Displaying publications 381 - 400 of 550 in total

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  1. Alazzawi MMJ, Husein A, Alam MK, Hassan R, Shaari R, Azlina A, et al.
    Prog Orthod, 2018 Apr 16;19(1):10.
    PMID: 29658096 DOI: 10.1186/s40510-018-0208-2
    BACKGROUND: Quality bone regeneration, which leads to the improvement of bone remodeling, is essential for orthodontic treatment. In order to improve bone regeneration and increase the amount of tooth movement, different techniques have been implemented. The object of this study is to compare the effects of low-level laser therapy (LLLT), low-intensity pulsed ultrasound (LIPUS), and their combination on bone remodeling during orthodontic tooth movement.

    METHODS: Eighty (80) male, 6-week-old Sprague Dawley rats were grouped in to four groups, the first group was irradiated with (940 nm) diode laser, second group with LIPUS, and third group with combination of both LLLT and LIPUS. A forth group used was a control group in an incomplete block split-mouth design. The LLLT and LIPUS were used to treat the area around the moving tooth once a day on days 0-7, then the experiment was ended in each experimental endpoint (1, 3, 7, 14, and 21 days). For amount of tooth movement, models were imaged and analyzed. Histological examination was performed after staining with (hematoxylin and eosin) and (alizarin red and Alcian Blue) stain. One step reverse transcription-polymerase chain reaction RT-PCR was also performed to elucidate the gene expression of RANK, RANKL, OPG, and RUNX-2.

    RESULTS: The amount of tooth movement, the histological bone remodeling, and the RT-PCR were significantly greater in the treatment groups than that in the control group. Among the treatment groups, the combination group was the highest and the LIPUS group was the lowest.

    CONCLUSION: These findings suggest that LLLT and LIPUS can enhance the velocity of tooth movement and improve the quality of bone remodeling during orthodontic tooth movement.

    Matched MeSH terms: Tooth Movement*
  2. Haque N, Abu Kasim NH
    Adv Exp Med Biol, 2017 7 22;1083:29-44.
    PMID: 28730381 DOI: 10.1007/5584_2017_74
    In regenerative therapy, in vitro expansion of stem cells is critical to obtain a significantly higher number of cells for successful engraftment after transplantation. However, stem cells lose its regenerative potential and enter senescence during in vitro expansion. In this study, the influence of foetal bovine serum (FBS) and pooled human serum (pHS) on the proliferation, morphology and migration of stem cells from human extracted deciduous teeth (SHED) was compared. SHED (n = 3) was expanded in KnockOut DMEM supplemented with either pHS (pHS-SM) or FBS (FBS-SM). pHS was prepared using peripheral blood serum of six healthy male adults, aged between 21 and 35 years old. The number of live SHED was significantly higher, from passage 5 to 7, when cultured in pHS-SM compared to those cultured in FBS-SM (p 
    Matched MeSH terms: Tooth, Deciduous/cytology*
  3. Shahrizaila N, Noto Y, Simon NG, Huynh W, Shibuya K, Matamala JM, et al.
    Clin Neurophysiol, 2017 Jan;128(1):227-232.
    PMID: 27940147 DOI: 10.1016/j.clinph.2016.11.010
    OBJECTIVE: The utility of quantitative muscle ultrasound as a marker of disease severity in Charcot-Marie-Tooth (CMT) disease subtypes was investigated.

    METHODS: Muscle ultrasound was prospectively performed on 252 individual muscles from 21 CMT patients (9 CMT1A, 8 CMTX1, 4 CMT2A) and compared to 120 muscles from 10 age and gender-matched controls. Muscle ultrasound recorded echogenicity and thickness in representative muscles including first dorsal interosseus (FDI) and tibialis anterior (TA).

    RESULTS: Muscle volume of FDI and thickness of TA correlated with MRC strength. Muscle echogenicity was significantly increased in FDI (65.05 vs 47.09; p<0.0001) and TA (89.45 vs 66.30; p<0.0001) of CMT patients. In TA, there was significantly higher muscle thickness (23 vs 18 vs 16mm; p<0.0001) and lower muscle echogenicity (80 vs 95 vs 108; p<0.0001) in CMT1A compared to CMTX1 and CMT2A. This corresponded to disease severity based on muscle strength (MRC grading CMT1A vs CMTX1 vs CMT2A: 59 vs 48 vs 44; p=0.002).

