Dental pulp stem cells and banking of teeth as a lifesaving therapeutic vista

Exfoliated deciduous or an extracted healthy adult tooth can be used to harvest,process,and cryogenically preserve dental pulp stem cells.Future stem cell-based regenerative medicine methods could benefit significantly from these mesenchymal stem cells.Teeth serve as a substantial source of mesenchymal stem cells,otherwise disposed of as medical waste.Care should be taken to store this treasure trove of stem cells.Collective responsibility of patients,dentists,and physicians is necessary to ensure that this valuable resource is not wasted and that every possible dental pulp stem cell is available for use in the future.The dental pulp stem cells(DPSC)inside teeth represent a significant future source of stem cells for regenerative medicine procedures.This review describes the ontogeny,the laboratory processing and collection,and isolation methods of DPSC.This review also discusses currently available stem cell banking facilities and their potential use in regenerative medicine procedures in dental and general medical applications in the future.

Risk aspects of dental restoratives: From amalgam to tooth-colored materials

Dental materials' choice of patients has considerably changed. Whereas cast gold and amalgam have been the predominant biomaterials for decades, today toothcolored materials like resin-based composites and ceramics are more and more successful. However, are we going to replace a good but biologically questionable material(amalgam) with an equal material(resin composite) being more esthetic but also biologically questionable? For amalgam, long-term clinical studies reported some significant hints that in single cases amalgam may be a health hazard for patients, finally Norway banned amalgam completely. The main advantage of a resin-based composite over amalgam is its tooth-like appearance and more or less absence of extensive preparation rules. For many years it was believed that resin-based composites may cause pulpal injury. However, pulpal injury associated with the use of resin-based composites is not correlated with their cytotoxic properties. Nevertheless, resin-based composites and other dental materials require rigorous safety evaluation and continuous monitoring to prevent adverse events similar like with amalgam. Because of nonbiocompatible pulp responses to resin-based composites and amalgam, they should not be placed in direct contact with the dental pulp. The less dentin remaining in the floor of preparations between resin-based composites or other dental materials is more likely to cause pulpitis. Percentage of patients and dental practitioners who display allergic reactions is between 0.7% and 2%. The release of cytotoxic monomers from resin-based materials is highest after polymerization and much lower after 1 wk. Substances released from resin-based composites have been shown to be toxic in cytotoxicity tests. Nevertheless, in vitro cytotoxicity assays have shown that amalgam has greater toxic effects than resin-based composites, sometime 100-700-fold higher. Altogether, the risk of side-effects is low, but not zero, especially for dental personnel.

Effects of low intensity laser irradiation phototherapy on dental pulp constructs

AIM: To investigate low intensity laser irradiation phototherapy(LILIP) on the proliferation, mineralization and degradation of dental pulp constructs.METHODS: Stem cells from human exfoliated deciduous teeth(SHED) were grown to confluence and seeded on collagen scaffolds to create dental pulp constructs. LILIP was delivered to the dental pulp constructs using an 830 nm GaA IAs laser at an output power of 20 m W. The LILIP energy density was 0.4, 0.8, 1.2, and 2.4 J/cm2. After 8 d, the cell proliferation and degradation within the dental pulp constructs were measured using histologic criteria. After 28 d, the effect of LILIP on SHED mineralization was assessed by von Kossa staining.RESULTS: SHED proliferation within the dental pulp constructs varied after exposure to the 0.4, 0.8, 1.2,and 2.4 J/cm2 LILIP energy densities(P < 0.05). The maximum proliferation of SHED in nutrient deficient media was 218% after exposure to a 1.2 J/cm2 LILIP energy density. SHED grown in nutrient deficient media after exposure to a 0.4, 0.8, and 1.2 J/cm2 LILIP energy density, proliferated by 167-218% compared to the untreated(non-LILIP) control group(P < 0.05).SHED exposed to a 0.4, 0.8, and 1.2 J/cm2 LILIP energy density, and grown in optimal nutritional conditions and proliferated by 147%-164% compared to the untreated(non-LILIP) control group(P < 0.05). The exposure of SHED to the highest LILIP energy density(2.4 J/cm2) caused a reduction of the cell proliferation of up to 73% of the untreated(non-LILIP) control(P < 0.05). The amount of mineral produced by SHED increased over time up to 28 d(P < 0.05). The 0.8 and 1.2J/cm2 LILIP energy densities were the most effective at stimulating the increased the mineralization of the SHED from 150%-700% compared to untreated(nonLILIP) control over 28 d(P < 0.05). The degradation of dental pulp constructs was affected by LILIP(P <0.05). The dental pulp constructs grown in optimal nutritional conditions exposed to a 0.8 J/cm2 or 1.2 J/cm2 LILIP energy density had 13% to 16% more degradation than the untreated(non-LILIP) control groups(P < 0.05). The other LILIP energy densities caused a 1%degradation of dental pulp constructs in optimal nutritional conditions(P > 0.05).CONCLUSION: LILIP can enhance or reduce SHED proliferation, degradation and mineralization within dental pulp constructs. LILIP could promote the healing and regeneration of dental tissues.

