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Chorion type, birthweight discordance and tooth-size variability in Australian monozygotic twins.

Chorion type is an important variable that can affect the prenatal environment of monozygotic (MZ) twin pairs, leading to differences in growth and development. In particular, vascular anastomoses between monochorionic (MC) MZ twin pairs can lead to an imbalance in nutrition between co-twins. One objective of this study was to determine whether maternal reports, hospital records or birthweight discordances found in MZ co-twins provide reliable indications of monochorionicity. The other objective was to test the hypotheses that in MZ twin pairs of known chorion type, MC twin pairs would show greater birthweight differences and greater within-pair variability in permanent tooth size than dichorionic (DC) twin pairs, reflecting greater differences in intrauterine environment between MC MZ pairs. Birthweights and tooth size data were recorded for 170 pairs of MZ Australian twins enrolled in an ongoing study of dentofacial growth and development. Chorion type based on maternal reports was compared with that based on hospital records for a subsample of 68 pairs of these MZ twins. Maternal reports were found to be unreliable for determining chorion type and hospital records often did not provide enough information to be certain about chorionicity. For 27 twin pairs with confirmed chorion type, associations were tested between birthweight discordances in MZ twin pairs and chorion type, and also between intrapair variances for tooth size and chorion type. A significant association was noted between birthweight discordance and chorion type (p < .05), with greater discordances occurring more often in MC twin pairs. Although significant heterogeneity of intrapair variances for tooth size was found in only 5 of 48 comparisons, intrapair variances for crown dimensions were greater significantly more often in MC pairs than DC pairs (p < .05). Our findings indicated that neither maternal reports nor often hospital records can be relied upon for information on chorion type. However, when analyses were performed on data for MZ twin pairs of known chorion type, we found evidence of a significant association between intrapair birthweight differences and chorion type and also between intrapair variances of dental crown measurements and chorion type. Consistent with our hypotheses, large birthweight discordances were found to occur more often in MC twin pairs than DC twin pairs, and intrapair variances for tooth size in MC twin pairs exceeded those in DC twin pairs more often than expected due to chance.

Adult↗

Molar tooth development in caspase-3 deficient mice.

Tooth morphogenesis is accompanied by apoptotic events which show restricted temporospatial patterns suggesting multiple roles in odontogenesis. Dental apoptosis seems to be caspase dependent and caspase-3 has been shown to be activated during dental apoptosis.Caspase-3 mutant mice on different genetic backgrounds were used to investigate alterations in dental apoptosis and molar tooth morphogenesis. Mouse embryos at E15.5 were analyzed to reveal any changes in enamel knots, which are transient structures eliminated by apoptosis. In caspase-3(-/-) mice on the B57BL/6 background, disorganization of the epithelium was found in the original primary enamel knot area and confirmed by altered expression of Shh. Despite this early defect in molar tooth development, these mutants showed correct formation of secondary enamel knots as indicated by Fgf-4 expression. Analyses of adult molar teeth did not reveal any major alterations in tooth shape, enamel structure or pattern when compared to heterozygote littermates. In caspase-3(-/-) mice on the 129X1/SvJ background, no defects in tooth development were found except the position of the upper molars which developed more posteriorly in the oral cavity. This is likely, however, to be a secondary defect caused by a physical squashing of the face by the malformed brain. The results suggest that although caspase-3 becomes activated and may be essential for dental apoptosis, it does not seem fundamental for formation of normal mineralised molar teeth.

Animals↗

Dynamic assembly of tight junction-associated proteins ZO-1, ZO-2, ZO-3 and occludin during mouse tooth development.

Tight junctions might play a role during tissue morphogenesis and cell differentiation. In order to address these questions, we have studied the distribution pattern of the tight junction-associated proteins ZO-1, ZO-2, ZO-3 and occludin in the developing mouse tooth as a model. A specific temporal and spatial distribution of tight junction-associated proteins during tooth development was observed. ZO-1 appeared discontinuously in the cell membrane of enamel organ and dental mesenchyme cells. However, endothelial cells of the dental mesenchyme capillaries displayed a continuous fluorescence at the cell membrane. Inner dental epithelium first showed an evident signal for ZO-1 at the basal pole of the cells at bud/cap stage, but ZO-1 was accumulated at the basal and apical pole of preameloblast/ameloblasts at late bell stage. Surprisingly, in the incisor ZO-1 decreased as the inner dental epithelium differentiated, and was re-expressed in secretory and mature ameloblasts. On the contrary, ZO-2 was confined to continuous cell-cell contacts of the enamel organ in both molars and incisors. The lateral cell membrane of inner dental epithelial cells was specifically ZO-2 labeled. However, ZO-3 was expressed in oral epithelium whereas dental embryo tissues were negative. In addition, occludin was hardly detected in dental tissues at the early stage of tooth development, but was distributed continuously at the cell membrane of endothelial cells of ED19.5 dental mesenchyme. In incisors, occludin was detected at the cell membrane of the secretory pole of ameloblasts. The occurrence and relation during tooth development of tight junction proteins ZO-1, ZO-2 and occludin, but not ZO-3, suggests a combinatory assembly in tooth morphogenesis and cell differentiation.

