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PubMed1989

[Consideration on the treatment of transposition of the teeth].

The two cases with the transposition of the teeth were treated orthodontically. One was a case in which the teeth which had changed places with each other were aligned in irregular sequence, the other was one with the teeth which had erupted at the unusual position were repositioned in order of the tooth number. Those causes and some problems involved in diagnosis and treatment were discussed. 1. The causes of transposition of the teeth in the two cases reported herein seemed to be premature loss of primary teeth and the malposition of permanent tooth germs, respectively. 2. At the time of the planning of the treatment, the following must be considered. 1) Perfect transposition or imperfect. 2) The positions of root apexes and axial inclinations of the teeth irregularly erupted. 3. Root paralleling is most important for the stability of the treatment results. Moreover, in case of unusual alignment, prevention of premature contact in jaw movement and improvement of appearance must be endeavored.

Humans↗
PubMed2001

Expression of cathepsin K mRNA and protein in odontoclasts after experimental tooth movement in the mouse maxilla by in situ hybridization and immunoelectron microscopy.

This study demonstrated the simultaneous expression of cathepsin K (CK) mRNA by in situ hybridization and CK protein by immunoelectron microscopy in odontoclasts in mouse maxillae after experimental tooth movement. On the pressure side (the area under pressure during tooth movement), CK mRNA was detected in odontoclasts in resorption lacunae in the tooth root, in osteoclasts in bone resorption lacuane, and in fibroblasts in the periodontal ligament. Using electron microscopy, CK protein was detected at the apex of odontoclasts, intracellularly in vesicles and granules, and extracellularly in irregularly shaped vacuoles (extracellular spaces), on the plasma membrane of the ruffled border, and on and between typical striated type I collagen fibrils in the lacunae. These vesicles and granules appeared to fuse with irregular vacuoles containing CK-positive fragmented fibril-like structures close to the ruffled border. In the basolateral portion of odontoclasts, small amounts of CK-positive rough endoplasmic reticulum (ER) were found. CK-positive intracellular vacuoles (not extracellular spaces) also appeared to fuse with the vesicles and granules. However, these fused organelles rarely contained fragmented fibril-like structures. They are probably endolysosomes. The distribution of CK in odontoclasts was similar to that previously seen in osteoclasts. Furthermore, CK-positive fibril-like structures were found in the vacuoles of fibroblasts. These results indicated that during tooth movement CK is synthesized in odontoclasts on the pressure side and secreted into the tooth resorption lacunae. Therefore, CK may take part in the degradation of the dentin matrix (type I collagen fibrils and non-collagenous protein) of the tooth root, and in the subsequent intracellular degradation of endocytosed fragmented fibril-like structures in endolysosomes.

Animals↗
PubMed2004

Variation in crown and root formation and eruption of human deciduous teeth.

The aim of this study was to document variation of deciduous tooth formation and eruption. The material comprises 121 individuals of known or estimated age (using tooth length) from Spitalfields in London, and radiographs of 61 healthy living children aged 2-5 years. Other skeletal material from two medieval Scottish archaeological sites (Whithorn, N=74; Newark Bay, N=59) was also examined. Stages of crown and root formation as well as eruption (alveolar, midway, and occlusal levels) were assessed for each developing maxillary and mandibular tooth from radiographs or direct vision. Age of attainment for individual stages was calculated by probit analysis, and these data were also adapted for use in estimating age. The timing of crown completion was similar to previously reported studies, but apex completion times were later. Analysis of data relative to the first and second molars at the two stages D (crown complete) and F (root length > or =crown height) allowed comparison with the Scottish material. No significant differences were observed between population groups for tooth formation or eruption. These data fill several gaps in the literature, and will be useful in assessing maturity and predicting age during early childhood.

Age Determination by Teeth↗
PubMed1992

The incidence of mandibular premolars with more than one root canal in a Turkish population.

One hundred and eighty seven mandibular premolars taken from a Turkish population were examined in this study. The teeth were soaked in India ink and then decalcified, cleared and used in an in vitro study to determine the number of root canals and their types, the ramifications of root canals, the location of apical foraminae and the frequency of apical deltas. It was found that the incidence of more than one canal in mandibular premolars was 27.76%; that of finding two or three separate canals in the same root was 9.62% and that of having more than one canal at the apex was 23.49%.

