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PubMed2006

Formation of new bone during vertical distraction osteogenesis of the human mandible is related to the presence of blood vessels.

We examined the effect of distraction rate on blood vessel growth in intramembraneous ossification after vertical distraction osteogenesis in the human mandible. Six edentulous patients (aged 60+/-9 years) with a severely atrophic mandible underwent bone augmentation with distraction osteogenesis. Two distraction rates (0.5 and 1 mm/day) were compared and for each group three patients were analyzed. Vascular histomorphometry was carried out in two different areas in the distraction gap: (1) in the first and (2) in the second 1 mm area from the osteotomy line, representing the oldest and younger new-bone area, respectively. Correlation analysis was performed between blood vessel parameters and the amount of new bone formed during distraction. Histological analysis demonstrated the presence of blood vessels throughout the soft connective tissue in the distraction gap. The volume density of blood vessels between the two investigated areas was significantly lower in the 1 mm/day groups, suggesting a delay in angiogenesis in this group of patients. A positive correlation between blood vessel volume and bone volume density was found in the younger new-bone area but not in the oldest new-bone area. This correlation was due to a higher number of blood vessels rather than to a larger size of the blood vessels. Our data suggest that the lower blood vessel density found in the patients with 1 mm/day distraction rate may be related to disruption of angiogenesis in the soft connective tissue of the gap or to a less optimal mechanical stimulation of cells involved in angiogenesis. This probably results in the slower rate of osteogenesis seen at the 1 mm/day distraction rate compared with the 0.5 mm/day distraction rate. The data support the concept that a positive relationship exists between the density of blood vessels and the formation of bone. For distraction of the human mandible in elderly patients, a distraction rate of 0.5 mm/day seems beneficial.

Age Factors↗
PubMed2007

Fully vs. partially rough implants in maxillary sinus floor augmentation: a randomized-controlled clinical trial.

OBJECTIVES: To compare implants with a rough surface in their whole length (FR) with implants having a 2 mm coronal machined portion (PR) when used in association with a sinus-lift procedure. MATERIAL AND METHODS: Twenty-six patients with 2 mm< or =x< or =9 mm residual alveolar crest were prosthetically restored with implants after a staged sinus-lift procedure using osteotomes. In 13 randomly chosen patients, no more than one FR implant was placed (test group), while the rest were PR implants. The other 13 patients received only PR implants (control group). For comparisons, only one implant from each patient was used, i.e., from the test group only the 13 FR implants were used, while from the control group, one PR implant was randomly chosen. The presence/absence of plaque, BOP, PPD and REC were registered at the day of delivery of the restorations and after 1 year. Residual alveolar crest height and marginal bone levels around the implants were evaluated on standardized periapical radiographs taken at various stages. RESULTS: Four FR and two PR implants were lost, and the cumulative survival rate was 82.9% (six lost out of 35). There were no significant differences between the two groups. Implant type, residual alveolar crest height, time of osseointegration, time of implant loading and smoking did not seem to influence implant survival. CONCLUSIONS: FR and PR implants placed in augmented sinuses did not differ in their clinical performance.

Alveolar Process↗
PubMed1992

Buccal attachment loss in Swedish adolescents.

A case referent study was performed to identify factors connected with loss of buccal attachment in adolescents. The study group was identified among 18-year-olds who had participated 2 years earlier in a study of periodontal conditions in adolescents. The criterion for inclusion in the case group was buccal attachment loss (greater than or equal to 1 mm) in one or more sites. Information on 28 variables, identified earlier as being related to recessions, was collected in a clinical examination, interview and observation. The referent group consisted of 66 subjects and the case group of 71 subjects. The case group comprised 2 subgroups, one identified as having buccal attachment loss in 1987 and the other with attachment loss occurring in the years 1987-89. Statistical analyses, using the chi 2 test, logistic regression and a variance component model, were performed to detect factors related to buccal attachment loss. These factors were thin alveolar tissue, narrow width of the attached gingiva and presence of teeth with buccal displacement. The results indicate that the anatomy of the buccal alveolar process is related to the presence of buccal attachment loss in populations with a high level of oral hygiene. To evaluate the importance of possible risk factors or etiological factors for development of buccal loss of tooth support, prospective epidemiological or experimental studies are needed.

Adolescent↗
PubMed1994

The topography of the vascular systems in the periodontal and peri-implant tissues in the dog.

