Tooth Form Research Articles

Drilling and Sawing Machines and their Operations: Review

The review of this paper pertaining to the present research topic has been carried out to gain knowledge and to become familiar with the established techniques and methodology. Drilling Machine designed to produce a cylindrical hole of required diameter and depth on metal workpieces. Though holes can be made by different machine tools in a shop, drilling machine is designed specifically to perform the operation of drilling and similar operations. Drilling can be done easily at a low cost in a shorter period of time in a drilling machine. Sawing is a process in which a narrow slit is cut into the work by a tool called saw consisting of a series of narrowly spaced teeth. Each tooth removes a small amount of material with each stroke or movement of the saw. Each tooth forms a chip progressively as it passes through the workpiece. This project presents the concept of Multi-Function Operating Machine mainly carried out for production-based industries.

Choosing the denture occlusion - A Systematic review.

Aim:The aim of the study is to acquire evidence for the choice of occlusion with anatomic/modified anatomic teeth in complete denture prosthesis.Settings and Design:Systematic review following PRISMA guidelines.Materials and Methods:The study reviewed original articles on various occlusal schemes bilateral balance occlusion (BBO), lingual occlusion (LO), Canine guided occlusion (CG), posterior group function occlusion (PGFO) have been applied to the complete dentures and were analyzed for the objective or subjective or both evaluations. The data were collected in standard format with the needed information such as year of publication, type of study, occlusal schemes compared, test methodology used, sample size for experiment and control, assessment of retention, stability, and other factors which determine the quality of life and period of follow-up. The risk of bias was calculated using tools RoB2.0 and robvis. At all stages, the inclusion and exclusion of studies were discussed among the reviewers.Statistical Analysis used:Due to the heterogeneity in the data of the included studies no statistical analysis was used.Results:Of the 1896 articles screened only 17 studies were included in the systematic review. These were discussed amongst the reviewers regarding the various occlusion schemes used. The subjective and objective criteria used in the studies was tabulated separately. They were then analyzed for the risk of bias using the robvis 2 tool.Conclusion:No scheme is more superior to the other with the anatomic tooth forms. The use of alternative unbalanced schemes produces a similar satisfactory clinical outcome. The ridge classification also has a significant role to play in the preference for an occlusal scheme.

Tooth form assessment in the aesthetic zone of the maxilla

Introduction: The accurate assessment of tooth form and gingival phenotype in the aesthetic zone of maxilla is of great importance for the correct preoperative planning in dental practice. Determining the tooth form as a key factor helps the clinicians in assessing the aesthetic risk in periodontal, restorative and implant therapy. Aim: The aim of this study is to investigate the prevalence of rectangular and triangular tooth form in the aesthetic zone of the maxilla and also to generalize the variations in this prevalence between males and females in the Bulgarian population. Materials and Methods: The tooth form in the aesthetic zone of maxilla is assessed in 223 individuals and determined according to four anatomic criteria: width and position of the interdental contact point, CW/CL ratio, height of interdental papillae, and the scallop of gingival margin. Results: The analysis of the results shows that the rectangular tooth form is more prevalent (70%) compared to the triangular tooth form (30%), and the triangular tooth form is more prevalent in males (32%) than in females (29%). Discussion: With regard to the tooth form in approximately 70% of the cases (prevalence of a square/rectangular tooth form) we can expect to have a lower aesthetic risk in the preoperative planning of implant therapy in the aesthetic zone of the maxilla. Conclusion: More prevalent in the study group is the rectangular/square tooth form (70%) compared to the triangular tooth form (30%) with a ratio of 2.33:1.

An observational study of dental abnormalities in the primary teeth

Pregnancy and early childhood are the most critical phases with regard to biological, cognitive, emotional, and social development. Adverse events in these periods of life may be related to alterations in dental development, including alterations in size, shape and mineralization. Objective: To evaluate the frequency of dental abnormalities and the factors associated with the developmental defects of the enamel in primary teeth. Material and methods: Information about family income, maternal education level, preterm birth, and hospitalization history up to 11 months of age were collected from the dental records of 544 children. Clinical examination of the children was performed to investigate abnormalities of tooth number, form, size, and developmental defects of the enamel (DDE). Data were analyzed using χ2 test and Poisson regression. Results: In all, 544 children were evaluated. Sixty children (11.0%) presented some alterations in the primary teeth; and 7.5% showed DDE. Children born preterm were 3.17 times more likely to develop DDE in primary teeth (prevalence ratio – PR = 3.17, 95% confidence interval – 95%CI 1.26–7.98, p = 0.014). Among the alterations of number, 1.7% was hypodontia, and among the abnormalities of shape, 1.7% was fused teeth. Conclusion: The prevalence of dental anomalies in this sample was, in general, expressive. Children born preterm were more vulnerable to present developmental defects of the enamel.

