Michele Runci

Effect of bisphosphonates on the mandibular bone and gingival epithelium of rats without tooth extraction

Osteonecrosis of the jaw (ONJ) is an adverse effect of bisphosphonate treatment that has become the subject of increasing investigations, in particular due to its poorly understood pathogenesis. Several experimental studies on animal models have been conducted; however, the majority of these replicate human ONJ following tooth extraction, and describe alterations in the bone and gingival epithelium when necrosis is manifested. The aim of the present study was to analyze the rat mandibular bone and gingival epithelium during 45 days of zoledronate treatment (which is a bisphosphonate agent), without tooth extraction. Intraperitoneal injections of zoledronate acid (0.1 mg/kg) were performed three times a week in normal male Wistar rats (n=20), while a control group of rats (n=20) was treated with saline solution for 45 days. After 7, 15, 30 and 45 days of drug treatment, all rats were sacrificed and hematoxilin and eosin staining, immunofluorescence and scanning electron microscopy analyses were performed. The results of the analyses after 7 and 15 days of treatment were similar in the treatment and control group. After 30 and 45 days of treatment, structural alterations were observed in the bone. No structural alterations to the gingival epithelium were observed. Based on these results, it was hypothesized that low doses of zoledronate act directly on the bone tissues to induce morphological alterations from bone to necrotic tissue following surgical procedures, although no cytotoxic effects were detected in the gingival epithelium.

Morphofunctional compensation of masseter muscles in unilateral posterior crossbite patients

Unilateral posterior crossbite is a widespread, asymmetric malocclusion characterized by an inverse relationship of the upper and lower buccal dental cusps, in the molar and premolar regions, on one side only of the dental arch. Patients with unilateral posterior crossbite exhibit an altered chewing cycles and the crossbite side masseter results to be less active with respect to the contralateral one. Few studies about morphological features of masticatory muscle in malocclusion disorders exist and most of these have been performed on animal models. The aim of the present study was to evaluate morphological and protein expression characteristics of masseter muscles in patients affected by unilateral posterior crossbite, by histological and immunofluorescence techniques. We have used antibody against PAX-7, marker of satellite cells, and against α-, β-, γ-, δ-, ε- and ζ-sarcoglycans which are transmembrane glycoproteins involved in sarcolemma stabilization. By statistical analysis we have evaluated differences in amount of myonucley between contralateral and ipsilateral side. Results have shown: i) altered fibers morphology and atrophy of ipsilateral muscle if compared to the contralateral one; ii) higher number of myonuclei and PAX-7 positive cells in contralateral side than ipsilateral one; iii) higher pattern of fluorescence for all tested sarcoglycans in contralateral side than ipsilateral one. Results show that in unilateral posterior crossbite hypertrophic response of contralateral masseter and atrophic events in ipsilateral masseter take place; by that, in unilateral posterior crossbite malocclusion masticatory muscles modify their morphology depending on the function. That could be relevant in understanding and healing of malocclusion disorders; in fact, the altered balance about structure and function between ipsilateral and contralateral muscles could, long-term, lead and/ or worsen skeletal asymmetries.

Histomorhological and clinical evaluation of maxillary alveolar ridge reconstruction after craniofacial trauma by applying combination of allogeneic and autogenous bone graft

A variety of techniques and materials for the rehabilitation and reconstruction of traumatized maxillary ridges prior to dental implants placement have been described in literature. Autogenous bone grafting is considered ideal by many researchers and it still remains the most predictable and documented method. The aim of this report is to underline the effectiveness of using allogeneic bone graft for managing maxillofacial trauma. A case of a 30-year-old male with severely atrophic maxillary ridge as a consequence of complex craniofacial injury is presented here. Augmentation procedure in two stages was performed using allogeneic and autogenous bone grafts in different areas of the osseous defect. Four months after grafting, during the implants placement surgery, samples of both sectors were withdrawn and submitted to histological evaluation. On the examination of the specimens, treated by hematoxylin and eosin staining, the morphology of integrated allogeneic bone grafts was revealed to be similar to the autologous bone. Our clinical experience shows how the allogeneic bone graft presented normal bone tissue architecture and is highly vascularized, and it can be used for reconstruction of severe trauma of the maxilla.

