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PubMed1991

Complex facial radicular groove in a maxillary lateral incisor.

A case report of a developmental anomaly known as a radicular groove is presented. This case is unusual in that it is believed to be the first reported case of complex involvement of the entire facial aspect of a tooth root. An alveolar crest to apex facial root defect in a maxillary right lateral incisor of a 12-yr-old black female led to early pulpal necrosis and periapical rarefaction. Clinical and histologic findings as well as morphologic and treatment ramifications are discussed.

Child↗

PubMed1993

Magnet overdentures.

Magnets were first used for overdenture retention in 1977. A novelty then, they are now an accepted alternative to conventional attachments, and available commercially from a number of manufacturers. Nearly all of them use a "closed field" magnet configuration, which provides optimum retention and eliminates any possibility of magnetic field effects on tissues. Initial corrosion problems are now being eliminated by improved designs. Clinical experience has shown that overdentures preserve alveolar bone and that magnetic retention can be used effectively on tooth roots which would have a poor prognosis with conventional attachments. Magnets can also be used to retain overdentures against implants as an inexpensive alternative to conventional implant dentures.

Adult↗

PubMed1993

Histological reconstruction of dental development and age at death of a juvenile Paranthropus robustus specimen, SK 63, from Swartkrans, South Africa.

There has been disagreement about whether the earliest hominids grew in a similar manner to great apes or modern humans. This has important biological implications, since it may have been inappropriate to apply modern human developmental standards to early hominids. The aim of the present study was to combine data from replicas of tooth surfaces, computed tomographic (CT) scans, and radiographs with data from a histological section of the canine crown, in order to provide a complete description of tooth crown and tooth root development in a single early hominid specimen (SK 63). Although partially destructive in nature, we have been able to determine the most reliable data yet for aspects of dental development in an important juvenile early hominid specimen. Appositional enamel formation time in the permanent right canine was estimated at between 305 and 418 days, imbricational enamel formation time at 819 days, and total crown formation time at between 3.18 and 3.48 years. The most likely age at death was estimated at around 4 years with a range of ages calculated between 3.18 and 4.23 years based on differences in timing of initial mineralization of the canine and differences in appositional enamel formation times. Crown formation times of the lower central and lateral incisors were estimated between 2.35-2.68 years and 2.57-2.91 years, respectively. Crown formation time of the first permanent molar was estimated at 2.4 years. Wear facets on the first permanent molars indicate that gingival emergence had occurred sometime prior to death, between 3 and 4 years of age. Estimates of root extension rates in the first permanent molars and in the permanent incisors are fast, and either within or above ranges of rates estimated for modern great apes. While we recognize that data for one individual may not be representative of data for a whole population of early hominids, the data for age at death, for age of M1 emergence, and for root extension rates presented here accord with those known for modern great apes and fall beyond the known ranges for modern humans.

Age Determination by Teeth↗

PubMed1985

Vital apicoectomy of the teeth: a 1-4 week histopathological study in Macaca mulatta.

Several studies have reported devitalization of teeth following surgical procedures in the area of the root apices. The purpose of this investigation was to observe the 1-4-week wound healing pattern in monkey dental tissues following intentional vital apicoectomy (IVA). Two adult Macaca mulatta were used in this study. All of the teeth were surgically transected within the apical one-third with a bur. The soft tissues were then closed. At death, a maxillary and a mandibular quadrant for 1, 2, 3 and 4 weeks following surgery were obtained after vascular perfusion. Each quadrant was demineralized in EDTA, processed, serially sectioned at 7 microns and alternately stained with hematoxylin and eosin, Preece's modified trichome, and McKay's bacterial stains. Examination of sequential IVA cuts showed an initial disruption of the pulpal neurovascular supply resulting in pulpal necrosis. The pulpal tissues underwent a process of replacement with PDL-like connective tissues and deposition of cementum on all cut dentin surfaces of the tooth roots as well as in some of the pulp chambers. No abscesses, external resorption or ankylosis were found.

Alveolar Process↗

PubMed1997

Keratinocyte growth factor mRNA expression in periodontal ligament fibroblasts.

