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1.
Int J Legal Med ; 135(4): 1565-1572, 2021 Jul.
Article in English | MEDLINE | ID: mdl-33586031

ABSTRACT

The South African Bill of Rights and the Children's Act define a 'child' as a person under the age of 18 years. The age of 18 years is therefore significant for legal purposes in South Africa. The third molar is an important indicator in determining the 18-year threshold. Human biological growth markers are accepted indicators of a subject attaining the age of 18 years. A recent study by Roberts et al. suggested that the relative width of the distal root canals (RCW) of the lower left permanent molars (Fédération Dentaire Internationale notation 36, 37 and 38) as visualised on dental panoramic radiographs can be used as such a growth marker. This study aimed to validate this human biological growth marker in both black and white populations living in South Africa according to Roberts' method. The findings of this validation study were in agreement with this method which showed that individuals with Demirjian stage H left molars and category RCW-C were indeed over the 18-year threshold. Important aspects regarding the rationality and application of Roberts' method are discussed. The authors conclude that this method should not be used in isolation but as an adjunct with other age estimation methods.


Subject(s)
Age Determination by Teeth/methods , Black People , Dental Pulp Cavity/growth & development , Mandible , Molar, Third/growth & development , White People , Adolescent , Dental Pulp Cavity/diagnostic imaging , Female , Humans , Male , Molar, Third/diagnostic imaging , Racial Groups , Radiography, Panoramic , Reproducibility of Results , South Africa/ethnology , Young Adult
2.
Arch Oral Biol ; 90: 33-39, 2018 Jun.
Article in English | MEDLINE | ID: mdl-29529483

ABSTRACT

OBJECTIVE: The bone morphogenetic proteins (BMPs) play crucial roles in tooth development. However, several BMPs retain expression in the dentin of the fully patterned and differentiated tooth. We hypothesized that BMP signaling therefore plays a role in the function of the differentiated odontoblast, the job of which is to lay down and mineralize the dentin matrix. DESIGN: We generated mice deficient in Bmp2 and 4 using a dentin matrix protein 1 (Dmp1) promoter-driven cre recombinase that was expressed in differentiated odontoblasts. RESULTS: The first and second molars of these Bmp2 and Bmp4 double conditional knockout (DcKO) mice displayed reduced dentin and enlarged pulp chambers compared to cre-negative littermate controls. DcKO mouse dentin in first molars was characterized by small, disorganized dentinal fibers, a wider predentin layer, and reduced expression of dentin sialophosphoprotein (DSPP), dentin matrix protein 1 (DMP1), and bone sialoprotein (BSP). DcKO mouse odontoblasts demonstrated increased type I collagen mRNA production, indicating that the loss of BMP signaling altered the rate of collagen gene expression in these cells. Bmp2 and Bmp4 single Dmp1-cre knockout mice displayed no discernable dentin phenotype. CONCLUSIONS: These data demonstrate that BMP signaling in differentiated odontoblasts is necessary for proper dentin production in mature teeth.


Subject(s)
Bone Morphogenetic Protein 2/physiology , Bone Morphogenetic Protein 4/physiology , Dentin/physiology , Dentinogenesis/physiology , Odontoblasts/physiology , Signal Transduction , Animals , Bone Morphogenetic Protein 2/genetics , Bone Morphogenetic Protein 4/genetics , Cell Differentiation/genetics , Collagen Type I/genetics , Collagen Type I/metabolism , Collagen Type I/physiology , Collagen Type I, alpha 1 Chain , Dental Pulp Cavity/cytology , Dental Pulp Cavity/diagnostic imaging , Dental Pulp Cavity/growth & development , Dental Pulp Cavity/physiology , Dentin/cytology , Dentin/diagnostic imaging , Dentin/growth & development , Extracellular Matrix Proteins/metabolism , Gene Expression Regulation, Developmental , In Situ Hybridization , Integrin-Binding Sialoprotein/metabolism , Mice , Mice, Knockout , Molar/cytology , Molar/diagnostic imaging , Molar/physiology , Odontoblasts/cytology , Phosphoproteins/metabolism , Sialoglycoproteins/metabolism , X-Ray Microtomography
3.
Forensic Sci Int ; 277: 115-121, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28645095

