema were present in 76.6% and 31.9% of the patients, which increased until day 1 post-op and decreased until the end of hospital stay. Preoperative diplopia was present in 83.0% of the patients and resolved postoperatively in all but 3 cases, in whom it persisted until end of the study. Occlusal disturbances and limited mouth opening were present in 21.3% of the patients and resolved by end of the study in all but 2 cases. Neither ophthalmologic nor occlusal changes correlated with the degree of displacement. Postoperatively no significant differences were detectable among the groups. In 44.8% of the patients neurosensory disturbances persisted until end of the follow-up. In the non-displaced fracture group none of the patients suffered from neurosensory disturbances at the 6-month follow-up. CONCLUSION: Although the degree of displacement has a significant impact on the incidence of sensory disturbances preoperatively, postoperatively no differences were observed between displaced and non-displaced fractures.

Analysis of inflammatory periimplant lesions during a 12-week period of undisturbed plaque accumulation--a comparison between flapless and flap surgery in the mini-pig.

This study's aim was to clarify the influence of soft tissue management on the development of periimplant infection. Four weeks after removal of all maxillary premolars in 12 mini-pigs, four BEGO Semados RI implants were inserted in each maxillary quadrant. Employing a split-mouth design, one quadrant was randomized to flapless insertion while the contralateral side was chosen for flap surgery. Following 1, 2, 4 and 12 weeks of transmucosal implant, healing biopsies were retrieved from the periimplant soft tissue and subjected to further analysis. Histomorphometrically, a significant reduction of transmigration of polymorphonuclear neutrophils (week 1, p = 0.007; week 2, p = 0.021; week 4, p = 0.023; week 12, p = 0.013) as well as the density of the subepithelial inflammatory infiltrates (week 1, p = 0.007; week 2, p = 0.046; week 4, p = 0.003; week 12, p = 0.032) was verified following flapless surgery. Quantification of inducible nitric oxide synthase showed significantly reduced expression in the flapless group 2 (p = 0.027), 4 (p = 0.005) and 12 (p = 0.004) weeks post-insertion. Analysis of CD31 and collagen I immunostained sections revealed more regular capillary distribution as well as higher vessel and collagen density in the flapless group. The data of the present study indicate that flapless placement reduces the incidence of inflammatory periimplant soft tissue lesions during a 12-week period. Considering the beneficial effects of flapless placement on early soft tissue healing and stability, the technique might be preferred in case of an uncomplicated locoregional anatomy with sufficient hard and soft tissue. However, this positive effect might disappear after manipulation of the implant and soft tissue during impression taking or try in of the prosthodontic supraconstruction.

Histomorphometric and whole-genome expression analysis of peri-implant soft tissue healing: a comparison of flapless and open surgery.

PURPOSE: The structure of peri-implant soft tissue that is regenerated after flapless and flap surgery has been shown to differ. However, its underlying mechanisms are relatively unknown. The present study sought to identify differences in the inflammatory cell infiltration and expression of gene transcripts during transmucosal healing between the two approaches with two different implant designs. MATERIALS AND METHODS: All mandibular premolars were removed from 12 minipigs. One month later, four implants (two NobelReplace Tapered Groovy and two NobelPerfect Groovy, Nobel Biocare) were placed in each quadrant. One quadrant was randomized to flapless insertion, while the other was chosen for flap surgery in each animal. Following 1, 2, 4, and 12 weeks of transmucosal implant healing, biopsy specimens were retrieved from the peri-implant soft tissue according to a standardized procedure to avoid crossover effects. Samples were subjected to a leukocyte count and a gene expression analysis. RESULTS: When the flapless placement technique was used, leukocyte influx in the peri-implant soft tissue was significantly smaller compared to open surgery for both implant designs. Gene expression analysis revealed significant overexpression of molecules associated with detoxification and reepithelialization in the flapless group. In contrast, myofibroblast-associated gene transcripts were significantly enriched in the flap surgery group. CONCLUSIONS: The present data indicate perpetuation of inflammatory reactions as well as increased fibrotic scar tissue deposition in the peri-implant area following implant placement by the flap approach. Flapless implant insertion results in less inflammation and early reepithelialization, providing the potential for the formation of a fully functioning as well as esthetically preferable peri-implant soft tissue collar.

