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PubMed1997

Regressive changes of the dental pulp complex in retained primary molars with congenitally missing successor teeth.

This study was undertaken to investigate the regressive changes occurring in the dental pulp complex (pulp, dentin, and cementum) of retained mandibular primary second molars with congenitally missing bicuspid teeth. Seventeen retained, caries free, primary molars were used. The specimens were fixed in 10% neutral buffered formalin. Fixed samples were decalcified, routinely prepared, embedded in paraffin, sectioned, and stained with hematoxylin and eosin. The results demonstrated a reduction in the pulp size, abnormal odontoblastic pattern, declined vascularity, pulp degeneration, pulp stones, accelerated formation of secondary dentin, and hypercementosis. This study suggests that these findings may be from aging and physiological defensive changes. These normal, age-induced changes are of considerable importance in the fields of endodontics, orthodontics, and pediatric dentistry.

Adult↗
PubMed1998

Microorganisms in closed periapical lesions.

The purpose of this study was to investigate the microorganisms of strictly selected closed periapical lesions associated with both refractory endodontic therapy and pulpal calcification. Definitive criteria were established that assured complete clinical isolation of the periapical lesion from the oral and periodontal environment. A total of 13 criteria-referenced lesions were selected from 70 patients with endodontic surgical indications. A well controlled culturing method was used in all cases and samples were taken by one clinician at three separate sites during each surgery. Samples taken at the surgical window and within the body of the lesion served as controls, whilst a third sample was taken at the apex. In all 13 cases, samples taken from the apex yielded microorganisms comprising 63.6% obligate anaerobes and 36.4% facultative anaerobes. Prevalence of the isolated species was 31.8% for Actinomyces sp., 22.7% Propionibacterium sp., 18.2% Streptococcus sp., 13.6% Staphlyococcus sp., 4.6% Porphyromonas gingivalis, 4.6% Peptostreptococcus micros and 4.6% Gram-negative enterics. The results of this investigation indicate that closed periapical lesions associated with calcified teeth or those resistant to root canal treatment harbour bacteria. The inability to eradicate all root canal microorganisms during root canal treatment, along with anatomical factors, may allow further bacterial colonization of the root apex and surrounding periapical tissues, and consequently prevent healing.

Bacteria, Anaerobic↗
PubMed2002

Outcome of tooth transplantation: survival and success rates 17-41 years posttreatment.

The literature contains no follow-up studies of transplanted teeth with mean observation times exceeding 10 years. This article describes long-term outcomes, including gingival and periodontal conditions, and the patients' attitudes about treatment and outcome. The material comprised all accessible patients in the files of the Department of Orthodontics, University of Oslo, Norway, on whom treatment had been performed at least 17 years ago (n = 28). Established clinical criteria were used to assess tooth mobility, plaque and gingival indexes, and probing pocket depth. Standardized radiography was used to evaluate the presence of pathology, pulp obliteration, and root length. Similar recordings were obtained from the in situ tooth contralateral to the initial position of the grafted tooth. Criteria for determining treatment success were established. All patients responded to questions about their treatment using visual analogue scales. The mean age at surgery was 11.5 years, and the mean observation period was 26.4 years (range, 17-41 years). Of the 33 teeth transplanted in the 28 patients, 3 teeth were lost after 9, 10, and 29 years, respectively. Therefore, the 30 teeth in the 25 patients we examined yielded a survival rate of 90%. The success rate was 79% because 2 transplants had ankylosed, and 2 others failed to fulfill the proposed criteria. The patients generally responded very favorably regarding their perception of the treatment. Their only hesitation was related to some discomfort during surgery. It was concluded that survival and success rates for teeth autotransplanted when the root is partly developed compare favorably in a long-term perspective with other treatment modalities for substituting missing teeth.

Adolescent↗
PubMed1977

Endodontic perforations: their prognosis and treatment.

Causes of tooth perforation include resorption, caries, and operator performance. The prognosis for a tooth with a perforation is related to the location of the perforation, negotiability of the canal, contamination, and treatment. Alternative treatment approaches include routine endodontic treatment, correction via the chamber, surgical correction, and stimulation of calcification. In most instances, a perforation can be treated so that satisfactory healing will occur.

Apicoectomy↗
PubMed1985

Endodontic treatment for traumatized immature permanent incisors.

Endodontic treatment of traumatized permanent incisor teeth in young children may often present special problems not encountered in the adult patient. They are determined primarily by (a) the pulpal response of an immature tooth to trauma, and (b) the mechanical difficulties encountered when attempts are made to obturate the root canal of a tooth with a widely patent apical foramen. The most appropriate intermediate and long term treatment will only be possible in individual cases if the tooth response is continuously monitored from the time of the initial injury to the point where the definitive treatment has been judged as successful. Thus at each attendance, clinical examination including pulp testing should be supplemented by the taking of routine periapical radiographs. Essentially three main pulpal responses are possible: i) Recovery ii) Calcification iii) Necrosis. The outcome in each case may be influenced by treatment procedures.