    CONCLUSION: In CMT, quantitative muscle ultrasound of FDI and TA is a useful marker of disease severity.

    SIGNIFICANCE: The current findings suggest that quantitative muscle ultrasound has potential as a surrogate marker of disease progression in future interventional trials in CMT.

    Matched MeSH terms: Charcot-Marie-Tooth Disease/physiopathology
  4. Ahmed HMA, Versiani MA, De-Deus G, Dummer PMH
    Int Endod J, 2018 Oct;51(10):1182-1183.
    PMID: 30191599 DOI: 10.1111/iej.12928
    Matched MeSH terms: Tooth Root/anatomy & histology*
  5. Khim TP, Sanggar V, Shan TW, Peng KC, Western JS, Dicksit DD
    J Conserv Dent, 2018 10 9;21(5):562-568.
    PMID: 30294122 DOI: 10.4103/JCD.JCD_115_18
    Introduction: Among the various causes of tooth discoloration after root canal treatment, percolation of sealer remnants into the dentinal tubules of the pulp chamber is the most common cause.

    Objectives: The aim of this study is to evaluate the efficacy of dentin bonding agent (DBA) in preventing coronal discoloration caused by four different root canal sealers- MTA Fillapex, Sealapex, Zical and Z. O. B seal at different time intervals by measuring chromatic alterations using digital images analysis method.

    Methodology: Ninety mandibular premolars were collected and sectioned at 1 mm below the cementoenamel junction. Standard access cavity preparations of dimensions (depth-3 mm, width-0.8 mm, and length-3 mm) were prepared with a No. 245 bur through the cervical access. Following the standard irrigation protocol, specimens were then randomly divided into nine groups (four groups without DBA [1-4] +4 groups with DBA [5-8] +1 negative control [9]). In Groups 1-4, four different root canal sealers (MTA Fillapex, Sealapex, Zical, and Z.O.B seal) were applied to the walls of the pulp chamber. For Groups 5-8, the samples were etched with 37% phosphoric acid and DBA application was done before the respective root canal sealer application. The cervical access in all specimens was sealed using glass ionomer cement. Digital photographs were taken under standard lighting and environmental conditions at different time intervals: preprocedural, postprocedural, and after 1, 2, 3, and 4 months. These images were analyzed using Adobe Photoshop CS6 from which laboratory values and subsequently Delta E values were obtained.

    Results: Statistical analysis performed using repeated measures ANOVA and post hoc Tukey's tests show that the groups with DBA application had significantly lower mean Delta E values (P < 0.05) compared to the groups without DBA application.

    Conclusion: DBAs applied to the dentinal walls of the pulp chamber before obturation can effectively reduce the sealer-induced coronal discoloration.