Actins↗

An evaluation of clinical tooth mobility measurements.

This study evaluated the reliability and reproducibility of the modified Miller Index of horizontal tooth mobility. Each of three periodontists utilizing the modified Miller Index assessed the horizontal tooth mobility of 50 teeth in five subjects. The same teeth were also evaluated by the periodontometer. The results of these two methods were then compared. It was found that: (1) there were a high positive correlation between the periodontists' (pooled) assessment of clinical tooth mobility and the measurements of the periodontometer, (2) in any given patient the three periodontists (pooled) were highly accurate in their ability to rank teeth in order of their mobility as determined by the periodontometer, and (3) the periodontists (individually) were not as consistent when comparing teeth with the Miller Index across different subjects. The periodontists did not accurately utilize the Miller Index as it was originally described. It appears that the periodontists either ignored the reference to 1 mm in the description of the Miller Index, or they were unable to estimate what constitutes 1 mm of movemnet in the mouth. The periodontists all consistently scored as a 2 degrees mobility a tooth that moved approximately 0.5 mm not 1.0 mm as described by Miller. It is suggested that the modified Miller Index as described here provides an efficacious system for evaluating horizontal tooth mobility. It provides accurate, reproducible mobility scores in clinical studies requiring an estimation of this parameter. However, for individual teeth, when the clinician or researcher is trying to evaluate the effects of therapy on the periodontium and relatively few evaluation are made, the modified Miller Index may not provide the required degree of sensitively.

Adult↗

Cigar, pipe, and cigarette smoking as risk factors for periodontal disease and tooth loss.

BACKGROUND: Our purpose was to test the hypotheses that cigar and pipe smoking have significant associations with periodontal disease and cigar, pipe, and cigarette smoking is associated with tooth loss. We also investigated whether a history of smoking habits cessation may affect the risk of periodontal disease and tooth loss. METHODS: A group of 705 individuals (21 to 92 years-old) who were among volunteer participants in the ongoing Baltimore Longitudinal Study of Aging were examined clinically to assess their periodontal status and tooth loss. A structured interview was used to assess the participants' smoking behaviors with regard to cigarettes, cigar, and pipe smoking status. For a given tobacco product, current smokers were defined as individuals who at the time of examination continued to smoke daily. Former heavy smokers were defined as individuals who have smoked daily for 10 or more years and who had quit smoking. Non-smokers included individuals with a previous history of smoking for less than 10 years or no history of smoking. RESULTS: Cigarette and cigar/pipe smokers had a higher prevalence of moderate and severe periodontitis and higher prevalence and extent of attachment loss and gingival recession than non-smokers, suggesting poorer periodontal health in smokers. In addition, smokers had less gingival bleeding and higher number of missing teeth than non-smokers. Current cigarette smokers had the highest prevalence of moderate and severe periodontitis (25.7%) compared to former cigarette smokers (20.2%), and non-smokers (13.1%). The estimated prevalence of moderate and severe periodontitis in current or former cigar/pipe smokers was 17.6%. A similar pattern was seen for other periodontal measurements including the percentages of teeth with > or = 5 mm attachment loss and probing depth, > or = 3 mm gingival recession, and dental calculus. Current, former, and non- cigarette smokers had 5.1, 3.9, and 2.8 missing teeth, respectively. Cigar/pipe smokers had on average 4 missing teeth. Multiple regression analysis also showed that current tobacco smokers may have increased risks of having moderate and severe periodontitis than former smokers. However, smoking behaviors explained only small percentages (<5%) of the variances in the multivariate models. CONCLUSION: The results suggest that cigar and pipe smoking may have similar adverse effects on periodontal health and tooth loss as cigarette smoking. Smoking cessation efforts should be considered as a means of improving periodontal health and reducing tooth loss in heavy smokers of cigarettes, cigars, and pipes with periodontal disease.