ABSTRACT

BACKGROUND: Assessment of an age of an individual whether living or dead through teeth is one of the most reliable and simple method to calculate age than skeletal remains especially when they are in poor conditions. OBJECTIVES: The study was carried out with aim of (i) to evaluate reliability of dental age assessment through two different methods for adults i.e. tooth coronal index and pulp/tooth ratio using digital panoramic radiographs and (ii) to compare these methods for their accuracy in age determination. MATERIALS AND METHODS: The digital panoramic radiographs of 180 subjects of Chhattisgarh aged 15-70 years were selected for the study. The measurements were performed on the JPEG images of selected panoramic radiographs by using Adobe Acrobat 7.0 professional software. For tooth coronal index (TCI), height of the crown i.e. coronal height (CH) and the height of the coronal pulp cavity i.e. coronal pulp cavity height (CPCH) of mandibular second premolars and first molars was measured in millimeter (mm) and then TCI was calculated for each tooth and calculated age was compared with chronological age. For pulp/tooth ratio, the measurements of pulp chamber height (PCH) and crown root trunk height (CRTH) were performed on the mandibular first and second molar teeth, the pulp chamber crown root trunk height ratios (PCTHR) of selected tooth were calculated. The acquired data were subjected to Pearson correlation test, unpaired t test and Analysis of Variance (ANOVA) analysis. RESULTS: Results suggested that TCI (mandibular first molar r=-0.178), second premolar (r=-0.187) and PCTHR(mandibular first molar r=-0.921, second molar r=-0.901) correlated negatively with chronological age suggesting decrease in size of pulp cavity. Mandibular first molar was found to be most reliable tooth to estimate dental age. CONCLUSION: The study showed that both PCTHR and TCI have negative association with chronological age. PCTHR showed slightly higher negative correlation and proved as a better tool for age estimation than TCI. Statistically significant differences were observed between chronological and calculated age by both methods thus emphasizing the need for future clinical trials.


Subject(s)
Age Determination by Teeth/methods , Dental Pulp Cavity/diagnostic imaging , Radiography, Dental, Digital , Radiography, Panoramic , Tooth Crown/diagnostic imaging , Adolescent , Adult , Aged , Dental Pulp Cavity/growth & development , Female , Humans , Male , Mandible , Middle Aged , Molar , Reproducibility of Results , Tooth Crown/growth & development , Young Adult
4.
J Dent Res ; 96(1): 100-106, 2017 Jan.
Article in English | MEDLINE | ID: mdl-27694153

ABSTRACT

It is not known to what extent residual infection may interfere with the success of pulp regeneration procedures. The aim of this study was to determine, radiographically and histologically, the effect of residual bacteria on the outcome of pulp regeneration mediated by a tissue-engineered construct as compared with traditional revascularization. Periapical lesions were induced in 24 canine teeth of 6 ferrets. After disinfection with 1.25% NaOCl and triple antibiotic paste, ferret dental pulp stem cells, encapsulated in a hydrogel scaffold, were injected into half the experimental teeth. The other half were treated with the traditional revascularization protocol with a blood clot scaffold. After 3 mo, block sections of the canine teeth were imaged radiographically and processed for histologic and histobacteriologic analyses. Associations between variables of interest were evaluated through mixed effects regression models. There were no significant differences between the 2 experimental groups in radiographic root development ( P > 0.05). There was a significant association between the presence of persistent periapical radiolucency and root wall thickness ( P = 0.02). There was also no significant difference in histologic findings between the 2 experimental groups ( P > 0.05). The presence of residual bacteria was significantly associated with lack of radiographic growth ( P < 0.001). The amount of dentin-associated mineralized tissue formed in teeth with residual bacteria was significantly less than in teeth with no residual bacteria ( P < 0.001). Residual bacteria have a critical negative effect on the outcome of regenerative endodontic procedures.


Subject(s)
Bone Regeneration/physiology , Dental Pulp/growth & development , Animals , Bacteria , Dental Pulp/diagnostic imaging , Dental Pulp/microbiology , Dental Pulp Cavity/diagnostic imaging , Dental Pulp Cavity/growth & development , Dental Pulp Cavity/microbiology , Ferrets , Male , Radiography, Dental , Root Canal Therapy/methods , Stem Cell Transplantation/methods , Tissue Scaffolds/microbiology , Treatment Outcome
5.
J Contemp Dent Pract ; 17(11): 884-889, 2016 Nov 01.
Article in English | MEDLINE | ID: mdl-27965495

ABSTRACT

AIM: The present study aimed to investigate the association between the tooth coronal index (TCI) and the pubertal growth stages (PGS) for children and adolescents. MATERIALS AND METHODS: A cross-sectional study was performed using retrospectively collected panoramic and hand-wrist radiographs of 262 individuals (125 males, 137 females). The coronal height (CH) and the coronal pulp cavity height (CPCH) of the left mandibular teeth were measured. Then the TCI for which was calculated according to Ikeda et al (1985). The estimated TCI for individuals with the following PGS after Fishman (1987) are: SMI 4 (S), SMI 5 (DP3 cap), SMI 6 (MP3 cap) and SMI 7 (Mp5 cap). The associations between the TCI and the PGS were investigated by correlation coefficient of Spearman's rho, and the validity values for the PGS were computed. RESULTS: Significant correlations were noted between the simple TCI values for premolars and molars and the PGS, and the highest correlation was for the summed TCI for both first and second molars. Utilizing the validity values of the summed TCI for both first and second mandibular molars, the PGS can be predicted as follows: S stage when TCI is 49.17 or lesser, DP3cap stage when TCI is 43.52 or lesser, MP3cap stage when TCI is 36.73 or lesser, and Mp5cap stage when TCI is 26.84 or lesser. CONCLUSION: The TCI values declined along with the maturational process in children and adolescents. The TCI for both first and second molars was the best predictor of the PGS. CLINICAL SIGNIFICANCE: Panoramic photographs can be beneficial for prediction of the skeletal maturity and treatment planning without resorting to hand-wrist radiographs.


