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A finite element analysis of ceramic restorations in endodontically treated premolars

Seow LL, Toh CG, Fok AS, Wilson NH

Am J Dent, 2008 Oct;21(5):331-6.
PMID: 19024261

PURPOSE: To investigate the level and distribution of stresses in endodontically treated maxillary premolar teeth restored using various cavity designs of bonded all-ceramic restorations. The hypothesis tested was that the various all-ceramic approaches, including incorporating a pulp chamber extension in the restoration, had no influence on the stresses in the restored tooth unit.
METHODS: Finite element packages Patran and Abaqus were used for the stress analysis. The cavity designs investigated include: (1) inlay (I); (2) inlay with palatal cusp coverage (IPC); (3) onlay (O); (4) inlay with pulp chamber extension (IPE); (5) inlay with palatal cusp coverage and pulp chamber extension (IPCPE); and (6) onlay with pulp chamber extension (OPE).
RESULTS: In each case, tensile stresses were found to be concentrated subjacent to the occlusal fossa. Peak tensile stress and peak shear stress values along the tooth/restoration interface for IPC, O IPCPE and OPE cavity designs were found to be associated with the axiogingival line angle. Overall, the order of the various forms of restoration investigated in terms of the maximum principal stress (from greatest to lowest) was as follows: IPE > IPCPE > OPE > I > IPC > O.

Matched MeSH terms: Bicuspid
Tooth mineralization stages as a diagnostic tool for assessment of skeletal maturity

Surendran S, Thomas E

Am J Orthod Dentofacial Orthop, 2014 Jan;145(1):7-14.
PMID: 24373650 DOI: 10.1016/j.ajodo.2013.09.007

The objective of this study was to determine whether dental calcification can be used as a first-level diagnostic tool for assessment of skeletal maturity.

Matched MeSH terms: Bicuspid/growth & development; Bicuspid/radiography
Osseous evidence behind micro-osteoperforation technique in accelerating orthodontic tooth movement: A 3-month study

Asif MK, Ibrahim N, Sivarajan S, Heng Khiang Teh N, Chek Wey M

Am J Orthod Dentofacial Orthop, 2020 Oct;158(4):579-586.e1.
PMID: 32826123 DOI: 10.1016/j.ajodo.2019.09.022

INTRODUCTION: The study aimed to investigate the effects of micro-osteoperforations (MOPs) on the mandibular bone volume/tissue volume (BV/TV) ratio changes and the rate of orthodontic tooth movement using cone-beam computed tomography images. Another objective was to evaluate the effects of MOP frequency intervals (4 weeks, 8 weeks, and 12 weeks) on the BV/TV ratio and rate of tooth movement.
METHODS: In 24 participants, 140-200 g of force was applied for mandibular canine retraction. Three MOPs were made according to the scheduled intervals of the 3 different groups: group 1 (MOP 4 weeks), group 2 (MOP 8 weeks), and group 3 (MOP 12 weeks) directly at the mandibular buccal cortical bone of extracted first premolars sites. Cone-beam computed tomography scans were obtained at the 12th week after MOP application. Computed tomography Analyzer software (version 1.11.0.0; Skyscan, Kontich, Belgium) was used to compute the trabecular alveolar BV/TV ratio.
RESULTS: A significant difference was observed in the rate of canine movement between control and MOP. Paired t test analysis showed a significant difference (P = 0.001) in the mean BV/TV ratio between control and MOP sides in all the frequency intervals groups. However, the difference was significant only in group 1 (P = 0.014). A strong negative correlation (r = -0.86) was observed between the rate of canine tooth movement and the BV/TV ratio at the MOP side for group 1 and all frequency intervals together (r = -0.42).
CONCLUSIONS: The rate of orthodontic tooth movement can be accelerated by the MOP technique with frequently repeated MOPs throughout the treatment.