Keratinocyte growth factor (KGF) is a fibroblast growth factor which mediates epithelial growth and differentiation. KGF is expressed in subepithelial fibroblasts, but generally not in fibroblasts of deep connective tissue, such as fascia and ligaments. Here we demonstrate that KGF mRNA is expressed in periodontal ligament fibroblasts, and that the expression is increased upon serum stimulation. Fibroblasts from human periodontal ligament, from buccal mucosa, from gingiva, and from skin were established from explants. Alkaline phosphatase activity was used as an indicator of the periodontal nature of fibroblasts. Cells were first cultured in DMEM with 0.5% fetal calf serum (FCS) and then incubated for 8 h, and 72 h in fresh DMEM with 10% FCS. Total RNA was isolated and used for Northern blotting with a P32-labeled KGF cDNA probe. Total RNA from cultured keratinocytes was used as negative controls. KGF mRNA was found in all cultured fibroblasts. Upon addition of 10% FCS to the cell cultures, an increase in KGF mRNA levels was noticed especially after 72 h. Furthermore, RT-PCR analysis of material scraped from the tooth root surface indicated the presence of KGF mRNA even in noncultured periodontal ligament cells.

Adolescent↗

PubMed1977

Oxytalan fibre organization in marsupial mandibular periodontal tissues.

The arrangement and distribution of oxytalan fibres in Australian marsupials has not previously been reported. Periodontal tissues of wombat, wallaby, possum, and marsupial mouse were examined to ascertain oxytalan fibre organization. Despite adaptation of the marsupial masticatory apparatus to different diets the oxytalan fibre organization in the periodontal ligament shows a basic pattern which corresponds with that reported in other animals. The oxytalan system forms a continuous meshwork of fine, branching fibres which completely invests each tooth root and connects adjacent teeth. Thick ribbon-like apico-occlusally orientated oxytalan fibres, thought to form by the coalescence of thinner fibres, are restricted to the periodontal ligament. The oxytalan fibres are embedded in cementum and attached to blood vessels in the pariodontal ligament. Oxytalan fibres do not insert into alveolar bone. Histological evidence indicates functional remodelling of the oxytalan fibre system in continuously erupting teeth.

Animals↗

PubMed1998

Recombinant human osteogenic protein-1 (OP-1) stimulates periodontal wound healing in class III furcation defects.

Osteogenic protein-1 (OP-1) is a member of the transforming growth factor beta superfamily and is a potent modulator of osteogenesis and bone cell differentiation. This preclinical study in dogs sought to assess the effects of OP-1 on periodontal wound healing in surgically created critical size Class III furcation defects. Eighteen male beagle dogs were subjected to the creation of bilateral mandibular 5 mm osseous defects. A split-mouth design was utilized which randomly assigned opposing quadrants to control therapy (surgery alone or collagen vehicle) or 1 of 3 ascending concentrations of OP-1 in a collagen vehicle (0.75 mg OP-1/g collagen, 2.5 mg/g, or 7.5 mg/g). Thus, 9 quadrants per test group received OP-1, 9 quadrants per control group received surgery alone, and 9 quadrants received collagen vehicle alone. Test articles were delivered by a surgeon masked to the treatment, and fluorogenic bone labels were injected at specified intervals post-treatment. Eight weeks after defect creation and OP-1 delivery, tissue blocks of the mandibulae were taken for masked histomorphometric analysis to assess parameters of periodontal regeneration (e.g., bone height, bone area, new attachment formation, and percent of defect filled with new bone). Histomorphometry revealed limited evidence of osteogenesis, cementogenesis, and new attachment formation in either vehicle or surgery-alone sites. In contrast, sites treated with all 3 concentrations of OP-1 showed pronounced stimulation of osteogenesis, regenerative cementum, and new attachment formation. Lesions treated with 7.5 mg/g of OP-1 in collagen regenerated 3.9+/-1.7 mm and 6.1+/-3.4 mm2 (mean +/-S.D.) of linear bone height and bone area, respectively. Furthermore, these differences were statistically different from both control therapies for all wound healing parameters (P < 0.0001). No significant increase in tooth root ankylosis was found among the treatment groups when compared to the surgery-alone group. We conclude that OP-1 offers promise as an attractive candidate for treating severe periodontal lesions.

Alveolar Process↗

PubMedDate not supplied

Morphometric analysis of mandibular canal: clinical aspects.