The Effect of Different Cleaning Protocols on Post Space: A SEM Study

Aim. Purpose of the present paper is to analyze the efficiency of different post-space irrigation protocols. Methods. 28 single rooted teeth were endodontically treated. After post-space preparation every sample was assigned to one of three experimental groups and to one control group. In each group different irrigation protocols were performed as follows: EDTA (Group A), 37% orthophosphoric acid (Group B), and EDTA + 37% orthophosphoric acid with ultrasounds activation (Group C). In the control group (Group D) the irrigate association was not activated by ultrasounds. Three zones (coronal, middle, and apical) of each sample were analyzed by using Scan Electron Microscopy (SEM) without any metallization procedures. The presence of smear layer on the canal surface was qualitatively evaluated by applying Serafinos score with values included between 0 and 2. Results. The results of the research showed how Group C recorded the better results (0.81 ± 0.72). Group A and Group B showed lower mean scores (1.06 ± 0.69 and 1.08 ± 0.77); Group D showed the lowest mean score of 1.30 ± 0.69. The SEM observation analysis demonstrated how the smear layer presence decreased in the crown-apical direction. Conclusions. The different post-space treatments statistically determine significant differences on the dentinal surfaces cleansing. The absence of ultrasonic activation lowers the cleansing efficacy of endocanalar irrigants, showing sensible differences among each post-space zone.

Facial and Orbital Fractures: A Fifteen Years Retrospective Evaluation of North East Sicily Treated Patients

Background: Orbital fractures are classified as diseases usually related to common midface trauma. It represents the most challenging treatment due to the complex anatomy, physiology, and aesthetic role. A midface trauma involves also the zygomatic complex and the nose, however the orbit fracture seems to be a more frequent disease due to its anatomical features. Objective: The purpose of this work is to retrospectively evaluate and record the frequency of the midfacial traumas and orbital fractures observed in the North Eastern Sicily. The results of the present data may be useful for the clinicians in order to recognize the kind of fracture just from the first general visit having a quick diagnosis and management. Methods: In the years between 2001 and 2016, about 1200 patients with midfacial trauma and about 100 patients involving the orbital floor have been evaluated. All those patients underwent the surgical fracture reduction and a CT scan follow up control at one month, three months, six months and one year. Results: Data showed high percentage of orbital floor, nose and mandibular body and ramus fractures; moreover the most frequent causes of fractures seem to be related to motor vehicle accident, followed by assaults, work and fall. Conclusion: The results have highlighted the changing trends in the causes of facial injuries, particularly the increasing incidence of assaults and the falling incidence of motor vehicle accidents in developed countries. The quick diagnosis and management proved fundamental for the successful treatment. Clinicians should be able to recognize the first symptoms in order to avoid possible complications.

Sarcoglycans and integrins in bisphosphonate treatment: immunohistochemical and scanning electron microscopy study.

Osteonecrosis of the jaw is an adverse outcome associated with bisphosphonate treatment. Bisphosphonates are used in conjunction with antineoplastic chemotherapy for the treatment of hypercalcaemia associated with malignancy, lytic bone metastasis and multiple myeloma. However, it is not known if the osteonecrosis of the jaw lesion originates in the bone or whether it initiates in the gingival epithelium. Two bisphosphonates are commonly used in cancer treatment. One of these is pamidronate disodium, a second-generation bisphosphonate that differs from the first-generation drug because it inhibits bone resorption at a dose that does not affect bone mineralization. The other widely used BP, zoledronate, is a third-generation drug that is the most potent bisphosphonate in clinical use, showing strong anti-osteoclastic activity, similar to pamidronate. The aim of the present study was to evaluate the modifications of human oral mucosa and underlying bone in patients after treatment with these nitrogen-containing bisphosphonates for 24 and 36 months. We analyzed the structural damage of the oral mucosa and damage of the perilesional mandibular bone observing possible correlations from them. Our results allow to express two hypotheses about the mechanism responsible for these results relating to mandible matrix necrosis; first, an increased skeletal microdamage associated with turnover suppression occurred early in treatment and progress with longer treatment duration, second, opening damage in osteonecrosis of the jaw modifies structural morphology of gingival epithelium.

Histochemical and morphological aspects of fresh frozen bone: a preliminary study

Bone graft are used in dentistry for the reconstruction of severely atrophic jaws. Fresh frozen bone has no osteogenic property but it has osteoconductive and osteoinductive properties because its matrix contains growth factors such as vascular endothelial growth factor. The purpose of the present study was to evaluate morphological and protein expression characteristics of fresh frozen bone before graft and after six months of graft in patients who needed maxillary reconstruction. After 6 month of graft we observed the presence of viable bone as evidenced by full osteocyte lacunae and by the presence of RANKR, osteocalcin positive cells and vascular endothelial growth factor. In conclusion, our findings show that the fresh frozen bone after six month of graft is for the most part viable bone, encouraging its use as an alternative to autogenous bone for reconstructing maxillary bone defects prior to implant.