    Matched MeSH terms: Tooth Discoloration; Tooth Cervix
  6. Salih NF
    Isotopes Environ Health Stud, 2019 Mar;55(1):80-91.
    PMID: 30241441 DOI: 10.1080/10256016.2018.1520708
    This study entails the measurement of the specific activity of natural radionuclides (226Ra, 40K and 232Th) in 18 tooth samples obtained from the clinic of the Universiti Sains Malaysia (USM), Penang, by using an HPGe detector. The specific activity of 226Ra, 40K and 232Th was measured to estimate the hazard index of the radionuclides, radium equivalent activities (Raeq), external, internal hazard indices (Hex, Hin), and absorbed dose (Dout, Din). The maximum values of concentration of 226Ra, 232Th and 40K in the tooth samples were found to be 60.82, 60.29 and 594.22 Bq kg-1, respectively. Maximum values of Raeq, Hex, Hin, Dout and Din were found to be 192.78 Bq kg-1, 0.520, 0.685, 89.29 and 169.81 nGy h-1, Iγ and Iα as 0.702 and 0.304, respectively. The results were lower than the average world value (UNSCEAR). In addition, a strong correlation was found between the concentrations of 226Ra and Raeq, between energy and net area, as well as between radionuclides (226Ra, 40K and 232Th) in tooth samples and age of volunteers. This study showed that the concentrations and hazard indices of tooth samples are below the recommended safe levels; therefore, the study area is considered safe in terms of radiological health hazards.
    Matched MeSH terms: Tooth/chemistry*
  7. Asif MK, Nambiar P, Mani SA, Ibrahim NB, Khan IM, Lokman NB
    Leg Med (Tokyo), 2019 Feb;36:50-58.
    PMID: 30415192 DOI: 10.1016/j.legalmed.2018.10.005
    Forensic odontology plays an important role in human identification and dental age estimation is an integral part of this process. The aim of the study was to investigate the association between chronological age and pulp/tooth volume ratio in a Malaysian population (Malays and Chinese) from cone-beam computed tomography (CBCT) scans, enhanced with Mimics software. Three hundred CBCT scans of 153 males and 147 females, aged between 16 and 65 years were divided into 5 age groups. Volumetric analysis of the pulp/tooth ratio was performed in maxillary left canines, maxillary right canines and maxillary right central incisors. Simple linear regression and Pearson correlation analysis indicated the strongest coefficient of correlation (R) values for maxillary right central incisors (0.83) followed by maxillary right canines (0.74) and maxillary left canines (0.73). Fisher's Z test indicated that dental age estimation is gender independent. The derived regression equations were further validated on an independent group of 126 teeth. The results indicated mean absolute error (MAE) values of 6.48 and 8.58 years for maxillary right central incisors and maxillary canines respectively. It was also noticed that MAE values were higher among the age groups ranging from 46 to 65 years. This study showed that a volumetric change in the pulp cavity with age is a valuable assessment method for dental age estimation among Malaysian population.
    Matched MeSH terms: Tooth/anatomy & histology
  8. Dung TM, Ngoc VTN, Hiep NH, Khoi TD, Xiem VV, Chu-Dinh T, et al.
    Sci Rep, 2019 02 28;9(1):3101.
    PMID: 30816230 DOI: 10.1038/s41598-019-39710-4
    This study aimed to define the width and length of the dental arch in 12-year-old Vietnamese children, and to elucidate differences between genders and among ethnic groups. A cross-sectional study was conducted in 4565 12 years-old children from the 4 major ethnic groups in Vietnam (Kinh, Muong, Thai, and Tay), with a healthy and full set of 28 permanent teeth that had never had any orthodontic treatment and with no reconstructive materials at the measured points. The mean variables in all subjects were 36.39 mm for upper inter-canine width; 46.88 mm for upper inter-first molar width; 59.43 mm for upper inter-second molar width; 10.41 mm for upper anterior length; 32.15 mm for upper posterior length 1; 45.52 mm for upper posterior length 2; 28.31 mm for lower inter-canine width; 41.63 mm for lower inter-first molar width; 54.57 mm for lower inter-second molar width (LM2W); 7.06 mm for lower anterior length (LAL); 26.87 mm for lower posterior length 1 (LP1L); and 41.29 mm for lower posterior length 2. Significant differences in these parameters between genders were found in all ethnic groups, except for LAL in the Kinh and Thai groups, and LP1L in the Tay group. Significant ethnic differences were also found in almost all parameters except LM2W in both males and females. Taken together, the representative sizes of dental arches of 12-year-old Vietnamese children have been defined. Our data indicate that there are some variations in dental arch dimensions among ethnic groups and between genders.
    Matched MeSH terms: Tooth/anatomy & histology*
  9. Balla SB, Banda TR, Galic I, N NM, Naishadham PP
    Forensic Sci Int, 2019 Apr;297:243-248.
    PMID: 30844636 DOI: 10.1016/j.forsciint.2019.02.009
    The aims of the present study were to validate the discriminatory potential of Cameriere's third molar maturity index (I3M) cut-off value of I3M 
    Matched MeSH terms: Tooth Apex/growth & development*
  10. Arora A, Khattri S, Ismail NM, Kumbargere Nagraj S, Prashanti E
    Cochrane Database Syst Rev, 2017 12 21;12:CD012595.
    PMID: 29267989 DOI: 10.1002/14651858.CD012595.pub2
    BACKGROUND: School dental screening refers to visual inspection of children's oral cavity in a school setting followed by making parents aware of their child's current oral health status and treatment needs. Screening at school intends to identify children at an earlier stage than symptomatic disease presentation, hence prompting preventive and therapeutic oral health care for the children. This review evaluates the effectiveness of school dental screening in improving oral health status.

