MyMedR

Displaying publications 61 - 69 of 69 in total

Abstract:

Sort:

A PCR-based sex determination method for possible application in caprine gender selection by simultaneous amplification of the Sry and Aml-X genes

Phua AC, Abdullah RB, Mohamed Z

J. Reprod. Dev., 2003 Aug;49(4):307-11.
PMID: 14967923

Sex determination of livestock is performed to achieve the objectives of livestock breeding programmes. Techniques for sex determination have evolved from karyotyping to detecting Y-specific antigens and recently to the polymerase chain reaction (PCR), which appears to be the most sensitive, accurate, rapid and reliable method to date. In this study, a PCR-based sex determination method for potential application in goat breeding programmes was developed. Primers were designed to amplify a portion of the X amelogenin gene (Aml-X) on the X chromosome to give a 300 bp product and Sry gene on the Y chromosome to give a 116 bp product. PCR optimization was performed using DNA template extracted from a whole blood sample of Jermasia goats (German Fawn x Katjang) of both sexes. It was possible to identify the sex chromosomes by amplifying both male- and female-specific genes simultaneously in a duplex reaction with males yielding two bands and females yielding one band. The Aml-X primer set, which served as an internal control primer, did not interfere with amplification of the Y-specific sequence even when a low amount of DNA (1 ng) was used. The duplex reaction subjected to a blind test showed 100% (14/14) concordance, proving its accuracy and reliability. The primer sets used were found to be highly specific and were suitable for gender selection of goats.

Matched MeSH terms: Dental Enamel Proteins/genetics
Measuring initial enamel erosion with quantitative light-induced fluorescence and optical coherence tomography: an in vitro validation study

Chew HP, Zakian CM, Pretty IA, Ellwood RP

Caries Res, 2014;48(3):254-62.
PMID: 24481141 DOI: 10.1159/000354411

BACKGROUND: Measurement of initial enamel erosion is currently limited to in vitro methods. Optical coherence tomography (OCT) and quantitative light-induced fluorescence (QLF) have been used clinically to study advanced erosion. Little is known about their potential on initial enamel erosion.
OBJECTIVES: To evaluate the sensitivity of QLF and OCT in detecting initial dental erosion in vitro.
METHODS: 12 human incisors were embedded in resin except for a window on the buccal surface. Bonding agent was applied to half of the window, creating an exposed and non-exposed area. Baseline measurements were taken with QLF, OCT and surface microhardness. Samples were immersed in orange juice for 60 min and measurements taken stepwise every 10 min. QLF was used to compare the loss of fluorescence between the two areas. The OCT system, OCS1300SS (Thorlabs Ltd.), was used to record the intensity of backscattered light of both areas. Multiple linear regression and paired t test were used to compare the change of the outcome measures.
RESULTS: All 3 instruments demonstrated significant dose responses with the erosive challenge interval (p < 0.05) and a detection threshold of 10 min from baseline. Thereafter, surface microhardness demonstrated significant changes after every 10 min of erosion, QLF at 4 erosive intervals (20, 40, 50 and 60 min) while OCT at only 2 (50 and 60 min).
CONCLUSION: It can be concluded that OCT and QLF were able to detect demineralization after 10 min of erosive challenge and could be used to monitor the progression of demineralization of initial enamel erosion in vitro.

Matched MeSH terms: Dental Enamel/pathology*
Fulltext Low levels of caries in aggressive periodontitis: A literature review

Sulugodu Ramachandra S

Saudi Dent J, 2014 Apr;26(2):47-9.
PMID: 25408595 DOI: 10.1016/j.sdentj.2013.12.002

This article is a traditional literature review on caries levels in aggressive periodontitis. Aggressive periodontitis generally affects systemically healthy individuals aged <30 years (older individuals can also be affected) and is characterized by a young age of onset, rapid rate of disease progression, and familial aggregation of cases. Dental caries is caused by the dissolution of enamel by acid-producing bacteria present in the plaque biofilm, especially when the biofilm reaches critical mass due to improper oral hygiene. The association between caries level and aggressive periodontitis has long been debated. Initial research indicated that caries levels were high in patients with aggressive periodontitis, but high-quality studies have consistently shown that caries and aggressive periodontitis are inversely related. A recent in vitro study showed that Streptococcus mutans was killed more readily in the saliva of patients with aggressive periodontitis and Aggregatibacter actinomycetemcomitans positivity than in patients with A. actinomycetemcomitans negativity. Other mechanisms possibly explaining the inverse relationship between caries and aggressive periodontitis in cases of Down's syndrome are also discussed in this literature review. The usefulness of caries level in the diagnosis of aggressive periodontitis in developing countries such as India, where the disease is diagnosed primarily on the basis of clinical and radiographic features and familial history is also discussed.

