Giorgio Pompa

Co-localization of multiple ErbB receptors in stratified epithelium of oral squamous cell carcinoma.

The expression of all four ErbB receptors was compared by immunohistochemistry, using receptor‐specific polyclonal antisera, in 32 invasive, 11 in situ carcinomas, six benign lesions, and 22 samples of histologically normal mucosa adjacent to specimens of carcinoma originating from oral cavity epithelium. Among invasive and in situ carcinoma, EGFR expression was the most prevalent (in 29/32 and 8/11 cases, respectively) followed by ErbB2 (17/32 and 2/11) and ErbB4 (9/32 and 1/10), while ErbB3 was only detected in invasive tumours (12/32). Specific patterns included invasive tumours with expression of EGFR (8/32) or ErbB4 (1/32) alone, as well as different receptor combinations (EGFR+ErbB2, EGFR+ErbB4, EGFR+ErbB2+ErbB3, EGFR+ErbB2+ErbB4, and all four receptors). Simultaneous expression of three or four ErbB receptors correlated with tumour invasion (p=2.2×10−4) and localized in the intermediate epithelial cell layer of well and moderately differentiated tumours. No other significant correlation with clinico‐pathological features was noticed. Some benign lesions and histologically normal mucosa adjacent to carcinomas showed weak immunostaining of EGFR (10/28), ErbB2 (4/28) or ErbB4 (3/28). By comparison, overexpression, as indicated by increased staining intensity, was observed in invasive tumours for EGFR (18/32), ErbB2 (8/32), ErbB4 (3/32), and ErbB3 (3/32). Statistical evaluation demonstrated a significant association of EGFR or ErbB2 overexpression with invasive carcinoma when compared with benign lesions and apparently normal epithelium (p=5.2×10−7 and p=5×10−3, respectively). Tumour‐specific overexpression of ErbB receptors and their co‐expression, most frequently involving EGFR and ErbB2, in the same cell layer of neoplastic epithelium, implicate receptor heterodimers in the pathogenesis of oral squamous carcinoma. Copyright

Craniofacial growth in children with nasal septum deviation: A cephalometric comparative study

OBJECTIVE Nasal-breathing impairment has been described as a possible determinant of maxillofacial development in children with adenoids/tonsils hypertrophy. However little is known about the possible influence of nasal septum deviation on craniofacial growth in childhood. We conducted a multicenter cephalometric study to compare skeletal and dental features in children with chronic nasal-breathing obstruction secondary to nasal septum deviation and nose-breathing controls. METHODS Ninety-eight children (59M, 39F; mean age 8.8 years; age range 7-12 years) with obligate mouth-breathing secondary to nasal septum deviation (group 1) and 98 age- and sex-matched nasal-breathing controls (group 2) were evaluated. Nasal-breathing function was assessed in all patients with clinical history, ENT instrumental examination and anterior active rhinomanometry. Cephalometric parameters were recorded in all subjects. RESULTS Patients of group 1 showed a statistically significant increase of upper anterior facial height (N-palatal plane) and total anterior facial height (N-Me) with regards to group 2. The angular relationships of the sella-nasion, palatal, and occlusal planes to the mandibular plane were greater in group 1 in comparison to controls. The gonial angle (Ar-Go-Me), palatal height and overjet were significantly higher in the mouth-breathing group. A significantly retrognatic position of the maxilla and mandible was recorded in group 1 in comparison to group 2. Most mouth-breathing children showed class II malocclusion, while the majority of control subjects presented normal occlusion. The prevalence of cross-bite was higher in group 1 with respect to controls (p=0.02). CONCLUSION Children with obligate mouth-breathing due to nasal septum deviations show facial and dental anomalies in comparison to nose-breathing controls. Possible physiologic explanations of our findings are reported.

Cyclic fatigue of nickel-titanium rotary instruments in a double (S-shaped) simulated curvature.

INTRODUCTION The goal of the present study was to test the fatigue resistance of nickel-titanium rotary files in a double curvature (S-shaped) artificial root canal and to compare those results with single curvature artificial root canals. METHODS Two nickel-titanium endodontic instruments consisting of identical instrument sizes (constant .06 taper and 0.25 tip diameter) were tested, ProFile instruments and Vortex instruments. Both instruments were tested for fatigue inside an artificial canal with a double curvature and inside a curved artificial canal with a single curvature. Ten instruments for each group were tested to fracture in continuous rotary motion at 300 rpm. Number of cycles to failure (NCF) was calculated to the nearest whole number, and the length of the fractured fragment was measured in millimeters. Data were statistically analyzed with a level of significance set at 95% confidence level. RESULTS The NCF value was always statistically lower in the double curved artificial canal when compared with the single curve (P < .05) in both the apical and coronal curvatures. Statistically significant differences (P < .05) were noted between instruments of the same size of different brand only in the single curve; ProFile registered a mean of 633.5 ± 75.1 NCF, whereas Vortex registered a mean of 548 ± 48.9 NCF. CONCLUSIONS Regardless of the differences between the instruments used in the present study, the results suggest that the more complex is the root canal, the more adverse are the effects on the cyclic fatigue resistance of the instruments.