The present investigation reports an animal experiment the objective of which was to study the vascular topography of the periodontium and the peri-implant soft and hard tissues in the beagle dog. 2 beagle dogs were used. The right mandibular premolars were extracted and healing allowed for 3 months. 2 titanium fixtures a.m. Brånemark were installed in the right premolar region. Abutment connection was performed 3 months later. The contra-lateral mandibular sites were used as tooth harboring control units. A 4-month period of meticulous plaque control was initiated. A clinical and radiographical examination was performed towards the end of this period and revealed that the gingiva and peri-implant mucosa were clinically healthy and that the bone tissue at teeth and implants had a normal height. The carotid arteries were perfused with a mixture of carbon and calf serum. 2 bucco-lingual sections, about 100-150 microns thick, and one mesio-distal section comprising the junctional epithelium and underlying connective tissue were sampled. The sections were treated, cleared and examined in a microscope. The results of the present investigation demonstrated that the vasculature of the gingiva and the supracrestal connective tissue at teeth is derived from two sources, namely the supraperiosteal vessels lateral of the alveolar process and the vessels of the periodontal ligament. The blood vessels of the peri-implant mucosa were found to be terminal branches of larger vessels originating from the periosteum of the bone of the implant site.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2005

Healing of extraction sockets and surgically produced - augmented and non-augmented - defects in the alveolar ridge. An experimental study in the dog.

OBJECTIVES: The current experiments had three aims (i) to determine whether the absence of the periodontal ligament (PDL) may alter features of the healing of an extraction socket, (ii) to examine if there were differences in the proportion of different tissues in resolved extraction sockets and surgically produced defects after 3 months of healing, (iii) to study the influence of different biomaterials on the healing of surgically produced bone defects. MATERIAL AND METHODS: Extraction sites: In five dogs, the 4th mandibular pre-molars were hemi-sected and the distal roots were removed. The extraction socket of one of the pre-molars was instrumented to eliminate all remnants of the PDL tissue. The socket of the contra-lateral pre-molar was left without instrumentation. The dogs were sacrificed after 3 months of healing. Defect sites: In five dogs, the pre-molars and 1st molars on both sides of the mandible were first removed and 3 months of healing allowed. After this interval three standardized cylindrical defects were prepared in each side of the mandible. The defects were 3.5 mm in diameter and 8 mm deep. In each quadrant one defect was grafted with Bio-Oss Collagen, one with Collagen Sponge and one defect was left non-grafted. The dogs were sacrificed 3 months after the grafting procedure. RESULTS: Extraction sites: The two categories of extraction sockets did not differ with respect to gross morphological features. The tissue of the extraction sites, apical of a newly formed bone bridge, was dominated by bone marrow. Few trabeculae of lamellar bone were also present. Defect sites: The non-augmented defect was sealed by a hard-tissue bridge. In the central and apical portions of the defect bone marrow made up about 61%, and mineralized bone 39% of the tissues. The invagination of the surface of this crestal bone was 0.8+/-0.3 mm. The defect augmented with Collagen Sponge was covered by a hard-tissue bridge 38% of the tissue within the defect was made up of bone marrow while the remaining 62% was occupied by mineralized bone. The invagination of the hard-tissue bridge was on the average 0.6+/-0.1 mm. In defects augmented with Bio-Oss Collagen the biomaterial occupied a substantial portion of the tissue volume. Eighty-five percent of the periphery of the Bio-Oss particles were found to be in direct contact with newly formed mineralized bone. Woven bone and bone marrow made up 47% and 26% of the newly formed tissue. The invagination of the most coronal part of the bone defect was 0.1+/-0.1 mm. CONCLUSION: Sockets that following tooth removal had their PDL tissue removed exhibited similar features of healing after 3 months as sockets which had the PDL retained. The tissues present in an extraction site appeared to be more mature than those present in a surgically produced defect of similar dimension. The Bio-Oss Collagen augmented defect exhibited less wound shrinkage than the non-augmented defect.

Alveolar Process↗
PubMed1975

Periodontal status of neighboring teeth after orthodontic closure of mandibular extraction sites.