Subject(s)
Dental Pulp Cavity/anatomy & histology , Dental Pulp Cavity/growth & development , Dental Pulp/anatomy & histology , Dental Pulp/growth & development , Adolescent , Analysis of Variance , Bicuspid , Bone Development , Child , Cross-Sectional Studies , Dental Pulp/diagnostic imaging , Dental Pulp Cavity/diagnostic imaging , Female , Humans , Male , Mandible , Molar , Radiography, Panoramic , Tooth Crown/anatomy & histology , Tooth Crown/growth & development
6.
Int J Med Sci ; 13(7): 500-6, 2016.
Article in English | MEDLINE | ID: mdl-27429586

ABSTRACT

Perforation of floor of the dental pulp is often encountered during root canal treatment in routine clinical practice of dental caries. If perforation were large, granulation tissue would grow to form periodontal polyp. Granulation tissue consists of proliferating cells however their origin is not clear. It was shown that the cells in granulation tissue are mainly from migration of undifferentiated mesenchymal cells of the bone marrow. Hence, this study utilized GFP bone marrow transplantation mouse model. The floor of the pulp chamber in maxillary first molar was perforated using ½ dental round bur. Morphological assessment was carried out by micro CT and microscopy and GFP cell mechanism was further assessed by immunohistochemistry using double fluorescent staining with GFP-S100A4; GFP-Runx2 and GFP-CD31. Results of micro CT revealed alveolar bone resorption and widening of periodontal ligament. Histopathological examination showed proliferation of fibroblasts with some round cells and blood vessels in the granulation tissue. At 2 weeks, the outermost layer of the granulation tissue was lined by squamous cells with distinct intercellular bridges. At 4 weeks, the granulation tissue became larger than the perforation and the outermost layer was lined by relatively typical stratified squamous epithelium. Double immunofluorescent staining of GFP and Runx2 revealed that both proteins were expressed in spindle-shaped cells. Double immunofluorescent staining of GFP and CD31 revealed that both proteins were expressed in vascular endothelial cells in morphologically distinct vessels. The results suggest that fibroblasts, periodontal ligament fibroblasts and blood vessels in granulation tissue were derived from transplanted-bone marrow cells. Thus, essential growth of granulation tissue in periodontal polyp was caused by the migration of undifferentiated mesenchymal cells derived from bone marrow, which differentiated into fibroblasts and later on differentiated into other cells in response to injury.


Subject(s)
Cell Differentiation/genetics , Cell Movement/genetics , Dental Caries/therapy , Polyps/therapy , Animals , Bone Marrow Cells/metabolism , Bone Marrow Cells/pathology , Bone Marrow Transplantation , Cell Proliferation/genetics , Dental Caries/pathology , Dental Pulp/pathology , Dental Pulp Cavity/growth & development , Dental Pulp Cavity/pathology , Disease Models, Animal , Fibroblasts/cytology , Fibroblasts/transplantation , Green Fluorescent Proteins/genetics , Humans , Mice , Periodontal Pocket/pathology , Polyps/pathology
7.
Chin J Dent Res ; 19(1): 49-54, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26981607

ABSTRACT

OBJECTIVE: To evaluate the use of platelet-rich fibrin (PRF) in the regenerative therapy of immature canine permanent teeth. METHODS: Eight immature premolars of beagle dogs were pulp extracted and cleaned with irrigation, then divided into two groups of empty root canals and those filled with a PRF clot. All of the eight premolars were sealed with mineral trioxide aggregate and glass ionomer cement. Two premolars were left naturally grown as a positive control. The root development was assessed radiographically and histologically after 12 weeks. RESULTS: The radiological findings showed greater increases in the thickness of lateral dentinal wall in the PRF group than in the vacant group. Histologically, dental-associated mineral tissue, connective tissue, and bone-like mineral tissue grew into the root canals independent of PRF clot use. The PRF was able to increase the thickness of dental-associated mineral tissue. However, the vital tissue differed from the pulp dentin complex. CONCLUSION: Our study demonstrated the feasibility of using PRF-mediated regenerative therapy in pulpless immature teeth for improving tissue repair.