Matched MeSH terms: Bicuspid
Effectiveness of microosteoperforations in accelerating alignment of maxillary anterior crowding in adults: A randomized controlled clinical trial

Shahrin AA, Ghani SHA, Norman NH

Am J Orthod Dentofacial Orthop, 2021 Dec;160(6):784-792.
PMID: 34452786 DOI: 10.1016/j.ajodo.2021.04.021

INTRODUCTION: This trial aimed to investigate the effectiveness of microosteoperforations (MOPs) in overall time taken for alignment of maxillary anterior crowding and to evaluate the alignment improvement percentage within 6 months between MOPs and control groups.
METHODS: Thirty adult participants (25 females and 5 males; mean age, 22.66 ± 3.27 years) with moderate upper labial segment crowding were randomly assigned into intervention and control groups using block randomization. All participants had first premolar extractions, bonded conventional fixed appliances, and 0.014-in, followed by 0.018-in nickel-titanium archwire placement for initial alignment. The intervention group received a 3-mm deep MOPs procedure under local anesthesia using a Propel device (Propel Ortho Singapore, Pte, Ltd, Winstedt Rd, Singapore) on the labial attached gingivae of maxillary incisors at monthly visits until complete alignment. Little's irregularity index was used to assess the overall changes and measure the change of tooth alignment of the 6 maxillary anterior teeth. Assessor blinding was employed.
RESULTS: There was no statistically significant difference in the median overall alignment duration between MOPs and control groups (139 days [95% confidence interval, 115.32-161.83] vs 143 days [95% confidence interval, 107.12-179.74]; hazard ratio, 0.829; P = 0.467). The MOPs procedure had no significant effect on the alignment duration (P = 0.657) and no overall significant difference in alignment improvement percentage among 2 groups on the basis of time (F = 2.53; P = 0.124). No harm was encountered.
CONCLUSIONS: The application of MOPs is no more effective in accelerating initial orthodontic alignment than conventional treatment.
TRIAL REGISTRATION: This trial was registered at the ISRCTN registry with the study ID ISRCTN15080404.
PROTOCOL: https://doi.org/10.1186/ISRCTN15080404.
FUNDING: This work was supported by the Postgraduate Trust Fund, Faculty of Dentistry, Universiti Teknologi MARA.

Matched MeSH terms: Bicuspid
Prevalence and patterning of maxillary premolar accessory ridges (MxPARs) in several human populations

Mihailidis S, Scriven G, Khamis M, Townsend G

Am. J. Phys. Anthropol., 2013 Sep;152(1):19-30.
PMID: 23913636 DOI: 10.1002/ajpa.22323

We present new data on the prevalence and patterning of the maxillary premolar accessory ridge (MxPAR), a common but understudied morphological dental trait that is expressed as a linear elevation extending from the buccal cusp ridge to the medial sulcus of maxillary premolar teeth. A total of 579 sets of dental casts, representing six ethnic groups, were scored using the five-grade system proposed by Burnett et al. (2010). The frequency and distribution of the MxPAR were determined by tooth type, sex, side, locus and ethnicity, and the applicability of the scoring system was assessed. The MxPAR was found in approximately two-thirds of premolar teeth, more often on second than first premolars, and more often on the distal aspect of the occlusal surface than the mesial. There was some evidence that more pronounced forms of the feature occurred more often in males than females, and that there may be some directionality in its expression between sides. Variation was also noted in the frequency of occurrence and degree of expression of the MxPAR between ethnic groups. Intra- and inter-observer concordance rates for scoring the MxPAR were low, confirming that it was difficult to score the trait identically on two different occasions. Our findings have clarified the distribution of the MxPAR within the dentition and between ethnic groups, and highlighted the need for researchers to carry out thorough replicability studies and to decide on an appropriate breakpoint for determining presence or absence of this feature before embarking on genetic studies or bio-distance analyses.

Matched MeSH terms: Bicuspid/anatomy & histology*
Fulltext Vertical play of straight wire appliance aids correction of gummy smile and bimaxillary incisor proclination with mini implant anchorage

Mohd Zambri M.M., Wan Nurazreena W.H.