Child↗
PubMed2002

Experimental evaluation of human teeth using noninvasive ultrasound: echodentography.

Anomalies present in the hard tissue of teeth are manifested in several ways such as cavities, decay, and caries. The most extensively and commonly used diagnostic modality for the assessment of these abnormalities are x-rays. Unfortunately, these rays are harmful to the human body and may be a source of health risk. This work describes the development of a new testing technique that uses ultrasound designed to complement, or even replace, existing tools used in dentistry applications. Previous studies have shown several models of acoustic field simulation, propagation, and interaction of ultrasound with the layers of several tooth structures. In this paper, experimental data is gathered for the purpose of assessing the viability of this technique in an attempt to detect cavities and fractures in extracted human teeth. A low-intensity, high-frequency ultrasonic set-up is used in all in vitro tests. Four cases have been examined: an intact tooth, a tooth containing an amalgam restoration and a natural surface fissure, a tooth containing a machine side-drilled hole that mimics a cavity, and a calcified tooth--a rare naturally occurring condition. Upon analysis of the obtained A-scans and B-scans, it is verified that these experimental measurements confirm predictions reported in earlier finite element and transmission line studies and suggest that ultrasound is a valuable tool which has the potential to be an addition to, or even an improvement upon, current dental imaging systems.

Dental Caries↗
PubMed1995

Time and position-specific expression of glycosaminoglycans in rat molar cementum related to physiological tooth movement.

The role of glycosaminoglycans (GAGs) and proteoglycans during cementogenesis is not known. In this study, we have analysed the temporal and spacial expression of GAGs in the cellular cementum of 10-30 weeks old rats, immunohistochemically using monoclonal antibodies 2B6 and 3B3, specific for chondroitin 4-sulfate/dermatan sulfate and chondroitin 6-sulfate, respectively. Both 2B6- and 3B3-epitopes were expressed at similar position and time in the rat cellular cementum. Two types of cellular cementum were identified; GAG-positive and GAG-negative cementum. The former corresponded to the lightly stained and the latter to the darkly stained cementum in sections stained with haematoxylin and eosin. The GAG-positive cementum was seen at the distal side of dentine surface and appeared most thick at, middle of the apical half roots, whereas the other parts of the cementum were the GAG-negative. Distribution of GAG-positive cementum showed changes with age of animals. In 10-15 week old rats, the GAG-positive cementum occupied most of the cementum layer, covering a thin layer of the GAG-negative cementum. The cellular cementum of 20-30 week old rats consisted of three layers; GAG-negative, GAG-positive and GAG-negative cementum from dentine to cementum surface, reducing the GAG-positive area. Because our previous study has demonstrated that the lightly stained cementum is uncalcified, the present result suggests a correlation between calcification and contents of GAGs in the cellular cementum. Further, time- and position-specific expression of GAGs indicates their relation to the physiological tooth movement, which has been known in the rat molars.

Age Factors↗
PubMed1978

Long-term follow-up and evaluation of transplantation of fully developed teeth.

Five cases of transplantation of fully developed third molars to second or first molar sites have been reported. Three of the transplants were in the mandibular molar region and two were in the maxillary molar region. There has been long-term follow-up and evaluation of the patients in these cases up to 13 years postoperatively. None of the patients had any complaint about the transplanted tooth at the long-term follow-up visit. In all five cases, at the long-term follow-up visit, the periodontal tissues were in excellent condition and there was growth of new attachment, as demonstrated by lamina dura and periodontal membrane space in the follow-up radiographs, deposition of secondary calcification of varying amounts within the root canals and pulp chamber, and regeneration of bone in the periapical and lateral areas. There was very little, if any, resorption demonstrated in any of these five cases. The ages of patients ranged from 17 to 23 years at the time of transplantation. Regeneration of the buccal plate was demonstrated by photographs in one of the two cases where there was surgical exposure of the region of the buccal plate at a postoperative follow-up visit.

Adolescent↗
PubMed1992

Root fractures in permanent teeth: a clinical review.

A retrospective study of 22 root fractures in 21 patients was performed. Ten patients were less than 11 years of age, and boys were involved more often than girls. Ten patients had more than one injured tooth, but there was no case of alveolar fracture. Twenty-one of the teeth were upper central incisors. Only 11 teeth were seen within the first week, so that not all teeth were splinted and not all displaced teeth were repositioned. Long-term clinical and radiographic review showed that loss of vitality of the coronal pulp could not be reliably detected for at least 1 year. No tooth became abscessed or developed a sinus tract, and resorption of bone at the fracture line was observed in only one out of five non-vital teeth. Lack of displacement and placing of a splint increased the chances of the pulp remaining vital and healing of the fracture occurring with hard tissue. Sclerosis of the coronal pulp occurred mainly when healing was by connective tissue. The apical pulp always remained vital, and there was sclerosis of the apical pulp in almost every case.

Adolescent↗
PubMed2005

Tooth transplantations: a descriptive retrospective study.