Comparative analysis of osseointegration of titanium implants with acid-etched surfaces and different biomolecular coatings.

OBJECTIVES: An increasing trend toward implantation in complex cases, as well as early loading, is beginning to emerge in dental implantology. Long-term stability of the inserted implants greatly depends on the osseointegration process. Although there are numerous current research efforts aimed at functionalizing implant surfaces, no single factor has proved to be beneficial for osseointegration. The aim of the present study was to investigate whether a combination coating of collagen I and different cytokines enhances osseointegration. STUDY DESIGN: Commercially available titanium implants (Semados S; Bego Implant Systems, Bremen, Germany) were coated with collagen I and either 1 µg or 10 µg of bone morphogenic protein 2, vascular endothelial growth factor 165, basic fibroblast growth factor 2, or a combination of all 3 factors by using the biodot method. Experimental implants (1 pure titanium, 1 collagen I coated and 8 different cytokine coatings) were inserted in the frontal skulls of 9 domestic pigs (10 implants in each animal). Implants were retrieved 2, 4, and 8 weeks after surgery. Samples were subjected to microradiography and immunohistochemistry for collagen I and osteocalcin. RESULTS: Implant coating with collagen I significantly increased collagen I (P = .028) and osteocalcin (P = .037) expression at the 2-week follow-up and osteocalcin expression (P = .042) as well as the bone implant contact (P = .049) at the 4-week follow-up compared with pure titanium. Additional cytokine coating had no significant effect compared with the collagen I coating. CONCLUSIONS: It can be concluded that collagen I coating enhances osseointegration. However, additional growth factor application has no further beneficial effects.

Transgenic overexpression of VEGF164 enhances topical neoangiogenesis without detectable local or systemic side effects.

Various routes of administration have been used for delivering angiogenic genes to ischemic regions. A previous, preliminary study proved the feasibility of in vivo neoangiogenesis stimulation by ex vivo vascular endothelial growth factor (VEGF)-transduced fibroblasts. Taking this into account our aim was to validate therapeutical efficacy of this approach and to investigate potential side effects.Allogenous collagen membranes were implanted at the groin in 30 Wistar rats. Either untransfected, GFP- or VEGF-transfected fibroblasts were injected at the implantation site at the time of surgery. Biopsies were obtained from the membranes, surrounding connective tissue, brain, lung, liver and blood at days 7 and 14 post operation. Samples were investigated for distribution of GFP-positive cells, VEGF-expression, and vessel architecture.Transgenic fibroblasts remained at the site of injection and showed no trafficking into blood or organs. VEGF-overexpression was detectable and resulted in enhanced neovascularization of the membranes. Vessel pathologies were neither detectable in the membrane nor the surrounding tissue.

Influence of insertion protocol and implant shoulder design on inflammatory infiltration and gene expression in peri-implant soft tissue during nonsubmerged dental implant healing.

OBJECTIVE: This study aimed at elucidating the influence of insertion protocol and implant shoulder design on peri-implant soft tissue healing. STUDY DESIGN: One month after removal of all maxillary premolars in 12 minipigs, 4 implants were installed in each quadrant. According to implant shoulder design, 3 groups were established: 1) rough, 0.4 mm; 2) smooth, 3 mm; and 3) smooth, 0.4 mm. One quadrant was randomized to flapless insertion, and the other was used for flap surgery in each animal. Mucosa biopsies were retrieved 1, 2, 4, and 12 weeks after surgery and subjected to a leukocyte count as well as pangenomic gene expression analysis. RESULTS: Flapless surgery shortened the period of postsurgical inflammation as shown by the leukocyte count and induced early constructive remodeling as indicated by the microarray. Regarding design of the implant shoulder, leukocyte count values were lowest for group 3. CONCLUSION: Flapless surgery in combination with group 3 implants appears to enhance peri-implant soft tissue healing.

Multivariate analysis of the influence of patient-, tumor-, and management-related factors on the outcome of surgical therapy for facial basal-cell carcinoma.