Ann Dent, 2018;25(1):1-10.
MyJurnal

This report aimed to describe an effective biomechanics to control the upper incisors inclination during the
correction of gummy smile with bimaxillary proclinations. A 14-year-old female presented with a Class II
division I incisor relationship complicated with bimaxillary proclination on a Class 2 skeletal base. The lips
were incompetent, showing 7 mm of upper incisors at rest and 5mm maxillary gingival display on smiling
with normal upper lip length. Treatment involved extraction of all first permanent premolars followed by
upper and lower fixed appliances. Intrusion of the upper incisors with controlled labial crown torque was
accomplished with mini-implant anchorage placed bilaterally on the infrazygomatic crests with the retraction
forces above the centre of resistance using 0.019x0.025-in stainless steel archwire in 0.022-in slot. The
0.019x0.025-in stainless steel archwire in 0.022-in slot provided the vertical play to favour lingual crown
tipping despite having forces above the centre of resistance for concurrent anterior segment intrusion.

Matched MeSH terms: Bicuspid
Fulltext Margin width, internal line angle and labial emergence profiles of maxillary metalloceramic

Yahya, N.A., Youngson, C.C.

Ann Dent, 2007;14(1):7-13.
MyJurnal

The purpose of this study were to compare the emergence profiles of crowns with their contralateral tooth, in vitro, and to determine if there is any association between the design of tooth preparations and the resultant emergence profile. 50 working models used for single crown construction were examined. Measurements of the faciolingual width of the crowns and contralateral teeth were taken using digital calipers. Internal line angles and the margin width of dies and the emergence profile of the corresponding crowns were measured from longitudinally sectioned polyvinylsiloxane indices mounted on a flat-bed scanner using image analysis software. Using Students t tests, no statistically significant differences (p>0.05) were found for shoulder width (mean 0.94 ± 0.23mm), internal line angle (mean 105.83 ± 13.57°) or emergence profiles (28.56 ± 12.95°) in the different (anterior, premolar or molar) preparations or crowns. The mean emergence profiles for all crowns was statistically significantly greater (p

Matched MeSH terms: Bicuspid
Fulltext Transposed Supernumerary Premolar In Alignment - A Case Report

Ngeow, W.C.

Ann Dent, 1996;3(1):-.
MyJurnal

Supernumerarypremolars have been reported to occur in 0.29% of the general populationand to represent about 9.1% of all supernumerary teeth. Most of the supernumerary teeth reported in the literature were detected by radiographsas most of them were unerupted or impacted.Asearch of the literature revealed not many cases of fully erupted and well aligned supernumerary premolars being reported. A case of a unilateral transposed supernumery premolarthat had erupted into alignment is presented here. The remarkable featureof this case is that the supernumery premolar is transposed between the first and second permanent maxillary molars. The etiology of supernumeraryteeth is also reviewed.

Matched MeSH terms: Bicuspid
Fulltext A practical model for endodontic radiography teaching

Che Ab Aziz, Z.A.

Ann Dent, 2008;15(2):67-70.
MyJurnal

Aim: To manufacture a clinical simulation apparatus for the undergraduates' endodontic radiography teaching Objectives: • To provide a model for teaching of parallax method using Kelly's forcep • To provide a model for undergraduates to practice radiographic localization employing parallax method. • To allow students to practice taking radiographs in a way that simulates the clinical situations with a good diagnostic quality Methods: Impressions of a dentate arch (maxillary and mandibullary) were used to form a stone cast. A section of the cast, in the area where the natural teeth were to be placed, is sectioned and removed. Three maxillary extracted teeth (canine, first and second premolar) were selected and mounted with acrylic resin at the sectioned area. The resin was cured in a light box. The arches were mounted in a phantom head with a placement of rubber cheek. The first premolar was isolated with rubber dam. The intraoral holder (Kelly's forcep) was attached to a robotic arm. The students were taught the correct angulations of the x-ray cone for the paralleling technique and parallax method using Kelly's forcep during root canal treatment. Results: All students managed to complete the exercise and were considered competent when they produced acceptable quality of radiographs. Conclusion: The model described was improvised from a model that has been used during the past 2 years for undergraduates' endodontic courses. It has been well accepted as it simulates the clinical situation more closely than was possible previously.