The gingival health, pocket depth and loss of fiber attachment of the mandibular first molars and first premolars were studied by clinical and radiographic methods after the embedded second premolar had been surgically removed on one side and extracted after eruption on the other, and the spaces had been closed orthodontically. Twenty-nine children participated in the study. Their mean age at the time of tooth removal was 11 years 3 months. The mean duration of the treatment was 20 months, and the children were examined 1 1/2 to 2 years after removal of the bands. The gingival status was generally similar on both sides. Some constriction of the alveolar process was observed in more than half the cases, both after extraction and after surgical removal. The loss of attachment on the buccal and lingual surfaces was approximately the same in both groups, whereas the radiographic distance from the cementoenamel junction to the bone margin on the proximal surfaces adjacent to the removed tooth was somewhat greater after extraction than after surgical removal.

Child↗
PubMed1998

Regeneration of periodontal ligament and cementum by BMP-applied tissue engineering.

Previously, we demonstrated that the inductive properties of bone morphogenetic protein (BMP) highly depend on the nature of the carrier material used for implantation. In this paper, we show that administration of BMP incorporated in a fibrous collagen membrane can help to regenerate periodontal ligament and cementum both in cat canines and in monkey molars. The partially purified bovine BMP was combined with one or two layers of a fibrous collagen membrane. Although the single layer approach showed partial regeneration of periodontal defects, it also quite often led to ankylosis. The double layer technique in artificially prepared class III furcation defects in monkey molars gave favorable results. After 12 wk, not only the alveolar process but also the periodontal ligament and cementum had regenerated along the entire treated dentin surface. Collagen fibers were arranged more or less perpendicular to the surface of the new cementum. Ankylosis was not seen. It is concluded that the double-layer approach is superior to the single-layer technique in regenerating cementum.

Animals↗
PubMed2004

Morphometric analysis of the mandible in growing rats with different masticatory functional demands: adaptation to an upper posterior bite block.

Functional appliances displace the mandible forward and/or downward, causing a stretching of the orofacial soft tissues, muscles included. The resulting forces are directly or indirectly transmitted to the underlying dento-skeletal tissues. The hypothesis underlying the present investigation was that the insertion of a bite-opening appliance influences the lateral morphology of the rat mandible during growth, and that, moreover, this influence depends on the masticatory functional demands. One-hundred and four 4-wk-old male albino rats were divided into two groups, fed a hard and soft diet, respectively. After 2 wk, half of the animals in each experimental group were fitted with upper posterior blocks, and 4 wk later they were killed. Their left hemi-mandibles were transilluminated, photographed under magnification, and digitized on screen. A total of 170 points were used to draw the lateral outline of the mandible. In addition to the inhibitory effect on the height of the dento-alveolar process, the upper bite block resulted in significant changes in the condyle inclination, the length of the coronoid process, and the occlusal plane inclination. Masticatory functional demands influenced this adaptation in an additive way. The results raise the question of whether orthodontic treatment with posterior bite blocks might have different effects on the mandible, depending on the characteristics of the orofacial soft tissues.

Adaptation, Physiological↗
PubMed2004

Multidisciplinary approach for the rehabilitation of dentoalveolar trauma.

Satisfactory dental rehabilitation of dentoalveolar trauma requires intense effort and time. Usually multidisciplinary treatment planning and teamwork are necessary to deal with multitask problems associated with these cases. Dental implants have been successfully used for replacement of missing teeth, but in trauma cases insufficient alveolar bone hinders implantation. In this report we present the multidisciplinary approach for the treatment of a trauma case. Maxillary segmental alveolar osteotomy in conjunction with interpositional and onlay bone grafting was performed to prepare the site for placement of osseointegrated implants. Titanium microplate and screws were used to provide orthodontic anchorage for intrusion of the extruded mandibular incisors. The patient was rehabilitated by implant supported fixed partial denture 6 months after implant placement.

Adult↗
PubMed2007

Replantation and transplantation following avulsion of two maxillary incisors.

Here we describe replantation and transplantation as a treatment conducted in a 16-year-old patient following a bicycle accident. An avulsed left central incisor in maxilla was replanted after extra-oral root canal treatment, and the lost right central incisor of the maxilla was replaced by a left lateral incisor of the mandible in the region of the fracture fissure. Follow-up examination at 34 months showed validity of treatment, although slight evidence of replacement resorption in the transplanted and replanted teeth was revealed.

Adolescent↗
PubMed2006

Mucoepidermoid carcinoma of minor salivary glands: a clinical study of 16 cases and review of the literature.