An observational study of dental abnormalities in the primary teeth

Introduction: Pregnancy and early childhood are the most critical phases with regard to biological, cognitive, emotional, and social development. Adverse events in these periods of life may be related to alterations in dental development, including alterations in size, shape and mineralization. Objective: To evaluate the frequency of dental abnormalities and the factors associated with the developmental defects of the enamel in primary teeth. Material and methods: Information about family income, maternal education level, pretermbirth, and hospitalization history up to 11 months of age were collected from the dental records of 544 children. Clinical examination of the children was performed to investigate abnormalities of tooth number, form, size, and developmental defects of the enamel (DDE). Data were analyzed using χ2 test and Poisson regression. Results: In all, 544 children were evaluated. Sixty children (11.0%) presented some alterations in the primary teeth; and 7.5% showed DDE. Children born preterm were 3.17 times more likely to develop DDE in primary teeth (prevalence ratio – PR = 3.17, 95% confidence interval– 95%CI 1.26–7.98, p = 0.014). Among the alterations of number, 1.7% was hypodontia, and among the abnormalities of shape, 1.7% was fused teeth. Conclusion: The prevalence of dental anomalies in this sample was, in general, expressive. Children born preterm were more vulnerable to present developmental defects of the enamel.

Fish fossils of Taiwan: a review and prospection

ABSTRACT Despite the frequent occurrence of fish fossils in the field, related studies are noticeably rare in Taiwan. The scant fossil record of fish in the literature sharply contrasts the high diversity of modern fish in this region. This is often due to the scarcity of well-preserved materials, limited exposure that covers long geological ages, and lack of comprehensive sampling design. Over the years, unstudied new fish fossils have been collected and accumulated. Several old and published specimens stored in private collections are lost. In this study, we evaluated potential horizons yielding fish fossils, examined the current status of published specimens with updated regional stratigraphic correlation, and finally explored possible directions for future work. Our extensive bibliographic reviews revealed a total of published 47 taxa, which are mostly in the form of teeth (elasmobranch) and otoliths (teleost). Skeletal specimens with taxonomic value are rare. Using Plio-Pleistocene otoliths from the famous Chochen-Tsailiao locality, we further demonstrated that they are numerous in the sediments, with high abundance and broad distribution. Study small fish remains for attaining a high resolution on the spatiotemporal dynamics of fish faunas through time and for providing the data necessary for conservational purposes is recommended.

Evaluation of esthetic parameters related to a single implant restoration by laypeople and dentists

Statement of problemCurrently available assessment tools for evaluating the esthetic outcome of implant restorations consist of objective indices created for dentists. The investigation of esthetic parameters according to the patient's perspective is lacking. PurposeThe purpose of this observational study was to evaluate and compare the importance of different soft-tissue and restoration-related esthetic parameters for patients and clinicians. Material and methodsA photoediting software program (Photoshop CC; Adobe Corp) was used to produce 10 photographs with modified smiles from the original photograph by altering 1 parameter of the pink esthetic score and white esthetic score (PES/WES) at a time. A total of 120 participants were recruited in the study, including 40 laypeople, 40 prosthodontists, and 40 periodontists. A total of 440 visual analog scale (VAS) values were obtained for each group to record participants' subjective esthetic assessments of all photographs (10 modified and 1 original photograph). Repeated-measures ANOVA and post hoc mean comparison (t grouping) were used to identify whether the individual alteration on the PES and WES indices was significant for each group. ResultsFor the laypeople, color (hue and value) appeared to be the most important parameter. After color, the order of importance was as follows: root convexity along with soft-tissue color and texture, level of facial mucosa, distal papilla, mesial papilla, translucency or characterization, surface texture, and tooth form. For the periodontists, color (hue and value) was also the most important parameter, but it was not separable from a cluster of other parameters: level of facial mucosa, root convexity along with soft-tissue color and texture, mesial papilla, and distal papilla. For the prosthodontists, color (hue and value) and level of facial mucosa were the most important parameters affecting esthetic assessment, followed by root convexity along with soft-tissue color and texture, mesial papilla, and distal papilla. ConclusionsAll groups graded color (hue and value) as the most important parameter affecting the esthetic outcome and the original unaltered photograph as the most esthetically pleasing image. All participants (laypeople and dental specialists) appeared to be able to perceive the same 5 parameters including color (hue and value), level of facial mucosa, mesial papilla, distal papilla, and root convexity along with soft-tissue color and texture that are negatively affecting esthetic outcomes. Except for color (hue and value), restoration-related esthetic parameters had a lesser effect on the overall esthetic assessments for all groups.