Matched MeSH terms: Bicuspid
Fulltext The effect of different dental adhesive systems on hybrid layer qualities

SH, Ku, YS, Tan, Yahya NA

Ann Dent, 2014;21(1):25-32.
MyJurnal

The study aimed to evaluate the quality of the hybrid
layer form by three different adhesive systems. Class V
cavities were prepared on the buccal surface of fourty
extracted human premolars. The prepared teeth were
randomly assigned into four groups according to the
adhesive system and application mode. The systems
were: Optibond S (OS, total-etch); Optibond Versa (OV,
two-bottles, self-etch); Single Bond Universal (SBU,
one-bottle, self-etch) and Single Bond Universal with
etchant (SBU + etchant). All cavities were restored with
composite (Filtek Z350XT). The samples were sectioned,
polished and pretreated to remove minerals, protein
and water prior to SEM evaluation. From the images,
thickness of the hybrid layers was measured. Present of
resin tags and adaptation failure were also recorded. The
data obtained were analyzed using ANOVA, Dunnett’s
T3, Kruskal-Wallis and Mann-Whitney tests. OS group
showed the highest average hybrid layer thickness (4.34
µm), followed by SBU + etchant (3.06 µm), OV (1.91 µm)
and SBU (0.95 µm). Both adhesive and cohesive failures
were observed in SBU group. Present of prominent resin
tags were seen in both OS and OV groups. In conclusion,
all the investigated adhesive systems were able to perform
distinguishable actions as shown in micro-morphological
alteration and hybrid layer thickness. Two-bottles, selfetch
adhesive (OV) was proven to produce negligible
adaptation failure compared to other adhesive systems in
the present study. Combined all-in-one adhesive (SBU)
was found to render a superior bonding performance in
total-etch mode comparing to self-etch mode.

Matched MeSH terms: Bicuspid
Fulltext Is Profile Alone Sufficient To Remove Gutta-Percha During Endodontic Re-treatment?

Lee, S.W., Tan, S.T., Che Ab Aziz, Z.A.

Ann Dent, 2005;12(1):-.
MyJurnal

Thirty extracted mandibular premolars were randomly divided into 3 groups. Canals were cleaned, obturated and the teeth incubated. Guttapercha removal was performed using: Hedström files with xylene (Group 1); ProFile® alone (Group 2) and combination of both (Group 3). Time required to remove the gutta-percha was recorded. Postoperative radiographs were taken. Specimens were split longitudinally and photographed. Amount of gutta-percha left at coronal, middle and apical thirds was calculated by computer (QWIN software) and the photographs were also evaluated visually by two endodontists. Results showed that the combined technique was fastest in removing gutta-percha. Radiographically, more residual was left in Group 2. Although computer analysis also showed more residual was left in Group 2, they were in a small percentage and there were no significant differences (P>0.05, SPSS paired-samples T test) among groups. Although there were significant differences between the two evaluators in their scoring, both generally agreed (Kappa’s analysis= 0.64) there was more guttapercha residual in Group 2 compared to Group 3 in the apical thirds. Although the differences in efficacy of guttapercha removal among these techniques were not significant, the use of ProFile® increased the speed of the procedure. The combined technique showed the most superior efficacy in gutta-percha removal.

Matched MeSH terms: Bicuspid
Fulltext Comparative Study On Microleakage Of Composite Inlays Using Various Resin Luting Cements

Annuar, W.A., Abdullah, H.

