436 resultados para Deçiduous dentition
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Objective: The aim of this prospective study was to compare the dentoalveolar effects produced by two types of palatal crib, removable (Rpc+C) and fixed (Fpc+C), combined with chincup in growing patients with anterior open bite. Material and Methods: Each group comprised 30 patients, in the mixed dentition phase, with similar cephalometric characteristics and skeletal ages. Group 1 (Rpc+ C) presented initial mean age of 8.3 years and mean anterior open bite of 4.0 mm. Group 2 (Fpc+C) presented initial mean age of 8.54 years and mean anterior open bite of 4.3 mm. The evaluation period comprised 12 months between initial (T1) and second lateral radiograph (T2). The T2-T1 changes were compared cephalometrically in the 2 groups using the non-paired t-test. Results: Vertical changes in the posterior dentoalveolar region were similar between the groups (about 1 mm) and no significant differences were found in molar mesialization. The Fpc+C group had in average 1.6 mm more improvement of the overbite as a result of greater maxillary incisor extrusion (1.3 mm). Patients in this group also presented less lingual tipping of maxillary incisors and more mandibular incisors uprighting. Conclusions: The Fpc+C combination was more efficient in the correction of the negative overbite mainly due to greater extrusion of the maxillary incisors. However, the Rpc+C appliance promoted better upper and lower incisor inclination, resulting in a more adequate overjet.
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Background. The prevalence of early childhood caries (ECC) is high in developing countries; thus, sensitive methods for the early diagnosis of ECC are of prime importance to implement the appropriate preventive measures. Aim. To investigate the effects of the addition of early caries lesions (ECL) into WHO threshold caries detection methods on the prevalence of caries in primary teeth and the epidemiological profile of the studied population. Design. In total, 351 3-to 4-year-old preschoolers participated in this cross-sectional study. Clinical exams were conducted by one calibrated examiner using WHO and WHO + ECL criteria. During the exams, a mirror, a ball-ended probe, gauze, and an artificial light were used. The data were analysed by Wilcoxon and Mc-Nemar's tests (a = 0.05). Results. Good intra-examiner Kappa values at tooth /surface levels were obtained for WHO and WHO + ECL criteria (0.93 /0.87 and 0.75 /0.78, respectively). The dmfs scores were significantly higher (P < 0.05) when WHO + ECL criteria were used. ECLs were the predominant caries lesions in the majority of teeth. Conclusions. The results strongly suggest that the WHO + ECL diagnosis method could be used to identify ECL in young children under field conditions, increasing the prevalence and classification of caries activity and providing valuable information for the early establishment of preventive measures.
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The aim of this study was to evaluate the short-and long-term treatment effects of rapid maxillary expansion (RME) on the soft tissue facial profile of subjects treated with a modified acrylic-hyrax device. The sample comprised 10 males and 10 females in the mixed dentition. Their average age was 9.3 years +/- 10 months pre-treatment (T1), with a narrow maxilla and posterior crossbite, treated with a modified fixed maxillary expander with an occlusal splint. Lateral cephalometric radiographs obtained at T1, immediately post-expansion (T2), and after retention (T3) were used to determine possible changes in the soft tissue facial profile. The means and standard deviations for linear and angular cephalometric measurements were analysed statistically using analysis of variance and Tukey's test (alpha = 0.05). The measurements at T2 differed significantly from those at T1 and T3. However, RME did not produce any statistically significant alteration (P > 0.05) in the soft tissue profile for any of the cephalometric landmarks evaluated when compared at T1 and T3. The use of a fixed expander associated with an occlusal splint did not cause significant alterations in the soft tissue facial profile at T3. This modified device is effective for preventing the adverse vertical effects of RME such as an increase anterior face height in patients with a crossbite.
