Giovanni Pietro Pilolli

Histologic and histomorphometric features of bisphosphonate-related osteonecrosis of the jaws: An analysis of 31 cases with confocal laser scanning microscopy

INTRODUCTION Patients undergoing bisphosphonate therapies may develop jaw lesions, mainly consisting in bone necrosis. No effective treatment has been proposed so far for such lesions, nor is there a uniform concept on the possible pathogenesis of this entity. METHODS The study population included 31 patients with bisphosphonate-related osteonecrosis of the jaws and 10 healthy donors. All patients underwent to jaw bone biopsy and the tissue samples were divided into two parts, one of which was fixed, decalcified and routinely processed. The second part was fixed, embedded in methylmetacrylate, cut and stained with methylene blue and basic fuchsine. All samples were subjected to light and confocal microscopic examination and to histomorphometric analyses to evaluate differences in bone structure between the two samples groups. RESULTS Three main histological patterns were identified in ONJ patients: 1 - Areas with active acute inflammation, characterized by predominance of soft tissues, inflammatory infiltrate, acellular necrotic debris, thin-walled and dilated blood vessel, intensely basophilic bone spiculae with scalloped borders showing prominent bone resorption. 2 - Areas characterized by predominance of bony structures showing wide acellular necrotic sequestra and large, scalloped Haversian canals containing inflammatory cells. 3 - Non-necrotic areas contained larger amounts of bone, showing increased trabecular thickness, inter-osteonic bone deposition and smaller and fewer Haversian canals. These differences were more evident after comparing the histomorphometrical data of samples from ONJ patients with controls. Also, lamellar bone from treated patients was composed of bigger osteones containing larger osteocytes. Two different types of newly-formed woven bone, mainly showing centrifugal spatial orientation, were easily detectable in these areas. Osteoclast-like cells detected in inflammatory areas from treated patients were small and contained few nuclei, but they were rare to absent in non-necrotic bone from the same patients. CONCLUSIONS These features point at a peculiar process of bone remodeling in patients undergoing bisphosphonate therapy, which showed scarce osteoclastic activity and subsequent deposition of newly-formed bone. The latter would be made up of thicker bone structures supplied by fewer blood vessels. Consequently, in case of increased metabolic requests, this modified bone would not be supported by adequate blood supply, thus leading to necrosis and superinfection.

Osteonecrosis of the Jaw Correlated to Bisphosphonate Therapy in Non-oncologic Patients: Clinicopathological Features of 24 Patients

Objective. Osteonecrosis of the jaws (ONJ) is a well known side effect of bisphosphonate therapies in patients with multiple myeloma or other malignancies. Its real incidence is still undetermined, and only few cases of ONJ in patients taking bisphosphonates for non-oncologic diseases have been reported. It was postulated that the clinical features, predisposing factors, and treatment outcome of this subset of patients might be different from those of oncologic patients. Methods. Over a 4 year period, a total of 102 bisphosphonate-treated patients affected by ONJ were identified. Among these, 24 patients underwent bisphosphonate therapy for non-neoplastic disease and their profile was analyzed. Results. In this study cohort, bisphosphonates had been administered mainly for postmenopausal osteoporosis (20/24 patients, 83.3%), the duration of therapy until presentation of ONJ ranging from 11 to 40 months and the most common triggering event being dentoalveolar surgery. All patients were nonsmokers; 6 manifested multiple ONJ lesions and only 3 of them had possible comorbidities. Surgical debridement was performed in 19 patients for a total of 22 lesions, which were individually considered in the followup. The latter showed complete remission of ONJ in 21/22 lesions. Conclusion. Although it might be considered a rare condition in non-oncologic patients, ONJ is a harmful side effect of bisphosphonate therapies. Clinicians must be aware of this entity, inform patients of the risks related to dental surgery, and possibly undertake adequate preventive measures.