Ann Dent, 2003;10(1):-.
MyJurnal

This study is conducted to compare two resin luting cements (Rely XTMARC,3M and Compolute™ESPE) on their microleakage with one composite inlay system (Filtek™ Z250 Universal Restorative Materials, 3M). Thirty conventional inlays, Class II MOIDO cavity with gingival margin I mm above the cementoenamel junction, were prepared in premolar teeth. The composite inlays were fabricated directly on the prepared teeth using layering technique. Fifteen of the inlays were cemented with RelyTMX ARC and fifteen with Compolute™ (ESPE). The specimens were kept at 370 C for 10 days before thermocycling and immersed in methylene blue 2% solution for 24 hours. The teeth were sectioned mesio-distally. The site and degree of leakage of each section was scored using a visual scoring system under a stereomicroscope at a magnification of 1.5X. Results showed that there was no significant difference in'leakage extent (p>O.05), between Rely X™ARC and Compolute™. For both materials, leakage occurred most commonly within the enamel surface and between the cement-tooth interfaces. None of the leakage occurred between inlay - cement interface. There is no significant difference in the extent of leakage between Rely XTMARC compared to Compolute™.

Matched MeSH terms: Bicuspid
Fulltext Shear bond strength of orthodontic adhesives on different tooth types : an in vitro study

Radzi, Z., Yahya, N.A., Kasim, N.H.A., Ismail, N.H., Ismail, N.A., Zamzam, N

Ann Dent, 2006;13(1):18-23.
MyJurnal

Introduction: Owing to the variety of materials and methods employed, comparison of the results and findings from bonding studies is difficult. Until recently, several types of teeth have been used in published research papers as a substrate in orthodontic bonding research including bovine incisors, fresh and rebonded human premolars. Objectives: The purpose of this study was to compare the shear bond strength of an adhesive bonded to different tooth surfaces (human premolar, bovine incisor and rebonded human premolar). Methods: Two groups of thirty premolar teeth and one group of bovine incisors had brackets attached in a standardized manner using Transbond XT (3M Unitek). The adhesive was cured using conventional halogen light and a specially designed tool to standardize the distance between the light curing tip and the adhesive. The debonding force was measured using Instron universal testing machine. ANOVA and Post Hoc Dunnett C test were performed to determine any significant difference among groups (p

Matched MeSH terms: Bicuspid
Fulltext Effect of luting cement to push-out bond strength of fibre reinforced post

Yahya, N.A., Lui, J.L., Chong, K.W.A., Abu Kasim, N.H., Radzi, Z., Lim, C.M.

Ann Dent, 2008;15(1):11-19.
MyJurnal

The objective of this study was to investigate the effect of various luting cement systems on bond strength of fibre-reinforced posts to root canal dentine. 40 extracted single rooted sound premolar teeth were root filled, decoronated and randomly divided into four groups. Fibre posts, Aestheti- Plus™ (Bisco,Inc. Schaumburg, IL, USA) were cemented using four luting cements: Group A (control): Elite 100® Zinc phosphate (GC Corp, Japan), Group B: Calibra ™ Esthetic Resin Cement (Dentsply Caulk, USA), Group C: RelyX ARC Adhesive Resin (3M ESPE), Group D: RelyX Unicem Aplicap (3M ESPE). Each root was sliced into 2 discs representing the coronal and middle portions of the root canal giving rise to 20 specimens per group. Bond strength was determined using push-out tests and data was analyzed using SPSS version 14.0. The mean bond strength of Group A to Aestheti-Plus™ post was 7.71 MPa (±2.51) and Group B was 5.69 MPa (±3.23). Group C exhibited the lowest mean bond strength, 4.29 MPa (±3.53) while the highest bond strength was obtained from Group D, 7.98 MPa (±2.61). One way ANOVA showed significant interaction between all groups (p=.OOI). Post-hoc Bonferroni test reve;iled that bond strength of Group C was significantly lower compared to Group A (p=.008) and D (p=.004). In conclusion, the mean bond strength of Aestheti- Plus™ post to root canal dentine was highest when cemented with RelyX Unicem resin cement followed by Elite 100® zinc phosphate cement, Calibra and RelyX ARC resin cements. However, the bond strengths of Cali bra and RelyX Unicem resin cements were not significantly different from Elite 100® zinc phosphate cement.