Subject(s)
Apexification/methods , Blood Platelets/physiology , Dental Pulp Cavity/drug effects , Fibrin/therapeutic use , Tooth Apex/drug effects , Aluminum Compounds/therapeutic use , Animals , Bicuspid/drug effects , Bicuspid/pathology , Calcification, Physiologic/drug effects , Calcium Compounds/therapeutic use , Connective Tissue/drug effects , Connective Tissue/pathology , Dental Pulp Cavity/growth & development , Dental Pulp Cavity/pathology , Dentin/drug effects , Dentin, Secondary/drug effects , Dentin, Secondary/pathology , Dogs , Drug Combinations , Glass Ionomer Cements/chemistry , Male , Oxides/therapeutic use , Regeneration/drug effects , Root Canal Filling Materials/therapeutic use , Root Canal Irrigants/therapeutic use , Root Canal Preparation/methods , Silicates/therapeutic use , Therapeutic Irrigation/methods , Tooth Apex/growth & development , Tooth Apex/pathology
8.
Arch Oral Biol ; 65: 87-94, 2016 May.
Article in English | MEDLINE | ID: mdl-26871985

ABSTRACT

OBJECTIVE: Different endodontic regeneration/revitalisation protocols have been suggested for the treatment of immature permanent teeth with pulp necrosis. Many aspects of these protocols require further investigating necessitating a suitable standardised animal model for research purposes. The focus of this study was to examine the anatomy and histology of sheep teeth at different stages of development to find an appropriate dental age for endodontic regeneration/revitalisation research. DESIGN: Sheep teeth at mature and immature dental ages were investigated. Standardized radiography, computed tomography, and histology were used to measure root length, apical-third dentine thickness and apex diameter, and to evaluate tissue development stages. RESULTS: A mature sheep tooth has an apical area which consists of a major foramen, intermediate dilatation and minor foramen. From the time of eruption to maturation no major changes occur in the incisor root lengths, but the apical foramen width decreases and the dentinal wall thickness increases. The two-tooth age exhibited the most similar features to that of an immature permanent human tooth. CONCLUSION: Sheep appears to be an appropriate animal model for endodontic regeneration/revitalization research with similar dimension and characteristics to human anterior teeth. Each dental age has its advantages and disadvantages. The two-tooth age showed the most favourable criteria making this age the most suitable for in vivo regeneration/revitalisation research.


Subject(s)
Endodontics/methods , Regeneration/physiology , Tooth Apex/cytology , Tooth Apex/growth & development , Animals , Dental Pulp/cytology , Dental Pulp/growth & development , Dental Pulp Cavity/cytology , Dental Pulp Cavity/growth & development , Dental Pulp Necrosis/pathology , Dentin/cytology , Dentin/growth & development , Humans , Incisor/cytology , Incisor/growth & development , Models, Animal , Odontogenesis , Sheep , Sheep, Domestic
9.
J Endod ; 42(3): 402-12, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26709200

ABSTRACT

INTRODUCTION: Recombinant DNA-produced amelogenin protein was compared with calcium hydroxide in a study of immature apex closure conducted in 24 young mongrel dogs. METHODS: Root canals of maxillary and mandibular right premolars (n = 240) were instrumented and left open for 14 days. Canals were cleansed, irrigated, and split equally for treatment with recombinant mouse amelogenin (n = 120) or calcium hydroxide (n = 120). RESULTS: After 1, 3, and 6 months, the animals were sacrificed and the treated teeth recovered for histologic assessment and immunodetection of protein markers associated with odontogenic cells. After 1 month, amelogenin-treated canals revealed calcified tissue formed at the apical foramen and a pulp chamber containing soft connective tissue and hard tissue; amelogenin-treated canals assessed after 3- and 6-month intervals further included apical tissue functionally attached to bone by a periodontal ligament. In contrast, calcified apical tissue was poorly formed in the calcium hydroxide group, and soft connective tissue within the pulp chamber was not observed. CONCLUSIONS: The findings from this experimental strategy suggest recombinant amelogenin protein can signal cells to enhance apex formation in nonvital immature teeth and promote soft connective tissue regeneration.