Adult↗

Long-term tooth survival following regenerative treatment of intrabony defects.

BACKGROUND: The longevity of the clinical benefits of guided tissue regeneration (GTR) has not been fully explored. The aim of this investigation was to assess the long-term survival of GTR treated sites in terms of clinical attachment level (CAL) stability and tooth loss. METHODS: A total of 175 patients with one deep intrabony defect were selected for a retrospective investigation of tooth retention and CAL stability. All sites had been treated with GTR more than 2 years previously and had received full periodontal examinations every 2 years for up to 16 years. Definitions of events for survival analyses were tooth loss, loss of > or = 2 mm compared with the CAL observed before GTR treatment, and loss of > or = 2 mm compared with the CAL observed 1 year after completion of GTR. RESULTS: Teeth were severely compromised by the presence of CAL loss of 10.7 +/- 2.4 mm, probing depths of 8.7 +/- 2.3 mm and deep intrabony defects (average depth 6.6 +/- 2.1 mm). After GTR, CAL gains were 4.6 +/- 2 mm. Average follow up was 8 +/- 3.4 years; 66.9% of subjects strictly complied with a periodontal maintenance program. Tooth survival was greater than 96% more than 10 years after GTR. CAL was equal or coronal with respect to pretreatment in 92% of cases followed for 15 years after treatment, while loss of CAL compared to the 1-year post-GTR result was observed in 37.8% of cases. Cox proportional hazard models indicated that incidence-free survival was negatively affected by smoking and positively affected by full compliance with a periodontal maintenance program in a specialist practice. CONCLUSIONS: Within the limits of this study, data suggest that tooth retention and clinical improvements following GTR treatment of intrabony defects can be maintained long term in the great majority of cases and thus that regenerative periodontal treatment represents an important alternative for the management of severely compromised teeth.

Adolescent↗

The use of surrogate variables to reflect long-term tooth survivability.

Clinical parameters used to monitor periodontal patients are usually measures of the disease process. They are considered surrogate variables because changes in their status are interpreted to have an impact on the ultimate goal of periodontal therapy, which is tooth retention. However, their ability to reflect tooth survivability has been questioned because there is a lack of long-term data to validate that stable or improved surrogates result in reduced tooth loss. Therefore, to clarify the utility of employing surrogates to reflect long-term tooth retention, a number of issues related to their use are discussed in this commentary: phraseology, benefits and shortcomings, biologic credibility, and their previous successful utilization in monitoring the effects of therapy. This commentary supports the reasonableness of using surrogates to monitor periodontal status and suggests that a combination of surrogates that represent "periodontal clinical health" should be considered a true endpoint of periodontal therapy, since this outcome provides a condition conducive to tooth retention.

Biomarkers↗

[Effect of the resin-bonded restorations on the tooth displacement and the loading force of the supporting tissues].

A mechanical simulation model of tooth and alveolar bone was made and analyzed using three-dimensional finite element technique. And the variations of tooth mobility and the periodontium supporting force caused by the absorption of alveolar bone was investigated. The results obtained were as follows: 1. When the physiological tooth mobility was 150 microns, the teeth were sufficiently fixed using the resin-bonded splint and bridge connected with more than three teeth in the case of 40 percent of alveolar bone absorption. However in the case of 60 percent of alveolar bone absorption, the teeth were not fixed with splint and bridge of six teeth connections. 2. In the application of resin-bonded splint and bridge, when the metal frame thickness was 0.5 mm, the effect of the connected place on tooth mobility was large, and the abutment teeth were sufficiently fixed when the abutment teeth were connected up to the neck. 3. The periodontium supporting force decreased markedly according to the increase of abutment teeth. 4. When the abutment teeth were less than five teeth, the inhibitory action for tooth mobility of the resin-bonded splint and bridge was widely different, and resin-bonded splint was more effective compared with bridge.

Alveolar Bone Loss↗

[A case report of median diastema with deep bite treated with resin bonded retainer after minor tooth movement].

PATIENT: A fifty-two-year old female patient visited our dental hospital due to periodontal disease and aesthetic complaint by median diastema. A resin bonded retainer for the upper anterior teeth was placed after periodontal treatment and minor tooth movement. Median diastema and periodontal disease have not relapsed for these 6 years. DISCUSSION: Prosthetic treatment combined with minor tooth movement enabled the recovery of healthy periodontal tissue and reduction of the amount of tooth structure to be prepared. As a result, pulp treatment was not involved and desirable tooth contour was successfully achieved. CONCLUSION: Prosthetic restoration by resin bonded retainer followed by periodontal treatment and minor tooth movement was useful to improve aesthetic problems and to recover and maintain healthy periodontal tissue in this case of a patient with periodontal disease and median diastema with deep bite.

