Development of a device to simulate tooth mobility

Objectives: The testing of new materials under simulation of oral conditions is essential in medicine. For simulation of fracture strength different simulation devices are used for test set-up. The results of these in vitro tests differ because there is no standardization of tooth mobility in simulation devices. The aim of this study is to develop a simulation device that depicts the tooth mobility curve as accurately as possible and creates reproducible and scalable mobility curves. Materials and methods: With the aid of published literature and with the help of dentists, average forms of tooth classes were generated. Based on these tooth data, different abutment tooth shapes and different simulation devices were designed with a CAD system and were generated with a Rapid Prototyping system. Then, for all simulation devices the displacement curves were created with a universal testing machine and compared with the tooth mobility curve. With this new information, an improved adapted simulation device was constructed. Results: A simulations device that is able to simulate the mobility curve of natural teeth with high accuracy and where mobility is reproducible and scalable was developed

Unilateral cross bite treated by corticotomy-assisted expansion: two case reports

<p>Abstract</p> <p>Background</p> <p>True unilateral posterior crossbite in adults is a challenging malocclusion to treat. Conventional expansion methods are expected to have some shortcomings. The aim of this paper is to introduce a new technique for treating unilateral posterior crossbite in adults, namely, corticotomy-assisted expansion (CAE) applied on two adult patients: one with a true unilateral crossbite and the other with an asymmetrical bilateral crossbite, both treated via modified corticotomy techniques and fixed orthodontic appliances.</p> <p>Methods</p> <p>Two cases with asymmetric maxillary constriction were treated using CAE.</p> <p>Results</p> <p>In both cases, effective asymmetrical expansion was achieved using CAE, and functional occlusion was established as well.</p> <p>Conclusions</p> <p>Unilateral CAE presents an effective and reliable technique to treat true unilateral crossbite.</p

Familial aggregation of maxillary lateral incisor agenesis

In spite of recent developments, data regarding the genes responsible for the less severe forms of hypodontia are still scarce and controversial. This study addressed the hypothesis that agenesis of maxillary lateral incisors (MLIA) is a distinct type of hypodontia, by evaluating its familial aggregation and the occurrence of other types of ageneses or microdontia in probands' relatives. Sixty-two probands with MLIA were identified, and information was collected on 142 first-degree relatives. Relative risk (RR) was calculated and compared by re-assessment of data previously published for the Swedish, Utah, and Israeli populations, for the same trait. A RR of 15 was obtained in the Portuguese, 16 in the Swedish, 12 in Utah, and 5 in the Israeli population. Our results support a significant familial aggregation of MLIA, show that MLIA almost never segregates with other forms of agenesis, and suggest that microdontia of maxillary lateral incisors is part of the same phenotype.The individuals who took part in this study are acknowledged. Carolina Lemos was the recipient of a PhD scholarship (FCT - SFRH/BD/17761/2004) and Teresa Pinho of a PhD scholarship from Instituto Superior de Ciencias da Saude Norte/CESPU. The other authors received no funding from any institution, department, or sponsor, other than salaries from the institutions with which they are affiliated

Regional Nerve Block of the Temporomandibular Joint Capsule: A Technique for Clinical Research and Differential Diagnosis

In previous studies in which regional anesthesia of the temporomandibular joint capsule was used to examine the role of the joint in mandibular movement and distinguish it from muscle control, the anesthetic techniques used have not been satisfactorily described. The accuracy of the injeetion technique described in this paper was determined by dissection and radiographic examination of fixed and fresh specimens. Using this technique, trial patient studies were made using an anesthetic solution to which a radiopaque medium was added. Radiographic examination of the patients affirmed the location of the injected material, while clinical assessment determined its functional effectiveness. Using the described technique, anesthetic solution was accurately and reproducibly introduced posteriorly and laterally to the temporomandibular joint to achieve anesthesia of the joint.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67376/2/10.1177_00220345800590110101.pd

Signs and symptoms of temporomandibular disorders and oral parafunctions in urban Saudi arabian adolescents: a research report

BACKGROUND: The aim of this study was to evaluate the prevalence of signs and symptoms of temporomandibular disorders (TMD) and oral parafunction habits among Saudi adolescents in the permanent dentition stage. METHODS: A total of 385 (230 females and 155 males) school children age 12–16, completed a questionnaire and were examined clinically. A stratified selection technique was used for schools allocation. RESULTS: The results showed that 21.3% of the subjects exhibited at least one sign of TMD and females were generally more affected than males. Joint sounds were the most prevalent sign (13.5%) followed by restricted opening (4.7%) and opening deviation (3.9%). The amplitude of mouth opening, overbite taken into consideration, was 46.5 mm and 50.2 mm in females and males respectively. TMJ pain and muscle tenderness were rare (0.5%). Reported symptoms were 33%, headache being the most frequent symptom 22%, followed by pain during chewing 14% and hearing TMJ noises 8.7%. Difficulty during jaw opening and jaw locking were rare. Lip/cheek biting was the most common parafunction habit (41%) with females significantly more than males, followed by nail biting (29%). Bruxism and thumb sucking were only 7.4% and 7.8% respectively. CONCLUSION: The prevalence of TMD signs were 21.3% with joint sounds being the most prevalent sign. While TMD symptoms were found to be 33% as, with headache being the most prevalent. Among the oral parafunctions, lip/cheek biting was the most prevalent 41% followed by nail biting 29%