    OBJECTIVES: To assess the effectiveness of school dental screening programmes on overall oral health status and use of dental services.

    SEARCH METHODS: Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 15 March 2017), the Cochrane Central Register of Controlled Trials (CENTRAL, the Cochrane Register of Studies, to 15 March 2017), MEDLINE Ovid (1946 to 15 March 2017), and Embase Ovid (15 September 2016 to 15 March 2017). The US National Institutes of Health Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on language or publication status when searching the electronic databases; however, the search of Embase was restricted to the last six months due to the Cochrane Centralised Search Project to identify all clinical trials and add them to CENTRAL.

    SELECTION CRITERIA: We included randomised controlled trials (RCTs) (cluster or parallel) that evaluated school dental screening compared with no intervention or with one type of screening compared with another.

    DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane.

    MAIN RESULTS: We included six trials (four were cluster-RCTs) with 19,498 children who were 4 to 15 years of age. Four trials were conducted in the UK and two were based in India. We assessed two trials to be at low risk of bias, one trial to be at high risk of bias and three trials to be at unclear risk of bias.None of the six trials reported the proportion of children with untreated caries or other oral diseases.Four trials evaluated traditional screening versus no screening. We performed a meta-analysis for the outcome 'dental attendance' and found an inconclusive result with high heterogeneity. The heterogeneity was found it to be, in part, due to study design (three cluster-RCTs and one individual-level RCT). Due to the inconsistency, we downgraded the evidence to 'very low certainty' and are unable to draw conclusions about this comparison.Two cluster-RCTs (both four-arm trials) evaluated criteria-based screening versus no screening and showed a pooled effect estimate of RR 1.07 (95% CI 0.99 to 1.16), suggesting a possible benefit for screening (low-certainty evidence). There was no evidence of a difference when criteria-based screening was compared to traditional screening (RR 1.01, 95% CI 0.94 to 1.08) (very low-certainty evidence).In one trial, a specific (personalised) referral letter was compared to a non-specific one. Results favoured the specific referral letter with an effect estimate of RR 1.39 (95% CI 1.09 to 1.77) for attendance at general dentist services and effect estimate of RR 1.90 (95% CI 1.18 to 3.06) for attendance at specialist orthodontist services (low-certainty evidence).One trial compared screening supplemented with motivation to screening alone. Dental attendance was more likely after screening supplemented with motivation, with an effect estimate of RR 3.08 (95% CI 2.57 to 3.71) (low-certainty evidence).None of the trials had long-term follow-up to ascertain the lasting effects of school dental screening.None of the trials reported cost-effectiveness and adverse events.

    AUTHORS' CONCLUSIONS: The trials included in this review evaluated short-term effects of screening, assessing follow-up periods of three to eight months. We found very low certainty evidence that was insufficient to allow us to draw conclusions about whether there is a role for traditional school dental screening in improving dental attendance. For criteria-based screening, we found low-certainty evidence that it may improve dental attendance when compared to no screening. However, when compared to traditional screening there was no evidence of a difference in dental attendance (very low-certainty evidence).We found low-certainty evidence to conclude that personalised or specific referral letters improve dental attendance when compared to non-specific counterparts. We also found low-certainty evidence that screening supplemented with motivation (oral health education and offer of free treatment) improves dental attendance in comparison to screening alone.We did not find any trials addressing cost-effectiveness and adverse effects of school dental screening.

