TRANSECTION OF INFERIOR ALVEOLAR NERVE IN THE RAT - NEUROANATOMICAL STUDY AND EXPERIMENTAL MODEL.

OBJECTIVE: Experimental lesions in the inferior alveolar nerve (IAN) are used for the study of peripheral and central alterations. The objective of our study was to contribute to a more precise description of the approach to the IAN and creating a lesion. MATERIAL AND METHODS: Twenty-six males of Wistar laboratory rats were used for the study. The animals were divided into three groups: control group (6 rats), experimental group (12 rats - a part of the bone above the mandibular canal was removed under general anaesthesia using extraoral approach, after exposing a part of the IAN, the nerve was excised in a length of 3 mm), and a sham group (8 rats - the nerve was only dissected but not transected). Persisting denervation was verified using surgical revision and histological and immunohistochemical analysis after the observation period (4 weeks). RESULTS: No evidence of re-innervation after 4 weeks. We found no statistically significant differences in mean weight gains between individual groups during the observation period. CONCLUSION: The described technique used in the study is one of the possible ways to create a nerve lesion at the site of the main trunk of the nerve. At the same time, the study provides a more precise description of the anatomical situation and approach to the IAN in the mandibular canal.

Multielemental Chemical Analysis of Elements in Mandibular Bone and Teeth in the Rat.

The purpose of the study was to test the hypothesis of different distribution spaces of elements in the rat mandibular bone and teeth. We used six adult males of Wistar laboratory rats for the study. After killing the animals, we extracted the molars and removed incisor crowns. The mandibular bone was divided into four parts (mesial-central-distal-ridge). Inductively coupled plasma mass spectrometry was used to determine the presence of 41 elements in the bone and tooth. Evidence of 14 elements was found in all samples (incisors-molarsbone). Generally, significant differences between the left and right side were found for K and Rb in the bone locations. As regards statistically significant differences in incisors-molars-bone locations, the elements for which these differences were found for all comparisons are listed as incisors versus individual molars, incisors versus bone locations, and individual molars versus bone locations: a) incisors-molars: Ba, Mn, Mo, Sr, Zn, K, Mg and Rb; b) incisors-bone: Fe, K, Mg, Mn, Na, Zn and Ba; c) molars-bone: Mn, Mo, Na and Mg. Statistically significant differences were also found between molars for Fe, Mg, Mn, and Sr and between bone locations for Ba, Ca, Mn, Sr, K, Rb, Zn, Mo, Mg, and Na. The elements Cu, Ni and Co were without pronounced differences. Twenty-seven elements were below the detection limit. Our results indicate different distributions of some elements in the rat mandibular incisors-molars-bone. We assume that the knowledge of chemical element contents in the laboratory rat bone and teeth will prove useful in experimental research of both these hard tissues.

Multielemental Chemical Analysis of Elements in Mandibular Bone and Teeth in the Rat.

The original article was published in Folia Biologica (Praha) Volume 64, No. 3 (2018), 84-96.

Team approach in treatment of extensive maxillofacial defects - five case report serie.

Long-lasting functional and esthetic rehabilitation and good health-related quality of life of patients with maxillofacial defects is based on effective interdisciplinary cooperation especially of surgeons, dentists and technicians. Extensive defects occur after the first phase of the oncologic surgery and immediately after injuries. Subsequent plastic surgery is the initial step of functional reconstruction and creates a base for future fabrication of post-operative dentures and implant-born epitheses. Five clinical reports demonstrate complex rehabilitation of typical maxillofacial defects solved within the multidisciplinary cooperation. Four patients with oncological diagnoses and complex surgical treatment, resp. radio- and chemotherapy are reported with interim and long-term prosthetic solutions. One patient suffered from a congenital malformation. Titanium implants were inserted in defect bone margins using two-phase method. Healing time was at minimum three months and after this period superstructures were applied. Artificial eyes were made of both glass and acrylic materials. Retention of presented postoperative prostheses was reliable; patients were satisfied with the functional and esthetical results of the reconstruction. Prognosis of the rehabilitation depends on the histological stability of adjacent tissues, quality of osseointegration and durability of materials used (silicones, acrylates). Satisfactory health-related quality of life of these patients is based on the multidisciplinary healthcare.