OBJECTIVE: Mucoepidermoid carcinoma (MEC) is the most common malignant tumor of salivary glands with a widely diverse biologic behavior that is correlated with the histological grade of the tumor. The purpose of this study was to evaluate the clinical outcomes of MEC of minor salivary glands in a group of 16 patients, who were treated in our clinic, and to discuss the management of this carcinoma. MATERIALS AND METHODS: Between 1985 and 2000, 16 patients with MEC of minor salivary glands were treated in the Clinic of Oral and Maxillofacial Surgery of the 'G. Papanikolaou' General Hospital, in Thessaloniki. The age range was 16-65 years. The distribution of the primary sites was: hard plate (one), soft palate (two), hard and soft palate (three), hard and soft palate with spread in paranasal sinus and nasal cavity (one), buccal mucosa (three), hard palate, alveolar process and buccal mucosa (two), and retromolar triangle (our). The tumors were clinically staged according to the tumor nodes metastase (TNM) system (Seifert, 1991). All patients were treated radically with surgery. The surgery was combined with radiotherapy in nine patients. Radiotherapy was delivered using Co-60. Doses ranged from 50 to 60 Gy and the duration of the therapy ranged from 25 to 35 days. Immunohistochemical assay of the expression of the Ki-67 antigen was performed on a subset of 15 cases. RESULTS: The mean follow-up range was 4-14 years. From the 16 patients with MECs 10 (62.5%) were alive and five (35.6%) had died from the disease. Four patients were free of the disease for more than 5 years (range 8-14), five patients were free of the disease for 5 years and one patient was free of the disease for 4 years. One patient lived more than 10 years and died from another cause. Local recurrence developed in one patient 10 years after the initial treatment. Lymph node metastases occurred in one patient within the first year after the initial surgical treatment. Distant metastases (two in bones and one in lungs) occurred in three patients within 2 years after completing the treatment. The Pearson chi-square statistical analysis was used for comparing the Ki-67 values in correlation with histological grade of the tumors. The Ki-67 expression was only 1% in low-grade MECs, while in intermediate-grade tumors it was estimated between 3 and 4%. The high-grade tumors had increased expression (10%) of tumor cells. CONCLUSION: Complete surgical excision is the treatment of choice for MECs. Adequate excision is important in all grades of tumors. Prognosis of MECs is a function of the histological grade, adequacy of excision and clinical staging. The immunohistochemical study of Ki-67 expression may provide additional prognostic information for this tumor.

Adolescent↗
PubMed1989

Varied appearance of AIDS-related lymphoma in the chest.

The authors reviewed all cases of acquired immunodeficiency syndrome (AIDS)-related lymphoma (ARL) seen at their institution between January 1982 and September 1988 to determine the frequency and appearance of ARL in the chest. Of 35 patients with ARL, 11 (31%) had biopsy-proved thoracic involvement. This frequency is significantly greater than that previously reported. The radiologic appearance of the thoracic involvement varied. Pleural effusion, interstitial and alveolar lung disease, nodules, and, infrequently, hilar and mediastinal adenopathy were observed. ARL of the chest was most commonly extranodal. Pleural effusion and lung disease were the two most common manifestations of ARL on chest radiographs and computed tomographic scans. The authors recommend that clinicians treating patients with suspected or known AIDS consider ARL when a pleural effusion or a noninfective interstitial or alveolar process is present.

Acquired Immunodeficiency Syndrome↗
PubMed1981

Effects of rehabilitation on the jaws and teeth of protein-deficient and calorie-deficient pigs.

The growth of the jaws and teeth was examined in pigs which had been fed protein-deficient and calorie-deficient diets for the first year of life and thereafter allowed unlimited food. After 2 years of rehabilitation, jaw size had almost reached that of well-fed controls, although in the mandible the labial alveolar process remained abnormally proclined and in both jaws the crowns of third permanent molars were smaller than in control animals. Calorie-deficient pigs did not recover as well as did protein-deficient animals. Pigs fed a calorie-deficient diet for the first 2 years of life before rehabilitation also made a good recovery and were only slightly smaller in most dimensions than those undernourished for 1 year and then rehabilitated. Despite the excellent recovery in jaw dimensions, some malposition of teeth persisted after rehabilitation, especially in animals which had been undernourished for 2 years.

Animals↗
PubMed2005

Morphological and radiologic evaluation of the human nasopalatine duct.