Results of morphometric analysis of the mandibular canal (MC), carried out on 105 conserved mandibles, 70 being dentate and 35 edentate, was performed. The analysis was carried out on consecutive sections, at mutual intervals of 0.5 cm. In the mandibular ramus sections were carried out obliquely, approximately in the frontal plane, and horizontally, from mandibular foramen to the lowest region of the vertical part of the MC (all together two sections). In the mandibular corpus, consecutive transversal sections were carried out between existing teeth, or at mutual intervals of 0.5 cm in edentate regions. The obtained results pointed out the very close relationship between the MC and lingual cortical plate of the mandibular ramus. In its horizontal part, the average diameter of the MC was 2.6 mm. It was situated more lingually in the molar region; towards the front, it approached the vestibular cortical plate, being closest to it in the region of the second premolar. Similar relationships of the MC and both cortical plates existed in edentate jaws. Relationships of the MC and tooth root apices varied; however, the MC was closest to the apices of the third molar. Mesially from the mental foramen, a clearly defined incisive canal was present in 92% of the dentale mandibles, but only in 31% of the edentate ones. The nearest to the incisive canal was the apex of the first premolar. The authors point out the importance of presented results in everyday practice, especially in oral and maxillofacial surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗

PubMed2004

Atypical hypercementosis versus cementoblastoma.

Hypercementosis is a non-neoplastic condition in which excessive cementum is deposited in continuation with the normal radicular cementum. Apart from the idiopathic nature of hypercementosis, this condition is associated with several local and systemic factors. Cementoblastoma is an odontogenic tumour characterized by the proliferation of functional cementoblasts that form a large mass of cementum or cementum-like tissue on the tooth root. Although hypercementosis and cementoblastoma are typical conditions with distinct clinical evolution, atypical cases may challenge their diagnosis. Because cementoblastoma is a neoplasm with unlimited growth potential, the usual treatment is complete surgical resection, whilst conservative treatment is recommended for hypercementosis. An atypical case of hypercementosis with similarities to cementoblastoma is reported and its differential diagnosis is discussed.

Cementoma↗

PubMed2003

[Epithelial cell rests of Malassez: tissue, cell, and molecular biology].

This review presents an analysis of the current data on the structural and functional organization and biological significance of epithelial cell rests of Malassez (ERM), which are formed by persisting fragments of epithelial (Hertwig) sheath that participates in the tooth root development. ERM, found within the periodontal ligament, undergo intensive age-related involution and are traditionally described as small clusters of functionally inactive cells. Meanwhile, recent findings are indicative of high functional activity of ERM which are both producers of and targets for various cytokines, growth factors, adhesive substances, their receptors and other biologically active molecules. It is suggested that ERM participate in sustaining the optimal conditions for the normal functioning and regeneration of periodontium structural components. When periodontal tissue homeostasis is disturbed, ERM may grow up and acquire the capacity to destroy the surrounding tissues.

Cytokines↗

PubMed1990

[Use of synthograft after tooth apicoectomy with extensive bone defect and marginal apical communication to periodontium].

Synthograft (beta-tricalcium phosphate) is a bioresorptive ceramic material which stimulates osteogenesis after implantation into bone defects and disappears from the site of implantation. In this study, Synthograft was used as a filling in bone defects following apicotomy of teeth with extensive periapical and lateral bone defects along the tooth root involving more than 1/3 of the root, and when an extended periodontal fissure was present in addition. The study included 13 patients with one or more teeth involved. The tricalcium phosphate powder was mixed with patient's own blood and inserted into bone cavities. The patients were followed up during 12 months after surgery by clinical and radiographic control examinations. In all the 13 cases, clinical results were very good, i.e. healing of the wound proceeded without any signs of inflammation, whereas later in the course of follow-up no signs of reaction to the foreign material were observed. Preoperatively loose teeth had gradually become firm and after 12 months were within the limits of physiological motility. Roentgenograms revealed the bone cavities to have filled with newly formed bone, and the periodontal ligament, otherwise lost, was also restored. Results of this study showed the Synthograft implant to be well tolerated by recipients, thus it can be recommended as a filling in extensive bone periapical and lateral defects after tooth apicotomy.

