Experimental assessment of histological and biological properties of the induced membrane and the membrane formed around the d-PTFE membrane: A pilot study.

BACKGROUND: The aim of this prospective pilot study is to find answers to the following question: In the treatment protocol of open membrane technique defined by Funakoshi, do the histological and biological properties of the tissue that has already covered the graft surface following the removal of the d-PTFE membrane resemble those properties of induced membrane? MATERIAL AND METHODS: 4 male, white Vienna rabbits were used for experiments. Bicortical and 10mm in diameter four bone defects were created on each calvarial bone. 2 rabbits (8 defects) were accepted as group I and other 2 rabbits (8 defects) were accepted as group II. Bone cement was placed into the all-defect in group I. 8 defects were filled with Bi-Oss graft material and covered with d-PTFE membranes in group II. After 8 weeks, sacrifice of the rabbits was performed. In group I, without damaging the formed membrane around it, the bone cement was removed from the defects and the achieved membrane was sent to the pathology department. In group II, the thin film layer that formed under the d-PTFE membrane was sent for histological evaluations. Inflammation, edema, foreign body reaction, synovial-like epithelium existence, thickness, vascularisation (CD31, VEGF), fibrosis were assessed. RESULTS: Inflammation, fibrosis and thickness measurements are significantly different between the groups (P<0,05) and for these parameters, the mean of d-PTFE group (Group II) is significantly higher than the mean of the induced-membrane group (Group I). There isn't any significant difference for other parameters. CONCLUSION: The morphological characteristics of membranes of the two groups were similar. There was a cell-rich, vascularised tissue with fibrous structures; fibroblasts, myofibroblast, and collagen, orientated parallel to the cement.

Histological evaluation of combined platelet-rich fibrin membrane and piezo-incision application in orthodontic tooth movement.

The aim of this study was to evaluate the effect of platelet-rich fibrin (PRF) membrane on tooth movement in comparison with shunt control and piezoelectric surgery. Sixteen White Vienna rabbits were included in the study and divided into two groups. Reciprocal forces (20 g) were applied on the maxillary incisors by an orthodontic appliance. In group 1, PRF membrane was placed sub-periosteally on the distal alveolar bone surface of the right central incisors and the left side was kept as control. In group 2, piezo-incisions 3 mm in depth were performed and combined with PRF membrane on the distal alveolar bone surface of the right central incisors, while the left side was kept as control. All rabbits were euthanized on day 21 and bilateral alveolar bone segments from the distal regions were removed for histological evaluation. Isolated PRF membrane application increased the blood vessel (8.3 ± 1.0; P = 0.026), osteoblast (6 ± 0.8; P = 0.027), and osteoclast (2.3 ± 0.8; P = 0.026) counts significantly compared to shunt control. Combined application of PRF membrane + piezo-incision increased the blood vessel (15.3 ± 0.8; P = 0.027), osteoblast (9.8 ± 1.4; P = 0.026), and osteoclast (3.3 ± 0.8; P = 0.024) counts significantly compared to shunt control. The increases in blood vessel count and osteoblast cell count were more evident in the combined application group (both P = 0.002). PRF membrane application significantly increased bone turnover, and the combined application of PRF membrane + piezo-incision was found to be the best method for increasing bone turnover.

Alveolar Ridge Splitting Versus Autogenous Onlay Bone Grafting: Complications and Implant Survival Rates.

PURPOSE: To compare the complications and implant survival rates of localized alveolar ridge deficiencies in the horizontal dimension reconstructed by alveolar ridge splitting (ARS) or autogenous onlay bone grafting (OBG). MATERIALS AND METHODS: Twenty-eight ARS and 28 OBG were performed. The survival rate of the all included implants was evaluated using the clinical and radiographical evaluation criteria of Misch et al. Temporary exposure of graft, mild infection, temporary paresthesia, and bad split were defined as minor complications; permanent exposure of graft, loss of graft, and permanent paresthesia were defined as major complications. Major and minor complications of ARS and OBG groups were statistically compared. RESULTS: When the minor and major complication rates are considered, there was not any statistically significant difference between OBG (P = 0.099) and ARS (P = 0.241) groups. The satisfactory survival rate of OBG group was 92% and was 100% in the ARS group, and the difference was not statistically significant (P = 0.116). CONCLUSION: When reconstructing vertically sufficient but horizontally insufficient alveolar ridges, ridge splitting technique could shorten the treatment period, decrease postoperative swelling and pain, eliminate the need for a second surgical site, reduce the treatment cost, and ease the patient cooperation to the surgery.

Evaluation of benign paroxysmal positional vertigo following Le Fort I osteotomy.

The Le Fort I osteotomy is widely used to correct dentofacial deformities. Benign paroxysmal positional vertigo (BPPV) is a common vestibular end organ disorder characterized by short, often recurrent episodes of vertigo. Head trauma is one of the known causes of BPPV. During pterygoid osteotomy, the surgical trauma induced by percussion with the surgical mallet and osteotomes can displace otoliths into the semicircular canal, resulting in BPPV. The aim of this study was to evaluate the potential risk of occurrence of BPPV in individuals undergoing Le Fort I osteotomy. Twenty-three patients were included in this study. The Dix-Hallpike manoeuvre, positional tests using electronystagmography, and vestibular evoked myogenic potential (VEMP) tests were performed 1 week before surgery (T0), 1 week after surgery (T1), and 1 month after surgery (T2). The results were compared statistically. BPPV was observed in three patients. Eleven patients had nystagmus at the T1 evaluation and seven at the T2 evaluation. The difference between the T0 and T1 time points was statistically significant (P=0.001). BPPV is a possible complication of Le Fort I osteotomy. Surgeons should be aware of this complication, and the diagnosis of BPPV should be considered in patients who have undergone Le Fort I osteotomy.

Changes in the lower lip soft tissue after bone graft harvesting from the mandibular symphysis.

Following the surgical release of the mentalis muscle, lip incompetence and/or an increase in lower incisor exposure may be seen due to undesirable attachment of the muscle fibres. The aim of this study was to evaluate the extent of lip ptosis, lower incisor exposure, and other soft tissue changes following bone graft harvesting from the mandibular symphysis when the mentalis muscle is reapproximated precisely to its original position. Seventeen consecutive patients who underwent bone graft harvesting from the mandibular symphysis were included in this study. The mentalis muscle was isolated, identified, marked, and reapproximated precisely during the bone harvesting operation. Digital lateral cephalograms obtained preoperatively and at 6 months postoperative were analyzed and compared by paired samples t-test to determine the horizontal and vertical soft tissue changes in the lower lip and chin. Although the soft tissue thickness at soft tissue point B and at soft tissue pogonion had increased significantly at 6 months after chin bone graft harvesting, there were no significant changes in lower incisor exposure or other positional alterations of the lower lip (P<0.05). Precise reattachment of the mentalis muscle in its original position helps to avoid significant vertical positional changes in the lower lip. Increases in soft tissue thickness can be observed following bone graft harvesting from the mandibular symphysis.