Matched MeSH terms: Bicuspid
Fulltext Assessment of microleakage of few restorative materials after erosion by acidic solution

Suhaida Sabdi, Wan Zaripah Wan Bakar, Adam Husein

Archives of Orofacial Sciences, 2011;6(2):26-32.
MyJurnal

Some restorative materials are susceptible to erosion but whether it also causes microleakage is still questionable. The aim of this study was to assess the microleakage of few restorative materials after immersion in acidic solution. Standardized ‘U’ shaped cavity of 4mm diameter and 2mm depth were prepared on buccal or lingual surface of 52 human premolar and molar teeth. The teeth were divided into 4 groups which contains 13 samples and 3 controls for each and were restored either with Filtek Z250 (Group 1), Fuji IX (Group 2), Fuji II LC (Group 3), or Silverfill amalgam (Group 4).
All surfaces were painted with nail varnish leaving only 2mm of tooth structure surrounding the restoration before the study samples were immersed in acidic solution, lemon juice (pH 2.74) and control samples in deionised distilled water for 24 hours. Surface photos for erosion were taken before immersion in methylene blue for 7 days. After sectioning, the assessment of dye penetration was done using Leica Imaging System DMLM (Germany). Photos showed that Fuji IX demonstrated severe erosion but no obvious changes were seen on other materials. Kruskal-Wallis test indicated that microleakage between all four groups were statistically significant. The most significant difference was between Filtek Z250 and Fuji IX (p

Matched MeSH terms: Bicuspid
Fulltext Effect of delayed light-cured activation on bond-strengths between composites and adhesives

Masudi, S.M., Padtong, E.A.

Archives of Orofacial Sciences, 2006;1(1):36-41.
MyJurnal

The objective of this study was to evaluate and compare the effect of times elapsed on the application of a single-step adhesive system and activation of light cured subsequently placed composite to the bond strength between composites and adhesives. This was an experimental study using fifteen teeth extracted human premolars, which were caries and pathology free. Sample of teeth were embedded up to cemento-enamel junction on box of acrylic resin. All teeth were cut to obtain flat occlusal dentin surfaces. The specimens were randomly selected and divided into three groups with five teeth each. All the teeth were assigned to single-step bonding system AQ Bond (Sun Medical Co. Ltd., Shiga, Japan) according to manufacturer’s direction. Group 1 was left for 45 seconds, group 2 for 2 minutes, while group 3 was 5 minutes before putting subsequently restorative material. Composite resin was applied in 3 mm diameter and 6 mm height of cylinder mold and cured according to manufacturer’s direction on the dentin surface. Shear bond strength were measured using a testing system (Instron 8874, Instron Corp., Canton, MA, USA) at a crosshead speed of 2 mm/min with cell load capacity of 25 KN. The bond-strengths between single step adhesive system (AQ Bond) and light cured composites were tested. Mann-Whitney test showed no significant differences in bond-strength between Group 1 and Group 2. However, there were significantly differences (p

Matched MeSH terms: Bicuspid
Fulltext An unusual case of chronic suppurative osteomyelitis of the mandible

Kamran Ali, Ashfaq Akram, Muhammad Usman Akhtar

Archives of Orofacial Sciences, 2012;7(1):1-5.
MyJurnal

Osteomyelitis of the mandible, a serious complication of untreated odontogenic infection has been reported. This case report describes an interesting presentation of chronic suppurative osteomyelitis (CSO) of the mandible in a 13 years old anaemic male patient. Investigations revealed inversion of his permanent teeth leading to trans-cutaneous extra-oral eruption along with marked destruction of mandible on the affected side. The treatment included a pre surgical course of antibiotics followed by the removal of the retained second premolar tooth, surgical debridement of the affected bone, and resection of the cutaneous sinus tract. The post-operative healing was uneventful. A combination of antibiotic therapy and surgical debridement were effective in the treatment of chronic suppurative osteomyelitis.

Matched MeSH terms: Bicuspid
Fulltext Effect of desensitizing agent on shear bond strength of an adhesive system

Awang, R.A.R., Masudi, S.M., Mohd Nor, W.Z.W.

