Biogas production from cheese whey wastewater: laboratory- and full-scale studies.

A two-phase system for biogas production from cheese whey wastewater (CWW) was designed, set up and operated at laboratory and full scale for a whole cheese production season (8-9 months). The high efficiency and stability of the laboratory-scale system was demonstrated under various organic loading rates (OLRs) reaching 13 g chemical oxygen demand (COD) L(-1)d(-1) and producing up to 9 L L(-1)d(-1) of biogas (approximately 55% in methane). The COD removal was above 95% and the pH was maintained above 6.3 without any chemical addition. The full-scale system was operated at lower OLRs than its normal capacity, following the good response and high stability in disturbances of the laboratory-scale unit.

Parapharyngeal space tumors: surgical approaches in a series of 13 cases.

Tumors originating in the parapharyngeal space are rare; they comprise approximately 0.5% of head and neck tumors. Most (70-80%) are benign and the most frequent origins are salivary and neurogenic. The aim of this study is to present the surgical procedures used for the treatment of 13 patients with parapharyngeal space tumors; 11 of them were suffering from benign tumors (the most frequent being pleomorphic adenoma; 8 cases) and 2 from malignant lesions. The following surgical approaches were used: intraoral (2 cases), transcervical (4 cases) and transmandibular (7 cases) with different types of mandible osteotomies. The type of surgical approach was dictated by the type of the lesion (malignant or benign), the exact location, the size, the vascularity and the relation of the tumor to the neck neurovascular bundle. In all cases the selected surgical approach allowed the complete resection of the tumor, obtaining clear margins in cases of malignancy, without adding to the patient's preoperative morbidity. It was concluded that the surgical approach to the parapharyngeal space tumors must be adjusted to the tumor characteristics and be as wide is necessary to achieve its complete removal with safety.

Nuclear fractal dimension as a prognostic factor in oral squamous cell carcinoma.

Strong theoretical reasons exist for using fractal geometry in measurements of natural objects, including most objects studied in pathology. Indeed, fractal dimension provides a more precise and theoretically more appropriate approximation of their structure properties and especially their shape complexity. The aim of our study was to evaluate the nuclear fractal dimension (FD) in tissue specimens from patients with oral cavity carcinomas in order to assess its potential value as prognostic factor. Relationships between FD and other factors including clinicopathologic characteristics were also investigated. Histological sections from 48 oral squamous cell carcinomas as well as from 17 non-malignant mucosa specimens were stained with Hematoxylin-Eosin for pathological examination and with Feulgen for nuclear complexity evaluation. The sections were evaluated by image analysis using fractal analysis software to quantify nuclear FD by the box-counting method. Carcinomas presented higher mean values of FD compared to normal mucosa. Well differentiated neoplasms had lower FD values than poorly differentiated ones. FD was significantly correlated with the nuclear size. Patients with FD lower than the median value of the sample had statistically significant higher survival rates. Within the sample of patients studied, FD was proved to be an independent prognostic factor of survival in oral cancer patients. In addition this study provides evidence that there are several statistically significant correlations between FD and other morphometric characteristics or clinicopathologic factors in oral squamous cell carcinomas.

Gingival fibromatosis and significant tooth eruption delay in an 11-year-old male: a 30-month follow-up.

This case report describes the dental management of an unusual case of idiopathic gingival fibromatosis with multiple impacted primary teeth, and the absence of eruption of permanent teeth, in an 11-year-old boy and at the 30-month follow-up. The patient presented with severely enlarged gingival tissues affecting both arches and multiple retained and non-erupted primary teeth. He had already been subjected to localized gingivectomies at the ages of 7 and 9 years. He had no known syndrome and there was no family history of any similar disorder. The patient was treated under general anaesthesia to remove the excessive gingival tissues using apically positioned flaps. During the surgical procedure, over-retained and unerupted impacted primary teeth were extracted in order to facilitate the eruption of the permanent successors. Two years postoperatively, there was no recurrence of the gingival enlargement. Overdentures were then constructed because none of the permanent teeth had yet erupted. Furthermore, pre-eruptive coronal resorption was detected radiographically affecting the crown of the unerupted 36. Thirty months postoperatively, no recurrence of gingival enlargement was seen, but the permanent teeth had still not erupted.

Epidermal nevus syndrome with development of a mandibular ameloblastoma.

Epidermal nevus syndrome (ENS) is a hamartoneoplastic syndrome characterized by the association of epidermal nevi with abnormalities in other organ systems. We report a 32-year-old woman with ENS that, in addition to cutaneous manifestations, showed red plaques on the maxillary and mandibular labial alveolar mucosa and a papillomatous lesion of the midline posterior hard palate. Radiographic examination of the jaws was noncontributory. Approximately 5 years later, a follicular ameloblastoma developed in the mandible. The tumor showed duct-like cystic spaces, continuity with the overlying epithelium, and globular myxomatous areas in the connective tissue. The palatal lesion was diagnosed as papilloma, whereas the maxillary plaques showed nonspecific mucositis. The association of ameloblastoma with ENS is discussed. This is the second case of ENS associated with ameloblastoma reported in the medical literature.