Adolescent↗

PubMed1985

Oro-maxillofacial development in patients with Turner's syndrome.

Detailed oro-maxillofacial studies using dental casts, pantomograms and cephalograms were performed in 28 patients with Turner's syndrome and compared statistically to the results from 23 normal short children. Small tooth crown size, short tooth roots and advanced dental age were characteristic of patients with Turner's syndrome. However, the incidence of peg shaped teeth, malocclusion, high arched palate and congenital anodontia were not characteristic of patients with Turner's syndrome. The coronal arch width (C.A.W.) and basal arch width (B.A.W.) were greater and the coronal arch length (C.A.L.) and basal arch length (B.A.L.) were less in patient's with Turner's syndrome. These data indicate underdevelopment of the maxilla in the forward direction forming the wide-, flat-shaped facial characteristic of patients with Turner's syndrome.

Adolescent↗

PubMed2004

Transalveolar screws and the incidence of dental damage: a prospective study.

The incidence of screw/tooth contact in the placement of transalveolar screws was prospectively studied. The clinical significance of such contact when it occurred was assessed. Patients with fractures of the mandible requiring intra- or post-operative control of their occlusion with transalveolar screws were entered into the study. Following screw removal, contact was assessed radiographically and all teeth adjacent to screws were tested for vitality. Any contacts were judged to be minor if less than 50% of the diameter of the screw hole impinged on a tooth root or major if this was more than 50%. Fifty-four male and one female patients completed the study. There were 232 screws placed in these patients adjacent to 440 teeth. Twenty-six screws (11.2%) had major contacts and 37 (15.9%) had minor contacts. Seventeen teeth tested as non-vital with electronic pulp testing but of these only 6 showed any impingement by screws. Two screws were associated with complications in two patients. Screw/tooth contact does occur using transalveolar screws, however, the incidence of clinically significant damage appears to be very low.

Adolescent↗

PubMed2000

Employing a transgenic animal model to obtain cementoblasts in vitro.

BACKGROUND: Proper formation of cementum, a mineralized tissue lining the tooth root surface, is required for development of a functional periodontal ligament. Further, the presence of healthy cementum is considered to be an important criterion for predictable restoration of periodontal tissues lost as a consequence of disease. Despite the significance of cementum to general oral health, the mechanisms controlling development and regeneration of this tissue are not well understood and research has been hampered by the lack of adequate in vitro experimental models. METHODS: In an effort to establish cementoblast cell populations, without the trappings of a heterogeneous population containing periodontal ligament (PDL) cells, cells were obtained from the root surface of first mandibular molars of OC-TAg transgenic mice. These mice contain the SV40 large T-antigen (TAg) under control of the osteocalcin (OC) promoter. Therefore, only cells that express OC also express TAg and are immortalized in vitro. Based on results of prior in situ studies, OC is expressed by cementoblasts during root development, but not by cells within the PDL. Consequently, when populations are isolated from developing molars using collagenase/trypsin digestion, only cementoblasts, not PDL cells, are immortalized and thus, will survive in culture. RESULTS: The resulting immortalized cementoblast population (OC/CM) expressed bone sialoprotein (BSP), osteopontin (OPN), and OC, markers selective to cells lining the root surface. These cells also expressed type I and XII collagen and type I PTH/PTHrP receptor (PTH1R). In addition to expression of genes associated with cementoblasts, OC/CM cells promoted mineral nodule formation and exhibited a PTHrP mediated cAMP response. CONCLUSIONS: This approach for establishing cementoblasts in vitro provides a model to study cementogenesis as required to enhance our knowledge of the mechanisms controlling development, maintenance, and regeneration of periodontal tissues.

Animals↗

PubMed1980

Attachment of oral Cytophaga species to hydroxyapatite-containing surfaces.