Archives of Orofacial Sciences, 2007;2(1):32-35.
MyJurnal

Desensitization of teeth after cavity preparation has been recommended in an attempt to avoid post-operative sensitivity. However, there is concern regarding application effect of desensitizing agent on shear bond strength of the adhesive system used. The purpose of our study was to compare the shear bond strength of adhesive system in two different dentin surface treatments, with and without desensitizing agent. Sixteen extracted human premolars were sectioned off at the coronal portion to expose the flat dentin surfaces. The surfaces were finished using 600 Grit Wet Silicon Carbide abrasive papers. The premolars were randomly assigned to two groups: control and treated with MS Coat desensitizing agent. The desensitizer was applied according to manufacturer’s instruction. Resin composite was bonded to each dentin surface using Prime & Bond ® adhesive system. The composite resin was debonded by shear stress. Mann-Whitney Test was used in statistical analysis. Our result showed that application of MS Coat desensitizing agent on dentin surface had significantly reduced the shear bond strength of the adhesive system used (z = - 0.14, p < 0.05). Thus, we conclude that shear bond strength of Prime & Bond ® NT (Dentsply, USA) adhesive system will be reduced if dentin surface is treated with MS Coat (Sun Medical, Japan) desensitizing agent.

Matched MeSH terms: Bicuspid
Fulltext The timing and sequence of emergence of permanent teeth in Malay school children in Kota Bharu, Malaysia

Hussin, A.S., Mokhtar, N., Naing, L., Taylor, J.A., Mahmood, Z.

Archives of Orofacial Sciences, 2007;2(1):36-40.
MyJurnal

The purpose of this study was to determine the timing and sequence of emergence of the first 28 permanent teeth in a cross-section of Malay children in the district of Kota Bharu, in northeastern Peninsula Malaysia. The sample consists of 478 boys and 908 girls of Malay descent aged between 5-19 years. The criterion for tooth emergence was the appearance of the tooth through the gingivae. Descriptive statistics were calculated and probit regression analysis performed to determine the mean age of emergence of the permanent dentition. The mean age at emergence was found to conform to general trends, with emergence seen earlier in girls than in boys. Comparisons were made with the Chinese (Hong Kong) and the Punjabi (Chandigarh) profiles, which showed earlier emergence timings in those ethnic groups. The emergence timing in Malays, however, was earlier than in Thais (Central Thailand). The sequence of emergence was determined by referring to the mean age of tooth emergence of individual teeth and conforms to the general trend seen in other studies.

Matched MeSH terms: Bicuspid
Fulltext Confocal laser scanning microscopy study of dentinal tubules in dental caries stained with alizarin red

Marzuki, A.F., Masudi, S.M.

Archives of Orofacial Sciences, 2008;3(1):2-6.
MyJurnal

Dentin morphology and the lesion found in dental caries have been studied for many years. It was first observed under optical microscopy, and later using electron microscopy. Confocal laser scanning microscopy (CLSM) applied with several fluorescent dyes such as alizarin red to see normal dentinal tubules. However, as far as authors aware, the CLSM studies of dentinal tubules in human caries using alizarin red is rare. The aim of this study is to examine histopathological and morphological changes in dentinal tubules of dentin caries stained with alizarin red using CLSM. Fifteen extracted carious teeth (premolar or molar) was collected and fixed in neutral formalin solution buffered with phosphate buffer, rinsed and stored in calcium free phosphate buffer saline (PBS) at 4°C. The specimens were dehydrated and embedded in resin. Longitudinal or cross sections were cut and polished and then stained with alizarin red S (100 μg/ml) in 0.5 M HCl solution for 24-48 hour at 37°C. After dehydration specimens were mounted on glass slide and examined under CLSM using epi-flourescent mode or transmission light mode with wave length of 512 nm. The images of dentinal tubules were taken serially and optimum images of three-dimensional structures were reconstructed using software of CLSM. Histopathological changes of dentinal tubules in human caries showed area of demineralized dentin, translucent zone, and normal area. The dentinal tubules were thin and had numerous branches. In conclusion, confocal microscopy revealed Study shows that confocal microscopy revealed histopathological changes in dentinal tubules affected by carious lesions.

Matched MeSH terms: Bicuspid

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