Bracket base remnants after orthodontic debonding

Objective:To evaluate whether the debonding procedure leads to restitutio ad integrum of the enamel surface by investigating the presence of enamel within the bracket base remnants after debonding.Materials and Methods:Sixty patients who completed orthodontic treatment with fixed appliances were included. A total of 1068 brackets were microphotographed; the brackets presenting some remnants on the base (n  =  818) were selected and analyzed with ImageJ software to measure the remnant area. From this population a statistically significant sample (n  =  100) was observed under a scanning electron microscope to check for the presence of enamel within the remnants. Energy dispersive x-ray spectrometry was also performed to obtain quantitative data.Results:Statistically significant differences in the remnant percentage between arches were observed for incisor and canine brackets (P < .0001 and P  =  .022, respectively). From a morphologic analysis of the scanning electron micrographs the bracket bases were categorized in 3 groups: group A, bases presenting a thin enamel coat (83%); group B, bases showing sizable enamel fragments (7%); group C, bases with no morphologic evidence of enamel presence (10%). Calcium presence was noted on all evaluated brackets under energy dispersive x-ray spectrometry. No significant difference was observed in the Ca/Si ratio between group A (16.21%) and group B (18.77%), whereas the Ca/Si ratio in group C (5.40%) was significantly lower than that of the other groups (P < .323 and P  =  .0001, respectively).Conclusion:The objective of an atraumatic debonding is not achieved yet; in some cases the damage could be clinically relevant.     

Snake bites by the jararacucu (Bothrops jararacussu): clinicopathological studies of 29 proven cases in Sao Paulo State, Brazil

The jararacucu, one of the most dreaded snakes of Brazil, southern Bolivia, Paraguay and northeastern Argentina, is a heavily-built pit viper which may grow to a length of 2.2 m. Up to 1000 mg (dry weight) of highly-lethal venom may be milked from its venom glands on a single occasion. It has accounted for 0.8% to 10% of series of snake bites in Sao Paulo State, Brazil. We examined 29 cases of proven jararacucu bites recruited over a 20-year period in two Sao Paulo hospitals. Severe signs of local and systemic envenoming, (local necrosis, shock, spontaneous systemic bleeding, renal failure) were seen only in patients bitten by snakes longer than 50 cm; bites by shorter specimens were more likely to cause incoagulable blood. Fourteen patients developed coagulopathy, six local necrosis (requiring amputation in one) and five local abscesses. Two became shocked and four developed renal failure. Three patients, aged 3, 11 and 65 years, died 18.75, 27.75 and 83 h after being bitten, with respiratory and circulatory failure despite large doses of specific antivenom and intensive-care- unit management. In two patients, autopsies revealed acute renal tubular necrosis, cerebral oedema, haemorrhagic rhabdomyolysis at the site of the bite and disseminated intravascular coagulation. In one survivor with chronic renal failure, renal biopsy showed bilateral cortical necrosis; the patient remains dependent on haemodialysis. Effects of polyspecific Bothrops antivenom were not impressive, and it has been suggested that anti-Bothrops and anti-Crotalus antivenoms should be given in combination.      

Orthodontics is temporomandibular disorder–neutral

Objectives:To assess if subjects with a clinical diagnosis of temporomandibular disorders (TMDs) have a similar prevalence of orthodontic history as a population of TMD-free individuals and to assess if those subjects who have a history of ideal orthodontics have fewer symptoms than those with a history of nonideal orthodontics.Materials and Methods:Two groups of age- and sex-matched individuals belonging to either a study (“TMD”) or a control group were recruited. Subjects who underwent orthodontic treatment were classified as having a history of ideal or nonideal orthodontics based on the current presence of normal values in five reference occlusal features.Results:The correlation with a history of orthodontic treatment was not clinically significant for any of the TMD diagnoses (ie, muscle pain, joint pain, disc displacement, arthrosis), with Phi (Φ) coefficient values within the −0.120 to 0.058 range. Within the subset of patients with a history of orthodontics, the correlation of ideal or nonideal orthodontic treatment with TMD diagnoses was, in general, not clinically relevant or was weakly relevant.Conclusions:Findings confirmed the substantial absence of clinically significant effects of orthodontics as far as TMD is concerned. The very low correlation values of a negative or positive history of ideal or nonideal orthodontics with the different TMD diagnoses suggest that orthodontic treatment could not have a true role for TMD.     

The role of the dentist and orthodontist in recognizing oro-facial manifestations of acromegaly: a questionnaire-based study

Pituitary - Oro-facial manifestations of acromegaly are among the earliest signs of the disease and are reported by a significant number of patients at diagnosis. Despite this high prevalence of...     