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Introduction: The literature suggests that individuals with history of cleft lip and palate who present with midfacial growth deficiency are at higher risk of presenting lisping. The relationship between distortions during production of linguoalveolar fricative sounds and the severity of malocclusion, however, has not been established for the population with cleft. Objective: To study the association between lisping and dental arch relationship. Methodology: Speech samples and dental arch casts were obtained from 106 children with operated unilateral cleft lip and palate (UCLP) during the stage of mixed dentition and before orthodontic treatment. Videotaped productions of the phrase/u saci saiw sedu/were rated by speech-language pathologists for the identification of lisping during [s]. Dental arch casts were rated by orthodontists using the Goslon Yardstick and the Five-Year Index to establish dental arch relationship. Results: Multiple logistic regression showed no significant association between lisping and dento-occlusal index (p = .802) and age (p = .662). Substantial interjudge agreement during auditory-perceptual ratings was found (kappa = .63). Almost perfect agreement was found between orthodontists while establishing the dental arch relationship (kappa = .81). Discussion: This study failed to reveal an association between lisping and dental arch relationship in children with operated UCLP. Multiple variables may play a role in determining occurrence of lisping, warranting further investigation.
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Objective: To evaluate the effect of different chewing gum brands on the salivary pH of children with primary dentition. Method: Forty children were selected and assigned to four groups: control (no chewing gum); sugarless chewing gum; chewing gum with casein phosphopeptide-amorphous calcium phosphate; and chewing gum with xylitol. The first saliva collection was made after supervised tooth brushing for stabilization of the oral pH. Next, all children were instructed to drink slowly 100 mL of a cola-based soft drink (Coca-Cola®) and a new saliva collection was made 10 min later. Then, each group chewed on the chewing gum for 5 min and discarded it after this time. Saliva was collected again at 5, 10 and 15 min intervals after start using the chewing gum. Measurement of salivary pH was made with colorimetric test papers and a digital pH-meter. Data were analyzed statistically by analysis of variance and Tukey’s test at a 5% significance level. Results: The use of chewing gums accelerated the increase of salivary pH to considerably alkaline levels after consumption of an acidic beverage, especially within the first minutes. The highest levels were obtained in the groups of children that used chewing gums containing xylitol and casein phosphopeptide-amorphous calcium phosphate. Conclusion: Children that used the chewing gums after ingestion of an acidic soft drink presented an increase in salivary pH, with the best results in the groups that used chewing gums containing casein phosphopeptide-amorphous calcium phosphate and xylitol.
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O tratamento da má oclusão de Classe II sem extrações dentárias vem ganhando popularidade na comunidade ortodôntica já há três décadas. Aparelhos funcionais fixos vêm sendo utilizados por profissionais, de maneira crescente, para promover compensações dentoalveolares e corrigir a má oclusão de Classe II. Os efeitos mais significativos são observados em pacientes com padrão de crescimento horizontal. Um caso clínico será relatado com o uso do aparelho fixo Twin Force Bite Corrector em uma paciente do sexo feminino, para a correção da Classe II. Esse dispositivo de ancoragem fixa dispensa o uso de aparelhos funcionais removíveis e não necessita da cooperação do paciente.
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O objetivo do presente estudo foi determinar a prevalência de supranumerários na região dos pré-molares nos estágios de dentadura decídua, mista e permanente, além de verificar sua associação com a presença de terceiros molares. Foram avaliadas radiografias panorâmicas de 1.976 pacientes matriculados no curso de Ortodontia Preventiva e Interceptiva da Profis (Sociedade de Promoção Social do Fissurado Lábio-Palatal), em Bauru-SP. As radiografias foram analisadas em negatoscópio, em ambiente escurecido, por um único examinador que determinou a presença de supranumerários na região dos pré-molares, bem como a presença de terceiros molares. A associação entre o aparecimento de supranumerários e a presença de terceiros molares foi verificada pelo Teste de McNemar. O Teste exato de Fisher foi aplicado para verificar o dimorfismo sexual. Constatou-se uma prevalência de 0,45% de supranumerários na região dos pré-molares na amostra estudada, sendo 11% na maxila e 89% na mandíbula, e não foi observado dimorfismo sexual em relação ao aparecimento dos supranumerários (p=0,32). Nas radiografias avaliadas, foi observado que os quatro terceiros molares estavam presentes sempre que verificada a presença dos supranumerários, detectando uma associação estatisticamente significante (p < 0,01) entre o aparecimento dos pré-molares supranumerários e a presença dos terceiros molares. Concluiu-se que a incidência de pré-molares supranumerários foi baixa na população estudada, e que existe associação entre o aparecimento destes supranumerários com a presença dos terceiros molares.