Matched MeSH terms: Dental Enamel
Fulltext Dental management of patient with Williams Syndrome - A case report

Wong D, Ramachandra SS, Singh AK

Contemp Clin Dent, 2015 9 1;6(3):418-20.
PMID: 26321847 DOI: 10.4103/0976-237X.161908

Williams syndrome is a multisystemic rare genetic disorder caused by deletion of 26-28 genes in the long arm of chromosome 7. It is characterized by developmental and physical abnormalities including congenital cardiovascular abnormalities, mental retardation, neurological features, growth deficiency, genitourinary manifestations, gastrointestinal problems, musculoskeletal problems, unique behavioral characteristics, and dental problems. Dental abnormalities include malocclusion, hypodontia, malformed teeth, taurodontism, pulp stones, increased space between teeth, enamel hypoplasia, and high prevalence of dental caries. Authors report a 17-year-old female patient with underlying Williams syndrome. Oral features and problems seen in the patient are listed. Malocclusion and screwdriver shaped teeth were noticed. Generalized widening of the periodontal ligament space with vital teeth was seen. This finding has not been reported in cases of Williams syndrome earlier. Precautions taken during dental treatment in patients with Williams syndrome are also discussed.

Matched MeSH terms: Dental Enamel Hypoplasia
Fulltext Co-Blend Application Mode of Bulk Fill Composite Resin

Al-Nabulsi M, Daud A, Yiu C, Omar H, Sauro S, Fawzy A, et al.

Materials (Basel), 2019 Aug 07;12(16).
PMID: 31394743 DOI: 10.3390/ma12162504

Objective: To evaluate the effect of a new application method of bulk-fill flowable composite resin material on bond-strength, nanoleakage, and mechanical properties of dentine bonding agents.
MATERIALS AND METHODS: Sound extracted human molars were randomly divided into: manufacturer's instructions (MI), manual blend 2 mm (MB2), and manual blend 4 mm (MB4). Occlusal enamel was removed and flattened, dentin surfaces were bonded by Prime & Bond universal (Dentsply and Optibond FL, Kerr). For the MI group, adhesives were applied following the manufacturer's instructions then light-cured. For MB groups, SDR flow+ bulk-fill flowable composite resin was applied in 2- or 4-mm increment then manually rubbed by a micro brush for 15 s with uncured dentine bonding agents and the mixture was light-cured. Composite buildup was fabricated incrementally using Ceram.X One, Dentsply nanohybrid composite resin restorative material. After 24-h water storage, the teeth were sectioned to obtain beams of about 0.8 mm2 for 24-h and thermocycled micro-tensile bond strength at 0.5 mm/min crosshead speed. Degree of conversion was evaluated with micro-Raman spectroscopy. Contraction gaps at 24 h after polymerization were evaluated and atomic force microscopy (AFM) nano-indentation processes were undertaken for measuring the hardness across the interface. Depth of resin penetration was studied using a scanning electron microscope (SEM). Bond strength data was expressed using two-way ANOVA followed by Tukey's test. Nanoindentation hardness was separately analyzed using one-way ANOVA.
RESULTS: Factors "storage F = 6.3" and "application F = 30.11" significantly affected the bond strength to dentine. For Optibond FL, no significant difference in nanoleakage was found in MI/MB4 groups between baseline and aged specimens; significant difference in nanoleakage score was observed in MB2 groups. Confocal microscopy analysis showed MB2 Optibond FL and Prime & Bond universal specimens diffusing within the dentine. Contraction gap was significantly reduced in MB2 specimens in both adhesive systems. Degree of conversion (DC) of the MB2 specimens were numerically more compared to MS1 in both adhesive systems.
CONCLUSION: Present study suggests that the new co-blend technique might have a positive effect on bond strengths of etch-and-rinse adhesives to dentine.

Matched MeSH terms: Dental Enamel
Fulltext Medico-legal implications of dental prenatal age estimation with reference to a case report

Nambiar, P., Paul, G., Swaminathan, D., Nadesan, K.