Bending stress analysis of eccentric straight and helical curve-face gear pair

As a new type of gear transmission developed in recent years, curve-face gear transmission has not appeared before. In order to solve the problem of root bending strength of the eccentric straight and helical curve face gear, a calculating method of the tooth root bending strength was proposed. According to the principle of space meshing, differential geometry and design of machinery, the parametric equations of pitch curve was obtained, the pressure angle and the contact ratio in the meshing process were derived. The plane equivalent pitch curve was obtained, and the formula for calculating the equivalent tooth form factor and the equivalent stress correction factor was acquired. The calculation method of the bending strength of the gear pair was established, and the influence of the basic structural parameters on the bending stress was also analyzed in detail. The position of the stress hazard of the eccentric curve-face gear was determined. Through the finite element analysis and transmission experiment, the accuracy of the calculation method of strength of the gear pair was verified.

Male aggression varies with consortship rate and habitat in a dolphin social network

Coalitions and alliances exemplify the core elements of conflict and cooperation in animal societies. Ecological influences on alliance formation are more readily attributed to within-species variation where phylogenetic signals are muted. Remarkably, male Indo-Pacific bottlenose dolphins in Shark Bay, Western Australia, exhibit systematic spatial variation in alliance behavior, not simply within a species or population, but within a single social network. Moving SE-NW along Peron Peninsula in Shark Bay, males ally more often in trios than pairs, consort females more often, and exhibit greater seasonal movements. Ecological models predict more male-male conflict in the north, but sufficient observations of aggression are lacking. However, dolphins often incur marks, in the form of tooth rakes, during conflicts. Here we report that the incidence of new tooth rake marks varies systematically in the predicted pattern, with greater marking in the north, where males form more trios and consort females at a higher rate. While our previous work demonstrated that alliance complexity has an ecological component, we can now infer that ecological variation impacts the level of alliance-related conflict in Shark Bay. To understand ecological influences on animal societies, researchers have focused on differences within species, where confounds due to evolutionary history are minimized. Such differences are usually found among geographically separated populations, but in Shark Bay, Western Australia, male dolphin alliance size and access to females increase along a spatial axis within a single social network. Here we report that aggression levels, evidenced by tooth rake marks, increase along the same axis. Alliances are of particular interest as they represent a complex kind of relationship, often implicated in the evolution of social intelligence. Our discovery of spatial variation in alliance behavior and aggression within a social network provides a unique opportunity to investigate the intersection of cognition, social structure, and ecology.

Design and Optimization of a Microchip Operating at Low-Voltage Pulsed Electric Field for Juice Sterilization

Microchip has been widely used in the biochemical field, but it is rarely applied in the food area. In this paper, an optimal microelectrode model was obtained via the improved evolutionary structural optimization (ESO) method, the effect of topological parameters on the sterilization efficiency was clarified, and the optimized microchip was applied to the sterilization of blueberry juice to verify its feasibility. The analysis of finite element method (FEM) results showed that planar comb teeth (PCT) form, quadrilateral electrode structure with 100-μm electrode spacing, was the ideal model for the microchip. On the basis of the optimal electrode model, a continuous low-voltage pulsed electric field (LPEF) experimental platform was built. Under 400 V and 0.2-ms conditions, LPEF processing better preserved vitamin C, anthocyanin, total phenolics content, and color parameters while reducing microbial counts in blueberry juice significantly. During 30 days of storage at 4 °C, LPEF-treated juices had more vitamin C, anthocyanin content, and brighter color under the premise of ensuring microbiological safety, compared with high temperature short time (HTST) and pulsed electric field (PEF)-treated juices. This study provides theoretical and technological support for the widespread use of LPEF technology in the application of a non-thermal processing technique for food.