Model systems simulating the cementum portion of teeth were used to characterize the attachment process by which certain species of oral Cytophaga initiate the colonization of the tooth root surface in vitro. The adsorption of these bacteria to spheroidal hydroxyapatite beads and mechanically powdered root material followed Langmuir isotherm kinetics. From such data, the number of binding sites per 20 mg of substrate and the affinity constants were evaluated for two strains of Cytophaga sp. Resting cells of the two strains tested adhered relatively tenaciously to hydroxyapatite beads in numbers similar to those observed with cells of Streptococcus sanguis. Attachment of bacteria to the substrates was partially inhibited by (i) coating the substrates with human serum or saliva, (ii) pretreating cell suspensions with proteinase K or phospholipase C or D, or (iii) exposing the cells to temperatures greater than 60 degrees C for 15 min. Treating resting cell suspensions with pronase, neuraminidase, phospholipase A2, or 0.1 M ethylenediaminetetraacetic acid had no effect on the attachment process.

Absorption↗

PubMed2000

Alternative to the median region of the palate for placement of an orthodontic implant.

Tooth-borne anchorage may be one of the greatest limitations of modern orthodontic treatment, because teeth move in response to forces. Previous investigators have placed temporary implants in the median-sagittal palate in order to establish maximum anchorage. This area, however, may be characterized by relatively low vertical bone support. The aim of this study was therefore to find an alternative palatal implant site which offers a higher amount of bone support. This study comprised 22 patients wishing for maximum anchorage underwent presurgical diagnostic evaluation by means of low-dose dental CT. The measuring results regarding vertical bone volume and the position of the neighbouring tooth roots were used as the basis for further treatment. The statistical data analysis indicated an area suitable for implant placement in the group of patients examined. This area was located 6 to 9 mm posterior to the incisive foramen and 3 to 6 mm paramedian, under avoidance of the mid-palatal suture. The patients showed such a great range of variation in vertical bone volume that a preoperative diagnostic evaluation also seems to be recommendable when very short implants are used in order to avoid perforations of the lower nasal duct.

Adolescent↗

PubMed1999

Self-reporting of periodontal health status.

OBJECTIVE: The objective was to develop a self-reporting questionnaire for use as an epidemiological measure of periodontal status. DESIGN: Oral survey. SUBJECTS AND METHODS: 100 (out of 102 who were approached) non-referred patients attending Dundee Dental Hospital and School agreed to complete a questionnaire concerning factors related to periodontal disease and then undergo a standardised periodontal examination in which four indicators were measured: the percentage of sites with plaque, the percentage of sites which showed bleeding on probing, tooth mobility and Community Index of Periodontal Treatment Needs scores. MAIN OUTCOME MEASURE: Sensitivity and specificity of questionnaire items to predict clinically measured periodontal disease indicators. Acceptable levels for sensitivity and specificity are largely dependent on the context of the test being evaluated, and many tests currently used in dentistry have very low sensitivity or specificity values. Nevertheless, in this case it was felt that any items which had a sensitivity and specificity greater than 0.80 would be reasonable predictors. RESULTS: Only four items were weakly predictive of the periodontal status indicators (sensitivity and specificity > 0.5). These concerned noticing gaps between teeth getting bigger, noticing tooth roots becoming more visible, experiencing pain when consuming hot, cold or sweet things and smoking. Other items, concerned with whether a dentist had told the patient they had periodontal disease or whether the person was aware of being treated for it, had very low sensitivities suggesting that people with periodontal disease indicators are failing to be informed of, or treated for it, by their dentist. CONCLUSIONS: Self-reporting of periodontal health was not successful as many people who had some indications of the periodontal diseases appeared to be unaware of their condition and also appeared not to have been informed nor were being treated for it.

Adult↗

PubMed2000

Radiographic evidence of enamel pearls in jordanian dental patients.

OBJECTIVE: An "enamel pearl" is an ectopic globule of enamel that is adherent to the tooth root surface. Such an anomaly may facilitate the progression of periodontal breakdown. Information on the prevalence of enamel pearls is sparse, and ethnic variations are thought to occur. Our objective was to assess the prevalence of enamel pearls in a group of Jordanian dental patients. STUDY DESIGN: A random sample of 819 dental records were selected, and a total of 1032 periapical radiographs were interpreted for the presence of enamel pearls. RESULTS: Enamel pearls were detected in 4.76% of the subjects and on 1.6% of the molars. No significant difference between sexes was observed. First molar teeth were the most commonly affected, whereas the third molars were the least affected with the condition. CONCLUSIONS: Enamel pearls are not uncommon among Jordanian dental patients, and their early detection could be important in prevention of periodontal disease.

Dental Enamel↗