Ann Dent, 2000;7(1):46-50.
MyJurnal

The estimation of age of human foetal remains is of great medico-legal importance. When the remains are intact and fresh, various morphological features such as crown-heel length, weight, appearance of ossification centres particularly around the ankles and knees and other parameters could be used to make a reasonable estimation of the period of gestation. In cases of criminal abortion, infanticide and child murder the question of age of the foetus, viability, live birth and a separate existence become very important. In practice, often at the time of detection, the remains are decomposed or skeletonised. In such a situation the examination of developing teeth will provide a reliable answer pertaining to the foetal age, the possibility of a separate existence and even the period of survival after birth. The.age determination from dental examination is possible from approximately 10 weeks intrauterine up to old age. The presence of neonatal line (birth line) in both dentine and enamel indicates live birth and a separate existence. It is possible that the time period of survival can be estimated by measuring postnatal deposition of these hard tissues. An intact human foetus that has undergone mild to moderate putrefaction was studied. The study of the morphological features and the ossification centres suggested that its approximate age was around nine months intrauterine. It was not possible to decide whether it was a live birth and had a separate existence. The examination of the developing first deciduous molar of the mandible suggested the approximate age was around 30-32 weeks intrauterine. The importance of examination of developing teeth in foetal remains (including neonates), particularly associated with putrefaction or skeletonisation is emphasized.

Matched MeSH terms: Dental Enamel
Fulltext Extraction of mitochondrial DNA from tooth dentin: application of two techniques

Ahmad Azlina, Berahim Zurairah, Sidek Mohamad Ros, Mokhtar Khairani Idah, Samsudin Abdul Rani

Archives of Orofacial Sciences, 2011;6(1):9-14.
MyJurnal

Mitochondrial DNA (mtDNA) is a hereditary material located in mitochondria and is normally maternally inherited. Mutational analysis performed on mtDNA proved that the mutations are closely related with a number of genetic illnesses, besides being exploitable for forensic identification. Those findings imply the importance of mtDNA in the scientific field. MtDNA can be found in abundance in tooth dentin where it is kept protected by the enamel, the hardest outer part of the tooth. In this study, two techniques of mtDNA extraction were compared to determine the efficacy between the two techniques. Teeth used for the study was collected from Dental Clinic, Hospital Universiti Sains Malaysia. After the removal of tooth from the tooth socket of the patient, the tooth was kept at -20C until use. Later, pulp tissue and enamel was excised using dental bur and only the root dentin was utilized for the isolation of mtDNA by crushing it mechanically into powdered form. MtDNA was extracted using the two published methods, Pfeifer and Budowle and then subjected to spectrophotometry DNA quantification and purity, Polymerase chain reaction (PCR) amplification of hypervariable-two region of mtDNA, followed by DNA sequencing to analyze the reliability of the extraction techniques. In conclusion, both techniques proved to be efficient and capable for the extraction of mtDNA from tooth dentin.

Matched MeSH terms: Dental Enamel
Fulltext Stem cells from childrens' teeth

Mohd Hilmi, A.B., Fazliah, S.N., Siti Fadilah, A., Asma, H., Siti Razila, A.R., Shaharum, S., et al.

Archives of Orofacial Sciences, 2008;3(1):29-31.
MyJurnal

The aim of this study was to isolate stem cells from dental pulp of primary molars and incisors to be used as possible source for tissue engineering. Human primary molars and incisors were collected from subjects aged 4-7 year-old under standardized procedures. Within 24 hours, the tooth was cut at the cemento-enamel junction using hard tissue material cutter. The dental pulp tissue was extracted, digested and then cultured in Alpha Modified Eagles's Medium (α-MEM) supplemented with 20% FCS, 100 mM L-ascorbic acid 2-phosphate, 200 mM L-glutamine and 5000 units/ml Penicillin/Streptomycin. The cells were observed daily under the microscope until confluence. Children's tooth pulp- derived progenitor cells were found positive for stem cell markers CD105 and CD166, which are consistent with the finding for mesenchymal stem cells (MSCs) from bone marrow.

Matched MeSH terms: Dental Enamel
The impact of surface preparation on shear bond strength of metallic orthodontic brackets bonded with a resin-modified glass ionomer cement

Elnafar AA, Alam MK, Hasan R

J Orthod, 2014 Sep;41(3):201-7.
PMID: 25143559 DOI: 10.1179/1465313314Y.0000000097

The aim of this study was to assess the effects of four enamel preparation techniques on shear bond strength (SBS) of brackets bonded with a resin-modified glass ionomer cement (RMGIC). Adhesive Remnant Index (ARI) and enamel surface roughness (Ra) were also investigated after cement removal.

Matched MeSH terms: Dental Enamel/ultrastructure*