Occlusive and Proliferative Properties of Different Collagen Membranes-An In Vitro Study.

Different collagen barrier membranes come in various sources and crosslinking that may affect barrier function and tissue integration. This study investigated barrier function and tissue integration of the three different collagen membranes (Jason®: porcine pericardium, GENOSS: bovine tendon, and BioMend® Extend: cross-linked bovine tendon) with human gingival fibroblasts. The barrier function and tissue integration properties were determined under confocal microscopy. Morphological characteristics were observed using scanning electron microscopy. Our results showed that all collagen membranes allowed a small number of cells to migrate, and the difference in barrier function ability was not significant. The cross-linked characteristics did not improve barrier ability. The native collagen membrane surfaces allowed evenly scattered proliferation of HGF, while the cross-linked collagen membrane induced patchy proliferation. Statistically significant differences in cell proliferation were found between Jason and BioMend Extend membranes (p = 0.04). Scanning electron microscope showed a compact membrane surface at the top, while the bottom surfaces displayed interwoven collagen fibers, which were denser in the crosslinked collagen membranes. Within the limitations of this study, collagen membranes of different origins and physical properties can adequately prevent the invasion of unwanted cells. Native collagen membranes may provide a better surface for gingival cell attachment and proliferation.

Increased Oral Dryness and Negative Oral Health-Related Quality of Life in Older People with Overweight or Obesity.

This cross-sectional study was to evaluate the association between the oral health-related quality of life (OHRQoL) of older Thai people with obesity and oral health indicators. General and oral conditions were assessed. Oral dryness was determined using the Xerostomia Inventory-11 (XI-11) and clinical oral dryness score (CODS). OHRQoL was evaluated by the oral health impact profile (OHIP-14). Participants were aged 60-86 years; 73 (59.3%) were overweight or obese, and 50 (40.7%) were normal weight. Older patients with obesity had almost four times the rate of hypertension (OR = 3.59; 95%CI:1.34-9.60; p = 0.002), more missing teeth (p = 0.025), and higher CODS (p = 0.014) than those without obesity. The total XI-11 scores were positively associated with the total CODS, after adjusting for BMI (r = 0.267, p = 0.003). Those with obesity had almost three times the tendency for a negative OHRQoL compared with the non-obese (OR = 2.73; 95%CI:1.12-6.71; p = 0.04). After adjusting for all related factors, the chances of predicting an OHIP-14 score of four based on obesity and total XI-11 score were 4.42 (95%CI:1.57-12.47; p = 0.005) and 1.11 (95%CI:1.02-1.20; p = 0.013), respectively. Obesity had an increasingly undesirable negative impact on the OHRQoL of older Thai people and was influenced by BMI and oral dryness.

Comparison of Different Types of Static Computer-Guided Implant Surgery in Varying Bone Inclinations.

This research aimed to compare the accuracy of dental implant placement among three types of surgical guide: metal sleeve with key handle (Nobel guide, Nobel Biocare, Göteborg, Sweden), metal sleeve without key handle, and non-sleeve without key handle (Dentium full guide kit, Dentium Co., Seoul, Korea) when placing the implant in different bone inclinations. A total of 72 polyurethane bone models were fabricated in different inclinations (0°, 45°, and 60°). The dental implants were placed in bone models following the company's recommendations. After dental implants were installed, the digital scans were done by an extraoral scanner. The deviations of the dental implant position were evaluated by superimposition between post-implant placement and reference model by using GOM inspect software. The deviation measurement was shown in 5 parameters: angular deviation, 3D deviation at the crest, 3D deviation at the apex, lateral linear deviation, and vertical linear deviation. The data were analyzed using One-way ANOVA and post-hoc tests at a significance level of 0.05. The accuracy of the dental implant position was not significantly influenced by the difference in the surgical guide system (p > 0.05). There were significant differences between placed and planned implant positions in the different inclinations of the bone. A significant difference was found in all parameters of 0° and 60° bone inclinations (p < 0.05). At 0° and 45°, angulated bone showed significant differences except in 3D deviation at the apex. Between 45° and 60° were significant differences only in angular deviation. Within the limitations of this study, the accuracy of implant placement among three types of surgical guides (Non-sleeve without key handle, Metal sleeve without key handle, and Metal sleeve with key handle) from two companies (Dentium and Nobel Biocare) was similar. Hence, the operators can choose the surgical guide system according to their preference. The inclination of bone can influence the angulation of dental implants.