Evolutionary transformation of mouthparts from particle-feeding to piercing carnivory in Viper copepods: Review and\xa03D analyses of a key innovation using advanced imaging techniques

BackgroundNovel feeding adaptations often facilitate adaptive radiation and diversification. But the evolutionary origins of such feeding adaptations can be puzzling if they require concordant change in multiple component parts. Pelagic, heterorhabdid copepods (Calanoida) exhibit diverse feeding behaviors that range from simple particle feeding to a highly specialized form of carnivory involving piercing mouthparts that likely inject venom. We review the evolutionary history of heterorhabdid copepods and add new high-resolution, 3D anatomical analyses of the muscular system, glands and gland openings associated with this remarkable evolutionary transformation.ResultsWe examined four heterorhabdid copepods with different feeding modes: one primitive particle-feeder (Disseta palumbii), one derived and specialized carnivore (Heterorhabdus subspinifrons), and two intermediate taxa (Mesorhabdus gracilis and Heterostylites longicornis). We used two advanced, high-resolution microscopic techniques — serial block-face scanning electron microscopy and two-photon excitation microscopy — to visualize mouthpart form and internal anatomy at unprecedented nanometer resolution. Interactive 3D graphical visualizations allowed putative homologues of muscles and gland cells to be identified with confidence and traced across the evolutionary transformation from particle feeding to piercing carnivory. Notable changes included: a) addition of new gland cells, b) enlargement of some (venom producing?) glands, c) repositioning of gland openings associated with hollow piercing fangs on the mandibles, d) repurposing of some mandibular-muscle function to include gland-squeezing, and e) addition of new muscles that may aid venom injection exclusively in the most specialized piercing species. In addition, live video recording of all four species revealed mandibular blade movements coupled to cyclic contraction of some muscles connected to the esophagus. These behavioral and 3D morphological observations revealed a novel injection system in H. subspinifrons associated with piercing (envenomating?) carnivory.ConclusionsCollectively, these results suggest that subtle changes in mandibular tooth form, and muscle and gland form and location, facilitated the evolution of a novel, piercing mode of feeding that accelerated diversification of the genus Heterorhabdus. They also highlight the value of interactive 3D animations for understanding evolutionary transformations of complex, multicomponent morphological systems.

MODELING OF IMPACT OF CENTRIFUGAL REINFORCEMENT MODES ON WEAR OF CUTTER TEETH OF DRILL BITS

A study was performed to improve the performance of drill bits. It is noted the main work item are cones, equipped with serrated arms, made in the form of solid or false teeth. It is noted reinforcement of cutters during destruction of rocks is subjected to intensive wear under the action of high loads at the bottom, significant temperature differences, in the presence of abrasive particles, changes in the rock hardness. To reduce the impact of these factors on the wear of rock-destruction weapons, comprehensive design and technological measures are proposed to create a rock-destructive tool and, in particular, its reinforcement. The efficiency criterion of such events is proposed to choose resistance of rock-cutting elements to various types of wear. For implementation of the proposed approach to creating effective reinforcement, a critical analysis of the design of the cutter teeth of drill bits equipped with teeth of various designs and technologies for their manufacture was performed, and rolling cutters with plug-in teeth made by centrifugal reinforcement were selected as the object of research as the most optimal. The design of such teeth, implemented by a centrifugal casting process, provides for location of the rock-breaking hard alloy in the tooth head. The tooth root, pressed into the cutter housing, is made of steel. A mathematical model of the process of centrifugal reinforcement of cutter teeth of drill bits was developed to study the impact of process conditions on their resistance to impact-abrasive wear. As independent variables, otherwise the factors determining the technological process modes of centrifugal reinforcement were selected X1, X2, X3, X4, their main level and intervals of variation, the upper and lower levels were established. A full factor experiment 24 was used in the research. An experimental plan was drawn up. In accordance with the chosen plan, 16 active experiments were performed; each experiment was repeated three times. Then, a mathematical model and its describing regression equation were developed. The impact degree of process factors on the value of shock-abrasive wear of teeth and their optimum values were determined.