PURPOSE: This retrospective, case-control study aimed at evaluating the influence of patient-, tumor-, and management-related factors on the outcome of surgical therapy for facial basal-cell carcinoma (BCC) employing a multivariate analysis. METHODS: One hundred one patients who underwent ablative surgery for BCC of the face at the Department of Oral and Maxillofacial Surgery/ Plastic Surgery, University Hospital Jena, between April 2005 and January 2009, were analyzed. Patients' charts were screened for anamnestic features as well as management- and follow-up-related details. Standardized photographs were subjected to an esthetic evaluation. Logistic regression was used to identify factors associated with postsurgical wound healing disorders, recurrence, and esthetic impairment. RESULTS: Following surgical BCC treatment, age and tumor location in the area of the eyes, nose, lips, and ears were independent predictors of wound healing disorders. Tumor location in the area of the eyes, nose, lips, and ears, subtype and class were independent predictors of recurrence. Female gender and location in the area of the eyes, nose, lips, and ears were independent predictors of esthetic impairment. Micrographic surgery and distant reconstruction technique were management-related predictors of wound healing disorders and esthetic outcome, respectively. CONCLUSIONS: The identified negative predictors of treatment outcome should be included in the informed consent to objectify the patient's preoperative expectations.

Late changes in cutaneous gene expression patterns after adjuvant treatment of oral squamous cell carcinoma (OSCC) by radiation therapy.

OBJECTIVE: The objective of this study was to investigate radiation-induced late changes in cutaneous gene expression using a microarray platform and quantitative, real-time, reverse-transcriptase polymerase chain reaction (RT-PCR) validation. STUDY DESIGN: Paired irradiated and nonirradiated skin biopsies were obtained from 19 patients with a history of oral squamous cell carcinoma (OSCC) treated by surgery and adjuvant radiotherapy at the time of secondary corrective surgery. Topic-defined PIQOR (Parallel Identification and Quantification of RNAs) skin microarrays were used to compare gene expression profiles between control and irradiated skin sample in 8 patients. The data were validated for matrixmetalloproteinase (MMP)-1 and tissue-inhibitor of matrixmetalloproteinase (TIMP)-1 by RT-PCR for all patients. RESULTS: Irradiation markedly enhanced the expression of molecules associated with the transforming growth factor (TGF)-beta(1) signaling pathway, blood vessel development, as well as extracellular matrix constitution and turn-over. CONCLUSIONS: Our data suggest that radiation-induced late changes in cutaneous gene expression mainly affect molecules related to extracellular matrix (ECM)-constitution and-remodeling.

Angiogenic gene-modified fibroblasts for induction of localized angiogenesis.

BACKGROUND: Induction of localized angiogenesis is of particular interest in the field of plastic surgery. Topical application of recombined vascular endothelial growth factor (VEGF) shows only little effect on graft healing. This study describes the establishment of an ex vivo engineered VEGF slow release system based on autogenous fibroblasts. METHODS: Primary fibroblasts were subjected to nucleofection and analyzed for transgene expression 1, 2, 3, 4, 7, and 9 d post-nucleofection using FACS. VEGF transgene expression was measured in cell culture supernatants using ELISA. Transgenic protein functionality was examined in the HUVEC proliferation assay. The effect of VEGF transgene expression on the neovascularization of a collagen membrane was investigated in a rat model. RESULTS: Primary fibroblasts were nucleofected with an efficiency of 63.331% and transgene expression showed persistence up to day 9 post-nucleofection. VEGF was expressed in the cell culture up to day 14 with an expression peak at day 3. The cytokine was functionally active. VEGF transgene was released in vivo at day 7 and enhanced neovascularization of a collagen membrane. CONCLUSIONS: Nucleofection is the ideal nonviral tool to engineer transgenic primary fibroblasts for transplantation purpose in an ex vivo gene therapeutic approach. Such ex vivo gene therapy is safe and efficient. Its suitability should be further evaluated in more complex flap models, for example the transfer of a free myocutaneous gracilis flap in the pre-irradiated neck region.

Combined treatment protocol for temporomandibular joint ankylosis: an observation on a clinical problem.

Various techniques have been defined for the treatment of temporomandibular joint ankylosis. However, in some cases, they are unsuccessful, resulting in continuing pain and limitation in interincisal distance after surgery. This report describes the case of a 32-year-old woman who has been experiencing temporomandibular joint ankylosis for a period of 8 years. Several surgical procedures failed. A treatment approach combining auricular cartilage interposition arthroplasty with postsurgical functional treatment using a spring activator is presented. Using this approach, pain settled and maximal interincisal distance was raised from 22 to 35 mm after 4 months and remained stable for further 10 months.