Subject(s)
Amelogenin/pharmacology , Dental Pulp/drug effects , Dental Pulp/pathology , Regeneration/drug effects , Tooth Apex/drug effects , Tooth Apex/pathology , Animals , Apexification/methods , Calcium Hydroxide/pharmacology , Dental Pulp/growth & development , Dental Pulp Cavity/drug effects , Dental Pulp Cavity/growth & development , Dental Pulp Cavity/pathology , Dogs , Mice , Models, Animal , Odontoblasts/drug effects , Recombinant Proteins/pharmacology , Root Canal Filling Materials/pharmacology , Tooth Apex/growth & development , Tooth, Nonvital/pathology
10.
Prog Orthod ; 14: 1, 2013 May 20.
Article in English | MEDLINE | ID: mdl-24326062

ABSTRACT

BACKGROUND: The objective of this research is to analyze the diagnostic performance of the circumpubertal dental maturation stages of the mandibular canine and second molar, as individual teeth and in combination, for the identification of growth phase. METHODS: A total of 300 healthy subjects, 192 females and 108 males, were enrolled in the study (mean age, 11.4±2.4 years; range, 6.8 to 17.1 years). Dental maturity was assessed through the calcification stages from panoramic radiographs of the mandibular canine and second molar. Determination of growth phase (as pre-pubertal, pubertal, and post-pubertal) was carried out according to the cervical vertebral maturation method. The diagnostic performances of the dental maturation stages, as both individual teeth and in combination, for the identification of the growth phase were evaluated using positive likelihood ratios (LHRs), with a threshold of ≥10 for satisfactory performance. RESULTS: For the individual dental maturation stages, most of these positive LHRs were ≤1.6, with values≥10 seen only for the identification of the pre-pubertal growth phase for canine stage F and second molar stages D and E, and for the post-pubertal growth phase for second molar stage H. All of the combined dental maturation stages yielded positive LHRs up to 2.6. CONCLUSIONS: Dental maturation of either individual or combined teeth has little role in the identification of the pubertal growth spurt and should not be used to assess timing for treatments that are required to be performed at this growth phase.


Subject(s)
Age Determination by Teeth/methods , Cuspid/growth & development , Molar/growth & development , Adolescent , Age Determination by Skeleton/methods , Age Determination by Skeleton/statistics & numerical data , Cephalometry/methods , Cephalometry/statistics & numerical data , Cervical Vertebrae/growth & development , Child , Cuspid/diagnostic imaging , Dental Pulp Cavity/growth & development , Female , Humans , Likelihood Functions , Male , Mandible/diagnostic imaging , Molar/diagnostic imaging , Odontogenesis/physiology , Puberty/physiology , Radiography, Panoramic/methods , Tooth Apex/growth & development , Tooth Calcification/physiology , Tooth Crown/growth & development , Tooth Root/growth & development
11.
Anat Rec (Hoboken) ; 296(8): 1247-54, 2013 Aug.
Article in English | MEDLINE | ID: mdl-23749549

ABSTRACT

The miniature pig is a useful large laboratory animal model. Various tissues and organs of miniature pigs are similar to those of humans in terms of developmental, anatomical, immunological, and physiological characteristics. The oral and maxillofacial region of miniature pigs is often used in preclinical studies of regenerative dentistry. However, there is limited information on the dentition and tooth structure of miniature pigs. The purpose of this study was to examine the time-course changes of dentition and tooth structure (especially the root) of the miniature pig mandibular cheek teeth through X-ray analyses using soft X-ray for two-dimensional observations and micro-CT for three-dimensional observations. The mandibles of male Clawn strain miniature pigs (2 weeks and 3, 5, 7, 9, 11, 14, 17, and 29 months of age) were used. X-ray analysis of the dentition of miniature pig cheek teeth showed that the eruption pattern of the miniature pig is diphyodont and that the replacement pattern is vertical. Previous definitions of deciduous and permanent teeth often varied and there has been no consensus on the number of teeth (dentition); however, we found that three molars are present in the deciduous dentition and that four premolars and three molars are present in the permanent dentition. Furthermore, we confirmed the number of tooth roots and root canals. We believe that these findings will be highly useful in future studies using miniature pig teeth.


Subject(s)
Mandible/diagnostic imaging , Mandible/growth & development , Swine, Miniature/growth & development , Swine/growth & development , Tooth/diagnostic imaging , Tooth/growth & development , Animals , Dental Pulp Cavity/anatomy & histology , Dental Pulp Cavity/diagnostic imaging , Dental Pulp Cavity/growth & development , Dentition , Male , Mandible/anatomy & histology , Swine/anatomy & histology , Swine, Miniature/anatomy & histology , Time Factors , Tooth/anatomy & histology , Tooth Root/anatomy & histology , Tooth Root/diagnostic imaging , Tooth Root/growth & development , X-Ray Microtomography , X-Rays
12.
Angle Orthod ; 83(4): 578-83, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23301999