Bicuspid↗
PubMed1991

An in vitro comparison of root canal content extrusion using ultrasonic and hand instrumentation.

The purpose of this study was to evaluate apical extrusion of root canal content using ultrasonic and hand instrumentation. Forty-nine tooth models were fabricated with clear resin. Each model contained a canal in the center. Each tooth model was mounted in a plastic cube (1 x 1 x 2 cm) with white dental plaster so that the coronal 2-3 mm of the model was exposed for instrumentation. Methylene blue dye with glycerin was used as a marker for root canal content. The study consisted of three groups. In group I, Enac ultrasonic instrumentation was used 1 mm from the apex; in group II, Enac ultrasonic instrumentation was used 3 mm from the apex; in group III, K files were used with a push-pull instrumentation technique, 1 mm from the apex. After instrumentation the resin models were extracted and the plaster blocks were sectioned through the long axis of the models. Photographs were made of the area of apical leakage and the amount of dye penetration was measured using a planimeter. There were no differences between hand instrumentation and both ultrasonic groups. At p less than 0.05, ultrasonic instrumentation 3 mm from the apex leaked significantly more than the ultrasonic instrumentation 1 mm from the apex.

Dental Cavity Preparation↗
PubMed1980

Ca and P concentrations of the urodele tooth as revealed by electron microprobe analysis.

The electron microprobe analysis has been used to determine the concentrations of Ca and P in different regions of functional teeth in adult Salamandra salamandra (Amphibia, Urodela). Ca and P levels were found to be more elevated in the dentine shaft below the apex than in its basal part and in the pedicel. The concentrations are similar to those measured in teeth of higher vertebrates.

Animals↗
PubMed1999

Canal configuration of the mesiobuccal root of the maxillary first molar of a Japanese sub-population.

AIM: The aim of this study was to determine the percentage of anatomical canal configurations of the mesiobuccal root of the maxillary first molar in Japanese patients. METHODOLOGY: Three hundred teeth were obtained from general dentists who knew absolutely that they were extracted from Japanese patients. The distobuccal and palatal roots were amputated for radiographic convenience. Preoperative radiographs were taken of the remaining crown and mesiobuccal root (MBR) from mesiodistal and buccopalatal directions for each tooth. Routine endodontic access cavities were prepared and size 08 files were placed through the orifice into the MBR until they were seen at the apex. In some cases preparation of the canal orifice with a long shank round burr was necessary to gain access. In seven teeth, no access to the apex was possible and these teeth were eliminated. In the other 293 teeth, the MBR canal(s) was (were) enlarged up to size 15 file. If another canal opening was found at the apex a 08 file was inserted into the second opening and passed coronally. Postoperative radiographs with file(s) in place were taken from the two directions, as before. RESULTS: Of the 293 teeth, 123 (42.0%) were Type II, 89 (30.4%) showed Type III systems and 10 (3.4%) were Type IV. Suggestions for identification and treatment of the second canal in the MBR are presented. CONCLUSIONS: The proportion of cases with two canals in the mesiobuccal root of maxillary first molars from Japanese patients was high and similar to that described from studies of other ethnic populations.

Asian People↗
PubMed2005

[Age estimation of children in south-western Hungary using the modified Demirjian method].