Analysis of Collagen Distribution in Human Crown Dentin by Confocal Laser Scanning Microscopy

The authors used confocal laser scanning microscope to analyze human crown dentin. Specimens from 10 teeth were divided in two groups, one of which was decalcified and stained with hematoxylin and eosin. In the second group an undecalcified section was analyzed. Both groups were scanned by confocal microscope to generate optically sectioned images. All of the analyzed samples presented an intense autofluorescent that was ascribed to collagens. The degree of autofluorescence intensity was variable and might be due to collagen expression. The results indicate that a confocal microscope may be of help in analyzing and defining the nature and extent of collagen fibrils in human dentin.

Calcifying Odontogenic Cysts Associated with Odontomas: Confocal Laser Scanning Microscopy Analysis of 13 Cases

The so-called calcifying odontogenic cyst (COC) represents a heterogeneous group of lesions that exhibit a variety of clinico-pathologic features. It is an uncommon lesion and represents less than 2% of all odontogenic cysts and tumors. Recently, these lesions have been reclassified as calcifying cystic odontogenic tumors (CCOT), according to the new World Health Organization (WHO) classification. CCOT are frequently found in association with, or containing areas histologically identical to, various types of odontogenic tumors, such as complex/compound odontomas. This work analyzed clinical and histological data deriving from 13 patients affected by CCOT associated with odontomas. Moreover, a confocal laser scanning microscope (CLSM) analysis was undertaken to further a better understanding of the nature of this peculiar lesion.

New Approach for Static Bone Histomorphometry: Confocal Laser Scanning Microscopy of Maxillo-Facial Normal Bone

To define the value of confocal laser scanning mcroscopy (CLSM) as a practical method for a qualitative and quantitative analysis of hard tissue, the authors have analyzed normal maxillo-facial bone. They obtained and analyzed 58 bone samples from 28 patients who underwent to implant surgery. All the samples presented intense autofluorescence primarily ascribed to collagen. Variable degrees of autofluorescence have been identified between osteones and interosteonic bone. CLSM allowed improved tissue imaging, bidimensional pictures with better resolution at cellular level, and, in particular, the possibility of different histomorphometric evaluation. The application of CLSM to bone histomorphometry represents a new and never described technique, which might produce many insights in the study of normal and pathological bone.

Confocal laser scanning microscopy of liesegang rings in odontogenic cysts: analysis of three-dimensional image reconstruction.

Liesegang rings are concentric noncellular lamellar structures, occasionally found in inflammatory tissues. They have been confused with various parasites, algas, calcification, and psammoma bodies. The authors examined Liesegang rings from oral inflammatory cysts by both optical and confocal laser scanning microscopy, and perfomed a three-dimensional reconstruction. These investigations indicate that Liesegang rings are composed of multiple birefringent concentric rings, resulting from a progressive deposition of organic substances, with an unclear pathogenesis.

Diode Laser Excision of Chondroid Lipoma of the Tongue with Microscopic (Conventional and Confocal Laser Scanning) Analysis

OBJECTIVE We describe a case of chondroid lipoma of the oral mucosa, which represents an unusual histological type of oral lipoma. Though its use is still debated, we used a diode laser to perform complete excision of the lesion, and histologically analyzed the specimen. BACKGROUND DATA Lipomas represent 0.1-5% of all benign oral neoplasms. Chondroid lipoma is a rare histological type first described in 1993; only a few cases have been described in the literature. Its clinical diagnosis is difficult because the clinical appearance is not specific. METHODS The lesion was excised by diode laser and the specimen was histologically evaluated using both conventional and confocal laser scanning microscopy. RESULTS The final diagnosis was lipoma (chondroid variant). Diode laser had several benefits in the clinical application and in the histological evaluation due to the lack of morphological and structural alterations of the surgical specimen. CONCLUSION We maintain that the diode laser is a useful electromedical device for surgery on both benign and malignant oral lesions, though good practice is mandatory in order to apply the best parameters to the clinical situation. When the preoperative biopsy is not performable because of small dimension, as in the reported case, surgical excision of all nodular lesions of the oral mucosa should be performed with lateral and deep margins distant from the central lesion. This prevents possible complications related to a possible final diagnosis of malignant neoplasm; in fact, the differential diagnosis in the reported case also included liposarcoma.