Postoperative Pain Management Using Supplemental Bupivacaine After Mandibular Orthognathic Surgery: A Triple-Blind Randomized Controlled Clinical Trial.

PURPOSE: The objective of this triple-blind, randomized, placebo-controlled trial was to assess the clinical analgesic efficacy of 0.5% bupivacaine in acute postoperative pain management after bilateral sagittal split ramus osteotomy (BSSO). METHODS: Patients were randomly allocated into the experimental (0.5% bupivacaine with 1:200000 epinephrine) or control group (normal saline - placebo) using block randomization. The interventions were administered at the inferior alveolar nerve block and buccal nerve block sites bilaterally after the BSSO surgery. Analgesic efficacy was assessed in terms of the patient's pain perception measured by a numerical rating scale (0 to 10), rescue drug requirement, and duration of analgesia for 24 hours after the surgery. The statistical analysis was blinded to the allocation groups, and P-value of <.05 was considered as a significant difference for all tests. RESULTS: In total, 28 patients underwent BSSO (ie, 14 in each group). There was no significant difference in pain perception of patients injected with 0.5% bupivacaine and those administered with placebo during the 24 hours after the surgery (P > .05). Three patients in the bupivacaine group took the rescue drug after the surgery (mean duration - 268 minutes) and 1 patient in the placebo group took the rescue drug after 27 minutes. CONCLUSIONS: Postoperative use of bupivacaine did not show a superior analgesic efficacy when compared with normal saline in controlling acute postoperative pain after BSSO.

Implant Site Preparation Application of Injectable Platelet-Rich Fibrin for Vertical and Horizontal Bone Regeneration: A Clinical Report.

Guided bone regeneration (GBR) using a combined injectable platelet-rich fibrin (i-PRF), leukocyte- and platelet-rich fibrin (L-PRF), and biocompatible bone substitute material, is a convenient and effective method to augment a combined vertical and horizontal bone defect. This approach can create sufficient bone quality and quantity for implant surgical sites. A 55-year-old Asian woman presented with a severe bone defect in posterior mandible. The edentulous mandibular alveolar ridge was severely resorbed vertically and horizontally. A GBR procedure using i-PRF and L-PRF combined with particulate bone graft was performed. Postoperative cone beam computed tomography scans, 8 months after the augmentation, revealed a large regeneration of the alveolar bone sufficient for implant placement. A combination i-PRF/L-PRF and particulate bone graft may provide biologically active molecules and a scaffold for osteogenesis. This treatment protocol may be a viable option for a large bone defect required augmentation before implant placement.

The Accuracy and Reliability of Tooth Shade Selection Using Different Instrumental Techniques: An In Vitro Study.