The biological age of a child, in contrast to his or her chronological age, may be described in terms of skeletal or dental maturity, the development of secondary sex characters etc. These factors can be applied separately or together to assess the degree of physiological maturity of a growing child. The determination of this physiological age and its correlation to the chronological age is of importance within many fields, such as archaeology, forensic medicine, endocrinology, orthodontics etc. Dental maturity was studied on 203 panoramic radiographs, taken between 1985 and 1995, of healthy Hungarian children aged 2.9 to 17.5 years from the south-west Transdanubian part of Hungary. The revised method of Demirjian was used for determination of the maturity score of each individual. For each tooth a score (on a scale A-H) was given according to the radiographic development, from first appearance of calcification to the closure of the apex. This score was then transformed into a self-weighted maturity score for the dental stages (0-19.3) as presented in the paper. The individual scores were then added giving a total maturity score (0-100). This total maturity score represents the biological maturity of the child and may then be compared with the known chronological age. The total maturity scores of the Hungarian population was plotted against the chronological (real) age, and a curve was fitted using the Lowess method of locally weighted least-square method. Our results show that each population needs its own standards. Hungarian boys and girls are approximately 1 year ahead of their French-Canadian counterparts at the age of 6-8. At older ages, the difference decreases. Similar to other studies, we found high individual variance up to 2 years, in tooth development, in the Hungarian population.

Adolescent↗
PubMed1993

Accuracy of an electronic apex locator: a clinical evaluation in maxillary molars.

Identifying the point of apical termination in endodontic therapy is of indisputable importance. In this study, the accuracy of an electronic apex locator was clinically evaluated in 26 maxillary molar teeth, and comparisons were made to the radiographic and direct anatomical measurements of tooth length. The results indicated that a higher percentage of acceptable measurements were obtained by the radiographic method as compared with the electronic method (88.5% to 73.1%). Additionally, inaccurate electronic estimates were long in every instance. The results of this study do not support the replacement of radiographs with electronic devices in endodontic therapy.

Aged↗
PubMed1995

A complex treatment of dens invaginatus.

Dens invaginatus is a developmental malformation of teeth. A case is presented of successful treatment of a peg lateral incisor with a severe dens invaginatus extending to the root apex. Both conventional endodontic therapy and periapical surgery were ineffective in resolving a persistent, long-standing sinus tract. Removal of the tooth in the present case would have created a difficult prosthetic problem. Intentional replantation, with improved access to the apical part of the canal was attempted as a last resort. A 10-month recall radiograph is presented showing successful healing of the periapical lesion. Pre-treatment and post-treatment photographs are presented to show successful esthetic treatment, using bonded composite resin.

Adult↗
PubMedDate not supplied

The use of an analog type apex locator to assess the position of dentine pins.

An analog type apex locator was used to check the position of dentine pins. The teeth restored with the pins were reviewed. The analog type apex locator was easy to use and the readings obtained correlated well with the presence or absence of later symptoms from the tooth. This electrical method of checking pin position was more discerning than the method of direct observation.

Dental Instruments↗
PubMed2006

The potential prognostic value of some periodontal factors for tooth loss: a retrospective multilevel analysis on periodontal patients treated and maintained over 10 years.

BACKGROUND: The great challenge in clinical periodontology is assigning a prognosis to a periodontally affected patient. Many different factors can affect the long-term maintenance of periodontally compromised teeth. The main questions usually considered by the periodontist are: 1) Will a tooth lose more bone in the future? 2) Will the tooth itself be lost in the future? The purpose of this retrospective study was to evaluate the value of some clinical, genetic, and radiographic variables in predicting tooth loss in periodontal patients (aged 40 to 60 years) treated and maintained for 10 years. METHODS: Sixty consecutive non-smoking patients (aged 46.77 +/- 4.96 years) with moderate to severe chronic periodontitis (CP) were treated with scaling and root planing (SRP). Some patients also underwent additional surgical treatments. All patients were maintained in the same private practice for 10 years. The frequency of recall appointments was 3.4 +/- 1.0 months. At baseline (T(0)) and 10 years later (T(2)) the following clinical variables were evaluated: the number of teeth, probing depths (PD), tooth mobility (TM), and presence of prosthetic restorations (PR). In addition, radiographic measurements were taken of the mesial and distal distances from the cemento-enamel junction (CEJ) to the bottom of the defect (BD), to the bone crest (BC), and to the root apex (RA). At T(2), a genetic test to determine the IL-1 genotype and genetic susceptibility for severe periodontal disease was performed for all 60 patients, and they were classified as IL-1 genotype positive (G+) or negative (G-) according to the test results. Tooth loss was used as the outcome variable. Different predictor variables were then tested using a two-level statistical model (patient and tooth levels). At the patient level, these were: age, gender, mean bone loss (mean CEJ-BD)(T0), the interleukin-1 (IL-1) genotype, the interaction between mean bone loss, and IL-1 genotype (mean CEJ-BD(T0) x IL-1 genotype). At the tooth level, the variables were: TM(T0), prosthetic restorations (PR)(T0), molar teeth (MT)(T0), the infrabony component of the defect (BC-BD)(T0), PD(T0), bone level (CEJ-BD)(T0), and residual supporting bone (BD-RA)(T0). RESULTS: Among the considered predictor variables, the following were significantly associated with the outcome variable: 1) MT(T0) (P <0.0001); 2) BC-BD(T0) (P = 0.0377); and 3) BD-RA(T0) (P <0.0001). MT(T0) were found to be more prone to loss and the amount of BD-RA(T0) prognostic for tooth loss: the lower the residual amount of supporting bone, the higher the probability of tooth loss. Conversely, the BC-BD(T0)was associated with a reduced probability of future tooth loss: the greater the infrabony component, the lower the probability of tooth loss. None of the other considered predictors proved predictive for tooth loss. CONCLUSIONS: Within the scope of this study, many traditional prognostic factors were ineffective in predicting future tooth loss and, therefore, were of no prognostic value. Conversely, a few specific factors at the tooth level emerged as viable prognostic factors. The use of these factors may be of great value to practitioners as predictors of tooth loss when assigning a prognosis.