Dental Bonding↗

[Mouthguard effect of tooth distortion during clenching].

PURPOSE: A mouthguard can protect stomatognathic systems from traumatic damage. However, severe occlusal wear of teeth and loss of teeth have often been found in players clinically. These problems might originate in strong clenching during sports. Although it is thought that a mouthguard may be effective for these types of clenching, the relation between mouthguards and clenching has not been sufficiently examined. In this study, the effect of a mouthguard (Drufosoft 3mm, EVA) on tooth distortion caused by clenching was measured and examined at three different clenching strengths. METHODS: As a test tooth, a lower first molar was selected. A strain gauge applied to the outer surface of the buccal cusp was used to measure the distortion. A muscle balance monitor (GC) was used to regulate clenching strengths (10, 50, and 100%). The maximum-effort clenching without a mouthguard was assumed to be the 100% clenching strength. Measurements were conducted with or without mouthguard. A maximum value during clenching was assumed to be date of distortion by using analytical software AcquKnowledge (BIOPAC System Inc.). Statistical analysis software SPSS (SPSS Japan Inc.) was used for the Mann-Whitney test. RESULTS: 1. The tooth distortion by clenching, regardless of the presence of the mouthguard, increased as clenching power strengthened, from 10, 50 to 100%. 2. The tooth distortion, regardless of strength of clenching, was decreased by wearing the mouthguard in all subjects. At 50 and 100% clenching, it was decreased significantly by the mouthguard in all subjects. CONCLUSIONS: Mouthguards decreaseed the tooth distortion caused by clenching. Therefore, a mouthguard may prevent not only traumatic injuries in contact sports but also damage to teeth and periodontal tissues and so on, which occur due to frequent strong clenching in many sports.

Adult↗

[Examination of cardiovascular function variables in tooth extraction under local anesthesia].

BACKGROUND/AIM: Local anesthesia is the one of the most used procedures in surgical practice. It is used for toot extraction to produce analgesic and anesthetic effects. However, there is a question if it is equally safe to apply a local anesthetic combined with a vasoconstrictor (adrenaline) in healthy persons, and in the patients with a certain cardiovasccular system disease. The aim of this stady was to determine whether there were differences in cardiovascular variables during tooth extraction in healthy persons, and in cardiovascular patients when an anesthetic was applyted with adrenaline, or without it. METHODS: The examinees were divided into the group with cardiovascular diseases (CV, n=57) of H and III type, according to the American Society of Anesthesiologists (ASA) qualification, and healthy persons (H, n=55). Both groups were randomly divided into two subgroups: CVa and Ha--where the anesthetic solution had the vasoconstrictor (3% lidocaine, and 1: 100,000 adrenaline); CVb and Hb--where the anesthetic solution was without the vasoconstrictor (3% lidocaine). During the preparation for tooth extraction, the application of anesthetics, extraction and relaxation puls (fc), systolic (TAs) and diastolic arterial blood pressure (TAd) and ECG were registered. RESULTS: The values of fc did not significantly differ among the groups in any measured term. The values of systolic and diastolic blood pressure in the groups CVa and CVb were significantly higher in all the terms of measuring (p < 0.05) from the values in the groups Ha and Hb. A significant increase of TAs was registered only in the phase of tooth extraction in the CVa and CVb group (< 0.05). The values of TAd did not significantly differ between the groups in all the measured terms. Extrasystolic beats were registered in 11 patients of the CV group and in 7 patients of the H group in the phase of anesthetic application or tooth extraction. CONCLUSION: This research shoved that tooth extraction under local anesthesia did not cause complications in cardiovascular patients who were in II or III ASA qualification group, regardless the presence of a vasoconstrictor in the local anesthetic solution.

Adult↗

Orthodontic buccal tooth movement by nickel-free titanium-based shape memory and superelastic alloy wire.