Erratum to “Application and Perception of Potassium Iodide Following Silver Diamine Fluoride Treatment”, Materials Sciences and Applications, Vol. 13 (2022), 506-518

The original online version of this article (Ramlal, C. and Triana, N. (2022) Application and Perception of Potassium Iodide Following Silver Diamine Fluoride Treatment. Materials Sciences and Applications, 13, 506-518. https://doi.org/10.4236/msa.2022.139031) was published without the coauthors mistakenly. To reflect the contribution and responsibility of the coauthors at the time of the study, we revised authorship and affiliation of the article. The author wishes to correct the authorship.

Low-power laser irradiation promotes the proliferation and osteogenic differentiation of human periodontal ligament cells via cyclic adenosine monophosphate

Retaining or improving periodontal ligament （PDL） function is crucial for restoring periodontal defects. The aim of this study was to evaluate the physiological effects of low-power laser irradiation （LPLI） on the proliferation and osteogenic differentiation of human PDL （hPDL） cells. Cultured hPDL cel Is were irradiated （660 nm） daily with doses of O, 1, 2 or 4 J .cm-2. Cell proliferation was evaluated by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide （MTT） assay, and the effect of LPLI on osteogenic differentiation was assessed by Alizarin Red S staining and alkaline phosphatase （ALP） activity. Additionally, osteogenic marker gene expression was confirmed by real-time reverse transcription-polymerase chain reaction （RT-PCR）. Our data showed that LPLI at a dose of 2 J.cm-2 significantly promoted hPDL cell proliferation at days 3 and 5. In addition, LPLI at energy doses of 2 and 4 J.cm-2 showed potential osteogenic capacity, as it stimulated ALP activity, calcium deposition, and osteogenic gene expression. We also showed that cyclic adenosine monophosphate （cAMP） is a critical regulator of the LPLI-mediated effects on hPDL cells. This study shows that LPLI can promote the proliferation and osteogenic differentiation of hPDL cells. These results suggest the potential use of LPLI in clinical applications for periodontal tissue regeneration.

Anxiolytic potential of ursolic acid derivative-a stearoyl glucoside isolated from Lantana camara L.(verbanaceae)

Objective:To investigate the anxiolytic activity of newly isolated compound by our lab called ursolic acid stearoyl glucoside(UASG) from the leaves of Lantana camam(L camam).Methods: Column chromatography was used to isolate UASG.Anxiolytic potential was experimentally proved and demonstrated through Elevated plus-maze,Open field and light and dark test. Results:The UASG showed marked increased in time spent(%) and number of frequent movements made by animals in open arm of elevated plus-maze apparatus.In light and dark model,UASG produced marked increase in time spent by animal,number of crossing and reduced duration of immobility in light box.Conclusions:UASG showed significant increase in number of rearing,assisted rearing and number of square crossed in open field established test model.UASG showed its anxiolytic effect in dose dependent manner.

Allogenic tooth transplantation using 3D printing: A case report and review of the literature

BACKGROUND The history of allogenic tooth transplantation can be traced back to the 16th century.Although there have been many successful cases,much needs to be better understood and researched prior to the technique being translated to everyday clinical practice.CASE SUMMARY In the present report,we describe a case of allogenic tooth transplantation between a mother and her daughter.The first left maxillary molar of the mother was diagnosed with residual root resorption and needed to be extracted.The 3rd molar of the daughter was used as a donor tooth.Prior to transplantation,a 3D printing system was introduced to fabricate an individualized reamer drill specifically designed utilizing the donor’s tooth as a template.The specific design of our 3D printed bur allowed for the recipient site to better match the donor tooth.With the ability to 3D print in layers,even the protuberance of the root can be matched and 3D printed,thereby minimizing unnecessary bone loss.CONCLUSION Our study is a pioneering case combining 3D printing with allogenic tooth transplantation,which could be able to minimize unnecessary bone loss and improve the implant stability.This article aims to enhance our understanding of allogenic tooth transplantation and 3D printing,and may potentially lead to tooth transplantation being utilized more frequently - especially since transplantations are so commonly utilized in many other fields of medicine with high success rates.