ABSTRACT

OBJECTIVE: To evaluate the timing of spontaneous maxillary canine eruption in relation to stages of mandibular second molar maturation. Potential confounding effects from such factors as age, growth phase, and facial features were also explored. SUBJECTS AND METHODS: A sample of 106 healthy subjects (48 females and 58 males; age range, 9.4-14.3 years) with both permanent maxillary canines during the final phase of intraoral eruption were included. Mandibular second molar maturation (stages E to H) was assessed according to the method of Demirjian. Skeletal maturity was determined using the cervical vertebral maturational (CVM) method. Facial vertical and sagittal relationships were evaluated by recording the Sella-Nasion/mandibular plane (SN/MP) angle and the ANB angle. An ordered multiple logistic regression was run to evaluate adjusted correlation of each parameter with the mandibular second molar maturational stage. RESULTS: Overall, the prevalence of the different second molar maturational stages was 36.8%, 37.8%, and 27.4% for stages E, F and G, respectively. According to the regression model, this relation was not influenced by sex, CVM stage, SN/MP angle, and ANB angle. CONCLUSIONS: Irrespective of sex, growth phase, and facial features, the maturational stage of the mandibular second molar may be a reliable indicator for the timing of spontaneous eruption of the maxillary canine.


Subject(s)
Cuspid/physiology , Mandible/growth & development , Maxilla/growth & development , Molar/physiology , Odontogenesis/physiology , Tooth Eruption/physiology , Adolescent , Age Determination by Skeleton/methods , Age Factors , Cephalometry/methods , Cervical Vertebrae/growth & development , Child , Cross-Sectional Studies , Dental Pulp Cavity/growth & development , Female , Humans , Male , Maxillofacial Development/physiology , Nasal Bone/growth & development , Puberty/physiology , Retrospective Studies , Sella Turcica/growth & development , Sex Factors , Tooth Apex/growth & development , Tooth Calcification/physiology , Tooth Crown/growth & development , Tooth Root/growth & development , Vertical Dimension
13.
Cell Biochem Funct ; 30(3): 217-23, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22147556

ABSTRACT

In this study, the activity of the antioxidant enzyme network was assessed spectrophotometrically in samples of dental pulp and dental papilla taken from third-molar gem extracts. The production of nitric oxide by the conversion of l-(2,3,4,5)-[3H] arginine to l-(3H) citrulline, the activity of haem oxygenase 1 (HO-1) through bilirubin synthesis and the expression of inducible nitric oxide synthase (iNOS), HO-1 proteins and messenger RNA by Western blot and reverse-transcribed polymerase chain reaction were also tested. The objective of this study was to evaluate the role of two proteins, iNOS and HO-1, which are upregulated by a condition of oxidative stress present during dental tissue differentiation and development. This is fundamental for guaranteeing proper homeostasis favouring a physiological tissue growth. The results revealed an over-expression of iNOS and HO-1 in the papilla, compared with that in the pulp, mediated by the nuclear factor kappa B transcription factor activated by the reactive oxygen species that acts as scavengers for the superoxide radicals. HO-1, a metabolically active enzyme in the papilla, but not in the pulp, seems to inhibit the iNOS enzyme by a crosstalk between the two proteins. We suggest that the probable mechanism through which this happens is the interaction of HO-1 with haem, a cofactor dimer indispensible for iNOS, and the subsequent suppression of its metabolic activity.


Subject(s)
Dental Papilla/enzymology , Dental Papilla/growth & development , Dental Pulp Cavity/enzymology , Dental Pulp Cavity/growth & development , Gene Expression Regulation, Developmental , Heme Oxygenase-1/genetics , Nitric Oxide Synthase Type II/genetics , Adolescent , Child , Female , Gene Expression Regulation, Enzymologic , Heme Oxygenase-1/metabolism , Humans , Male , NF-kappa B/genetics , NF-kappa B/metabolism , Nitric Oxide Synthase Type II/metabolism , Up-Regulation
14.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 46(8): 489-93, 2011 Aug.
Article in Chinese | MEDLINE | ID: mdl-22169747

ABSTRACT

OBJECTIVE: To observe the process of pulp revitalization of immature permanent teeth after pulpectomy. METHODS: Thirty-two single-rooted teeth with open apices from 4 Beagle dogs aged 4 months were included in the study. The pulpal tissues of 8 front teeth with single root of each dog were removed, and a blood clot was produced to the level of the cementoenamel junction followed by a double seal of mineral trioxide aggregate and composite resin. At day 7, 14, 21 and 28, respectively after operation, the dog was sacrificed, and then longitudinal paraffin sections were made for histologic investigation. RESULTS: After 7 days, about one thirth of the pulp chamber had an ingrowth of new tissue. After 14, 21, 28 days, there were more and more new tissue in the chamber. This new tissue consisted of well-organized and well-vascularized connective tissue. Hard tissue was too observed in the root canal. In some cases, the newly generated hard tissue even deposited against the canal dentinal walls. CONCLUSIONS: The pulp of immature permanent teeth can revitalize after removal of the original pulp tissue under suitable conditions.