OBJECTIVE: To examine the mechanical properties and the usefulness of titanium-niobium-aluminum (Ti-Nb-Al) wire in orthodontic tooth movement as compared with nickel-titanium (Ni-Ti) wire. MATERIALS AND METHODS: The load deflection of expansion springs was gauged with an original jig. The gradient of the superelastic region was measured during the unloading process. Expansion springs comprising the two types of alloy wires were applied to upper first molars of rats. The distance between the first molars was measured with micrometer calipers. RESULTS: The force magnitude of the Ti-Nb-Al expansion spring was lower than that of the Ni-Ti expansion spring over the entire deflection range. The initial force magnitude and the gradient in the superelastic region of the Ti-Nb-Al expansion springs were half those of the Ni-Ti expansion springs. Thus, Ti-Nb-Al expansion springs generated lighter and more continuous force. Tooth movement in the Ni-Ti group proceeded in a stepwise fashion. On the other hand, tooth movement in the Ti-Nb-Al group showed relatively smooth and continuous progression. At 17 days after insertion of expansion springs, there were no significant differences between the Ti-Nb-Al and Ni-Ti groups in the amount of tooth movement. CONCLUSIONS: These results indicate that Ti-Nb-Al wire has excellent mechanical properties for smooth, continuous tooth movement and suggest that Ti-Nb-Al wire may be used as a practical nickel-free shape memory and superelastic alloy wire for orthodontic treatment as a substitute for Ni-Ti wire.

Animals↗

Comparative Ki-67 expression and apoptosis in the odontogenic keratocyst associated with or without an impacted tooth in addition to unilocular and multilocular varieties.

It is not known whether the presence of an impacted tooth or the radiographic types in an odontogenic keratocyst (OKC) change the clinical biologic behavior and therapeutic approaches. This study evaluated the comparative proliferative activity and apoptosis in OKC associated with or without an impacted tooth, as well as between the unilocular and multilocular OKC varieties. Immunohistochemical expression of Ki-67 as a proliferation marker and the apoptotic reactions were assessed by the TUNEL method for 32 cases of OKC (OKC with impacted tooth, n=16; OKC without impacted tooth, n=16) and 10 cases of dentigerous cyst (DC). OKC showed a greater proliferative potential and more apoptotic reactions than DC. In particular, OKC contained proliferating and apoptotic cells situated predominantly in the suprabasal and superficial layers, respectively. However, no significant difference was found between OKC associated with or without impacted tooth, or between the unilocular and multilocular OKC varieties, in terms of proliferative activity or apoptosis. In conclusion, OKC is characterized by an increase in both cell proliferation and apoptosis, suggesting a unique proliferative and differentiation process. It is believed that incomplete removal or other contributing factors, rather than intrinsic growth or apoptosis, may be the main reasons for the aggressive biologic behavior or recurrence in multilocular OKC.

Adult↗

Antagonistic regulation of Dlx2 expression by PITX2 and Msx2: implications for tooth development.

The transcriptional mechanisms underlying tooth development are only beginning to be understood. Pitx2, a bicoid-like homeodomain transcription factor, is the first transcriptional marker observed during tooth development. Because Pitx2, Msx2, and Dlx2 are expressed in the dental epithelium, we examined the transcriptional activity of PITX2 in concert with Msx2 and the Dlx2 promoter. PITX2 activated while Msx2 unexpectedly repressed transcription of a TK-Bicoid luciferase reporter in a tooth epithelial cell line (LS-8) and CHO cell line. Surprisingly, Msx2 binds to the bicoid element (5'-TAATCC-3') with a high specificity and competes with PITX2 for binding to this element. PITX2 binds to bicoid and bicoid-like elements in the Dlx2 promoter and activates this promoter 45-fold in CHO cells. However, it is only modestly activated in the LS-8 tooth epithelial cell line that endogenously expresses Msx2 and Pitx2. RT-PCR and Western blot assays reveal that two Pitx2 isoforms are expressed in the LS-8 cells. We further demonstrate that PITX2 dimerization can occur through the C-terminus of PITX2. Msx2 represses the Dlx2 promoter in CHO cells and coexpression of both PITX2 and Msx2 resulted in transcriptional antagonism of the Dlx2 promoter. Electrophoretic mobility shift assays demonstrate that factors in the LS-8 cell line specifically interact with PITX2. Thus, Dlx2 gene transcription is regulated by antagonistic effects between PITX2, Msx2, and factors expressed in the tooth epithelia.

Animals↗

[Histological study on experimental tooth movement in alveolar bone defects implanted with decalcified bone powder].