    Matched MeSH terms: Tooth Diseases/diagnosis*
  11. Asif MK, Nambiar P, Mani SA, Ibrahim NB, Khan IM, Sukumaran P
    J Forensic Leg Med, 2018 Feb;54:53-61.
    PMID: 29324319 DOI: 10.1016/j.jflm.2017.12.010
    The methods of dental age estimation and identification of unknown deceased individuals are evolving with the introduction of advanced innovative imaging technologies in forensic investigations. However, assessing small structures like root canal volumes can be challenging in spite of using highly advanced technology. The aim of the study was to investigate which amongst the two methods of volumetric analysis of maxillary central incisors displayed higher strength of correlation between chronological age and pulp/tooth volume ratio for Malaysian adults. Volumetric analysis of pulp cavity/tooth ratio was employed in Method 1 and pulp chamber/crown ratio (up to cemento-enamel junction) was analysed in Method 2. The images were acquired employing CBCT scans and enhanced by manipulating them with the Mimics software. These scans belonged to 56 males and 54 females and their ages ranged from 16 to 65 years. Pearson correlation and regression analysis indicated that both methods used for volumetric measurements had strong correlation between chronological age and pulp/tooth volume ratio. However, Method 2 gave higher coefficient of determination value (R2 = 0.78) when compared to Method 1 (R2 = 0.64). Moreover, manipulation in Method 2 was less time consuming and revealed higher inter-examiner reliability (0.982) as no manual intervention during 'multiple slice editing phase' of the software was required. In conclusion, this study showed that volumetric analysis of pulp cavity/tooth ratio is a valuable gender independent technique and the Method 2 regression equation should be recommended for dental age estimation.
    Matched MeSH terms: Tooth Calcification*
  12. Asghar M, Omar RA, Yahya R, Yap AU, Shaikh MS
    J Esthet Restor Dent, 2023 Mar;35(2):322-332.
    PMID: 36628650 DOI: 10.1111/jerd.13013
    OBJECTIVE: To the effectiveness of different strategies to overcome silver diamine fluoride (SDF)-mediated tooth staining.

    MATERIALS AND METHODS: Four online databases (PubMed, ScienceDirect, Scopus, and Web of Science) were searched using different MeSH terms and Boolean Operators to retrieve the articles (until June 2021), followed by a hand-search of the reference list of the included articles. All full-text, original studies in English that evaluated SDF staining and at least one SDF modification/alternative were included.

    RESULTS: Among the assessed studies, nine studies explored the stain-minimization effect of potassium iodide (KI) post-application following SDF treatment. Among these, eight concluded that KI application after SDF treatment significantly reduced tooth staining, while one showed marginal staining following glass ionomer restoration of the SDF-treated dentine. Additionally, one study applied potassium fluoride (KF) and silver nitrate (AgNO3 ) concurrently to mitigate SDF-mediated staining. One study compared SDF staining with polyethylene glycol (PEG)-coated nanoparticles containing sodium fluoride (NaF), and another used nanosilver fluoride (NSF) for staining comparison with SDF.

    CONCLUSIONS: Within the limitations of this study, the addition of different materials to SDF has proven to be a beneficial strategy for overcoming tooth staining associated with SDF. Future studies are warranted, particularly clinical trials, to validate these findings.

    CLINICAL SIGNIFICANCE: SDF-mediated tooth staining is a serious concern that limits its clinical use. A review of various strategies to overcome this problem will help clinicians enhance its clinical use and patient acceptance.