Medication-related osteonecrosis of the jaw: Clinical and practical guidelines

Medication-related osteonecrosis of the jaw (MRONJ) is a severe adverse drug reaction, consisting of progressive bone destruction in the maxillofacial region of patients. ONJ can be caused by two pharmacological agents: Antiresorptive (including bisphosphonates (BPs) and receptor activator of nuclear factor kappa-B ligand inhibitors) and antiangiogenic. MRONJ pathophysiology is not completely elucidated. There are several suggested hypothesis that could explain its unique localization to the jaws: Inflammation or infection, microtrauma, altered bone remodeling or over suppression of bone resorption, angiogenesis inhibition, soft tissue BPs toxicity, peculiar biofilm of the oral cavity, terminal vascularization of the mandible, suppression of immunity, or Vitamin D deficiency. Dental screening and adequate treatment are fundamental to reduce the risk of osteonecrosis in patients under antiresorptive or antiangiogenic therapy, or before initiating the administration. The treatment of MRONJ is generally difficult and the optimal therapy strategy is still to be established. For this reason, prevention is even more important. It is suggested that a multidisciplinary team approach including a dentist, an oncologist, and a maxillofacial surgeon to evaluate and decide the best therapy for the patient. The choice between a conservative treatment and surgery is not easy, and it should be made on a case by case basis. However, the initial approach should be as conservative as possible. The most important goals of treatment for patients with established MRONJ are primarily the control of infection, bone necrosis progression, and pain. The aim of this paper is to represent the current knowledge about MRONJ, its preventive measures and management strategies.

Analysis of human alveolar osteoblast behavior on a nano-hydroxyapatite substrate: an in vitro study.

BackgroundNano-hydroxyapatite (nHA) is a potential ideal biomaterial for bone regeneration. However, studies have yet to characterize the behavior of human osteoblasts derived from alveolar bone on nHA. Thus, the aim of the present study was to evaluate the influence of nHA on the adhesion, proliferation and differentiation of these alveolar bone-derived cells.MethodsPrimary human alveolar osteoblasts were collected from the alveolar ridge of a male periodontal patient during osseous resective surgery and grown on culture plates coated with either polylysine or polylysine with nano-hydroxyapatite (POL/nHA) composite. The cells were grown and observed for 14 days, and then assessed for potential modifications to osteoblasts homeostasis as evaluated by quantitative reverse transcriptase-polymerase chain reaction (real time RT-PCR), scanning electron microscopy and atomic force microscopy.ResultsReal time PCR revealed a significant increase in the expression of the selected markers of osteoblast differentiation (bone morphogenetic protein (BMP)-2,-5,-7, ALP, COLL-1A2, OC, ON) in cells grown on the POL/nHA substrate. In addition, as compared with the POL surface, cells grown on the POL/nHA substrate demonstrated better osteoconductive properties, as demonstrated by the increase in adhesion and spreading, likely as a result of the increased surface roughness of the composite.ConclusionsThe increased expression of BMPs and osteoinductive biomarkers suggest that nano-hydroxyapatite may stimulate the proliferation and differentiation of local alveolar osteoblasts and thus encourage bone regeneration at sites of alveolar bone regeneration.

An initial investigation on torsional properties of nickel‐titanium instruments produced with a new manufacturing method

A new manufacturing process involving twisting of a ground blank combined with heat treatment has been recently developed to produce nickel-titanium rotary files for root canal preparation. The aim of this study was to compare torsional resistance of prototype instruments produced using the new manufacturing method versus traditional nickel-titanium instruments produced by the customary grinding process. Twenty prototypes instruments of the same design and dimensions were divided in two groups of 10 each, according to the different manufacturing method. A file-testing apparatus specifically designed to perform torsional testing was used in accordance with the International Organization for Standardization 3630-1. The results indicated that instruments manufactured by the new manufacturing process demonstrated significantly higher average maximum torque levels than those manufactured by the existing grinding process (P < 0.05). Since instruments design and dimensions of the instruments were the same, the different manufacturing process could be the only explanation for this improvement in torsional resistance.

Patients with Peri-Implantitis, unlike Those with a Healthy Peri-Implant Microenvironment, Display Antibodies to More Than One Heat Shock Protein (HSP 27, HSP 65 and HSP 90) Linear Epitope:

The success of a dental implant treatment requires hard and soft tissue integration and osseointegration, mechanisms that entail a direct anchorage of the implant in the bone without interposition of soft tissue. Peri-implantitis is defined as an inflammatory reaction of the tissues surrounding a functioning dental implant. During inflammation, a high incidence of autoantibodies has been reported. The hypothesis of the present study is that the occurrence of autoantibodies to self-antigens including extracellular matrix (ECM) molecules and heat shock proteins (HSPs) might affect the dental implant outcome. Therefore, we evaluated the occurrence of antibodies to ECM molecules (Collagen (C) I, III, IV, V, fibronectin, laminin) and HSPs (HSP 27, HSP 65, HSP 90) in subjects with a healthy peri-implant microenvironment (n=29) as compared to patients with peri-implantitis (n=13). We also evaluated the HSP 27 expression in gingival fibroblasts grown in an inflammatory microenvironment. Antibodies to conformational ECM epitopes of CI, CIII and laminin were observed both in subjects with healthy peri-implant conditions and peri-implantitis. Antibodies to more than one HSP linear epitope were found in patients with peri-implantitis but not with healthy peri-implant conditions (p=0.024). Gingival fibroblasts grown in an inflammatory microenvironment showed increased HSP 27 cytoplasmic and plasma membrane expression as compared to fibroblasts grown in normal conditions. Immunity to multiple linear HSPs epitopes in patients with peri-implantitis and not in patients with a healthy peri-implant microenvironment might be relevant for monitoring the implant outcome and help to understand the role of subsets of autoantibodies in implant osseointegration.

Comparison of Conventional Methods and Laser-Assisted Rapid Prototyping for Manufacturing Fixed Dental Prostheses: An In Vitro Study

This study assessed whether there are differences in marginal fit between laser-fusion and conventional techniques to produce fixed dental prostheses (FDPs). A master steel die with 2 abutments was produced to receive a posterior 4-unit FDPs and single copings. These experimental models were divided into three groups (n = 20/group) manufactured: group 1, Ni-Cr alloy, with a lost-wax casting technique; group 2, Co-Cr alloy, with selective laser melting (SLM); and group 3, yttria-tetragonal zirconia polycrystal (Y-TZP), with a milling system. All specimens were cut along the longitudinal axis and their adaptation was measured at the marginal and shoulder areas on the right and left sides of each abutment. Measurements were made using a stereomicroscope (×60 magnification) and a scanning electron microscope (×800 magnification). The data were analyzed using one-way analysis of variance and the Bonferroni post hoc test, with a significance cutoff of 5%. Significant differences (P < 0.05) were observed between group 3 and the other groups. The marginal opening was smallest with Co-Cr alloy substructures, while the shoulder opening was smallest with Ni-Cr alloy substructures. Within the limitations of this study, the marginal fit of an FDP is better with rapid prototyping (RP) via SLM than conventional manufacturing systems.

Incidence and intensivity of postoperative pain and periapical inflammation after endodontic treatment with two different instrumentation techniques

Apical extrusion of infected debris to the periradicular tissues is considered one of the possible factors related to the occurrence of postoperative pain and inflammation. The goal of the present study is to evaluate and compare the incidence and intensity of postoperative pain using two different nickel-titanium instrumentation techniques: a rotary crown-down technique using TF instruments (SybronEndo, Orange, Ca, USA) and a reciprocating single-file technique using Reciproc instruments (VDW, Munich, Germany). Sixty patients requiring endodontic treatment on permanent premolar and molar teeth with non-vital pulps preoperatively were included in the study. The patients were divided into two groups of 30 patients each, trying to make the groups very similar, concerning the number of root canals, presence of initial pain and periapical lesions. The teeth in group 1 (n = 30) were treated with a crown-down technique using TF instruments whilst those in group 2 (n = 30) were treated with, a single-file technique using Reciproc 08 25. All canals were shaped, cleaned and obturated in a single-visit. The assessment of postoperative pain was carried out at 3 days by using a visual analogue scale. CAi-square tests and independent-sample t-tests to compare the incidence and intensity of postoperative pain of two groups were carried out. A statistically significant difference was found between the two techniques. When comparing patients who developed no pain, the TF instrumentation technique showed significantly better results (chi-square = 4.059 P = 0.039). When evaluating patients experiencing severe pain the incidence of symptoms was significantly higher with the Reciproc technique (chi-square = 7.246 P = 0.023). Since the incidence of preoperative pain, the type of tooth and the pulp and periodontal pathology were quite similar between the two tested groups, and all the other variables (operator, irrigation, and obturation) were identical, the difference in postoperative pain can be mainly related to the different instrumentation technique

Bisphosphonate and Osteonecrosis of the Jaw: The Oral Surgeon's Perspective

Bisphosphonates (BPs) are an important class of drugs, useful in the treatment of some metabolic and oncologic skeletal diseases. BPs have shown a sure effectiveness in the treatment and in the palliative care of such pathologies; on the other hand, an avascular osteonecrosis of the jaws (B-ONJ = Bisphosphonate OsteoNecrosis of the Jaw) has recently been reported as an adverse effect not only of BP intravenous infusions, but also of their prolonged oral administration. B-ONJ normally follows a dental extraction or other surgical procedure in the oral cavity, but it also can develop spontaneously. In the latter case, some systemic risk factors, such as comorbidities and co-therapies or jaw anatomical conditions, can play a leading role in the onset of this pathologic condition. B-ONJ is an uncommon but potentially serious complication of BP therapy that can gravely affect the patients quality of life, producing significant morbidity. To date, no therapies are completely effective and predictable in the treatment of B-ONJ, therefore prevention should be strongly promoted by sharing knowledge in the involved medical community.