ETIOPATHOGENESIS AND DIAGNOSTICS OF THE MANDIBULAR PERMANENT FIRST MOLARS RETENTION

The eruption of the first permanent molars is very important as it provides the harmony of the growth of the face and sufficient occlusion support. A delay in the eruption of this tooth can cause morphological, functional and aesthetic disturbances. These include reduced vertical size of the lower face, extruding the antagonist teeth, malloclusion formation, follicular cyst formation, pericoronal inflammation, and roots resorbtion of the adjacent teeth, as well as functional problems of dentoalveolar area, etc. In this regard, the issue of etiology, pathogenesis, early diagnostics and further treatment of lower first permanent molars retention is very relevant for modern orthodontics. In the literary review, morphological and radiological diagnostic criteria of eruption of first permanent lower molars have been presented. Materials and methods of the research. The article reviews and analyzes literature on the etiology, pathogenesis, early diagnostics of retention of the lower first permanent molars. Results The analysis of the literature pointed to a small number of studies regarding the disrupted eruption of first lower permanent molars. In most cases, they are presented as clinical cases. According to the world literature, the prevalence of delayed eruption of the first molar of the mandible was 0.01% to 0.04%. Data from the world literature indicate that the retention of the lower first molar is a polyfactoral disease. According to the etiological factors authors distinguish general and local. Local factors causing delay in teeth eruption include impaired pathway for teeth eruption, abnormality of the tooth form, hyperplasia, displacement of the rudiment because of the cyst and the tumour, loss of space for eruption, gingival fibrosis, idiopathic conditions. Systemic factors include endocrine disorders such as hypothyroidism, hyperthyroidism, hypoparathyroidism, rickets, craniofacial hypertrophy. In the literary review morphological and radiological diagnostic criteria of eruption disturbance of the first permanent lower molars are presented. Thus, the Korean scientists proposed to determine the depth of the retention, the angle of inclination and the space for their eruption on panoramic radiographs. The review presents the classification of retention types for the first permanent molars of the mandible.

Characteristics for the External Identification of Black Carp From Grass Carp

AbstractBlack Carp Mylopharyngodon piceus and Grass Carp Ctenopharyngodon idella are morphologically similar species native to eastern Asia and imported to North America as biological control organisms. Preferred identification methods are coloration and pharyngeal tooth form. Grass Carp possess serrated teeth and Black Carp molariform teeth. Examination of pharyngeal teeth causes extensive damage to a specimen and is labor and time intensive. Coloration can vary within a species and fades with preservation. We present a suite of external characteristics consisting of a truss network canonical variate analysis of distance measurements among landmarks on the lateral view of the head of each fish, the ratio of head length to mouth width, the visible presence of the premaxilla viewed dorsally with the mouth fully closed, and anterior lateral line angles among scales. Canonical variate analysis suggested that Grass Carp have a deeper head at the preoperculum and Black Carp a more elongate head relative to the preoperculum and eye. Comparisons of head length to mouth width ratio, visibility of the premaxilla dorsally with the mouth fully closed, and anterior lateral line angles all served as external characteristics of species, but outliers were present for each method. Because of the plastic morphology of wild populations, we suggest that a combination of characters be applied for identification.

Revitalising the rudimentary replacement dentition in the mouse.

Most mammals have two sets of teeth (diphyodont) - a deciduous dentition replaced by a permanent dentition; however, the mouse possesses only one tooth generation (monophyodont). In diphyodonts, the replacement tooth forms on the lingual side of the first tooth from the successional dental lamina. This lamina expresses the stem/progenitor marker Sox2 and has activated Wnt/β-catenin signalling at its tip. Although the mouse does not replace its teeth, a transient rudimentary successional dental lamina (RSDL) still forms during development. The mouse RSDL houses Sox2-positive cells, but no Wnt/β-catenin signalling. Here, we show that stabilising Wnt/β-catenin signalling in the RSDL in the mouse leads to proliferation of the RSDL and formation of lingually positioned teeth. Although Sox2 has been shown to repress Wnt activity, overexpression of Wnts leads to a downregulation of Sox2, suggesting a negative-feedback loop in the tooth. In the mouse, the first tooth represses the formation of the replacement, and isolation of the RSDL is sufficient to induce formation of a new tooth germ. Our data highlight key mechanisms that may have influenced the evolution of replacement teeth.This article has an associated 'The people behind the papers' interview.

Digital techniques for anterior teeth form selection in complete edentulism

The aim of this study was to compare two computerized digital esthetic design methods (DSD and Visagismile) in order to properly choose the appropriate form of the maxillary frontal teeth for complete bimaxillary edentulous patients and to validate the use of these applications in complete edentulism. An online questionnaire was submitted to a group of 100 persons (dental doctors, dental medicine students and persons activating in other fields); the respective persons were requested to choose the form of maxillary frontal teeth for a group of four complete bimaxillary edentulous patients, whose esthetic design had been performed by using the two computerized progams. Following the respondents’ analysis of the esthetic previews elaborated for the four patients 60% of the total answers were in favour of DSD while the remaining 40% were in favour of Visagismile; these percentages are identical with the ones obtained on the basis of the answers given by dental doctors and dental medicine students. In case of the respondents activating in other fields the percentages were 66% in favour of DSD and 34% in favour of Visagismile. Based on the results of the study the two computerized methods were validated also for cases of complete edentulism but further studies to confirm this validation are still required. These two methods improve the dental doctor/patient communication and certainly provide a higher predictability of the esthetic results of prosthetic restorations not only for dentate patients but also in cases of complete edentulism.