Subject(s)
Dental Pulp Cavity/growth & development , Dental Pulp/growth & development , Incisor/growth & development , Animals , Bone Regeneration , Connective Tissue/growth & development , Dental Pulp/blood supply , Dental Pulp Cavity/blood supply , Dentition, Permanent , Dogs , Incisor/blood supply , Male , Neovascularization, Physiologic/physiology , Pulpectomy
15.
Braz. j. microbiol ; 42(3): 973-979, July-Sept. 2011. ilus, tab
Article in English | LILACS | ID: lil-607527

ABSTRACT

The objective of this study was to determine the ecological relationships between bacterial species that colonize infected root canals. Root canal bacteria recovered from one patient with pulp canal necrosis were evaluated in vitro for synergistic and antagonistic activities determined by mono and co-culture growth kinetics and the production of bacteriocin-like substances using the double layer diffusion method. Peptostreptococcus prevotii triggered a significant increase of Fusobacterium nucleatum growth, while the former bacteria did not affect the growth of P. prevotii. The bacterial species did not produce antagonism activity against itself or against any of the other two species. Despite many studies have demonstrated the capability of root canal microorganisms to produce antagonistic substances, these in vitro experimental tests show the synergistic effect of P. prevotii on the growth of F. nucleatum.


Subject(s)
Humans , Dental Pulp Cavity/growth & development , Dental Pulp Cavity/microbiology , Endodontics , Fusobacterium Infections , Fusobacterium nucleatum/growth & development , Gram-Positive Bacterial Infections , In Vitro Techniques , Peptostreptococcus/growth & development , Periapical Tissue/growth & development , Periapical Tissue/microbiology , Drug Synergism , Methods , Microbiology , Methods
16.
Article in English | MEDLINE | ID: mdl-21112534

ABSTRACT

OBJECTIVE: The aim of this study was to investigate the association between dental and skeletal maturity. STUDY DESIGN: Digital panoramic radiographs and lateral skull cephalograms of 302 patients (134 boys and 168 girls, ranging from 8 to 16 years of age) were examined. Dental maturity was assessed by calcification stages of the mandibular canines, first and second premolars, and second molars, whereas skeletal maturity was estimated by the cervical vertebral maturation (CVM) stages. The Spearman rank-order correlation coefficient was used to measure the association between CVM stage and dental calcification stage of individual teeth. RESULTS: The mean chronologic age of girls was significantly lower than that of boys in each CVM stage. The Spearman rank-order correlation coefficients between dental maturity and cervical vertebral maturity ranged from 0.391 to 0.582 for girls and from 0.464 to 0.496 for boys (P < 0.05). In girls, the mandibular second molar had the highest and the canine the lowest correlation. In boys, the canine had the highest and the first premolar the lowest correlation. CONCLUSIONS: Tooth calcification stage was significantly correlated with cervical vertebral maturation stage. The development of the mandibular second molar in females and that of the mandibular canine in males had the strongest correlations with cervical vertebral maturity. Therefore, it is practical to consider the relationship between dental and skeletal maturity when planning orthodontic treatment.


Subject(s)
Age Determination by Skeleton , Age Determination by Teeth , Adolescent , Bicuspid/growth & development , Cephalometry , Cervical Vertebrae/growth & development , Child , China , Cohort Studies , Cuspid/growth & development , Dental Pulp Cavity/growth & development , Female , Humans , Male , Mandible , Molar/growth & development , Odontogenesis/physiology , Radiography, Dental, Digital , Radiography, Panoramic , Sex Factors , Tooth Apex/growth & development , Tooth Calcification/physiology , Tooth Crown/growth & development , Tooth Root/growth & development
18.
Int Endod J ; 41(10): 828-35, 2008 Oct.
Article in English | MEDLINE | ID: mdl-18822010

ABSTRACT

AIM: To investigate differences in the root canal morphology of permanent mandibular molar teeth at various ages. METHODOLOGY: Four hundred and eighty permanent mandibular first and second molars were examined. First and second molars were divided into six and five groups, respectively, according to the age of the patient at the time of extraction. Root canal morphology was studied using a clearing technique. The canal morphology of the mesial root was classified into three stages depending on its developmental pattern. When the root canal system was completely differentiated, the canal classification and the number of lateral canals and inter-canal communications were recorded. Vertucci's classification was taken as the main reference. Canal morphology was compared amongst age groups. RESULTS: In both first and second molars, developmental stages of canal morphology amongst age groups were significantly different (P < 0.0001). The prevalence of inter-canal communications was highly significantly different in the first (P < 0.0001) and less significant in the second molar (P < 0.05). After completion of the canal differentiation, the mesial roots of first molars had type IV and II canal forms. The majority of the mesial roots of second molars had type I and III canals. C-shaped canals were found in 3% of second molars. CONCLUSIONS: Mesial roots of first and second molars mostly had one large canal until 11 and 15 years of age, respectively. In both molars, the canal system was completely defined at 30-40 years. The prevalence of inter-canal communications was low at young and old ages but high at intermediate ages.