RESULTS OF 15 YEARS OF COLLABORATION BETWEEN THE DEPARTMENTS OF OPHTHALMOLOGY AND STOMATOLOGY IN ONCOLOGICAL SURGERY OF THE ORBIT: A DIAGNOSTIC AND THERAPEUTIC APPROACH.

AIM: To report an overview of the most frequent tumors of the orbit, suggest diagnostic approach and possible solution according to experience with own cohort of patients. MATERIAL AND METHODS: From patients files from the Department of Ophthalmology and Department of Stomatology, First Medical Faculty, Charles University, and General Faculty Hospital in Prague, Czech Republic, there were selected patients, who underwent the surgery due to the suspicion of malignant development in the orbit during the period 2005 - 2019. From the surgical records we found information about 497 cases. At the Department of Stomatology, there were 282 surgeries under general anesthesia performed, and at the Department of Ophthalmology, there were 215 surgeries, mostly under local anesthesia performed. RESULTS: The number of surgeries in men and women was equal; patients of all ages were present. The median of patients age operated on at the Department of Stomatology was 53 years, and at the Department of Ophthalmology 63 years. The most common primary benign tumor was the cavernous hemangioma (9 %), the most common non-tumorous expansion was the dermoid cyst (7 %); the most common malignant tumor was the lymphoma (17,5 %). The last mentioned tumor was the most common diagnosis in the whole cohort as well. CONCLUSION: Our cohort of patients is comparable with large cohorts published in the literature concerning age and gender distributions. Differences in frequencies of some lesions may be explained by that our cohort includes patients after the surgery only. The malignant lymphoma is the most common diagnosis indicated to surgical procedure, mostly biopsy. Comparing the two cohorts from our departments 20 years apart, the malignant lymphoma remains the most common indication for surgery, but the incidence of adenomas and adenocarcinomas of the lacrimal gland decreased. It is not the goal of this paper to evaluate all possible orbital affections. Suggested surgical approaches are just recommendations according to years of experience; however, in some situations, to choose an individual surgical approach is necessary.

Individual replacement of the frontal bone defect: case report.

The objective of the skeletal defects reconstruction using individual implants is an attempt to replace lost and damaged anatomical bone structures, renew their original function, and at the same time, to restore the original aesthetic visual aspect. This work is focused on a demonstration of the design methods, fabrication and surgical techniques of the custom-made replacement of a large defect of the frontal bone on the skull. The patient was a 30-year-old woman with a defect of the frontal bone in the size of 7 x 3 x 2 cm after a serious polytrauma. The size and character of the defect excluded the use of commonly supplied augmentations. The geometry of the individual replacement was designed on the basis of a 3D model of the defect obtained from a series of CT scans. After verification of the shape accuracy of the defect made from plastic on a 3D printer, the individual replacement was fabricated from an ultra high molecular weight polyethylene (UHMWPE) by machining with the use of the CNC technology. The success of the augmentation depends on the accurate and precise fabrication of the individual replacement, which is highly demanding on the used advanced technologies.

Ozone and its usage in general medicine and dentistry. A review article.

Ozone, an allotropic form of oxygen, is successfully used in the treatment of different diseases for more than a hundred years. It is highly valued for various effects, such as antimicrobial, antihypoxic, analgesic, immunostimulating etc. on biological systems. These mechanisms of action supported with a lot of case reports and scientific studies allow using it in different fields of medicine. This review of literature is another attempt to summarize different modalities of ozone application in dentistry. Further studies are necessary to standardize indications and treatment protocols of this promising medical agent.

