Effect of platelet concentration in platelet-rich plasma on peri-implant bone regeneration.

This study analyzed the effect of the platelet count in platelet-rich plasma (PRP) on bone regeneration in vivo. Twenty male New Zealand white rabbits were used. PRP was produced using the Platelet Concentrate Collection System (PCCS) (3i, Miami, FL, USA). After inducing ketamine-xylazine anaesthesia, a self-tapping titanium screw (Branemark MK III TiUnite, 3.75 x 7 mm) was inserted in each distal femur; the femurs were randomized so that one side was treated with PRP while the other (control) was not. Intravital fluorochrome staining was performed on days 1, 7 (1.5 ml of 2% doxycycline/kg bodyweight), 14 (6% xylenol orange, 1.5 ml/kg), and 21 (1% calcein green, 5 ml/kg). Animals were euthanized on day 28 (n = 20). Specimens were prepared for histomorphological evaluation according to Donath and Breuner [J. Oral Pathol. 11 (1982) 318]. Comparing the bone regeneration (fluorochrome staining) in the 4-week implants (n = 19), the only significant difference (sign test, P = 0.004) was seen with intermediate platelet concentrations (n = 9,503,000-1,729,000 platelets/microl PRP). There were no differences in the bone/implant contact rates between the test and the control side among the three groups. The platelet concentration required for a positive PRP effect on bone regeneration seems to span a very limited range. Advantageous biological effects seem to occur when PRP with a platelet concentration of approximately 1,000,000/microl is used. At lower concentrations, the effect is suboptimal, while higher concentrations might have a paradoxically inhibitory effect. On the other hand, the effect of this type of platelet concentrate was not beneficial to accelerate the osseointegration of enosseous dental implants.

[Partsch's chronic granulomatous inflammation, the cutaneous manifestation of a dental cause]. / Chronisch granulierende Entzündung nach Partsch. Chirurgisches Problem dentogener Ursache.

Dentogenous inflammatory diseases can lead to typical dermatological facial symptoms with formation of cutaneous sinuses. Partsch's chronic granulomatous inflammation can result from conducted inflammation of a nonvital tooth via a chronic apical inflammation. In this rare disease, the granulomatous tissue perforates the bone, channels through the overlying skin, and drains via cutaneous or oral sinuses. A frequent localization of the cutaneous sinus is the skin inferior to the body of the mandible, and it is caused by an inflammation of the lower molars. Treatment consists of identifying the responsible teeth and eliminating the focus of infection. Chronically progressive periradicular granuloma and/or radicular cysts can be present with impressive dermatological symptoms. Therefore, X-ray examinations are necessary to exclude possible dentogenic causes in cases of badly healing processes of the face or neck.

Correlation of platelet concentration in platelet-rich plasma to the extraction method, age, sex, and platelet count of the donor.

An important reason to improve methods of isolating platelet-rich plasma (PRP) is the potential use of autologous platelet growth factors. In addition to discontinuous plasma separation, a second method for extraction of PRP has now become available, which can be performed directly by the surgeon. In this study, the suitability of the 2 methods of producing PRP was compared. Whole blood was drawn from 158 healthy donors (112 men, 46 women) aged 20 to 62 years (mean 34, SD 10). The PRP was separated by the discontinuous plasma separation method (by the blood bank) or by the so-called "buffy coat" method (the "self-concentration" method, analogous to the PRP Kit, Curasan, Kleinostheim, Germany). Platelet counts differed significantly according to donor blood (median men 237,500/microL, women 272,000/microL), blood bank PRP preparation (median men 1,302,000/microL, women 1,548,500/microL), and self-concentrated PRP (median men 944,000/microL, women 1,026,000/microL). The platelet concentration of the blood bank PRP correlated with the platelet count in the donor whole blood (Spearman's correlation coefficient r(s) = 0.73). However, there was no significant correlation between the platelet count of self-concentrated PRP and donor whole blood (r(s) = 0.22). Significant but irrelevant influences of sex on platelet concentration were found, but no influence of age was detected.

[Cytokeratin expression in botryoid odontogenic cyst. A rare differential keratocyst and ameloblastoma diagnosis]. / Zytokeratinexpression der botryoiden odontogenen Zyste. Eine seltene Differentialdiagnose zu Keratozyste und Ameloblastom.

The botryoid odontogenic cyst (BOC) is considered a rare multilocular variant of the lateral periodontal cyst. The origin of the BOC can be seen in aberrant odontogenic tissue. The BOC is found especially in the premolar region of the mandible, as well as in the frontal region of the maxilla of patients aged between 60 and 70 years. Most of the 11 published articles of BOC have shown high rates of recurrence. Histopathologically the BOC is marked by multilocular cysts lined by a thin, nonkeratinized epithelium. Clusters of glycogen-rich epithelial cells may be noted in nodular thickenings of the cyst lining. For the clinician, the differentiation of the BOC from the keratocyst and ameloblastoma is relevant. One case of a large BOC (65-year-old male, BOC regio 33-45, diameter 5 cm, radiographically and histologically multilocular) is presented with a review of the literature, including the therapeutic management, and the possible diagnostic criteria are discussed. The immunohistochemically determined expression of cytokeratin (CK) 13 implicates the histogenetic origin of the BOC from the squamous epithelium of the oral cavity and excludes the origin from the small salivary glands. The expression of CK 19 and the lack of expression of p53, as well as the higher proliferation rate of the basal epithelial cell layer by the BOC, may be useful for distinction between the keratocyst.

An unusual complication of anticoagulant therapy: bloody tears.

A seventy-two-year-old white male developed bleeding from a right eye subconjunctival hemorrhage. The patient had been taking warfarin and, it was immediately discontinued. Two doses of 15 mgs. each of vitamin K given parentally reduced the prothrombin time, but not the oozing of blood which finally stopped after the administration of fresh frozen plasma. Fortunately, no retrobulbar or intra-ocular bleeding occurred. This complication during the use of anticoagulants has never, to our knowledge, been reported before in the medical literature.