Subject(s)
Aging/pathology , Dental Pulp Cavity/anatomy & histology , Molar/anatomy & histology , Adolescent , Adult , Child , Classification , Dental Pulp/anatomy & histology , Dental Pulp/growth & development , Dental Pulp Cavity/growth & development , Dental Pulp Cavity/ultrastructure , Female , Humans , Male , Mandible , Molar/growth & development , Tooth Apex/anatomy & histology , Young Adult
19.
J Morphol ; 267(9): 1048-65, 2006 Sep.
Article in English | MEDLINE | ID: mdl-16724309

ABSTRACT

Most nonmammalian species replace their teeth continuously (so-called polyphyodonty), which allows morphological and structural modifications to occur during ontogeny. We have chosen Pleurodeles waltl, a salamander easy to rear in the laboratory, as a model species to establish the morphological foundations necessary for future molecular approaches aiming to understand not only molecular processes involved in tooth development and replacement, but also their changes, notably during metamorphosis, that might usefully inform studies of modifications of tooth morphology during evolution. In order to determine when (in which developmental stage) and how (progressively or suddenly) tooth modifications take place during ontogeny, we concentrated our observations on a single tooth family, located at position I, closest to the symphysis on the left lower jaw. We monitored the development and replacement of the six first teeth in a large growth series ranging from 10-day-old embryos (tooth I1) to adult specimens (tooth I6), using light (LM), scanning (SEM), and transmission electron (TEM) microscopy. A timetable of the developmental and functional period is provided for the six teeth, and tooth development is compared in larvae and young adults. In P. waltl the first functional tooth is not replaced when the second generation tooth forms, in contrast to what occurs for the later generation teeth, leading to the presence of two functional teeth in a single position during the first 2 months of life. Larval tooth I1 shows dramatically different features when compared to adult tooth I6: a dividing zone has appeared between the dentin cone and the pedicel; the pulp cavity has enlarged, allowing accommodation of large blood vessels; the odontoblasts are well organized along the dentin surface; tubules have appeared in the dentin; and teeth have become bicuspidate. Most of these modifications take place progressively from one tooth generation to the next, but the change from monocuspid to bicuspid tooth occurs during the tooth I3 to tooth I4 transition at metamorphosis.


Subject(s)
Salamandridae/growth & development , Tooth/growth & development , Animals , Dental Pulp Cavity/blood supply , Dental Pulp Cavity/growth & development , Dental Pulp Cavity/ultrastructure , Dentin/blood supply , Dentin/growth & development , Dentin/ultrastructure , Larva/anatomy & histology , Larva/growth & development , Microscopy, Electron, Scanning , Microscopy, Electron, Transmission , Salamandridae/anatomy & histology , Tooth/blood supply , Tooth/ultrastructure , Vision Disorders/embryology
20.
Angle Orthod ; 75(6): 935-40, 2005 Nov.
Article in English | MEDLINE | ID: mdl-16448234

ABSTRACT

The aim of this study was to determine the influence of growth stunting on the maturation stage of the medium phalanx of the third finger (MP3) and the dental development of the left mandibular canine in 280 high school children (140 stunted and 140 normal controls; equally distributed by sex) between 9.5 and 16.5 years of age, from a representative Peruvian school. Periapical radiographs of the MP3 from the left hand were used to determine the skeletal maturity stage, according to an adaptation of the Hägg and Taranger method. Panoramic radiographs were used to determine the dental maturity stage of the lower left canine, according to Demirjian method. Stunting was determined by relating height and age, according to the World Health Organization recommendations. There was no statistically significant difference in the skeletal maturation stage (P = .134) and the dental development stage (P = .497) according to nutritional status, even when considering different age groups (P > .183). A high correlation (r = 0.85) was found between both maturity indicators regardless of the nutritional status (growth stunted, r = 0.855 and normal controls, r = 0.863) or sex (boys, r = 0.809 and girls, r = 0.892). When skeletal level was considered, correlations values were similar between advanced (r = 0.903) and average (r = 0.895) maturers but lower (r = 0.751) for delayed maturers. Growth stunting was not associated with dental development and skeletal maturity stages in Peruvian school children.


Subject(s)
Bone Development/physiology , Growth Disorders/physiopathology , Odontogenesis/physiology , Adolescent , Age Determination by Skeleton , Age Determination by Teeth , Age Factors , Body Height/physiology , Body Weight/physiology , Child , Cuspid/growth & development , Dental Pulp Cavity/growth & development , Epiphyses/growth & development , Female , Fingers/growth & development , Humans , Male , Nutritional Status , Peru , Radiography, Panoramic , Tooth Apex/growth & development , Tooth Crown/growth & development , Tooth Root/growth & development
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