Hasil Pencarian  ::  Simpan CSV :: Kembali

"ABSTRAKObjective: Tooth agenesis is a multifactorial condition accompanied by morphological differences. This study aimed to investigate the effects of different patterns of tooth agenesis on tooth dimensions. Methods: Records of children registered at the Department of Pedodontics and had tooth agenesis were reviewed, and those aged between 7 and 18 years of age with no systemic diseases, syndromes, or fluorosis were included in the study; the third molars were excluded. The study sample comprised 82 patients with one to six teeth missing (Group 1; hypodontia), 26 with more than six teeth missing (Group 2; oligodontia), and 31 with no missing teeth (Group 3; control). Mesiodistal widths, buccopalatal/labiolingual depths, and cervicoincisal/cervicoocclusal heights of permanent teeth were measured. Data were analyzed statistically. Results: Majority of the teeth in Group 2 were smaller than those in the other groups. Tooth agenesis was correlated with a dimensional decrease in mesiodistal width. Tooth dimensions were generally smaller in patients with tooth agenesis in both jaws (upper and lower) and regions (anterior and posterior). Conclusion: Decrease in tooth dimensions increased with the increase in the number of missing teeth. Teeth with clinically reduced dimensions or modifications during formation should receive additional attention from clinicians with regard to tooth agenesis."

"ABSTRACTThe objective of this study is to characterize and compare tooth agenesis codes and their prevalence in a population of Spanish patients with unilateral cleft lip and palate (UCLP) and bilateral cleft lip and palate (BCLP), and to determine if the extent of the cleft (BCLP or UCLP) was associated with the number of absent teeth. This retrospective cross-sectional human study included 118 patients with complete BCLP (29) or UCLP (89) and permanent dentition from first molar to first molar. Congenitally missing teeth were identified on panoramic radiographs using the tooth agenesis code (TAC) to identify agenesis codes. Agenesis prevalence was 50.6 and 51.7% for UCLP and BCLP patients, respectively. The lateral upper incisor was the most frequently absent tooth, especially in the cleft quadrant. Numbers of absent teeth ranged from 1 to 6. This study represents a different approach from previous agenesis investigations in cleft patients. These Spanish patients showed a high number of ageneses, presenting nineteen different tooth agenesis codes. A total of five TACs were unique, in other words, observed in a single patient in the sample. No statistically significant relationship was found between the extent of the cleft and the number of absent teeth. The TAC system makes it possible to identify agenesis codes with simultaneous absence of teeth not detected in general prevalence studies."

"The purposes of this study were to establish normative data for mesiodistal tooth crown diameters and arch dimensions in Mongolian adults and to compare them with those of Japanese adults. The study materials comprised dental casts of 100 modern Mongolian and 100 Japanese subjects (50 males, 50 females for each) with Angle Class I normal occlusion. The mean ages were 20 years 8 months for the Mongolian subjects and 20 years 0 months for the Japanese subjects. On the dental casts, the mesiodistal tooth crown diameters (excluding wisdom teeth) and dental arch dimensions were measured. The following arch dimensions were measured: inter-canine lingual, inter-premolar lingual, inter-molar lingual, inter-molar central, coronal arch length, basal arch length, and basal arch width. In the Mongolian samples, significant sex differences were noted, and most of the items were significantly larger in males than in females. Significant differences between the Mongolian and Japanese samples were mainly noted in the premolar and moral regions, rather than in the anterior region, and were significantly smaller in the Mongolian samples. In the Mongolian samples, the molar section widths and basal arch width and length were significantly larger in males and females compared with the Japanese samples. These results suggest that the tooth crown size and arch dimensions in the Mongolian samples differed from those in the Japanese samples, and that establishment of the clinical norm for Mongolian adults might be helpful in formulating treatment plans for Mongolian patients, given that these parameters are the basic tools for diagnosis."