Adult↗
PubMed2005

Dental morphology and variation in theropod dinosaurs: implications for the taxonomic identification of isolated teeth.

Isolated theropod teeth are common Mesozoic fossils and would be an important data source for paleoecology biogeography if they could be reliably identified as having come from particular taxa. However, obtaining identifications is confounded by a paucity of easily identifiable characters. Here we discuss a quantitative methodology designed to provide defensible identifications of isolated teeth using Tyrannosaurus as a comparison taxon. We created a standard data set based as much as possible on teeth of known taxonomic affinity against which to compare isolated crowns. Tooth morphology was described using measured variables describing crown length, base length and width, and derived variables related to basal shape, squatness, mesial curve shape, apex location with respect to base, and denticle size. Crown curves were described by fitting the power function Y = a + bX(0.5) to coordinate data collected from lateral-view images of mesial curve profiles. The b value from these analyses provides a measure of curvature. Discriminant analyses compared isolated teeth of various taxonomic affinities against the standard. The analyses classified known Tyrannosaurus teeth with Tyrannosaurus and separated most teeth known not to be Tyrannosaurus from Tyrannosaurus. They had trouble correctly classifying teeth that were very similar to Tyrannosaurus and for which there were few data in the standard. However, the results indicate that expanding the standard should facilitate the identification of numerous types of isolated theropod teeth.

Analysis of Variance↗
PubMed1999

Changes in root surface temperatures with in vitro use of the system B HeatSource.

The purpose of this study was to measure root surface temperatures while using the System B HeatSource at various temperature settings. A split-tooth model of a human maxillary central incisor was prepared with 10 thermocouples to record root surface temperatures at 1-mm increments from the root apex. A System B HeatSource model 1005 was used to warm and compact gutta-percha to within 3 mm of the working length using the Buchanan technique. Twenty obturations were recorded at each of the following temperature settings: 250 degrees, 300 degrees, 350 degrees, 400 degrees, 450 degrees, 500 degrees, 550 degrees, and 600 degrees C. Examination of the mean temperatures recorded for each position and at each temperature setting revealed that the thermocouple 5 mm from the apex (T5) detected the highest increases in root surface temperatures. Only this site exceeded the 10 degrees C rise in temperature for one full minute that could cause damage to the supporting structures. The range of instantaneous temperatures at this site was 8.85 to 12.06 degrees C, with a mean of 10.62 +/- 0.93 degrees C. The results of this in vitro study indicate that any temperature setting of the System B HeatSource at or above 250 degrees C has the potential to cause the root surface temperature to rise 10 degrees C. Whether this occurs in vivo or if it does is maintained long enough to cause any tissue damage remains to be determined.

Body Temperature↗