Investigation of shear behavior of soil-concrete interface

The shear behavior of soil-concrete interface is mainly affected by the surface roughness of the two contact surfaces. The present research emphasizes on investigating the effect of roughness of soil-concrete interface on the interface shear behavior in two-layered laboratory testing samples. In these specially prepared samples, clay silt layer with density of 2027 kg/m3 was selected to be in contact a concrete layer for simplifying the laboratory testing. The particle size testing and direct shear tests are performed to determine the appropriate particles sizes and their shear strength properties such as cohesion and friction angle. Then, the surface undulations in form of teeth are provided on the surfaces of both concrete and soil layers in different testing carried out on these mixed specimens. The soil–concrete samples are prepared in form of cubes of 10*10*30 cm. in dimension. The undulations (inter-surface roughness) are provided in form of one tooth or two teeth having angles 15 and 30, respectively. Several direct shear tests were carried out under four different normal loads of 80, 150, 300 and 500 KPa with a constant displacement rate of 0.02 mm/min. These testing results show that the shear failure mechanism is affected by the tooth number, the roughness angle and the applied normal stress on the sample. The teeth are sheared from the base under low normal load while the oblique cracks may lead to a failure under a higher normal load. As the number of teeth increase the shear strength of the sample also increases. When the tooth roughness angle increases a wider portion of the tooth base will be failed which means the shear strength of the sample is increased.

First impression of teeth design on others: A facial and personality analysis in the Central Indian population.

Facial features and personality types vary with different geographical boundaries, culture, and ethnicity. The impression created by teeth design differs with the face and personality of males and females. This study evaluated the dominant facial and personality types and their correlation among males and females in Central Indian population. The full-face photographs of 120 people, with a broad smile and visible dentition, were calibrated to generate a facial map with digital software. The participants filled a personality questionnaire. Facial form and personality type were classified as a combination of strong, dynamic, delicate, and calm. Descriptive and inferential statistics using Chi-square and Kappa tests. The dominant facial form was calm (66.67%, 71.67%) with the second dominant facial form being dynamic (50%, 51.67%) both for males and females respectively. While the dominant personality type was dynamic (50%), the second dominant personality type was calm (35%, 30%) for both males and females. Kappa analysis showed moderate agreement between the dominant facial and personality types (P = 0.41 in males, P = 0.10 in females). The software used was SPSS 22.0 version and P < 0.05 is considered as the level of significance. A varying number of combinations are essential in characterizing the face. The personality type has a predominance of one type over other. The interpretation of these combinations in dentistry can help to select appropriate tooth forms and design a harmonious smile.

Abnormal tooth forms

Abnormal tooth forms

KINEMATICS OF A ROLLER CONE BIT WITH A DIRECT FACET TOOTH

The advanced technique of shock-kinematic analysis of the bit roller cone interaction with rock in the process of oil and gas wells drilling is proposed. Preliminary investigations of the interaction of the roller cone bits with rock were based on assumptions far from reality: the concept of the instantaneous axis of rotation of the roller cone constant contact with rock, the absence of slipping, as well as the tooth reforming and sinking into rock. The principle of the roller cones action is the gradual destruction of the surface of the bottomhole due to the cutting-crushing chipping of rock with a bit tooth.The axial roller cone is considered, and the original method of planes projection is used to determine the regulation of tooth motion, taking into account: bit roller cones slipping along the surface of the bottomhole; phases of roller cone tooth sinking into rock; real change in the distance of the axis of rotation of the roller cone to the surface of the bottomhole due to tooth penetration into the rock; the substantiation of the conditions for avoiding the roller cone tooth entering to the previously obtained hole in the process of bottomhole crushing. Besides the moment of the drill string inertia, the moments of roller cones inertia are additionally taken into account under the condition of the oblique impact of the tooth on the rock.The technique allows to calculate the volume of the disintegrated rock on the bottomhole, both taking into account and without taking into account rock chipping and tooth forming. The obtained dependencies allow us to select transmitted ratios from the drill string to the crowns of the roller cones under the condition of avoiding the roller cone tooth to the previously obtained hole during rock destruction on the bottomhole. It allows increasing the efficiency of drilling by roller cones.