Tamás Huszár

Effect of Platelet-Rich Plasma on the Healing of Intrabony Defects Treated With an Anorganic Bovine Bone Mineral: A Pilot Study

BACKGROUND Periodontal therapy using the combination of platelet-rich plasma (PRP) and different grafting materials has been suggested as a modality to enhance the outcome of regenerative surgery. In most clinical studies, a barrier membrane was used to cover the defects, and thus, the effects of PRP may have been masked by the effects of the barrier. The data from controlled clinical studies evaluating the effect of regenerative therapy using various grafting materials with or without PRP are still limited. The purpose of this study was to clinically compare the healing of intrabony defects treated with either a combination of an anorganic bovine bone mineral (ABBM) and PRP to those obtained with ABBM alone. METHODS Thirty patients with advanced chronic periodontal disease and displaying one intrabony defect were randomly treated with PRP + ABBM or ABBM alone. The following clinical parameters were evaluated at baseline and 1 year after treatment: plaque index (PI), gingival index (GI), bleeding on probing (BOP), probing depth (PD), gingival recession (GR), and clinical attachment level (CAL). The primary outcome variable was CAL. RESULTS No statistical significant differences in any of the investigated parameters between the two groups were observed at baseline. Healing was uneventful in all patients. In the PRP + ABBM group, mean PD decreased from 8.6 +/- 1.8 mm to 3.4 +/- 1.4 mm (P <0.001) and mean CAL changed from 9.9 +/- 1.7 mm to 5.3 +/- 1.8 mm (P <0.001). In the ABBM group, mean PD decreased from 8.5 +/- 2.0 mm to 3.2 +/- 1.3 mm (P <0.001) and mean CAL changed from 9.6 +/- 1.9 mm to 4.9 +/- 1.5 mm (P <0.001). CAL gains >or=3 mm were measured in 80% (12 of 15 defects) of cases treated with PRP + ABBM and in 87% (13 of 15 defects) of cases treated with ABBM alone. No statistically significant differences in any of the investigated parameters were observed between the two groups at the 1-year reevaluation. CONCLUSIONS Within the limits of the present study, it can be concluded that 1) at 1 year after regenerative surgery with PRP + ABBM and ABBM alone, significant PD reductions and CAL gains were found, and 2) the use of PRP failed to improve the results obtained with ABBM alone.

The use of a second reporter plasmid as an internal standard to normalize luciferase activity in transient transfection experiments may lead to a systematic error

beta-galactosidase reporter plasmids containing different viral or minimal promoters are commonly used to correct variable transfection efficiencies in transient transfection experiments. The transcriptional activity of these promoters is thought to be stable under most circumstances. To determine if expression of beta-galactosidase from the commonly used beta-galactosidase plasmids remains stable upon stimulation of the cells with agonists we performed transient transfection experiments. CHO cells stably expressing the rat AT(1A) receptor were transfected with RSVbeta- or CMVbeta- or pTKbeta plasmids alone or together with a reporter construct in which luciferase transcription is driven by the c-fos promoter. Luciferase and/or beta-galactosidase activity was measured from the lysate of cells treated with angiotensin II or serum. We found that agonists increased the transcriptional activity of the different beta-galactosidase plasmids. The effect of angiotensin II and serum was different on the different promoters. Finally, cotransfection of other plasmids also modulated beta-galactosidase activity. These agonist induced variations of beta-galactosidase activity may influence the analysis and interpretation of the results in a systematic manner. Consequently we conclude that the use of a second reporter system to control for transfection efficiency in certain types of experiments may lead to a systematic error and is questionable as a general procedure.

Atypical courses of the mandibular canal: Comparative examination of dry mandibles and x-rays

Knowledge of the course of the mandibular canal and its anatomic variations is of great importance in oral surgery, especially in preprosthetic operations and the insertion of endosteal implants and during the planning of removable dentures prepared in cases involving extensively atrophied mandibles. We review the literature on duplicated mandibular canals, which is based exclusively on radiologic findings. Then, we compare this with an examination of dry mandibles and further radiologic studies. The incidence of duplicated mandibular canals observed in macroscopic examinations of mandibles was substantially higher than that revealed by radiographs. One case involving a novel variation, a triple mandibular canal, is reported.

Histomorphometric and densitometric evaluation of the effects of platelet-rich plasma on the remodeling of beta-tricalcium phosphate in beagle dogs.