Analyses of the temporomandibular disc.

This project is the beginning of a large research work with a goal to develop a new total replacement of temporomandibular (TM) joint. First aim of this work was to determine the relative displacement of the TM disc and the mandible during mouth opening. The movement of the TM disc was studied using a magnetic resonance imaging. Sagittal static images in revolved sections of the TM joint were obtained in various positions of jaw opening from 0 to 50 mm. The results provided a description of the TM disc displacements as a function of jaw opening. The displacements of the mandible and TM disc were about 16 mm and 10 mm respectively at mouth opening of 50 mm, maximum rotation of the mandible was 34s. The results of these measurements can be used for clinical diagnostics and also they were used as inputs for the follows finite element analysis (FEA). Second aim of this work was to create stress and strain analysis of TM joint using non-linear FEA. Complex of TM joint consists of mandibular disc, half skull and half mandible during normal jaw opening. The results illustrate the stress distributions in the TMJ during a normal jaw opening.

Changing of facial skeleton for treatment of obstructive sleep apnoea syndrome.

Obstructive sleep apnoea syndrome (OSAS) is a potentially life-threatening disorder. It is characterized by at least five episodes of apnoea or hypopnoea during sleep lasting for more than 10 seconds. Apnoea or hypopnoea are accompanied by respiratory efforts. Changes of the facial skeleton by mandibular or maxillo-mandibular advancement belong to surgical techniques which might affect moderate and severe OSAS. In the surgical procedure mandible alone or the upper and lower jaws are moved forward by at least 10 mm. Thus also muscles fixed to the facial skeleton and upper airway dilatators are moved forward. The discussion also mentions possible complications and limitations of this surgical technique.

The examination of the temporomandibular joint on 1,5T magnetic resonance.

The most frequent intraarticular disorder of the temporomandibular joint (TMJ) represents the disorder of the functional relation between the articular disc and mandible condyle, i.e. dislocation of the articular disc. Magnetic resonance (MR) optimally visualizes the soft and hard articular tissues (articular disc, articular socket and condyle of the mandible) and its surroundings. The aim of the study was to evaluate findings of MR investigation of the TMJ. We investigated billateraly 26 patients with TMJ disorders during the years 1996 and 2003. All patients were examined on 1,5 T MR. Joints were studied in T1 and T2 weighted images with closed mouth and during mouth opening in dynamic study. MR verified dysfunction was observed in 48 investigated TMJ (92,3 %), hydrops of the joint was observed in 3 joints (5,8 %), arthrosis of the condylar head in 4 patients (7,6 %). Only four TMJ had normal MR finding (7,6 %). MR represents the best method for studying clinically affected joints, for the evaluation of the morphological state of TMJ and the analysis of the dynamic process during mouth opening. Method is also useful for revealing of a disorder in clinically silent joints. T2 weighted image in TSE mode brought best imaging of the joint. The fat saturation sequence was advantageous mainly in liquid storage (hydrops of the joint, edema in the adjacent bone). The dimensions of the articular cleft and bone components of the joint were well-visualized in T1 weighted images.

[Solitary "traumatic" mandibular cyst]. / Solitární "traumatická" cysta mandibuly.

A 34-year old man had an unusually localized cyst at the lower margin of mandibular body. It was sharply defined by X-rays. Microscopy showed necrotic masses with numerous cholesterol crystals and groups of lipophages which represented a solitary so called "traumatic" mandibular cyst. History of the case did not prove unequivocal relation to traumatic pathogenesis of the cyst.

[Classification of epithelial odontogenic tumors]. / Klasifikace epitelových odontogenních nádoru.