Clear-cell variant of calcifying epithelial odontogenic tumor (Pindborg tumor) in the mandible

We present an uncommon case （female patient aged 59 years） of the clear-cell variant of calcifying epithelial odontogenic tumor （CEOT） （also known as Pindborg tumor） in the mandible. The clinical characteristics and probable origins of the clear tumor cells of previously reported cases of clear-cell variant of intraosseous CEOT are also summarized and discussed.

Prevalence of Dysmenorrhea among Female Adolescents in Dubai: A Cross-Sectional Study

Objective: This study aimed to investigate the prevalence of dysmenorrhea among adolescents in Dubai, and its effect on their academic and athletic performance. Methods: This was a cross-sectional study conducted in ten randomly selected private and government high schools in Dubai, United Arab Emirates. Using both the English and Arabic translated version of the Women’s Health Symptom Survey Questionnaire World, data was collected from 456 female students of grades 7 - 12, aged 11 - 19 years. Results: Dysmenorrhea was a crucial problem reported by 432 (94.7%) of the participants. Of the total number, 208 (45%) participants reported experiencing severe pain during menstruation and 152 (33.4%) students reported being absent from school during every menstrual cycle. Nonsteroidal anti-inflammatory drugs (NSAIDs) were used by 147 (32.3%) students, and majority reported no or little improvement. The percentage of students who experienced menstrual pain with micturition or defecation was 43.1% and 46.7%, respectively. None of the participants reported the use of hormonal agents. Conclusion: The unexpected high number of female adolescents who reported symptoms of primary dysmenorrhea necessitating treatment, as well as subsequent school absenteeism, calls for implementation of a screening questionnaire for early detection of persistent primary dysmenorrhea. Moving from surgical to clinical diagnosis of endometriosis can contribute greatly to improving the quality of life and reproductivity of female adolescents with severe dysmenorrhea.

Minireview of the clinical efficacy of platelet-rich plasma, platelet-rich fibrin and blood-clot revascularization for the regeneration of immature permanent teeth

The aim of this mini-review was to investigate and compare the clinical efficacy of platelet-rich plasma(PRP) and platelet-rich fibrin(PRF), vs blood clot revascularization(BCR) for the regeneration of immature permanent teeth. The clinical efficacy of PRP, PRF, and BCR to regenerate 90 immature permanent teeth after one year, were compared for their ability to accomplish apical closure, a periapical lesion healing response, root lengthening, and dentinal wall thickening. The 90 cases were published in three different articles. The mean success rate for apical closure after one year was: PRP(89.2%) PRF(80%), and BCR(75.6%). The mean success rate for root lengthening after one year was: BCR(88.9%), PRP(68.2%), and PRF(65%). The periapical lesion healing response was 100% for BCR and 100% for PRP. Dentinal wall thickening was 100% for BCR, and 100% for PRP. All the PRP, PRF, and BCR treatments appeared to be effective. The published clinical results for PRP, PRF, and BCR indicate that these treatments are effective for the regeneration of immature permanent teeth.

Guidelines for Patients with Bleeding Disorders Undergoing Dentalveolar Surgeries

Dental practitioners must be well informed about the pathology, complications and treatment options associated with bleeding disorders patients. Prolongation of bleeding time can seriously complicate the patient’s condition during and after surgery, especially if there is iron deficiency anemia or any other condition accompanied by a decrease in hematopoiesis. For this reason, the dentist surgeon must be aware about the presence of such diseases in advance, in order to prevent the development of bleeding and its undesirable consequences promptly. Blood loss becomes apparent when blood exits through a natural opening in the body, for instance the nose & mouth. In this article, common medical bleeding situations with the potential to compromise the successful outcome of dental surgical procedures have been presented. Bleeding disorders is a disease group, which can be classified as deficiencies of coagulation factors, platelet disorders, vascular disorders, fibrinolytic defects and so on. Fragile blood vessels can cause bleeding, petechiae, bruising, etc. In most cases, vascular disease does not cause serious blood loss, with the exception of hereditary hemorrhagic telangiectasia. In this paper, we discuss the most common hereditary diseases associated with a deficiency of plasma coagulation factors VIII and IX, the disease of platelet deficiency (Glansman disease), the prophylaxis of bleeding in this kind of patients, and the effect of drugs on coagulation processes as well.