This study aimed to investigate and compare the reliability and accuracy of tooth shade selection in the model using 30 milled crowns via five methods: (1) digital single-lens reflex (DSLR) camera with twin flash (TF) and polarized filter (DSLR + TF), (2) DSLR camera with a ring flash (RF) and polarized filter (DSLR + RF), (3) smartphone camera with light corrector and polarized filter (SMART), (4) intraoral scanner (IOS), and (5) spectrophotometer (SPEC). These methods were compared with the control group or manufacturer's shade. The CIE Lab values (L, a, and b values) were obtained from five of the methods to indicate the color of the tooth. Adobe Photoshop was used to generate CIE Lab values from the digital photographs. The reliability was calculated from the intraclass correlation based on two repetitions. The accuracy was calculated from; (a) ΔE calculated by the formula comparing each method to the control group, (b) study and control groups were analyzed by using the Kruskal-Wallis test, and (c) the relationship between study and control groups were calculated using Spearman's correlation. The reliability of the intraclass correlation of L, a, and b values obtained from the five methods showed satisfactory correlations ranging from 0.732-0.996, 0.887-0.994, and 0.884-0.999, respectively. The ΔE from all groups had statistically significant differences when compared to the border of clinical acceptance (ΔE = 6.8). The ΔE from DSLR + TF, DSLR + RF, SMART, and SPEC were higher than clinical acceptance (ΔE > 6.8), whereas the ΔE from IOS was 5.96 and all of the L, a, and b values were not statistically significantly different from the manufacturer's shade (p < 0.01). The ΔE of the DSLR + RF group showed the least accuracy (ΔE = 19.98), whereas the ∆E of DSLR + TF, SMART, and SPEC showed similar accuracy ∆E (ΔE = 10.90, 10.57, and 11.57, respectively). The DSLR camera combined with a ring flash system and polarized filter provided the least accuracy. The intraoral scanner provided the highest accuracy. However, tooth shade selection deserves the combination of various techniques and a professional learning curve to establish the most accurate outcome.

Comparative efficiency of the preoperative pterygomandibular space injection of two doses of dexamethasone in mandibular third molar surgery.

BACKGROUND: Impacted mandibular third molar removal is one of the most commonly performed oral surgical procedures. This procedure can lead to several postoperative complications, such as trismus, facial swelling, and pain, which occur as a result of the inflammatory responses to surgery. This study compared the efficiency of preoperative injections of 4 mg versus 8 mg dexamethasone into the pterygomandibular space to reduce postoperative sequelae. METHODS: This was a randomized, prospective, split-mouth, controlled study, including 52 mandibular third molar surgeries in 26 patients. Each patient was randomized to either the 4 mg or 8 mg dexamethasone injection group. Dexamethasone was injected into the pterygomandibular space after numbness from local anesthesia. Data were collected for trismus, facial swelling, visual analog scale (VAS) pain score, and the number of analgesics taken during the evaluation period. The level of significance was set at P < 0.05. RESULTS: Statistically significant differences in postoperative facial swelling (P = 0.031, diff = 1.4 mm) and pain (P = 0.012, diff = 0.020) were found between the 8 mg and 4 mg dexamethasone groups. However, there were no significant differences between the groups for trismus and the total number of analgesics consumed (P > 0.05). CONCLUSION: Compared to the 4 mg preoperative dexamethasone injection, the 8 mg preoperative dexamethasone injection into the pterygomandibular space was more effective in reducing postoperative swelling and pain following the surgical removal of the impacted mandibular third molar. However, the difference in trismus could not be evaluated clinically. Therefore, the recommendation of administering the 4 mg dexamethasone preoperative injection is optimal in the third molar surgical procedure.

Single buccal infiltration of high concentration lignocaine versus articaine in maxillary third molar surgery.