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Introduction: This retrospective cephalometric study analyzed the influence of intentional ankylosis of deciduous canines in patients with Class III malocclusion and anterior crossbite, in the deciduous and early mixed dentition stages, treated by orthopedic maxillary expansion followed by maxillary protraction. Methods: Lateral cephalograms of 40 patients were used, divided in 2 groups paired for age and gender. The Ankylosis Group was composed of 20 patients (10 boys and 10 girls) treated with induced ankylosis and presenting initial and final mean ages of 7 years 4 months and 8 years 3 months, respectively, with a mean period of maxillary protraction of 11 months. The Control Group comprised 20 patients (10 boys and 10 girls) treated without induced ankylosis, with initial and final mean ages of 7 years 8 months and 8 years 7 months, respectively, with a mean period of maxillary protraction of 11 months. Two-way analysis of variance and covariance analysis were applied to compare the initial and final cephalometric variables and the treatment changes between groups. Results: According to the results, the variables evidencing the significant treatment changes between groups confirmed that the intentional ankylosis enhanced the sagittal response of the apical bases (Pg-NPerp) and increased the facial convexity angles (NAP and ANB). Conclusions: The protocol involving intentional ankylosis of deciduous canines enhanced the sagittal response of the apical bases.
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Background: In epidemiological surveys, a good reliability among the examiners regarding the caries detection method is essential. However, training and calibrating those examiners is an arduous task because it involves several patients who are examined many times. To facilitate this step, we aimed to propose a laboratory methodology to simulate the examinations performed to detect caries lesions using the International Caries Detection and Assessment System (ICDAS) in epidemiological surveys. Methods: A benchmark examiner conducted all training sessions. A total of 67 exfoliated primary teeth, varying from sound to extensive cavitated, were set in seven arch models to simulate complete mouths in primary dentition. Sixteen examiners (graduate students) evaluated all surfaces of the teeth under illumination using buccal mirrors and ball-ended probe in two occasions, using only coronal primary caries scores of the ICDAS. As reference standard, two different examiners assessed the proximal surfaces by direct visual inspection, classifying them in sound, with non-cavitated or with cavitated lesions. After, teeth were sectioned in the bucco-lingual direction, and the examiners assessed the sections in stereomicroscope, classifying the occlusal and smooth surfaces according to lesion depth. Inter-examiner reproducibility was evaluated using weighted kappa. Sensitivities and specificities were calculated at two thresholds: all lesions and advanced lesions (cavitated lesions in proximal surfaces and lesions reaching the dentine in occlusal and smooth surfaces). Conclusion: The methodology purposed for training and calibration of several examiners designated for epidemiological surveys of dental caries in preschool children using the ICDAS is feasible, permitting the assessment of reliability and accuracy of the examiners previously to the survey´s development.
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Crown dilaceration of permanent teeth occurs due to the non-axial displacement of the already formed hard tissue portion of the developing crown at an angle to their longitudinal axis due to trauma to the primary predecessors. This is a rare condition, representing only 3% of the total of injuries to developing teeth and usually occurs in permanent maxillary incisors because of the close proximity of their tooth germs to the primary incisors, which are more susceptible to trauma. This alteration frequently results from the intrusion of a primary tooth when the child is around 2 years of age, at which time half of the crown of the permanent successor is already formed. Teeth with dilacerated crowns may either erupt with buccal or lingual displacement or remain impacted. The treatment may involve endodontic, orthodontic, restorative and prosthetic procedures. This paper reports the restorative treatment proposed to reestablish the esthetics and function of the affected teeth in three cases of crown dilaceration in permanent maxillary incisors after trauma to their primary predecessors.