A pilot study on maternal oral health and birth weight of twins

Background: Oral health has been implicated in low birth weight or preterm birth. However, this relationship has not yet been studied in twins. We investigated whether maternal oral health was associated with the birth weights of twins by a cross-sectional study conducted at Helsinki University Central Hospital. Methods: Utilizing linear mixed effect models to recognize the correlation between twins from the same mothers and the independence between different mothers. 40 birth weights of twins were modeled as main outcomes. In model 1, poor periodontal health (PPH) was fitted as the main explanatory variable. In model 2, presence of non-specific oral mucositis (NSOM) was fitted as the main predictor. Results: In model 1, babies from mothers with PPH weighed approximately 158.2 grams less than babies of mothers without PPH. However, this association was not statistically significant (p = 0.11). When a stricter criterion for PPH (3 sites of pocket depth > 4 mm) was used, p-value decreased to 0.09 showing a dose response to PPH. In model 2, mothers with NSOM had babies weighing 224.9 grams less than mothers without these lesions. This was nearly significant (p = 0.08). Conclusion: Although not significant, the results from this small data of twins suggest that maternal oral health may be associated with birth weight of twin neonates. Our results are appropriate to generate hypothesis for future studies.

Application and Perception of Potassium Iodide Following Silver Diamine Fluoride Treatment

Silver Diamine Fluoride (SDF) is colorless and alkaline with a pH of 10. It has been used in Japan and other international countries for decades. The Food and Drug Administration gave approval for it as a means of treating hypersensitivity for individuals with chronic teeth pain. SDF is also used as a method to treat and arrest dental caries. SDF application is limited due to its negative esthetic effects, which is a black stain where the cavity was present on the tooth. Topical application of potassium iodide applied immediately after SDF has been shown in studies to reduce the color change caused by SDF. This study used topical application of silver diamine fluoride (SDF) and potassium iodide (KI) treatments on bovine teeth to determine if SDF and KI were efficacious in the treatment for carious lesions. The color change was detected by use of spectrophotometric analysis to determine L, a and b readings that demarcate light and color values following staining. The conclusion was made that the application of SDF followed directly by KI treatment produced L, a and b spectrophotometric values that indicated a significant reduction in teeth staining than the application of SDF alone. Therefore, this study supports the idea that SDF and KI can be used to treat carious lesions on bovine teeth while retaining surface enamel coloration.

What is the purpose of launching the World Journal of Stomatology?

Congratulations to the publisher,members of the editorial board of the journal,all the authors and readers for launching the World Journal of Stomatology(WJS)as a new member of the World series journal family!Significant scientific advances and important breakthroughs need to be published to impact dental care and reach an audience of researchers and clinicians who can create more effective dental treatments for their patients.There is a need to share scientific information,methodologies,therapies,and hypotheses related to stomatology,through an open-access format,to reach the widest possible audience.The WJS was created to fulfill the role of disseminating the most significant,innovative and transformational cutting edge research in dentistry.The WJS is a peer-reviewed open-access periodical centered in stomatology,with a multidisciplinary coverage that will publish high-impact articles in all areas of the dental clinical specialties,applied science,epidemiology,trauma and dental care,dental materials,oral biology and microbiology.The WJS is not scared of controversy or challenges to existing doctrine,since they are supported by high-quality science or unequivocal clinical outcomes.The WJS will avoid publishing confirmatory and low-impact articles.The WJS will only publish articles directly relevant to stomatology and dentistry because this is what our readers expect.If you need to share any exciting dental research discoveries and reach the widest possible audience,you will find in the WJS the most helpful resource to publish your papers!