Recently, secondary bone grafting for the alveolar cleft of cleft lip and palate patients has carried out generally with the object of connecting the alveolar cleft, of leading the tooth eruption, of control the tooth axis. In this study, the experimental tooth movements to the area were tested and the histological changes were investigated with adult cats. The experimental defects of 2mm in diameter were made at the alveolar bone mesial to the both maxillary first molar. At the experimental side, DBP were stuffed into the defect. Only defects were made at the control side. The tooth were moved for 6 weeks. The restoration of the defect hadn't occurred at the control side after 14 weeks. While appositional bone growth and new bone formation surrounding the DBP were observed, and complete restoration had be already occurred at experimental side after only 8 weeks. In the group which tooth movement were started after 1 week, the existing alveolar bone were bent to mesial at both side. In the group were started after 8 weeks, the existing alveolar bone were bent to mesial at the control side, either. The DBP and new bone were resorbed at the same time at the experimental side.

Alveolar Bone Loss↗

Laboratory assessment of tooth whitening by sodium bicarbonate dentifrices.

The increasing emphasis on dental aesthetics has made tooth whitening an important function of a dentifrice. This laboratory study investigated the whitening effect of toothbrushing with sodium bicarbonate-based dentifrices compared with standard dentifrices that do not contain sodium bicarbonate. Six dentifrices and a distilled water control were tested for their ability to whiten teeth with intrinsic stain. The dentifrices contained different abrasive systems: (1) 45% NaHCO3; (2) 65% NaHCO3 (Arm and Hammer Dental Care); (3) 94% NaHCO3; (4) 94% NaHCO3 + 1.5% H2O2; (5) silica (Crest Regular Toothpaste); and (6) dicalcium phosphate (Colgate Regular Toothpaste). After a thorough rubber cup cleaning with a pumice slurry, the intrinsic color of the test teeth with a Vita shade of A3 or darker was measured with a spectrophotometer using the standard L*a*b* color scale. Measurements were taken on a total of 12 teeth per test dentifrice before treatment, and after 30, 60, 90 and 120 minutes of mechanical toothbrushing. No changes in L* (lightness/brightness) or a* (red-green hue) occurred, but significant differences in b* (yellow-blue hue) were observed over time. Compared to baseline tooth color, all four sodium bicarbonate-based dentifrices were significantly effective in removing the yellow intrinsic tooth stain, while the water control, silica dentifrice, and dicalcium phosphate dentifrice demonstrated no significant change. Between-group comparisons showed that the four dentifrices containing sodium bicarbonate were significantly more effective than the water and dicalcium phosphate dentifrice groups. The commercial dentifrice containing 65% sodium bicarbonate was also more effective than the commercial silica dentifrice. Although continued toothbrushing from 30 to 120 minutes resulted in additional stain removal, most of the tooth whitening by the sodium bicarbonate-based dentifrices occurred in the first 30 minutes of brushing. In the studies conducted, dentifrices containing high concentrations of sodium bicarbonate were more effective at removing intrinsic tooth stain than dentifrices that do not contain sodium bicarbonate.

Dentifrices↗

[Effects of IL-1 on experimental tooth movement in rabbits].

The purpose of this study was to search the effects of IL-1 on the orthodontic tooth movement and alveolar bone by animal experiment. The distance of tooth movement was measured and histologic changes were observed. 12 rabbits were divided into two groups. IL-1 was injected in the gingiva around the moving tooth of the experimental group. The rate of tooth movement and the number of osteoclasts of the two groups were compared. The results suggested that IL-1 can promote the tooth movement and increase the number of osteoclasts and can also promote bone remodelling.

Alveolar Process↗

Age estimation by occlusal tooth wear.

The purpose of the present investigation was to test the accuracy of a new scoring system in recording tooth wear for age estimation. The material consisted of dental stone casts of 383 volunteers who had sound premolars and molars with normal occlusion. The degree of occlusal wear for all premolar and molar teeth was scored with the new system. The high intra- and inter-examiner concordances showed that the new score system was very reliable. The degree of tooth wear showed a significant positive correlation with age in each and every examined tooth of both males and females. Tooth wear scores of males were higher than those of females. Calculating tables for age estimation were designed and the accuracy of age estimation was obtained with the General Linear Models procedures. Our system could provide estimation of an individual's age within +/-3 years in 42.4% of males and 49.4% of females, within +/-5 years in 61.8% of males and 63.3% of females. When the subjects were divided into two age groups and data were re-treated, the accuracy of age estimation was increased. Collectively, it was shown that our new system for scoring tooth wear is a reliable and accurate method for age estimation.

Adolescent↗