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OBJECTIVE: The influence of asthma, its severity levels and onset time on malocclusion occurrence were investigated. METHODS: The sample was composed by 176 children/adolescents, of both genders, aged 3 to 15 years, that were divided in two groups. The asthma group (AG) enrolled 88 children/adolescents that were seen at the Breathe Londrina Program. The asthma-free group (AFG) enrolled 88 preschool and school children recruited in 2 public schools. Malocclusion diagnosis was made according to WHO criteria (OMS, 1999). RESULTS: A higher prevalence in malocclusions in asthmatic patients in mixed dentition was observed when compared to controls (p<0.05). On the other hand, these results were not observed for deciduous (p>0.05) and permanent dentition (p>0.05). A significant association was seen between asthma onset time and marked maxillary overjet (p<0.05), and open bite (p<0.05) in the mixed dentition, being both conditions more common among those that have presented the symptoms of asthma prior to 12 months of age. CONCLUSION: The results of this study indicate that the early manifestation of asthma at first year of life can cause dentofacial changes. Therefore, the prompt diagnostic of the illness, as well as the establishment of a proper therapy could improve the symptoms and chronic complications of asthma and also reduce its impact on craniofacial development.
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OBJECTIVE: This study compared the dental arch morphology of adult patients with isolated cleft palate in order to verify the influence of palatoplasty on occlusion. METHODS: Cast models of 77 patients, 30 males and 47 females, with an average age of 21 years and no syndromes were taken. They were in the permanent dentition and had not undergone orthodontic treatment. The sample was divided into non-operated and operated patients, the latter having been submitted to palatoplasty at a mean age of 2.2 years. RESULTS: Almost 80% of the sample exhibited sagittal discrepancies in the inter-arch relationship, with a Class II malocclusion prevailing (59.74%) followed by Class III (20,78%), regardless of palatoplasty. Transverse analysis showed a 23% incidence of posterior crossbite also not influenced by palatoplasty. Intra-arch relationship indicated that constriction and crowding on the upper arch were more frequent in the operated group (p=0.0238 and p=0.0002, respectively), showing an influence of palatoplasty on its morphology. The predominant morphological characteristics in patients with isolated cleft palate were a Class II malocclusion, upper dental arch constriction and upper and lower anterior crowding. CONCLUSION: The influence of palatoplasty was restricted to constriction and crowding of the upper dental arch, with no interference from the extension of the cleft, except for the upper crowding, which occurred more in patients with complete cleft palates.
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In the present study, pterosaur skull constructions were analysed using a combined approach of finite element analysis (FEA), static investigations as well as applying classical beam theory and lever mechanics. The study concentrates on the operating regime „bite“, where loads are distributed via the dentition or a keratinous rhamphotheca into the skull during jaw occlusion. As a first step, pterosaur tooth constructions were analysed. The different morphologies of the tooth construction determine specific operational ranges, in which the teeth perform best (= greatest resistance against failure). The incomplete enamel-covering of the pterosaur tooth constructions thereby leads to a reduction of strain and stress and to a greater lateral elasticity than for a complete enamel cover. This permits the development of high and lateral compressed tooth constructions. Further stress-absorption occurs in the periodontal membrane, although its mechanical properties can not be clarified unambiguously. A three-dimensionally preserved skull of Anhanguera was chosen as a case-study for the investigation of the skull constructions. CT-scans were made to get information about the internal architecture, supplemented by thin-sections of a rostrum of a second Anhanguera specimen. These showed that the rostrum can be approximated as a double-walled triangular tube with a large central vacuity and an average wall-thickness of the bony layers of about 1 mm. On base of the CT-scans, a stereolithography of the skull of Anhanguera was made on which the jaw adductor and abductor muscles were modelled, permitting to determine muscular forces. The values were used for the lever mechanics, cantilever and space frame analysis. These studies and the FEA show, that the jaw reaction forces are critical for the stability of the skull construction. The large jugal area ventral to the orbita and the inclined occipital region act as buttresses against these loads. In contrast to the orbitotemporal region which is subject to varying loading conditions, the pattern in the rostrum is less complex. Here, mainly bending in dorsal direction and torsion occur. The hollow rostrum leads to a reduction of weight of the skull and to a high bending and torsional resistance. Similar to the Anhanguera skull construction, the skulls of those pterosaur taxa were analysed, from which enough skull material is know to permit a reliable reconstruction. Furthermore, FEA were made from five selected taxa. The comparison of the biomechanical behaviour of the different skull constructions results in major transformational processes: elongation of rostra, inclination of the occipital region, variation of tooth morphology, reduction of the dentition and replacement of teeth by a keratinous hook or rhamphotheca, fusion of naris and antorbital fenestra, and the development of bony and soft-tissue crests. These processes are discussed for their biomechanical effects during bite. Certain optional operational ranges for feeding are assigned to the different skull constructions and previous hypotheses (e.g. skimming) are verified. Using the principle of economisation, these processes help to establish irreversible transformations and to define possible evolutionary pathways. The resulting constructional levels and the structural variations within these levels are interpreted in light of a greater feeding efficiency and reduction of bony mass combined with an increased stability against the various loads. The biomechanical conclusive pathways are used for comparison and verification of recent hypothesis of the phylogenetic systematics of pterosaurs.