BACKGROUND: This research evaluated the numbness produced by lignocaine at an equal or higher concentration than that of 4% articaine through a single point of injection for maxillary third molar surgery. This randomized double-blind study was conducted to compare the anesthetic efficiency of 4% lignocaine with that of 4% articaine in impacted maxillary third molar surgery using a single buccal infiltration alone. METHODS: The study participants were 30 healthy patients requiring the bilateral surgical removal of symmetrically-positioned maxillary third molars. Using a split-mouth design, each patient randomly received buccal infiltration of 1.7 ml of 4% lignocaine and 1.7 ml of 4% articaine during two separate appointments. After 15 minutes of anesthetic injection, surgery was performed by the same surgeon using a consistent technique on both sides. Pinprick test pain scores of the buccal and palatal gingiva of the maxillary third molar after 10 minutes and 15 minutes latencies, pain scores during the surgery, the need for supplemental anesthesia, and patients' satisfaction with anesthetic efficiency were recorded. Surgery performed without supplemental anesthesia was categorized as successful. RESULTS: The success rates of 4% lignocaine and 4% articaine (83.34% vs. 86.67%, P = 1.00) were not significantly different. Only 5 cases (4 cases in the articaine group and 1 case in the lignocaine group) reported mild pain and pressure sensation (NRS ≤ 1) on probing at the palatal side after 15 minutes of latency (P = 0.25). The pain scores of maxillary third molar surgery in the two groups were not significantly different (P > 0.05). Moreover, the statistical analysis confirmed the comparable patient satisfaction of two study groups (P = 0.284). CONCLUSION: This study provides evidence that single buccal infiltrations of 4% lignocaine and 4% articaine have comparable anesthetic efficacy and success rates for impacted maxillary third molar surgery. Both 4% lignocaine and 4% articaine can produce effective palatal anesthesia and pain control using buccal infiltration alone after 15 minutes of latency.

Red and Yellow Injectable Platelet-Rich Fibrin Demonstrated Differential Effects on Periodontal Ligament Stem Cell Proliferation, Migration, and Osteogenic Differentiation.

The biological benefits of using two fractions derived from injectable platelet-rich fibrin (i-PRF) in bone regeneration remain unclear. Thus, the current study examined two fractionation protocols producing yellow i-PRF and red i-PRF on periodontal ligament stem cells (PDLSCs). The i-PRF samples from five donors were harvested from two different levels, with and without a buffy coat layer, to obtain red and yellow i-PRF, respectively. The PDLSCs were isolated and characterized before their experimental use. The culture medium in each assay was loaded with 20% of the conditioned medium containing the factors released from the red and yellow i-PRF. Cell proliferation and cell migration were determined with an MTT and trans-well assay, respectively. Osteogenic differentiation was investigated using alkaline phosphatase and Alizarin red staining. The efficiency of both i-PRFs was statistically compared. We found that the factors released from the red i-PRF had a greater effect on cell proliferation and cell migration. Moreover, the factors released from the yellow i-PRF stimulated PDLSC osteogenic differentiation earlier compared with the red i-PRF. These data suggest that the red i-PRF might be suitable for using in bone regeneration because it induced the mobilization and growth of bone regenerative cells without inducing premature mineralization.

Platelet-rich plasma stimulated proliferation, migration, and attachment of cultured periodontal ligament cells.

OBJECTIVE: The aim of this study is to evaluate the effects of platelet-rich plasma (PRP) on the proliferation, migration, and attachment of cultured periodontal ligament (PDL) cells. MATERIALS AND METHODS: 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to assess number of PDL cells cultured in medium with or without PRP. Cell migration toward medium with or without PRP was assessed using the Boyden chamber. Cell attachment was assessed by counting cells on PRP or non-PRP coated dentin specimens. Group differences were analyzed using two-way ANOVA at 0.05 significance level. RESULTS: In the MTT and cell migration assay, the number of cells in 5% and 10% PRP-treated groups were significantly higher than that in the non-PRP-treated group (P < 0.05). In the attachment assay, the number of cells on the dentin specimens in 10% PRP-treated group was significantly higher than that in the non-PRP treated group (P < 0.05). CONCLUSION: PRP could stimulate proliferation, migration, and attachment of PDL cells.

Inferior alveolar nerve block by intraosseous injection with Quicksleeper® at the retromolar area in mandibular third molar surgery.