Morphological and protein expression aspects of masseter muscle fibers and extracellular matrix in malocclusion disease.

Unilateral posterior crossbite is an asymmetric malocclusion characterized by an inverse relationship of the upper and lower buccal dental cusps on one side only of the dental arch. Patients with unilateral posterior crossbite exhibit altered coordination of the masseter muscles during mastication. Changes in masticatory musculature structure and function may be either developmental or adaptive (1) and they depend on the remodeling processes of muscle fibers and connective tissue (2). The aim here was to investigate morphological and protein expression aspects of masseter muscle fibers and of extracellular matrix in malocclusion disease. Three patients, affected by unilateral posterior crossbite, were recruited to participate in this study; biopsies of masseter muscle have been withdrawn from left and right sides for each patients. We performed histological colorations and immunofluorescence reaction using antibody against Myf-5, MyoD, fibronectin, collagen I, III, IV and laminin. Results of crossbite side have shown altered fibers morphology, consistent increase of extracellular matrix and its proteins; a lower number of Myf-5 and MyoD positive cells than contralateral side has been observed. In contralateral side we observed normal muscle fibers and extracellular matrix morphology, a lower expression of extracellular matrix proteins and an higher number of Myf-5 and MyoD positive cells than crossbite side. These findings suggest us that in contralateral side, the high workload determines an hypertrophic response of muscle fibers, evidenced by the high number of Myf-5 and MyoD positive cells and probably an increased turnover of extracellular matrix which is poorly represented; the crossbite side muscle, instead, seems to show alterations of the remodeling processes as evidenced by the reduction of fibers dimension in favor of an increase of the extracellular matrix components. That could be relevant in understanding and healing of malocclusion disorders.

Mandibular bone and gingival epithelium during bisphosphonates treatment: an experimental study

Bisphosphonates (BP) are stable analogues of pyrophosphate with a P-C-P structure and 2 side chains attached to the carbon atom. Intravenous bisphosphonates are primarily used and effective in the management of cancer-related conditions in the context of solid tumors, such as breast cancer, prostate cancer, and lung cancer. Moreover bisphosphonates are subministred to patients with metabolic bone disease such as osteoporosis and Paget disease. Bisphosphonate-associated osteonecrosis of the jaws (BONJ) is a really complication of intravenous bisphosphonates therapy in patients with cancer. It is common knowledge that the jaws have a greater blood supply than other bones and a fasterbone turnover rate, related both to their daily activity and presence of teeth which mandates daily bone remodeling around the periodontal ligament; moreover bisphosphonates toxicity to epithelial cells has been well documented. On this basis, the aim of this experimental study is to evaluate the pathological changes of the mandibular bone and oral mucosa in rat treated with bisphosphonates. In details we have analyzed, by immunoistochemical and scanning electron microscopic methods, biopsy of mandibular bone and of gingival mucosa in rat treated with bisphosphonates after 7, 15, 30, 45, 60 days of assumption of drugs and after 7 and 30 days from the end of the treatment. Our results show great area demineralization bone mixed to normal bone, moreover in the demineralization bone it’s possible to observe numerous micro lacunae. In the correspondence samples of gingival epithelium we observe changes of histological structure and the disappearance of protein adhesion system cells to cells and cells to matrix. On this basis it is intriguing to speculate that the adverse effects of BP on oral epithelium may play a critical role in the initiation of BONJ an “outside-in” hypothesis.

DT-MRI study on masticatory muscles in normal and pathological subjects

In our recent research we tested the use of DTI in the study of muscles, considering anatomical and clinical application. We have demonstrated the possibility to detect even minor muscle injuries of athletes undetectable with traditional ultrasound techniques. In this report we intend to apply this method to the study of the anatomical and volumetric masticatory muscles and particularly of masseter muscle. We selected a sample of 5 healthy subjects and 5 patients with cross-bite. Our results demonstrate the possibility to distinguish, on the basis of the different orientation of the muscle fibers, masseter muscles from pterygoid muscles. In addition, with post-elaboration of DTI anisotropy map, we evaluated different masticatory muscles density revealing their reduction along cross-bite side and a light increment in contralateral muscle. These evidences confirm our previous results obtained with elettromiography and histochemistry techniques.