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In the marine Jurassic deposits of Europe, a group of marine crocodilians, the Thalattosuchia, belongs to the frequently found reptiles. Thalattosuchia are widely spread in Central Europe from the Jurassic to Lower Cretaceous, and some taxa are also distributed worldwide. The task of the work was to examine all taxa known from the Liassic of Europe. The most frequently known taxa Steneosaurus bollensis and Pelagosaurus typus are anatomically revised. New discoveries at the skull of Pelagosaurus typus e.g., the fact of a partly paired frontal are described by means of computed tomography investigations. In addition, juvenile specimens of this taxon are studied in detail for the first time. The rarely occurring taxon Platysuchus multiscrobiculatus is anatomically described in detail for the first time. It shows both in the skull and in the postcranial material morphological differences to Steneosaurus bollensis and Pelagosaurus typus. Thus Pl. multiscrobiculatus possesses, e.g., an ilium with a deeper acetabulum and a femur with a distinctly flexed femoral head. A juvenile specimen of Pl. multiscrobiculatus is now discovered and is described in parts for the first time, too. Furthermore, Steneosaurus gracilirostris and Steneosaurus brevior known from Lower Jurassic deposits of England are examined and in parts revised. In this work, Steneosaurs brevior is discovered with one specimen from the Upper Liassic of Holzmaden, Germany for the first time, and provides new evidence for the palaeobiogeographical distribution of the taxon. Because of the high number of investigated specimens, it is possible to study ontogenetic development from juvenile to adult stage in Steneosaurus bollensis, Pelagosaurus typus, and Platysuchus multiscrobiculatus. Biometric data are collected from thalattosuchians and extant crocodilians (e.g. Gavialis gangeticus) to investigate intraspecific variation, ontogenetic development, and taxa differentiation. The skulls of Platysuchus multiscrobiculatus and Steneosaurus bollensis are reconstructed three-dimensionally as wax models. The skull reconstructions form the basis of the jaw muscle restoration of Steneosaurus bollensis in connection with comparative studies at extant crocodilians. By means of functional morphologic analysis of the jaw musculature, the dentition, and the locomotor system of S. bollensis, possible conclusions are drawn for the prey options and the hunting behaviour. To clarify the relationships within the Thalattosuchia, a computer-based cladistic phylogenetic in-group analyse of 25 Thalattosuchia taxa is performed. For the analysis, following Thalattosuchia taxa are studied likewise at original material for comparisons: Metriorhynchus superciliosus, Metriorhynchus hastifer, Metriorhynchus leedsi, Geosaurus gracilis, Geosaurus giganteus, Teleidosaurus calvadosi, Teleidosaurus gaudryi, Teleosaurus cadomensis, Teleosaurus geoffroyi, Steneosaurus priscus, Steneosaurus edwardsi, Steneosaurus heberti, Steneosaurus leedsi, Steneosaurus boutilieri, Steneosaurus megarhinus, Steneosaurus obtusidens, and Machimosaurus hugii. The phylogenetic in-group analyse based on 115 characters, reveals a sister-group relationship of the monophyletic Teleosauridae and monophyletic Metriorhynchidae. Within the groups, some taxa are probably paraphyletic. The taxon Pelagosaurus typus is nested inside the Teleosauridae and not outside or within the Metriorhynchidae, as many authors suggested it so far. Based on these results, a tentative palaeobiogeographical-evolutionary scenario is developed.