"Polimorfisme gen Pax9 yang telah dikenal sebagai gen yang bertanggung jawab terhadap terjadinya agenesis gigi. Penelitian terdahulu memperlihatkan adanya hubungan antara agenesis gigi dengan pertumbuhan skeletal maksila dan mandibula sehingga penelitian ini bertujuan untuk mengevaluasi asosiasi polimorfisme gen Pax9 rs8004560, rs2073245 dan rs2073246 terhadap Variasi Maloklusi Skeletal, Pertumbuhan Maksila dan Mandibula serta Agenesis Gigi. Penelitian cross-sectional dilakukan pada 150 pasien ortodontik RSKGM FKG UI dan diklasifikasikan berdasarkan maloklusi skeletal. Ekstraksi DNA dilakukan dengan sampel rambut yang kemudian genotyping dilakukan dengan polymerase chain reaction (PCR) dan Sanger Sequencing. Polimorfisme gen Pax9 rs2073245 dan rs2073246 konsisten dengan Hardy Weinberg Equilibrium. Asosiasi ditemukan pada polimorfisme Pax9 rs8004560 dengan agenesis gigi (p= 0.025, OR= 2.895, CI= 1.101-7.614). Tidak ditemukan asosiasi polimorfisme gen Pax9 pada studi ini dengan maloklusi skeletal.  Jumlah sampel yang lebih tinggi dengan sistem klusterisasi latar belakang etnis disarankan pada penelitian berikutnya untuk mendeterminasi peran gen Pax9 terhadap maloklusi skeletal pada subpopulasi Indonesia.

---

Polymorphism Pax9 has been widely researched and known as a gene responsible for tooth agenesis, and recently been found associated with skeletal malocclusion. This study aimed to determine the association of gene polymorphism Pax9 rs8004560, rs2073245 and rs2073246 to skeletal malocclusion in Indonesia. Cross sectional study was performed to 150 Orthodontics patients and classified according to their skeletal malocclusion by cephalometric analysis. Genomic DNA was extracted from hair samples and then genotyped by polymerase chain reaction and Sanger sequencing. Gene polymorphism Pax9 rs2073245 and 2073246 are consistent with Hardy Weinberg Equilibrium. Significant association was found in polymorphism Pax9 rs8004560 with Tooth Agenesis (p= 0.025, OR= 2.895, CI= 1.101-7.614). There were no association between PAX9 polymorphisms assessed in this study with skeletal malocclusion. Our result suggested further research using larger sample size and clustered background ethnicity is required to determine the role PAX9 gene relate to skeletal malocclusion in Indonesian subpopulation."

"Human teeth enamel have been irradiated with gamma radiation from Co60 at room temperature and at liquid nitrogen temperature. Paramagnetic centers are formed and have been detected by using electron spin resonance (ESR) spectrometer at room temperature. The main signal is very stable asymmetric singlet, and attributed to h centers in the hydroxyapatite crystals. It is revealed that several factors influence the amplitude of the asymmetric signal. The amplitude and pattern of the asymmetric signal which depend on the orientation of the sample with respect to the magnetic field are analyzed. Based on the properties of the asymmetric signal the difference between the microcrystal arrangement of healthy and diseased teeth are explained."

"Summary:This book critically reviews theory, assumptions, methods and literature to examine the unique role of teeth in preserving records of human growth."

"The purpose of this study was to investigate the patterns of third molar agenesis and incidence of agenesis of other permanent teeth in a Japanese orthodontic patient group. A total of 417 Japanese subjects (134 males and 283 females) with agenesis of one or more third molars were divided into four groups according to the agenesis pattern, and 874 other Japanese subjects (302 males and 572 females) without third molar agenesis were assigned to a control group. Panoramic radiographs and medical and dental records were used to examine for tooth agenesis. The Chi-square test and odds ratio were used to make statistical comparisons. The prevalence of third molar agenesis worked out at 32.3 % with no statistically significant gender difference. A high prevalence rate of agenesis of third molars, unilateral or bilateral, could be considered characteristic of the Japanese orthodontic population. Significant increases in occurrence of oligodontia, and unilateral or bilateral agenesis of other teeth, including maxillary lateral incisors and maxillary and mandibular second premolars, were observed in all or almost all of the third molar agenesis groups, compared with the controls. A significantly increased prevalence rate of mandibular lateral incisor agenesis was observed in almost all of the third molar agenesis groups. The Japanese patients with third molar agenesis had a significantly increased occurrence of oligodontia, and unilateral or bilateral agenesis of maxillary and mandibular lateral incisors and second premolars, except for bilateral agenesis of mandibular lateral incisors."