The aim of the present study was to perform a retrospective study of autogeneously transplanted teeth in order to examine the influence of clinical criteria such as the type of the donor tooth, the root length at the time of transplantation, donor eruption stage and others on the overall success rate of the transplantation. The material of this study consisted of 194 patients in whom 273 teeth were transplanted. The mean age at the time of autotransplantation was 18.1 years with a standard deviation of 7.5 years. Transplantations were performed in two hospitals. The follow-up period varied from 15 days to 11 years, and the mean follow-up time was 3.8 years. 58/273 teeth showed one or other form of resorption, 37/273 teeth showed ankylosis, 30/273 showed no important changes in pulp chamber size, 104/273 showed major discoloration after transplantation, 92/273 teeth showed positive results for cold test after transplantation and 26/273 teeth showed clinically unacceptable pocket depth. Clinical and radiological evaluations were performed. An association was found between successful transplantation and donor tooth type (P<0.01), root length at the time of transplantation (P<0.0001) and recipient tooth site (P=0.03). There was a borderline association between successful transplantation and donor eruption stage (P=0.05). In conclusion, autotransplantation of teeth performed with a careful surgical procedure at the stage of 1/2-3/4 of their intended or expected root length can render a very useful service to patients.

Adolescent↗
PubMed1993

Immobilized DPP and other proteins modify OCP formation.

Osteonectin, gamma-carboxyglutamic acid-containing (Gla) protein, and dentin phosphoprotein were covalently attached to sepharose beads and inoculated in solutions at two different degrees of supersaturation with respect to both octacalcium phosphate (OCP) and hydroxyapatite. In both solutions, the inhibitory activity towards de novo formation of calcium phosphate that these proteins display when freely dissolved in solution was completely eliminated when they were immobilized on the sepharose at concentrations of up to 5 micrograms/mg wet beads. In the solution that was more highly supersaturated with respect to OCP, the immobilized dentin phosphoprotein, moreover, was found to induce de novo formation of OCP in proportion to the concentration of the protein immobilized. For example, at 10 micrograms/ml of the immobilized dentin phosphoprotein, the induction period was reduced more than 50%. However, in the solution considerably less supersaturated with respect to OCP, none of the immobilized proteins were capable of inducing OCP or apatite deposition. These findings suggest that the immobilized dentin phosphoprotein could work as a nucleating substrate for the OCP phase in solutions where calcium and phosphate concentrations are sufficiently higher than equilibrium saturation levels for the OCP phase.

Animals↗
PubMed2003

Synchrotron X-ray studies of the keel of the short-spined sea urchin Lytechinus variegatus: absorption microtomography (microCT) and small beam diffraction mapping.

In sea urchin teeth, the keel plays an important structural role, and this paper reports results of microstructural characterization of the keel of Lytechinus variegatus using two noninvasive synchrotron x-ray techniques: x-ray absorption microtomography (microCT) and x-ray diffraction mapping. MicroCT with 14 keV x-rays mapped the spatial distribution of mineral at the 1.3 microm level in a millimeter-sized fragment of a mature portion of the keel. Two rows of low absorption channels (i.e., primary channels) slightly less than 10 microm in diameter were found running linearly from the flange to the base of the keel and parallel to its sides. The primary channels paralleled the oral edge of the keel, and the microCT slices revealed a planar secondary channel leading from each primary channel to the side of the keel. The primary and secondary channels were more or less coplanar and may correspond to the soft tissue between plates of the carinar process. Transmission x-ray diffraction with 80.8 keV x-rays and a 0.1 mm beam mapped the distribution of calcite crystal orientations and the composition Ca(1-x)Mg(x)CO(3) of the calcite. Unlike the variable Mg concentration and highly curved prisms found in the keel of Paracentrotus lividus, a constant Mg content (x = 0.13) and relatively little prism curvature was found in the keel of Lytechinus variegatus.

Animals↗
PubMed2006

Calcifying odontogenic cyst: radiologic findings in 11 cases.

OBJECTIVE: This retrospective study examines the relationship between histopathologically diagnosed cases of in calcifying odontogenic cysts (COCs) on the adjacent dentition. STUDY DESIGN: The records including diagnostic radiograph images of 11 patients treated for COCs from 1991 to 2004 were analyzed and correlations made between radiologic and histopathologic features. Special attention was applied to the associations between COCs and adjacent teeth. RESULTS: Radiologic and histopathologic features of the 11 lesions were variable, with some lesions being more solid and others more cystic. Calcifications varied from small flecks to solid calcified areas of frank odontoma. In 7 cases, the COC was associated with an impacted tooth and 5 of these cases involved COC-enveloping teeth. All cases excepting one in an edentulous jaw segment showed positional changes of adjacent teeth, including impaction. CONCLUSIONS: The radiographical features of COCs are varied but there is a high frequency of changes in adjacent teeth, including dental impaction. The presence of impaction or displacement of teeth for COCs occurring in the posterior segments of the jaw, and absence of this finding for anteriorly placed lesions may be indicative of the timing of COC development.

Adolescent↗