BACKGROUND: There are many techniques of inferior alveolar nerve block injection (IANBI); one among them is the computer-assisted intraosseous injection (CAIOI). Here we aim to evaluate the effectiveness of CAIOI with Quicksleeper® in mandibular third molar surgery. METHODS: This study is a clinical, single-blind, randomized, split-mouth, controlled trial including 25 patients (10 males and 15 females, mean age 21 years). The patients underwent surgical removal of bilateral mandibular third molars with two different IANBI techniques. One side was injected using Quicksleeper®, and the other side was injected using a conventional IANBI. Both techniques used one cartridge (1.7 ml) of 1:100,000 epinephrine 4% articaine. A supplementary injection was used if necessary. All volumes of anesthetic agent used were recorded. Statistical analysis was performed using paired t-test and Wilcoxon test. RESULTS: This research showed that CAIOI has faster onset and shorter duration of action than IANBI (P < 0.05). The pain was similar in both techniques. In the CAIOI group, one-third of the cases could be completed without additional anesthesia. The remaining two-thirds required minimal supplementary volume of anesthesia. The success rates were 68% for CAIOI and 72% for IANBI, respectively. CONCLUSION: CAIOI is an advantageous anesthetic technique. It can be used as an alternative to conventional IANBI for mandibular third molar surgery.

The efficacy of dexamethasone injection on postoperative pain in lower third molar surgery.

BACKGROUND: Surgery on the lower impacted third molar usually involves trauma in the highly vascularized loose connective tissue area, leading to inflammatory sequelae including postoperative pain, swelling, and general oral dysfunction during the immediate post-operative phase. This study aimed to investigate the effectiveness of preoperative injection of a single dose of 8 mg dexamethasone for postoperative pain control in lower third molar surgery. METHODS: A controlled, randomized, split-mouth, prospective study involving lower third molar surgery was performed in 31 patients. The randomized sampling group was preoperatively injected, after local anesthesia, with a single dose of dexamethasone (8 mg in 2 ml) through the pterygomandibular space; 2 ml of normal saline (with no dexamethasone) was injected as a placebo. RESULTS: The pain VAS score was significantly different on the day of the operation compared to the first post-operative day (P = 0.00 and 0.01, respectively), but it was not significantly different on the third and seventh postoperative day between the control and study groups. There was a significant reduction in swelling on the second postoperative day, and a difference between the second postoperative day and baseline value in the study group (P < 0.05). Trismus was highly significantly different on the second postoperative day and between baseline and second postoperative day between the groups (P = 0.04 and 0.02, respectively). Descriptive statistics and independent-samples t- test were used to assess the significance of differences. CONCLUSIONS: Injection of 8 mg dexamethasone into the pterygomandibular space effectively reduced the postoperative pain and other postoperative sequalae.

Accuracy of linear measurements using cone beam computed tomography and panoramic radiography in dental implant treatment planning.

PURPOSE: The aim of this study was to investigate the accuracy of linear measurements from cone beam computed tomography (CBCT) images and digital panoramic radiographs at various implant sites. MATERIALS AND METHODS: Fifty implant sites from six skulls were marked with gutta-percha and subjected to CBCT with five different voxel protocols: 0.125 mm, 0.160 mm, and 0.250 mm with the 3D Accuitomo 170 CBCT machine and 0.200 mm and 0.300 mm with the CS 9500 CBCT machine. Images were also taken with the CS 9000 panoramic machine with three protocols: normal head, chin-up, and chin-down positions. Electronic linear measurement of bone height using the corresponding machine's software was recorded by two observers. Physical measurement using a digital caliper with ± 0.02-mm accuracy was directly recorded at the corresponding regions as the gold standard. All image measurements were compared with the physical measurements. The paired sample correlations for physical measurement, mean difference, standard deviation, absolute error, absolute percentage error, and inter- and intraobserver reliability were calculated. RESULTS: Intraobserver and interobserver reliability was more than 0.99. Paired sample correlation between all image measurements and physical measurements was considered statistically significant at P < .05. All image measurements were underestimated by less than 2 mm, except for the chin-down position of the maxilla in the panoramic radiograph. The absolute error and absolute percentage error in the mandible were less than those in the maxilla, and values obtained with CBCT were less than those from panoramic radiographs. CONCLUSION: CBCT images using the 3D Accuitomo 170 and CS 9500 machines and digital panoramic radiographs via a picture archiving and communication system are sufficiently accurate for vertical linear measurements in dental implant treatment planning.