Remission with Imatinib mesylate treatment in a patient with initially unresectable dermatofibrosarcoma protuberans--a case report.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a rare, malignant dermal mesenchymal neoplasm characterized by a slow, infiltrative growth. These neoplasms have a high tendency to recur locally after surgical excision. However, metastasizing cases are exceedingly rare. Cytogenetically, DFSP is characterized by a t(17;22)(22;q13) aberration with fusion of the COL1A1 gene on chromosome 17 with the PDGFB gene on chromosome 22. Here, we report on a successful treatment of a patient with a targeted therapy using the tyrosine kinase inhibitor Imatinib mesylate in neoadjuvant intention. PATIENTS AND METHODS: A patient with recurrent and initially unresectable but non-metastatic DFSP of the scalp received Imatinib over 3 months with increasing dosage from 400 mg/day to 800 mg/day orally. Due to the location of the DFSP in our patient, we intended to decrease tumor size preoperatively to allow complete surgical resection. Response to therapy was assessed by computed tomography. RESULTS: Preoperative treatment with Imatinib resulted in decrease of tumor size by over 60% in the greatest dimension during 3 months of therapy, enabling the complete resection of the DFSP by radical surgery with achieving an acceptable cosmetic result. Surgery was followed by adjuvant Imatinib therapy over 6 months. CONCLUSIONS: Imatinib mesylate is effective in neoadjuvant treatment of primary unresectable dermatofibrosarcoma protuberans and can be considered as a useful option in the therapy regimen.

Bone regeneration in osseous defects-application of particulated human and bovine materials.

OBJECTIVE: Different bone substitute materials are used to manage the challenge of local bone loss subsequent to craniofacial reconstructive surgery. In this animal study we examined the de novo bone formation in bone defects after insertion of Puros Allograft of human origin or Navigraft of bovine origin, and compared the regenerative potential of each material to that of autogenous bone. STUDY DESIGN: Using the adult domestic pig as the animal model, we created identical bone defects in the frontal skull and filled them with the different test materials using random assignment. A defined number of defects remained unfilled to serve as control. We performed microradiographic, histologic, and polychromatic fluorescence labeling evaluations of the bone specimens at 1, 8, and 12 weeks after the procedure. RESULTS: Both of the materials that we tested allowed for complete bony consolidation of the defects by the end of the test period. After 12 weeks, the microradiographically measured mineralization rate was 5% to 10% lower than the mineralization rate of autogenous bone grafts. CONCLUSION: Both Puros Allograft and Navigraft met the clinical requirements for bone substitutes, promoting predictable regeneration of the bony defects.

Sinus floor elevation using autogenous bone or bone substitute combined with platelet-rich plasma.

OBJECTIVE: Sinus augmentation is a common approach for patients with severe alveolar ridge atrophy. However, autogenous bone sometimes results in donor site complications. Bone substitutes with platelet-rich plasma (PRP) promote early bone formation with autogenous bone. Use of PRP on autogenous bone and a bovine bone substitute were investigated in this split-mouth animal study. STUDY DESIGN: Premolars were extracted from minipigs. Each animal received sinus augmentation using a lateral approach with simultaneous insertion of 3 implants in each site. Groups were randomized using autogenous bone alone and combined with PRP or a bovine hydroxyapatite alone in combination with PRP. RESULTS: Microradiographic findings in the autogenous group did not show significantly different rates by using autogenous bone alone or combined with PRP. Using the bovine hydroxyapatite as augmentation material only at 8 weeks, a nonsignificant effect in the PRP group could be seen. At all other observation periods, no significant influence was observed. CONCLUSION: No significant influence of PRP was found.

Interdisciplinary treatment and ophthalmological findings in Parry-Romberg syndrome.

Parry-Romberg syndrome is a rare pathologic process, characterized by progressive hemifacial atrophy. A case of Parry-Romberg syndrome with ocular involvement is reported. A 27-year-old male patient with Parry-Romberg syndrome was interdisciplinary investigated and treated. For reconstruction of hemifacial soft tissues a free vascular parascapular graft was performed. Opthalmological findings included an evident enophthalmos and an eyelid lag with keratopathy and epiphora. Furthermore pupillary disturbances and endothelial precipitates were detectable. Complete fundus examination showed a unilateral optic disc swelling, central vitreous opacities and peripheral pigmentary disturbances. In the presented case of Parry-Romberg syndrome a rare association to ophthalmological involvement could be found. Beside the enophthalmos and eyelid alterations, also a panuveitis with papillitis should be treated by steroid therapy.