Vergleichende computergestützte funktionsmorphologische Analyse an Molaren cercopithecoider Primaten
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Die Analyse funktioneller Zusammenhänge zwischen Ernährung und Zahnmorphologie ist ein wichtiger Aspekt primatologischer und paläontologischer Forschung. Als überdauernder Teil des Verdauungssystems geben Zähne die bestmöglichen Hinweise auf die Ernährungsstrategien (ausgestorbener) Arten und eine Fülle weiterer Informationen. Aufgrund dessen ist es für die wissenschaftliche Arbeit von größter Bedeutung, die Zähne so detailliert und exakt wie möglich in ihrer gesamten Struktur zu erfassen. Bisher wurden zumeist zweidimensionale Parameter verwendet, um die komplexe Kronenmorphologie von Primatenmolaren vergleichend zu untersuchen. Die vorliegende Arbeit hatte das Ziel, Zähne verschiedener Arten von Altweltaffen mittels computerbasierter Methoden dreidimensional zu erfassen und neue Parameter zu definieren, mit denen die Form dieser Zähne objektiv erfasst und funktionell interpretiert werden kann. Mit einem Oberflächen-Scanner wurden die Gebisse einer Stichprobe von insgesamt 48 Primaten von fünf verschiedenen Arten eingescannt und mit Bildverarbeitungsmethoden so bearbeitet, dass dreidimensionale digitale Modelle einzelner Backenzähne zur Analyse vorlagen. Es wurden dabei sowohl Arten ausgewählt, die eine für ihre Gattung typische Ernährungsweise besitzen - also Frugivorie bei den Cercopithecinen und Folivorie bei den Colobinen - als auch solche, die eine davon abweichende Alimentation bevorzugen. Alle Altweltaffen haben sehr ähnliche Molaren. Colobinen haben jedoch höhere und spitzere Zahnhöcker, dünneren Zahnschmelz und scheinen ihre Zähne weniger stark abzukauen als die Meerkatzen. Diese Beobachtungen konnten mit Hilfe der neuen Parameter quantifiziert werden. Aus der 3D-Oberfläche und der Grundfläche der Zähne wurde ein Index gebildet, der die Stärke des Oberflächenreliefs angibt. Dieser Index hat bei Colobinen deutlich höhere Werte als bei Cercopithecinen, auch bei Zähnen, die schon stark abgekaut sind. Die Steilheit der Höcker und ihre Ausrichtung wurden außerdem gemessen. Auch diese Winkelmessungen bestätigten das Bild. Je höher der Blätteranteil an der Ernährung ist, desto höher sind die Indexwerte und umso steiler sind die Höcker. Besonders wichtig war es, dies auch für abgekaute Zähne zu bestätigen, die bisher nicht in funktionelle Analysen miteinbezogen wurden. Die Ausrichtung der Höckerseiten gibt Hinweise auf die Kaubewegung, die zum effizienten Zerkleinern der Nahrung notwendig ist. Die Ausrichtung der Höcker der Colobinen deutet darauf hin, dass diese Primaten flache, gleitende Kaubewegungen machen, bei denen die hohen Höcker aneinander vorbei scheren. Dies ist sinnvoll zum Zerschneiden von faserreicher Nahrung wie Blättern. Cercopithecinen scheinen ihre Backenzähne eher wie Mörser und Stößel zu verwenden, um Früchte und Samen zu zerquetschen und zu zermahlen. Je nachdem, was neben der hauptsächlichen Nahrung noch gekaut wird, unterscheiden sich die Arten graduell. Anders als bisher vermutet wurde, konnte gezeigt werden, dass Colobinen trotz des dünnen Zahnschmelzes ihre Zähne weniger stark abkauen und weniger Dentin freigelegt wird. Dies gibt eindeutige Hinweise auf die Unterschiede in der mechanischen Belastung, die während des Kauvorgangs auf die Zähne wirkt, und lässt sich gut mit der Ernährung der Arten in Zusammenhang bringen. Anhand dieser modellhaften Beobachtungen können in Zukunft ausgestorbene Arten hinsichtlich ihrer Ernährungsweise mit 3D-Techniken untersucht werden.