The efficacy of an elevated concentration of lidocaine HCl in impacted lower third molar surgery.

BACKGROUND: There have been few studies on the effect of an elevated concentration of lidocaine hydrochloride in the surgical removal of an impacted lower third molar. This study aimed to examine the efficacy of 4% lidocaine along with 1:100,000 epinephrine compared to 2% lidocaine along with 1:100,000 epinephrine as inferior alveolar nerve block for the removal of an impacted lower third molar. METHODS: This single-blind study involved 31 healthy patients (mean age: 23 y; range: 19-33 y) with symmetrically impacted lower third molars as observed on panoramic radiographs. Volunteers required 2 surgical interventions by the same surgeon with a 3-week washout period. The volunteers were assigned either 4% lidocaine with 1:100,000 epinephrine or 2% lidocaine with 1:100,000 epinephrine as local anesthetic during each operation. RESULTS: We recorded the time of administration, need for additional anesthetic administration, total volume of anesthetic used. We found that the patient's preference for either of the 2 types of local anesthetic were significantly different (P < 0.05). However, the extent of pulpal anesthesia, surgical duration, and duration of soft tissue anesthesia were not significantly different. CONCLUSIONS: Our study suggested that inferior alveolar nerve block using 4% lidocaine HCl with 1:100,000 epinephrine as a local anesthetic was clinically more effective than that using 2% lidocaine HCl with 1:100,000 epinephrine; the surgical duration was not affected, and no clinically adverse effects were encountered.

Hemodynamic changes associated with a novel concentration of lidocaine HCl for impacted lower third molar surgery.

BACKGROUND: The authors studied the hemodynamic effect influent by using the novel high concentration of lidocaine HCl for surgical removal impacted lower third molar. The objective of this study was to evaluate the hemodynamic change when using different concentrations of lidocaine in impacted lower third molar surgery. METHODS: Split mouth single blind study comprising 31 healthy patients with a mean age of 23 years (range 19-33 years). Subjects had symmetrically impacted lower third molars as observed on panoramic radiograph. Each participant required 2 surgical interventions by the same surgeon with a 3-week washout period washout period. The participants were alternately assigned one of two types of local anesthetic (left or right) for the first surgery, then the other type of anesthetic for the second surgery. One solution was 4% lidocaine with 1:100,000 epinephrine and the other was 2% lidocaine with 1:100,000 epinephrine. A standard IANB with 1.8 ml volume was used. Any requirement for additional anesthetic and patient pain intra-operation was recorded. Post-operatively, patient was instructed to fill in the patient report form for any adverse effect and local anesthetic preference in terms of intra-operative pain. This form was collected at the seven day follow up appointment. RESULTS: In the 4% lidocaine group, the heart rate increased during the first minute post-injection (P < 0.05). However, there was no significant change in arterial blood pressure during the operation. In the 2% lidocaine group, there was a significant increase in arterial blood pressure and heart rate in the first minute following injection for every procedure. When the hemodynamic changes in each group were compared, the 4% lidocaine group had significantly lower arterial blood pressure compared to the 2% lidocaine group following injection. Post-operatively, no adverse effects were observed by the operator and patient in either local anesthetic group. Patients reported less pain intra-operation in the 4% lidocaine group compared with the 2% lidocaine group (P < .05). CONCLUSIONS: Our results suggest that a 4% concentration of lidocaine HCl with 1:100,000 epinephrine has better clinical efficacy than 2% lidocaine HCl with 1:100,000 epinephrine when used for surgical extraction of lower third molars. Neither drug had any clinical adverse effects.

Prevalence and associated factors of musculoskeletal pain among the dental personnel in a dental school.