Changes of mineralization of free autogenous bone grafts used for sinus floor elevation.

For augmentations before implant placement in areas of minor bone quantity, autogenous bone is considered the reference to all bone substitutes used alternatively. Autogenous bone transplants originate from various donor areas and can be prepared in different ways before augmentation. They may either be used as block grafts or may be milled to granules that can be used solitarily or in combination with a bone substitute. In a prospective study, 61 patients of the Maxillofacial Surgery Department of our University receiving two-stage sinus floor elevation because of insufficient bone supply were randomly selected. At first-stage surgery, the local augmentation procedure, monocortical probes were obtained on the site of bone harvesting. At second-stage surgery, the implant insertion 6 months after the elevation procedure, bone cores were harvested in the areas of implant placement. Donor regions were the following three areas: the posterior (N=28) and anterior pelvic region (N=15) and the chin region (N=18). The implanted bone in all three groups was particulated to granules of 2-3 mm(2) using a bone mill. All biopsies were analyzed by means of microradiography. The anterior pelvic bone grafts showed a mineralized tissue grade of 35.1+/-7.6% before milling and augmentation. The posterior pelvic bone grafts exhibited a mineralization of 30.7+/-9.5% and the chin bone grafts 74.6+/-8.6%. At second-stage surgery after 6 months, the mineralization was 36.1+/-7.59% in the areas where bone grafts from the anterior pelvic crest were used. Probes harvested from sites with posterior pelvic bone augmentations showed a mineralization rate of 34.5+/-6.5%, and sites were chin bone grafts were applied expressed a mineralization of 54+/-8.6% (P=0.003 compared with the pre-operative value). The comparison of the microradiographical results demonstrated significant differences in the mineralization grades depending on the origin of the graft. The origin of the grafts and their remodeling influenced the mineralization rates found at 6 months. How these data may influence the long-term clinical outcome considering implant survival and bone resorption has to be examined in further long-term studies.

Expression of bone matrix proteins during the osseus healing of topical conditioned implants: an experimental study.

OBJECTIVES: Osseointegration of implants depends on time and local bone conditions regarding quality and quantity. This led to the bone classification by Lekholm et al. The aim of the present study was to follow the expression of bone matrix proteins during the phase of osseointegration after conditioning of the bone bed by means of immunohistochemistry. METHODS: In the porcine frontal skull, implant beds of identical size were created. Before placement of the implants (Ankylos 4 x 3.5 mm), the implant beds were conditioned using bone condensation (cond), an osteoinductive collagen (Co) and platelet-rich plasma (PRP). These conditioning methods were compared with standard procedure. The animals were sacrificed after 2, 4 and 8 weeks. The specimens were then analyzed by light microcopy and immunohistochemistry for expression of bone morphogenic proteins (BMP)2, procollagen I and osteocalcin (OC). RESULTS: Light microscopy revealed an initial effect of condensation and the bovine collagen at 2 weeks in comparison with the standard group. The PRP did not achieve a significant effect. At 8 weeks, the results of the standard, bone condensation and the bovine collagen group had aligned. The PRP group showed a significantly lower bone-implant contact (BIC) (P=0.003) compared with the standard group. BMP2 expression was significantly higher in all evaluated test groups at 4 and 8 weeks, as well as at 2 weeks in the condensation group. The procollagen I expression at 2 weeks was significantly increased for PRP and lower in the collagen and condensation group compared with standard procedure. Values for 4 and 8 weeks were slightly higher than in the standard group. No significant differences were obvious in the OC group at any time. CONCLUSIONS: During the initial healing phase, an effect of the evaluated methods of topical bone conditioning can be demonstrated by differences in the expression of BMP2 and procollagen I. These findings had leveled at 8 weeks and were, in contrast, not detectable in the expression of OC or by means of light microscopy.

Lack of beneficial effects of platelet-rich plasma on sinus augmentation using a fluorohydroxyapatite or autogenous bone: an explorative study.