"Terjadi fenomena retak tertunda (delayed crack) pada produk bucket tooth PT. X yang merupakan salah satu komponen pada excavator. Proses pembuatan produk bucket tooth melalui beberapa tahapan proses perlakuan panas mulai dari tahap pengecoran, normalisasi, lalu dilanjutkan dengan tempering. Kemudian austenisasi dan quenching dengan medium polialkilen glikol (PAG) dan terakhir adalah proses double tempering. Hasil pengamatan mikrostruktur menunjukkan terjadinya fenomena dekarburisasi pada bagian permukaan material baja HSLA yang terlihat dari semua sampel produk mulai dari hasil pengecoran hingga double tempering. Kemudian terlihat pula adanya struktur dendritik dan/atau zona transformasi yang tidak hilang dari tahap awal perlakuan panas hingga sampel produk hasil double tempering walaupun telah melalui poses perlakuan panas normalisasi. Ini mengindikasikan proses normalisasi yang dilakukan belum optimal untuk menyeragamkan mikrostruktur produk bucket tooth. Selain itu juga teridentifikasi adanya austenit sisa sebesar 2,8% pada mikrostruktur sampel produk hasil double tempering yang merupakan tahap akhir proses perlakuan panas pada pembuatan produk bucket tooth. Hal ini berisiko untuk memicu terjadinya delayed crack pada produk bucket tooth. Temuan tersebut juga didukung oleh hasil pengujian kekerasan microvickers yang menunjukkan nilai kekerasan sebesar 296 VHN pada area terang pengamatan mikrostruktur produk hasil double tempering yang berada dalam rentang nilai kekerasan austenit.

---

Delayed cracking phenomenon occurs in the bucket tooth products of PT. X, which are one component of excavators. The bucket tooth productss making process goes through several stages of the heat treatment process starting from the casting, normalization, then proceed with tempering process. Then austenisation and quenching with polyalkylene glycol (PAG) medium and finally the double tempering process. Microstructure observation results show the phenomenon of decarburization on the surface of HSLA steel material which is seen from all product samples ranging from casting to double tempering. Then it also shows the dendritic structure and/or transformation zone that does not disappear from the initial stage of heat treatment to the sample of the double tempering product even though it has been through the normalized heat treatment process. This indicates that the normalization process is not optimal to uniform the bucket tooth product microstructure. In addition, 2,8% of the retained austenite was identified in the microstructure of the double tempering product sample which is the final stage of the heat treatment process in the production of bucket tooth products. This is a risk to trigger delayed cracks in bucket tooth products. This finding was also supported by the results of microvickers hardness testing which showed a hardness value of 296 VHN in the bright area of ​​of microstructure observation on double tempering product where in the range of the austenite hardness value."

""Researchers have long had an interest in dental morphology as a genetic proxy to reconstruct population history. Much interest was fostered by the use of standard plaques and associated descriptions that comprise the Arizona State University Dental Anthropology System, developed by Christy G. Turner, II and students. This system has served as the foundation for hundreds of anthropological studies for over 30 years. In recognition of that success, this volume brings together some of the world's leading dental morphologists to expand upon the concepts and methods presented in the popular The Anthropology of Modern Human Teeth (Cambridge University Press, 1997), leading the reader from method to applied research. After a preparatory section on the current knowledge of heritability and gene expression, a series of case studies demonstrate the utility of dental morphological study in both fossil and more recent populations (and individuals), from local to global scales."--Publisher's website."

"ABSTRAK Tooth loss is considered a major end point sequela of preventable oral diseases. In Malaysia, tooth mortality is a common oral health problem. Objective: To assess the impact of tooth loss, preferences for tooth replacement, and the relationship between impact of tooth loss and number of missing teeth. Methods: This descriptive crosssectionalsurvey involved 244 patients attending a primary health center and dental clinic at a public university. The respondents completed self administered questionnaires on personal background, tooth replacement status, impact of tooth loss using a 12 item modified Geriatric Oral Health Assessment Index (GOHAI), and preferencesfor tooth replacement. A dental examination was performed to determine the number of missing teeth. Results: The mean age of the respondents was 56.2 years (standard deviation (SD), 8.1 years). The mean number of missing teeth was 8.3; 62.7% of patients had at least 20 natural teeth. The majority were not wearing a dental prosthesis.The mean GOHAI score was 16.3. Of the patients, 66.0% experienced some food biting difficulty, 59.4% worried about oral health, and 57.8% experienced eating discomfort. Dental implants were the most preferred replacement option (38.9%). The GOHAI scores were not related to the number of missing teeth. Conclusion: Tooth loss anduse of dental prostheses had some impact on quality of life, although the impact was not high. "