Difference in expression between AQP1 and AQP5 in porcine endometrium and myometrium in response to steroid hormones, oxytocin, arachidonic acid, forskolin and cAMP during the mid-luteal phase of the estrous cycle and luteolysis

BACKGROUND: Recently, we demonstrated in vitro that AQP1 and AQP5 in the porcine uterus are regulated by steroid hormones (P4, E2), arachidonic acid (AA), forskolin (FSK) and cAMP during the estrous cycle. However, the potential of the porcine separated uterine tissues, the endometrium and myometrium, to express these AQPs remains unknown. Thus, in this study, the responses of AQP1 and AQP5 to P4, E2 oxytocin (OT), AA, FSK and cAMP in the porcine endometrium and myometrium were examined during the mid-luteal phase of the estrous cycle and luteolysis.METHODS: Real-time PCR and western blot analysis.RESULTS: Progesterone up-regulated the expression of AQP1/AQP5 mRNAs and proteins in the endometrium and myometrium, especially during luteolysis. Similarly, E2 also stimulated the expression of both AQPs, but only in the endometrium. AA led to the upregulation of AQP1/AQP5 in the endometrium during luteolysis. In turn, OT increased the expression of AQP1/AQP5 mRNAs and proteins in the myometrium during mid-luteal phase. Moreover, a stimulatory effect of forskolin and cAMP on the expression of AQP1/AQP5 mRNAs and proteins in the endometrium and myometrium dominated during luteolysis, but during the mid-luteal phase their influence on the expression of these AQPs was differentiated depending on the type of tissue and the incubation duration.CONCLUSIONS: These results seem to indicate that uterine tissues; endometrium and myometrium, exhibit their own AQP expression profiles in response to examined factors. Moreover, the responses of AQP1/AQP5 at mRNA and protein levels to the studied factors in the endometrium and myometrium are more pronounced during luteolysis. This suggests that the above effects of the studied factors are connected with morphological and physiological changes taking place in the pig uterus during the estrous cycle.</p

Developmental disturbances associated with agenesis of the permanent maxillary lateral incisor

The aim of this study was to characterise the intra and extra-oral phenotype associated with agenesis of the permanent maxillary lateral incisor. We compared three groups: (1) subjects with agenesis of one or both permanent maxillary lateral incisors (n=80); (2) first and second degree relatives of group 1 with no agenesis of the permanent maxillary lateral incisor and (3) subjects with no agenesis of the maxillary lateral incisor or family history of it (n=49). For each of the 201 subjects detailed clinical information was reviewed and panoramic radiographs were analysed. Considering only the sample with unilateral agenesis, microdontia of the contralateral permanent maxillary lateral incisor was significantly more frequent in group 1 (82.4%) than in group 2 (25%) and the control group (2%). This supports the theory that microdontia is a variable expression of the same developmental disturbance that causes tooth agenesis. The absence of third molars occurred more often in group 1 (36.2%) than in groups 2 and 3 (18.6% and 18.9% respectively), confirming that agenesis of third molars was markedly associated with the agenesis of the permanent maxillary lateral incisor. Agenesis of teeth other than third molars was not significantly different among subjects with agenesis of the permanent maxillary lateral incisor and their relatives. The frequencies of supernumerary teeth, permanent maxillary canine impaction, general health condition and minor anomalies were not significantly different between the three groups

What is the value of orthodontic treatment?

Orthodontic treatment is as popular as ever. Orthodontists frequently have long lists of people wanting treatment and the cost to the NHS in England was £258m in 2010-2011 (approximately 10% of the NHS annual spend on dentistry). It is important that clinicians and healthcare commissioners constantly question the contribution of interventions towards improving the health of the population. In this article, the authors outline some of the evidence for and against the claims that people with a malocclusion are at a disadvantage compared with those without a malocclusion and that orthodontic treatment has significant health benefits. The authors would like to point out that this is not a comprehensive and systematic review of the entire scientific literature. Rather the evidence is presented in order to stimulate discussion and debate

Evaluation of crown-root angulation of lateral incisors adjacent to palatally impacted canines

BACKGROUND: The objective of this study is to explore differences in crown-to-root angulation between lateral incisors adjacent to palatally impacted canines (PICs) and lateral incisors adjacent to normally erupted canines (NECs). METHODS: Orthodontic records of 100 subjects (51 with PICs and 49 with NECs) were reviewed. Crown-to-root angulations of all lateral incisors were measured manually on the final panoramic radiographs. Also, three experienced orthodontists were asked to visually inspect the morphology of the lateral incisors on the panoramic radiographs. A mixed model was used to test the difference in crown-to-root angulation of the lateral incisor between the experimental and the control groups. The association between the examiners' observations and the presence of a canine impaction was assessed by means of a chi-square test. All analyses were performed at the 0.05 level of statistical significance. RESULTS: A significant (p = 0.009) difference of 2.3° in crown-to-root angulation was found between groups. Also, 66.7% of the lateral incisors that were identified as “abnormal” by the panel of orthodontists were adjacent to a PIC. A percentage of 65.2 of lateral incisors that were identified as “normal” were located adjacent to NECs. CONCLUSIONS: The root of lateral incisors adjacent to PICs is angulated more mesially compared to lateral incisors adjacent to NECs. In addition, clinicians are somewhat able to predict if a canine is palatally impacted by visually observing the crown-to-root angulation of the adjacent lateral incisor. Evaluating the crown-to-root angulation of a lateral incisor on a panoramic image might facilitate an early diagnosis of palatally impacted canines