量表评估效度的项目反应理论(英文)

项目反应理论(Item response theory,IRT)是用来评估精神病学领域那些尚未被充分使用的测量量表效度一种重要方法。IRT描述了潜在心理特征(例如,该量表拟评估心理问题的架构)、量表中各项目的属性、以及被测试者对各项目应答之间的关系。本文介绍了IRT的基本前提,假设和方法。为了帮助解释这些概念,我们依据流行病学调查中心抑郁量表修订版中三个答案为是/否二分类选项的问题制定了一个假设的量表。流行病学调查中心抑郁量表已经用于19,399被测试者。我们首先用因子分析确认这三个项目的单维性,然后用Mplus软件建立2-Parameter Logic(2-PL)IRT模型,这是一种用来评估量表中各项目两两差异和项目难度的方法。本文将就这些分析结果的临床意义和在量表结构中的用途展开讨论。

Low-power laser irradiation inhibits arecoline-induced fibrosis:an in vitro study

Oral submucous fibrosis （OSF） is a potentially malignant disorder that is characterized by a progressive fibrosis in the oral submucosa. Arecoline, an alkaloid compound of the areca nut, is reported to be a major aetiological factor in the development of OSF. Low-power laser irradiation （LPLI） has been reported to be beneficial in fibrosis prevention in different damaged organs. The aim of this study was to investigate the potential therapeutic effects of LPLI on arecoline-induced fibrosis. Arecoline- stimulated human gingival fibroblasts （HGFs） were treated with or without LPLI. The expression levels of the fibrotic marker genes alpha-smooth muscle actin （a-SMA） and connective tissue growth factor （CTGF/CCN2） were analysed by quantitative real- time reverse transcription polymerase chain reaction （RT-PCR） and western blots. In addition, the transcriptional activity of CCN2 was further determined by a reporter assay. The results indicated that arecoline increased the messenger RNA and protein expression of CCN2 and a-SMA in HGF. Interestingly, both LPLI and forskolin, an adenylyl cyclase activator, reduced the expression of arecoline-mediated fibrotic marker genes and inhibited the transcriptional activity of CCN2. Moreover, pretreatment with SQ22536, an adenylyl cyclase inhibitor, blocked LPLI＇s inhibition of the expression of arecoline-mediated fibrotic marker genes. Our data suggest that LPLI may inhibit the expression of arecoline-mediated fibrotic marker genes via the cAMP signalling pathway.

Sphere-forming-like cells(squamospheres) with cancer stem-like cell traits from VX2 rabbit buccal squamous cell carcinoma

Previous studies have demonstrated that spheroid type cells grown under suspension culture conditions have cancer stem cell（CSC） traits in a number of cancers, but this phenomenon has not yet been reported in the VX2 rabbit oral cancer model. Hence, this study aimed to study the spheroid cells from VX2 rabbit buccal squamous cell carcinomas（SCCs） and assess their CSC characteristics. Five adult male New Zealand white outbred rabbits were used to generate VX2 rabbit buccal SCC. Sphere-forming cell culture was performed for the VX2 rabbit buccal SCC specimens. The self-renewal capability; cluster of designation（CD） 44, CD133, acetaldehyde dehydrogenase 1（ALDH1）, B cell-specific Moloney murine leukemia virus integration site 1（Bmi-1）, Nestin, octamer-binding transcription factor 4（Oct4）and reduced expression protein-1（Rex-1） expression with reverse transcription-polymerase chain reaction（RT-PCR）; chemoresistance to cisplatin and 5-fluorouracil; and in vivo tumorigenicity of spheroid cell transplantation in nude mice were evaluated to determine the CSC characteristics of the resulting spheroid cells. We successfully obtained spheroid cells from the VX2 rabbit OSCC tissues. The spheroid cells exhibited CSC traits, including the expression of CSC and stem cell markers（CD44, Bmi-1, Nestin, Oct4 and Rex-1）, capacity to generate new spheroid colonies within 1 week of reseeding from single-dissociated spheroid cells, chemoresistance capacity and generation of tumour xenografts（with histological features resembling those of the original VX2 rabbit buccal SCC） from the transplantation of 103 undifferentiated spheroid cells into nude mice. In summary, we demonstrated that spheroid cells with CSC cell traits can be derived from VX2 rabbit buccal SCCs, indicating that this animal cancer model is applicable for studying CSCs in human oral cancers.