In several mammals, a direct connection between the nasal cavity and the oral cavity is a common finding. The structure is named the nasopalatine duct (NPD). It has been hypothesized to be functional in terms of transportation of odorants from the oral cavity to the nasal cavity. In humans, the NPD exists during embryological development. The connection between the nasopalatine infundibulum and the incisive fossa is typically closed at the time of birth. We present the case of a 24-year-old man who presented with a persistent NPD. By means of a thin, soft tube, it was possible to probe the NPD. Magnetic resonance imaging revealed a bony gap between the hard palate and the alveolar process of the maxillary bone with a length of 16 mm and a width of 6 mm. In light of the literature of the past 500 years, this represents a rare finding of a persistent NPD.

Adult↗
PubMed1987

Movement of fibroblasts in the periodontal ligament of the mouse incisor is related to eruption.

Movement of fibroblasts in the periodontal ligament of the lower incisor of the mouse was studied by pulse-labeling with tritiated thymidine and proline. 3H-Thymidine was administered to mark the nuclei of the cells in the proliferative compartment near the basal end of the tooth; 3H-proline gave rise to a narrow band of radioactivity in the dentin, which served as a reference line for measurement of eruption. One or three weeks after injection in each animal, the lower right incisor was prevented from further eruption by being pinned to its alveolar process. The animals were killed 0, 1, or 2 weeks later, and their mandibles processed for LM-radioautography. It was found that in the left incisors, which were not inhibited in their eruption, labeled cells in the tooth-half of the periodontal ligament moved incisally at a rate similar to the eruption rate. In the pinned incisors, no further incisal migration could be established. It is concluded that fibroblast migration in the tooth-half of the ligament is strictly coupled to the eruptive process.

Animals↗
PubMedDate not supplied

Results of 60Co-teletherapy in oral cancer.

Our study reports 282 oral cancer cases treated with 60Co-teletherapy (TCT), taken from 736 oral carcinomas treated with radiotherapy on the primary tumor from January 1959 to December 1970. They were mainly locally advanced cases which often had regional node involvement. In fact, during that period, the more advanced cases were submitted to TCT. There were only 9 (3.2%) patients with T1 lesions, while there were 134 (47.5%) T2 and 139 (49.3%) T3, T4 cases; there were respectively 106 (37.6%) and 44 (15.6%) N1 or N2 and N3 cases. Almost half of the patients were greater than or equal to 66 years old at onset of the treatment (138/282 cases, or 47.2%); the women were a small minority (18/282, or 6.4%). There were 58 (20.6%) carcinomas of the mucosal surface of the cheeks, 60 cases arising from the retromolar areas, the upper-lower alveolar processes and the hard palate (21.3%), 72 carcinomas of the mobile portion of the tongue (25.5%) and 92 arising from the floor of the mouth (32.6%). All the patients considered in the study were treated with conventional techniques by doses, field dimensions and fractionation. The overall results were objectively disappointing, even though they should be evaluated keeping in mind the nature and the gravity of oral carcinomas submitted to TCT. Actuarial survival at 5 and 10 years from the onset of treatment was respectively 11.6% and 6.4%. None of the N1, N3 cases survived beyond the fourth year from onset of the treatment. Long-term survival differs very little in relation to the site of origin in the oral cavity. Nowadays, TCT alone may have only a palliative role in the treatment of oral cancer, reserving it for those cases which, due to their extreme gravity or the various contraindications, do not permit more aggressive treatments. In a combined therapeutic approach the aim of TCT today is to control the minimum disease foci. Its association with surgery appears to be most effective.

Aged↗
PubMed1999

Ceramic-coated implant systems.

Practitioners have used hydroxyapatite-coated (HA-coated) endosseous and subperiosteal implants in various forms for many years. These have included root forms in both screw and cylindrical shapes, blades, and subperiosteals. The clinical predictability remains controversial and subject to claims and counterclaims. The early days of dental implantology involving root-form implants recommended their placement in fully edentulous cases only, and anterior to the maxillary sinus and mental foramen. Today's philosophy and rationale of dental implantology include the placement of a single implant replacing a missing natural tooth (especially where the teeth adjacent to the edentulous site have no caries or restorative experience). Implants are used to replace the natural dentition in one quadrant/segment, often preceded or accompanied by ridge augmentation and/or sinus grafting if sufficient bone is not present. So we have to address the clinical predictability of survival in terms of indications, quantity, and quality of bone. Clinical data and experience suggest that hydroxyapatite-coated (HA) dental implants may (and possibly should) be used in (1) Type IV bone, (2) fresh extraction sites, (3) grafted maxillary and/or nasal sinuses, or (4) with short implants (< or = 10 mm in length).

Alveolar Process↗