BACKGROUND: Maxillary sinus augmentation is frequently necessary before placement of dental implants in the posterior maxilla. Besides autogenous bone graft, various bone substitutes have been used, with favourable results. Although platelet-rich plasma (PRP) has been used in the field of oral and maxillofacial surgery for years, its beneficial effects on osseous regeneration still remain unclear. The aim of this study was to evaluate the short and long time effects of PRP on single-stage sinus augmentation using autogenous bone or a fluorohydroxyapatite (Algipore) in a randomized prospective animal study. METHODS: After extraction of maxillary premolars of sixteen minipigs, the wounds were allowed to heal for 2 months. Then, sinus augmentations were performed bilaterally using one of the following grafting materials: autogenous bone and Algipore with or without PRP. Three dental implants (Ankylos) were installed in each sinus simultaneously. Four animals were euthanized at each period of observation (1, 2, 8 and 12 months). Implant-bearing specimens were sectioned bucco-lingually along the long axis of implants and undecalcified ground specimens were prepared. The bone-implant-contact (BIC) was measured by means of microradiographic examination. For histological evaluation, the specimens were stained with toluidin blue, and the percentage of the newly formed bone and the remaining bone substitute were evaluated. RESULTS: The grafting materials chosen showed increasing levels of BIC and newly formed bone throughout the period of observation in both PRP and non-PRP groups. Adding PRP resulted in lower BIC and newly formed bone compared with autogenous bone grafts or Algipore alone. However, a statistical significance was not found. The percentages of the remaining bone substitute in both the PRP and non-PRP groups were closely comparable in all observation periods. CONCLUSIONS: The application of PRP could not reveal significant beneficial effects on the BIC, the percentage of the newly formed bone and the remaining bone substitute in this study.

Influence of platelet-rich plasma on a bioglass and autogenous bone in sinus augmentation. An explorative study.

Platelet-rich plasma (PRP) has been introduced to the field of oral and maxillofacial surgery for a decade, but its beneficial effects on maxillary sinus augmentation remain unclear. The aim of this study was to evaluate the short- and long-term effects of PRP on osseointegration following single-stage sinus augmentation in a randomized prospective animal study. The maxillary premolars of 24 minipigs were extracted bilaterally and allowed to heal for 2 months. Consecutively all animals underwent bilateral sinus floor elevation using autogenous bone, Biogran as well as a combination of the materials with PRP. Three dental implants (Ankylos, Dentsply Co., Mannheim, Germany) were installed in each sinus simultaneously. Four animals were sacrificed at each period of observation (1, 2, 8 and 12 months). Microradiographic images of the specimens were made for quantitative evaluation of the bone-implant contact (BIC) and light microscopic images were made for qualitative analysis. An increment of the BIC during the observation time could be seen over the observation time in all groups. Autogenous bone exhibited a level of BIC from 25.1 +/- 9.96% at 1 month to 55.1 +/- 13.10% at 12 months; on adding PRP, the BIC ranged from 28.4 +/- 4.64% to 52.5 +/- 17.06%. Biogran with and without PRP led to BIC levels from 16.3 +/- 4.64% to 37.6 +/- 16.40% and 21.7 +/- 4.33% to 46.6 +/- 19.37%, respectively. The results of this study did not show a significantly positive effect of PRP on the BIC following sinus augmentation in both groups.

Acceleration of de novo bone formation following application of autogenous bone to particulated anorganic bovine material in vivo.

OBJECTIVE: This prospective animal study examined the de novo bone formation following application of deproteinized bovine bone matrix (DBBM) with or without autogenous bone (AB) to osseous defects. STUDY DESIGN: Defects of defined size were created in the frontal skull of domestic pigs and filled with DBBM alone (group A) and DBBM+25%AB (group B). De novo bone formation was analyzed qualitatively and quantitatively at 9 different times (0.5, 1, 2, 3, 4, 6, 8, 12, 26 weeks) by means of light microscopy, microradiography, and statistical analysis. RESULTS: Histological analysis indicated sufficient osseointegration of DBBM in both groups. Microradiography demonstrated a significant increase of bone formation in group B after 6 weeks (P = .0159) and 8 weeks (P = .0317). CONCLUSION: The addition of 25%AB to DBBM results in accelerated de novo bone formation in osseous defects. This effect is likely caused by osteoinductive properties of cellular elements transplanted with the autogenous bone.