    Matched MeSH terms: Tooth Discoloration*
  13. BURNETT GW, MOREIRA BJ, IMM BC, IDRIS F
    Mil Med, 1965 Jan;130:68-72.
    PMID: 14219191
    Matched MeSH terms: Tooth Calcification*
  14. Nik-Hussein NN, Abdul Majid Z
    J Clin Pediatr Dent, 1996;21(1):15-9.
    PMID: 9161200
    The study consisted of analysis of all cases of anomalies in the primary dentition that were seen or treated by the authors in the Department of Children's Dentistry and Orthodontics. A total of 79 occurrences of anomalies was seen in 65 children. The anomalies detected were double teeth, hypodontia and supernumerary teeth. Radiographic examinations of the affected children showed that over 60% of the cases with anomalies in the primary dentition are associated with anomalies of the succadeneous permanent dentition. All subjects with hypodontia of the primary dentition presented with hypodontia of the permanent dentition. However, anomalies of the permanent dentition were seen in 59% of subjects with primary double tooth and 50% of subjects with primary supernumerary tooth.
    Matched MeSH terms: Tooth, Supernumerary/epidemiology
  15. Gopinath VK, Ling KT, Haziani KN, Ismail NM
    J Clin Pediatr Dent, 2008;33(1):39-42.
    PMID: 19093650
    This study reports on the predisposing factors and prevalence of fractured anterior teeth among 12 and 16 years-old school children in Kubang Kerian, Kelantan, West Malaysia.
    Matched MeSH terms: Tooth Fractures/epidemiology*
  16. Ahmed SZ, Khan AS, Nasser WW, Alrushaid MA, Alfaraj ZM, Aljeshi MM, et al.
    Microsc Res Tech, 2025 Feb;88(2):595-610.
    PMID: 39501540 DOI: 10.1002/jemt.24725
    This study aimed to investigate the efficacy and durability of bioactive glass-based dental resin infiltrants. Resin infiltrants were formulated by combining photoinitiated dimethacrylate monomers with three variations of bioactive glass: 45S5 Bioglass (RIS), boron-substituted (RIB), fluoride-substituted (RIF), and pure resins (PR), whereby TOOTH group (TH) and ICON (CN) served as commercial control groups. Teeth samples were prepared, and experimental and control infiltrants were applied on demineralized human-extracted teeth. All the samples were subjected to immersion in artificial saliva and pH cycling for 30 days. The samples from another group underwent tooth brushing simulation for 9600 cycles. Following artificial saliva immersion, the samples' hardness values showed that RIB had the highest values (318.44 ± 3.83) while PR (212.52 ± 9.02) had the lowest values. After immersing into the pH cycling solution, the RIF showed the highest hardness (286.86 ± 5.11), while the lowest values for the CN (143.76 ± 3.50). After the tooth brushing simulation, the teeth samples with RIB showed maximum microhardness values (312.06 ± 16.30) and the weakest for the TH (189.60 ± 6.43). The commercial and experimental enamel resin infiltrants showed almost similar results overall, with RIB demonstrating better microhardness and comparable surface roughness. In contrast, RIF proved more resistant to pH cycling, exhibited higher microhardness, and performed better in surface roughness analysis. These findings suggest that resin infiltrant materials, especially RIF, have promising potential for effectively and esthetically managing white spot lesions.
    Matched MeSH terms: Tooth/chemistry
  17. Bijle MN, Sharaf D, Bahdar MAM, Daood U, Yiu C
    J Dent, 2025 Feb;153:105500.
    PMID: 39626842 DOI: 10.1016/j.jdent.2024.105500
    OBJECTIVE(S): The aim of the study was to examine the potential of arginine (Arg)-enriched fancy waters in preventing erosive tooth wear.

    METHODS: L-arginine (2 % w/v.) was added to five commercial fancy waters: Oasis-Lemon, Oasis-Lemon Mint, Perrier-Lemon, Perrier-Grapefruit, Pellegrino-Lemon; and deionized water served as a negative control. The pH, buffer capacity of added Arg, and F- concentrations were measured. Tooth specimens were prepared and baseline volumetric assessment (T0) was conducted using micro-CT. Subsequently, the specimens were immersed in fancy waters for 72 h, kept in an incubator (37 ℃) and solutions were changed every 24 h. After the experimental cycle (T1), 3D volumetric analysis was performed, and 3D structural images were reconstructed for qualitative assessment.

    RESULTS: The pH and F- concentrations of fancy waters with Arg were significantly higher than the control (p < 0.001). The buffer capacity of added Arg with Perrier-Grapefruit was significantly higher than Oasis-Lemon, Oasis-Lemon Mint & Pellegrino-Lemon (p < 0.05), except for Perrier-Lemon (p > 0.05). At T1, the specimen volume in Oasis-Lemon Mint (+/- Arg) and Pellegrino-Lemon (control) was significantly lower than T0 (p < 0.05). At T1, the specimen volume of Oasis-Lemon Mint and Pellegrino-Lemon (control) was significantly lower than Arg-containing fancy waters (p < 0.05). Surface contrast indicating wear was evident from T0 to T1 in specimens from the Oasis-Lemon Mint (+/- Arg) and Pellegrino-Lemon (- Arg).