A retrospective series of 31 purely epithelial odontogenic tumours consisted of 21 ameloblastomas, 2 adenomatoid odontogenic tumours, 2 calcifying epithelial odontogenic tumours, and 6 calcifying odontogenic cysts. Modern histological classification gives an accurate picture of some of the structural and biological differences between the above types of tumour. In spite of the, their common basis does result in some of the common features so that the precise classification of the specific tumour may pose problems or give rise to terminological disputes. For practical work it will do in the group of epithelial odontogenic tumours to insist strictly on the basic condition of the absence of either proliferating mesenchyma or hard dental tissues. This requirement naturally leads to the placing of ameloblastic odontoma outside the field of purely epithelial odontongenic tumours. Judging the biological nature of epithelial odontogenic tumours according to their structure is not reliable, a fact brought out by comparisons of ameloblastoma and adenomatoid odontogenic tumours. Rather one could rely on the nature of tumour growth. An evidently carcindependent classification pattern. Suspicion of a higher degree of malignity can be expressed by description.

[Classification of epitheliomesenchymal odontogenic tumors]. / Klasifikace epitelomezenchymových odontogenních nádoru.

In a group of 34 epitheliomesenchymal odontogenic tumours no difficulties were encountered in recognizing the seven-member group of ameloblastic fibroma (with ameloblastic odontoma and dentinoma included as variants) as distinct from group of odontomas (ameloblastic o. - 2x, complex o. - 20x, combined o. - 5x) The definition is rather a general one with the distinction of variants only sometimes possible. No ameloblastic fibrosarcoma or ameloblastic odontosarcoma were seen in the group; therefore, the question should be asked whether it is really expedient to keep independent places in the classification for so rare tumours.

[Classification of mesenchymal odontogenic tumors]. / Klasifikace mezenchymových odontogenních nádoru.

A retrospective series of 9 purely mesenchymal odontogenic tumours was found to consist of 3 odontogenic fibromas, 2 myxomas, and 4 cementomas including one true benign cementoblastoma and two cementifying fibromas. One as seen to contain a conspicuously blood supplied proliferating fibrous component giving the tumour the appearance of a malignant process though no relapse was noted after the jaw resection. Periapical cement dysplasia was seen in only one case of the group; there was no case of gigantiform cementoma. The problems of mutual differential diagnosis and distinction from osteogenic tumours are subject to discussion.

Influence of the method of TM joint total replacement implantation on the loading of the joint on the opposite side.

The temporomandibular (TM) joint is one of the most used joints in the human body, and any defect in this joint has a significant influence on quality of life. The objective of this study was to create a parametric numerical finite element (FE) analysis to compare the effect of surgical techniques used for total TM joint replacement implantation on loading the TM joint on the other side. Our hypothesis is that for the optimal function of all total TM joint replacements used in clinical practice it is crucial to devise a minimally invasive surgical technique, whereby there is minimum resection of masticatory muscles. This factor is more important than the design of the usually used total TM joint replacements. The extent of muscle resection influences the mechanical loading of the whole system. In the parametric FE analyses, the magnitude of the TM joint loading was compared for four different ranges of muscle resections during bite, using an anatomical model. The results obtained from all FE analyses support our hypothesis that an increasing extent of the muscle resection increased the magnitude of the TM joint overloading on the opposite side. The magnitude of the TM joint overloading increased depending on the muscle resection to 235% for bite on an incisor and up to 491% for bite on molars. Our study leads to a recommendation that muscle resection be minimised during replacement implantation and to a proposal that the attachment of the condylar part of the TM joint replacement be modified.

[Diagnostic considerations apropos of a case of keratoacanthoma in a child]. / Considérations diagnostiques à propos d'un cas de kératoacanthome chez l'enfant.

A seven year old child presented with a keratoacanthoma, sometimes defined as a primary idiopathic pseudoepitheliomatous hyperplasia, on the mandibular alveolar process. The lesion showed typical proliferation of a tumoral nature, clinical manifestations and microscopic findings being those of a spindle cell carcinoma and easily mistaken for the latter. The solitary oral form of the tumor is a rare benign affection that does not recur after extirpation. A literature review identified only four similar cases.