OBJECTIVE: To study the prevalence and associated factors of musculoskeletal (MS) pain among the dental personnel. In addition, impacts and treatment of MS pain were reported. MATERIAL AND METHOD: Random sampling of 390 participants from the name lists of dental personnel working in each department. Self-administered questionnaires were equally distributed to three groups of dental personnel namely clinical instructors, postgraduate students, and dental assistants. The present study was conducted as a survey in the Faculty of Dentistry, Mahidol University, Bangkok between December 2008 and January 2009. RESULTS: Three hundred and ninety questionnaires were delivered and 164 questionnaires were returned (response rate 42.5%). The participants with MS pain were 32 clinical instructors (20.3%), 52 postgraduate students (32.9%), and 74 dental assistants (46.8%). Their mean age was 33.0 +/- 9.1 years old. The MS pain found respectively was shoulder pain 72.2% (n = 114), neckpain 70.3% (n = 111), and low backpain 50.6% (n = 80). The participants with shoulder and neckpain were combined and defined as cervicobrachial pain. The associated factor of cervicobrachial pain was working status. Being a clinical instructor and postgraduate student were associated with cervicobrachial pain with OR being 4.7 [1.3, 7.1] and 4.6 [1.6, 13.4], respectively. The impacts of MS pain among the dental personnel included usage of pain relieving medication (34.8%), seeking medical evaluation (32.3%), reduction in working hours (27.2%), difficulty sleeping (22.8%), and work absence (10.8%), respectively. The treatments of MS pain utilized to alleviate those impacts were Thai traditional massage (51.9%), medication (28.5%), physical therapy (15.8%), acupuncture (7.6%), and alternative medicine (4.4%), respectively. CONCLUSION: Cervicobrachial pain was the most prevalent MS pain among the dental personnel and working status was associated with their MS pain problems. The impact of MS pain was predominantly usage of pain relieving medication. Thai traditional massage was the most utilized treatment.

Osseointegration of zirconia implants compared with titanium: an in vivo study.

BACKGROUND: Titanium and titanium alloys are widely used for fabrication of dental implants. Since the material composition and the surface topography of a biomaterial play a fundamental role in osseointegration, various chemical and physical surface modifications have been developed to improve osseous healing. Zirconia-based implants were introduced into dental implantology as an alternative to titanium implants. Zirconia seems to be a suitable implant material because of its tooth-like colour, its mechanical properties and its biocompatibility. As the osseointegration of zirconia implants has not been extensively investigated, the aim of this study was to compare the osseous healing of zirconia implants with titanium implants which have a roughened surface but otherwise similar implant geometries. METHODS: Forty-eight zirconia and titanium implants were introduced into the tibia of 12 minipigs. After 1, 4 or 12 weeks, animals were sacrificed and specimens containing the implants were examined in terms of histological and ultrastructural techniques. RESULTS: Histological results showed direct bone contact on the zirconia and titanium surfaces. Bone implant contact as measured by histomorphometry was slightly better on titanium than on zirconia surfaces. However, a statistically significant difference between the two groups was not observed. CONCLUSION: The results demonstrated that zirconia implants with modified surfaces result in an osseointegration which is comparable with that of titanium implants.

Malignant fibrous histiocytoma of the face: report of a case.

BACKGROUND: Soft tissue sarcomas in the head and neck region are rare and often present a difficult differential diagnosis. The aim of our presentation is to point out the complexity of the diagnosis, treatment and follow up. CASE PRESENTATION: An eighty-seven year old female patient was referred to our unit with a fast growing brownish lump on the face. Four months beforehand, a benign fibrous histiocytoma (BFH) had been removed from the same location by excision biopsy with wide tumour-free resection margins. Excision biopsy of the recurrent lesion revealed a malignant fibrous histiocytoma (MFH). Radical tumour resection was completed by extended parotidectomy and neck dissection; the skin defect was covered by a regional bi-lobed flap. No adjuvant radio- or chemotherapy was administered. Full functional and cosmetic recovery was achieved; follow-up has been uneventful more than two years postoperatively. DISCUSSION: Malignant transformation of BFH is extremely rare and if so, extended radical surgery may give a fair chance for a favourable outcome even in patients with advanced age.