    CONCLUSION: Incorporating Arg in fancy waters reduces the potential of erosive tooth wear associated with these beverages.

    CLINICAL SIGNIFICANCE: Consuming fancy water beverages (flavoured sparkling/carbonated) can lead to erosive tooth wear in young people. Incorporating Arg in fancy water beverages can prevent the erosive wear potential of these beverages while alleviating the burden of oral care on individuals at risk to erosive wear.

    Matched MeSH terms: Tooth Wear/prevention & control
  18. Matsumura H, Hudson MJ
    Am J Phys Anthropol, 2005 Jun;127(2):182-209.
    PMID: 15558609
    This article uses metric and nonmetric dental data to test the "two-layer" or immigration hypothesis whereby Southeast Asia was initially occupied by an "Australo-Melanesian" population that later underwent substantial genetic admixture with East Asian immigrants associated with the spread of agriculture from the Neolithic period onwards. We examined teeth from 4,002 individuals comprising 42 prehistoric and historic samples from East Asia, Southeast Asia, Australia, and Melanesia. For the odontometric analysis, dental size proportions were compared using factor analysis and Q-mode correlation coefficients, and overall tooth size was also compared between population samples. Nonmetric population affinities were estimated by Smith's distances, using the frequencies of 16 tooth traits. The results of both the metric and nonmetric analyses demonstrate close affinities between recent Australo-Melanesian samples and samples representing early Southeast Asia, such as the Early to Middle Holocene series from Vietnam, Malaysia, and Flores. In contrast, the dental characteristics of most modern Southeast Asians exhibit a mixture of traits associated with East Asians and Australo-Melanesians, suggesting that these populations were genetically influenced by immigrants from East Asia. East Asian metric and/or nonmetric traits are also found in some prehistoric samples from Southeast Asia such as Ban Kao (Thailand), implying that immigration probably began in the early Neolithic. Much clearer influence of East Asian immigration was found in Early Metal Age Vietnamese and Sulawesi samples. Although the results of this study are consistent with the immigration hypothesis, analysis of additional Neolithic samples is needed to determine the exact timing of population dispersals into Southeast Asia.
    Matched MeSH terms: Tooth/anatomy & histology*
  19. 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: Tooth Crown/anatomy & histology*
  20. Wahab RM, Idris H, Yacob H, Ariffin SH
    Eur J Orthod, 2012 Apr;34(2):176-81.
    PMID: 21478298 DOI: 10.1093/ejo/cjq179
    This prospective study investigated the difference in clinical efficiency between Damon™ 3 self-ligating brackets (SLB) compared with Mini Diamond conventional ligating brackets (CLBs) during tooth alignment in straightwire fixed appliance therapy. Twenty-nine patients (10 males and 19 females), aged between 14 and 30 years, were randomly divided into two groups: 14 patients received the SLB and 15 received the CLB. Upper arch impressions were taken for pre-treatment records (T(0)). A transpalatal arch was soldered to both maxillary first molar bands prior to extraction of the maxillary first premolars, followed by straightwire fixed appliances (0.022 × 0.028 inch). A 0.014 inch nickel titanium (NiTi) wire was used as the levelling and aligning archwire. Four monthly reviews were undertaken and impressions of the upper arch were taken at each appointment (T(1), T(2), T(3), and T(4)). Displacements of the teeth were determined using Little's irregularity index (LII). Data were analysed using the Mann-Whitney U-test. In the aligning stage, the CLB group showed significantly faster alignment of the teeth compared with the SLB group at the T(1)-T(2) interval (P < 0.05). However, there were no differences at T(2)-T(3), and T(3)-T(4) for either group (P > 0.05). The CLB group showed 98 per cent crowding alleviation compared with 67 per cent for the SLB after 4 months of alignment and levelling. Mini Diamond brackets aligned the teeth faster than Damon™ 3 but only during the first month. There was no difference in efficacy between the two groups in the later 3 weeks. Alleviation of crowding was faster with CLB than with SLB.
    Matched MeSH terms: Tooth Extraction; Tooth Movement/instrumentation*
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