The use of the buccal fat pad for reconstruction of oral defects: review of the literature and report of 15 cases.

PURPOSE: Although the buccal fat pad (BFP) was originally used as an alternative method for the closure of small to medium-sized oroantral and oronasal communications, its use has now been extended to use after excision of oral malignancies. This report describes experience with this technique. PATIENTS AND METHODS: The BFP was used as a pedicled graft to reconstruct medium-sized surgical defects of the oral soft and hard tissues in 15 patients suffering from oral malignant tumors. Six of the defects were in the maxilla, 3 in the retromandibular area, and 6 in the cheek and oral commissure. The BFP was left uncovered to epithelialize in 14 patients, and in one it was covered with lyophilized dura. RESULTS: The BFP healed without complications within 3 to 4 weeks in 13 patients, whereas in 2 patients with maxillary defects there was partial loss of the graft, requiring the additional use of an obturator in 1 case and a tongue flap in another to prevent oronasal leakage. Harvesting the graft proved to be extremely easy, and care was only necessary to avoid severing the supporting vascular plexus and the thin capsule covering the BFP. CONCLUSIONS: The findings support the view that the BFP is a useful, easy, and uncomplicated alternative method for the reconstruction of small to medium-sized surgical defects of the oral hard and soft tissues.

Functional stress modification after high condylectomy surgery.

Surgical removal of the head of the condyles inevitably leads to radical redistribution of loads applied to the mandible. The nature of this redistribution can have important implications on the surgical approach and subsequent reconstructive procedures. The purpose of this investigation was to visualize photoelastically the functionally delivered stresses after high condylectomy surgery. Three identical models of a dentate human mandible were constructed from a photoelastic material. One mandible simulated a unilateral and the other simulated a bilateral high condylectomy. The third mandible had both condyles intact and served as basis for comparisons. Silicone implants were placed on the sectioned condylar heads. The condyles, with the silicone implants, were fitted into simulated fossae and the mandibles were loaded unilaterally and bilaterally. The resulting stresses were observed and photographed in the field of a circular polariscope. Substantial differences in load-generated stresses were observed as a result of both unilateral and bilateral condylectomies, compared to the normal case. The most severe stress conditions occurred with the unilateral condylectomy, where stresses associated with torsion were most evident.

A new endodontic stabilizer implant device.

A new endodontic stabilizer implant device is presented that can be used immediately after enucleation of large periapical cysts. The force transmission characteristics of this implant were evaluated by means of photoelasticity. The implant served to distribute incisal forces within the supporting structure. Improved stress conditions resulted at the tooth apex and between the apex and the superior border of the implant when the tooth was subjected to apicoectomy.

Distribution of stresses in the human skull.

A three-dimensional photoelastic model was reproduced from a human skull. The insertions of the superficial and deep portions of the masseter muscle, the temporalis muscle, the medial pterygoid muscle and the temporalis fascia were simulated with leather bonded to the appropriate areas. The following loading conditions were employed: (i) all three muscles were bilaterally loaded without occlusal loads; (ii) all three muscles were bilaterally loaded while occlusal loads were simultaneously applied on the maxillary teeth. The stress freezing technique was used to lock the resulting stress patterns into the model skull. The stress trajectories were observed and photographed in a circular polariscope. The mandibular closing muscles and the occlusal loads produced stresses which progressed through the maxilla, following a nasal, a zygomatic and a pterygoid route, while stress concentrations were seen in the frontonasal, zygomaticomaxillary and the pterygopalatine sutures. In the malar bone area the stresses were seen to branch superiorly to the frontozygomatic suture and posteriorly along the zygomatic arch to the zygomaticotemporal suture and the temporal bone. Generally, the stresses were concentrated in those areas of the skull where architectural reinforcement had been demonstrated by other methods.

Periodontal ligament changes in patients with progressive systemic sclerosis.

Progressive systemic sclerosis (PSS) is a generalized collagen disease which has oral manifestations, including widening of the periodontal ligament (PDL) space. The purpose of this study was to measure the extent of thickening of the PDL space in a group of 26 patients with PSS and in a similar group of age and sex-matched control patients. The width of the PDL was measured from periapical radiographs at four sites around seven selected teeth for every patient. The mean PDL width was found to be larger in all the patients with PSS than in the control patients, around both anterior and posterior teeth. One third of the teeth of patients with PSS had PDL widths thicker than the range observed in the control patients. When average thickness of PDL widths for each patient is compared, at least 65% of the patients with PSS have mean PDL widths which are greater than the range for control patients. The increased thickness of the PDL space associated with PSS is more pronounced in posterior teeth than in anterior teeth.