Countless possibilities are available in maxillofacial surgery for the filling of bone defects. The best bone substitute known at present is osteogenic autogenous bone, but its use is accompanied by numerous disadvantages. The question has arisen of whether results attained with osteoconductive bone substitutes approach those achieved by the transplantation of autogenous bone. The aims of the investigation were to measure the effects in animal experiments of the growth factors to be found in the platelets on the rate of remodeling of β-tricalcium phosphate, and on the quality of the new bone formed. Defects formed in the mandibles of 10 Beagle dogs were filled with β-tricalcium phosphate or with a mixture of β-tricalcium phosphate and platelet-rich plasma obtained from autogenous blood. The quality of the hard tissue formed and the effect of the platelet-rich plasma were examined by statistical analysis of the densitometric results obtained after 6 weeks and the histological and histomorphometric results obtained after 12 weeks. The densitometric study revealed that the bone formation was significantly more effective when platelet-rich plasma was used; at this stage, histomorphometric evaluation did not indicate a significant difference. After 12 weeks, however, the histomorphometric study demonstrated a significant difference in favor of the bone substitute used together with platelet-rich plasma. The results strongly suggest that use of the platelet-rich plasma suspension accelerates the remodeling of β-tricalcium phosphate and leads to the formation of hard tissue with a quality similar to that of the autogenous bone.

Five-Year Results Evaluating the Effects of Platelet-Rich Plasma on the Healing of Intrabony Defects Treated With Enamel Matrix Derivative and Natural Bone Mineral

BACKGROUND Regenerative periodontal surgery using the combination of enamel matrix derivative (EMD) and natural bone mineral (NBM) with and without addition of platelet-rich plasma (PRP) has been shown to result in substantial clinical improvements, but the long-term effects of this combination are unknown. METHODS The goal of this study was to evaluate the long-term (5-year) outcomes after regenerative surgery of deep intrabony defects with either EMD + NBM + PRP or EMD + NBM. Twenty-four patients were included. In each patient, one intrabony defect was randomly treated with either EMD + NBM + PRP or EMD + NBM. Clinical parameters were evaluated at baseline and 1 and 5 years after treatment. The primary outcome variable was clinical attachment level (CAL). RESULTS The sites treated with EMD + NBM + PRP demonstrated a mean CAL change from 10.5 ± 1.6 to 6.0 ± 1.7 mm (P <0.001) at 1 year and 6.2 ± 1.5 mm (P <0.001) at 5 years. EMD + NBM-treated defects showed a mean CAL change from 10.6 ± 1.7 to 6.1 ± 1.5 mm (P <0.001) at 1 year and 6.3 ± 1.4 mm (P <0.001) at 5 years. At 1 year, a CAL gain of ≥4 mm was measured in 83% (10 of 12) of the defects treated with EMD + NBM + PRP and in 100% (all 12) of the defects treated with EMD + NBM. Compared to baseline, in both groups at 5 years, a CAL gain of ≥4 mm was measured in 75% (nine of 12 in each group) of the defects. Four sites in the EMD + PRP + NBM group lost 1 mm of the CAL gained at 1 year. In the EMD + NBM group, one defect lost 2 mm and four other defects lost 1 mm of the CAL gained at 1 year. No statistically significant differences in any of the investigated parameters were observed between the two groups. CONCLUSIONS Within their limits, the present results indicate that: 1) the clinical outcomes obtained with both treatments can be maintained up to a period of 5 years; and 2) the use of PRP does not appear to improve the results obtained with EMD + NBM.

Overexpression of the type II transforming growth factor-β receptor inhibits fibroblast proliferation and activates extracellular signal regulated kinase and C-Jun N-terminal kinase

Transforming growth factor‐β (TGF‐β) is a bimodal regulator of cellular growth. The cellular effects of TGF‐β depend on the intensity of signals emanating from TGF‐β receptors. Low levels of receptor activity are sufficient to stimulate cell proliferation, while higher degrees of receptor activation are associated with growth inhibition. To study the mechanisms of these effects, a tetracycline‐inducible expression system was used to overexpress type II TGF‐β receptors in NIH 3T3 fibroblasts. Overexpressed type II TGF‐β receptors suppressed fibroblast proliferation elicited by TGF‐β1, fibroblast growth factor (FGF) or platelet‐derived growth factor (PDGF). Accompanying these anti‐proliferative effects, increases in extracellular‐signal regulated kinase (ERK) and c‐Jun N‐terminal kinase (JNK) activity were detected. Furthermore, PDGF α‐, but not PDGF β‐receptor protein levels were reduced by type II TGF‐β receptor overexpression. In conclusion, our system is an excellent tool to study the molecular mechanisms of growth inhibition by TGF‐β in fibroblasts. Activation of JNK and ERK, or modulation of PDGF receptor expression may be involved in this process.

False diagnosis caused by Warthin tumor of the parotid gland combined with actinomycosis.