Another Look at Skeletal Maturation Using Hand Wrist and Cervical Vertebrae Evaluation

Introduction and Aims—The Growth stage of a patient can have considerable influence on diagnosis, treatment goals, timing and planning and the eventual outcome of orthodontic/orthopedic treatment. The purpose of this study was to analyze associations between the cervical vertebrae maturation score (CVMS) and skeletal maturation index (SMI). The second objective was to determine the reproducibility of the measurements on lateral cephalograms and hand-wrist radiographs. Materials and Methods—Lateral cephalometric and left hand-wrist radiographs of 92 untreated subjects (44 females and 48 males) aged from 8 to 17 years were obtained from the files of the Columbia University, Division of Orthodontics and measured for growth stage using cervical vertebrae and hand-wrist methods. Results—A high correlation was revealed between the hand-wrist and cervical vertebrae measurements. The Spearman’s rho correlation coefficient was 0.925 and significant at the 0.01 level. The correlation between hand-wrist and age (0.665, p < 0.01) was slightly greater than that of the CVMS (0.611, p < 0.01). Intra rater reliability was high. When the three categorically modified methods of the Fishman’s 11 skeletal maturation stages in hand and wrist analysis were used to compare with CVMS, methods 2 and 3 were both statistically significantly different according to the Wilcoxon signed ranks test and the Sign test at a significance level of less than 0.05. However, for method 1, the tests showed probability scores of 0.028 and 0.151, respectively, showing no significant difference at the 0.01 level in the Wilcoxon Signed Ranks Test, and no significant difference in the 0.01 and 0.05 level in the Signed Test. Conclusions—The Fishman’s hand and wrist skeletal maturation index and Bacetti’s cervical vertebrae maturation stages are both useful tools in evaluating growth stages. Fishman’s hand-wrist method is slightly more accurate.

Artificial intelligence in dentistry:Harnessing big data to predict oral cancer survival

BACKGROUND Oral cancer is the sixth most prevalent cancer worldwide.Public knowledge in oral cancer risk factors and survival is limited.AIM To come up with machine learning(ML)algorithms to predict the length of survival for individuals diagnosed with oral cancer,and to explore the most important factors that were responsible for shortening or lengthening oral cancer survival.METHODS We used the Surveillance,Epidemiology,and End Results database from the years 1975 to 2016 that consisted of a total of 257880 cases and 94 variables.Four ML techniques in the area of artificial intelligence were applied for model training and validation.Model accuracy was evaluated using mean absolute error(MAE),mean squared error(MSE),root mean squared error(RMSE),R2 and adjusted R2.RESULTS The most important factors predictive of oral cancer survival time were age at diagnosis,primary cancer site,tumor size and year of diagnosis.Year of diagnosis referred to the year when the tumor was first diagnosed,implying that individuals with tumors that were diagnosed in the modern era tend to have longer survival than those diagnosed in the past.The extreme gradient boosting ML algorithms showed the best performance,with the MAE equaled to 13.55,MSE 486.55 and RMSE 22.06.CONCLUSION Using artificial intelligence,we developed a tool that can be used for oral cancer survival prediction and for medical-decision making.The finding relating to the year of diagnosis represented an important new discovery in the literature.The results of this study have implications for cancer prevention and education for the public.

Re-Visiting the Decay, Missing, Filled Teeth (DMFT) Index with a Mathematical Modeling Concept

Background: The well-established DMFT index has been used for over 75 years as a key for measuring dental caries in dentistry. DMFT is applied to permanent dentition and expressed as the total number of teeth decayed (D), missing (M), or filled (F), tooth (T) in an individual. Objectives: The objective of this study is to build a mathematical model for the existing DMFT index and compare its parameters by suggested new mathematical model. Mathematical Models: Fixed Model: Is a mathematical model for the existing DMFT index and will be considered as fixed model;in which all individuals under screening will have the same probability θ, 0 ≤ θ ≤1 of dental caries. In this fixed model the unit of the screening is the individual, and will be evaluated for caries as a dichotomous (0, 1) variable. Random Model: The new suggested model is a random model that suggests a mouth of an individual as an environment and the tooth is a unit of research. In this random model, only the teeth in one mouth have the same probability θ, 0 ≤ θi ≤ 1 where i =1, 2...,k ;number of screening individuals. Expected Outcome: Mathematically, the fixed model will highlight what the value 1 will hide as information and hence this may explain why the average of DMFT is may be overestimated for any sample studied using fixed model. The random model will yield a cumulative weighed probability on the function of the number of teeth screened per mouth θ, 0 ≤ θ ≤ 1, hence the average DMFT index will be weighed against the number of teeth screened per all subjects. Conclusion: The random model yields an average and more realistic expected value for the population studied. Furthermore, in such model, it is easy to estimate the variance and it is obvious that this model yields the smallest variance.