A case is reported in which a unilateral parotid gland cystadenolymphoma was combined with actinomycosis. A 48-year-old woman presented with a mass in the left parotid region and paresis of the lower left palpebra. The computed tomography, echography, and parotid radiographic findings did not exclude a neoplasm of the left parotid gland. The ramus of the mandible was involved in the process. Intraoperative freezing histology, total parotidectomy, and partial mandibulectomy were performed, with sacrifice of the facial nerve followed by nerve reconstruction. The final histological evaluation was Warthin tumor with actinomycosis. Four years after treatment, the patient is free of disease. No similar cases seem to have been reported thus far.

Extracellular Signal-Regulated Kinase and the Small GTP-Binding Protein p21Rac1 Are Involved in the Regulation of Gene Transcription by Angiotensin II

To study the role of extracellular-signal-regulated kinase (ERK) cascade and the small GTP-ase proteins in the activation of the c-fos promoter by angiotensin II (AII), transient transfection experiments were performed in CHO cells stably expressing the rat AT1A receptor. In this system AII activated ERK in 1 min and also increased the transcriptional activity of the c-fos promoter-luciferase reporter gene construct. The activation of the promoter proved to be dependent on the Ras-Raf-ERK cascade as cotransfection of expression vectors known to specifically inhibit this cascade blocked the effect of AII. Dominant-negative p21Rac1 mutant partially blocked the activation of the c-fos promoter by AII. However, activation of the c-fos promoter was independent of protein kinase C (PKC) as bisindolylmaleimide I, a specific PKC inhibitor did not block the effect of AII. These results suggest that AII activates the transcription of the c-fos through the Ras-Raf-ERK cascade. Furthermore, p21Rac1 is involved in the modulation of the c-fos promoter by AII.

Comparison of postoperative complications following bone harvesting from two different donor sites for autologous bone replacement (hipbone and proximal epiphysis of the tibia)

Whereas autologous bone replacement was earlier applied in maxillofacial surgery virtually only for the restoration of mandibular defects and for the osteoplasty of patients with cleft alveolar process, the free transplantation of autologous bone (spongiosa or cortical bone or both) is nowadays primarily used for implantation purposes. Autologous bone is still the gold standard for bone replacement. This is the case even though a wide selection of bone substitutes is currently available, with which new bone equivalent to autologous bone can be produced in certain cases. Autologous bone is often obtained from intraoral sources, but if a larger quantity of spongiosa is required, these sites (the chin, the retromolar area of the mandible, the muscular process, etc.) are not suitable. Of the extraoral donor sites, the most frequently used site is the iliac crest, but the proximal epiphysis of the tibia is also appropriate for this purpose since we have recently performed bone transplantations on appreciable numbers of patients, we decided to compare the morbidity data relating to the two donor sites. In the 9 months between March and November 2007, sinus elevations were carried out on 14 patients with bone taken from the tibia, while in 38 patients bone was taken from the iliac crest for osteoplasty on clefted alveolar process. The comparison was based on postoperative clinical examinations, the complaints of the patients and objective study of the morbidity relating to the two donor sites. Clinically the patients tolerated both interventions well. Mobilization took place on the day of intervention. There were no major complications; one minor haematoma was observed after each type of surgery. The postoperative complaints of the patients did not reveal any essential difference. Following bone harvesting from the iliac crest, the gait of the patients slightly hampered for up to 10 to 14 days. In the tibia cases, the patients experienced no pain on walking by the second day. As regards donor site morbidity, protracted (1-2 weeks) oedema was observed after hip surgery, with paraesthesia of the area of innervation of the n. cutaneous femoris lateralis in 1 case, while there was a minor seroma following tibia surgery in 1 case. Our clinical experience suggests that, if 10-15 cm(3) spongiosa is required for augmentation purposes and there is no need for cortical bone, the patient is exposed to less stress when bone is taken from the proximal epiphysis of the tibia.

Modified procedure for secondary facial rehabilitation following total bilateral irreversible peripheral facial palsy.

We present the case of a middle-aged gentleman who developed total bilateral irreversible peripheral facial palsy over a period of 10 years, starting with palsy of the marginal mandibular and buccal branches of the facial nerve and progressing to the zygomatic and temporal branches. The patient did not develop any other neurological symptoms, and all neurological and other tests have remained negative over the last 10 years. Dripping of saliva and inability to close the mouth necessitated reanimation of the perioral region with the help of a fascia lata graft fixed to the fascia of the masseter muscles. The increasing lagophthalmos and associated eye problems were alleviated with a temporal muscle transposition combined with a lengthening procedure using the temporal fascia, passed through the upper and lower eyelids and hooked around the medial canthal ligament. The fascia strips were sutured not to the canthal ligament itself, but to each other, thereby placing equal self-adjusted tension on the upper and lower eyelids. Both operations were successful and improved eating and eye closure functions, allowing resolution of the eye symptoms.