Thrombin-induced increase in surface expression of epitopes on platelet membrane glycoprotein IIb/IIIa complex and GMP-140 is a function of platelet age

Platelets are heterogeneous in the content of membrane glycoprotein (GP)IIb/IIIa complex. To determine whether this heterogeneity is related to changes associated with platelet aging in the circulation, newly released platelets, obtained during recovery from nonimmune- mediated acute experimental thrombocytopenia in baboons, were studied. Monoclonal antibody (MoAb) binding to epitopes expressed on GPIIb/IIIa complex (LJ-CP8), GMP-140 (S12), and GPIa/IIa (12F1) was measured on control platelets (comprising platelets with a normal age distribution; mean age 60 to 72 hours) and newly formed platelets (mean age 12 hours), both in the resting state and after thrombin stimulation. Whereas LJ-CP8 binding to resting control platelets increased by 34% upon stimulation by gamma-thrombin from 30,885 +/- 1,171 to 41,458 +/- 1,311 molecules/platelet at saturating concentrations of antibody, LJ- CP8 binding to resting young platelets did not increase significantly upon thrombin stimulation (31,878 +/- 3,330 and 33,791 +/- 3,486 molecules/platelet, respectively). Similarly, binding of antibody S12 in response to maximal thrombin stimulation was reduced by 42% from 10,246 +/- 834 molecules/platelet at saturating concentrations of S12 for control platelets to 5,971 +/- 665 molecules/platelet for young platelets (P = .001). S12 binding to unstimulated platelets was less than 10% of the binding observed after thrombin stimulation at all concentrations of S12 for both control and young platelets. However, maximal binding of antibody 12F1 to resting control platelets did not differ significantly from that observed with resting young platelets (2,926 +/- 167 and 2,857 +/- 208 molecules/platelet, respectively), and 12F1 binding was unchanged after thrombin stimulation for both control and young platelets. We conclude that the thrombin-induced increase in the expression of epitopes on platelet membrane GPIIb/IIIa complex and GMP-140 is a function of platelet age.     

Quantitative evaluation with CBCT of palatal bone thickness in growing patients

The purpose of this study was to evaluate the most suitable region of the palate for the insertion of miniscrews. We analysed 4 different paracoronal sections of Digital Volumetric Tomographies of 52 patients with ages ranging between 10 and 15 years and measured the thickness of the palatine bone in 20 different sites. For each section we measured the height of the palatal bone at 0, 3 and 6 mm increments laterally from the midline. The results indicate that the thickest part of the palate is found 6 mm to the left and right of the suture in the anterior part of the palate, 4 mm from the incisal foramen. In the other paracoronal sections, the thicknesses tend to decrease progressively, but the highest values are always found corresponding to suture. Therefore, we can conclude that the thickest part of the palate is the anterior region. Although the bone is thinner in the posterior region of the palate, it is also suitable for the insertion of miniscrew.     

Trattamento di un caso con discrepanza dell’indice di Bolton

Objectives

To show the treatment of Bolton Index discrepancies by the Invisalign System.

Case Report

A 20 year-old female patient came to our attention complaining of poor aesthetics and spacing among her upper teeth. The patient asked for an Invisalign treatment for the upper arch only. A request more and more frequent in our clinical practice due to the excellent comfort and aesthetics of these devices.

Discussion and Conclusion

At the end of the treatment, a good alignment of both upper and lower teeth was obtained together with the elimination of the spacing among upper teeth. The Invisalign system also proved to be particularly suitable for this type of problem from a clinical and a biomechanical point of view.     

Imaging speech production using fMRI

Human speech is a well-learned, sensorimotor, and ecological behavior ideal for the study of neural processes and brain-behavior relations. With the advent of modern neuroimaging techniques such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), the potential for investigating neural mechanisms of speech motor control, speech motor disorders, and speech motor development has increased. However, a practical issue has limited the application of fMRI to issues in spoken language production and other related behaviors (singing, swallowing). Producing these behaviors during volume acquisition introduces motion-induced signal changes that confound the activation signals of interest. A number of approaches, ranging from signal processing to using silent or covert speech, have attempted to remove or prevent the effects of motion-induced artefact. However, these approaches are flawed for a variety of reasons. An alternative approach, that has only recently been applied to study single-word production, uses pauses in volume acquisition during the production of natural speech motion. Here we present some representative data illustrating the problems associated with motion artefacts and some qualitative results acquired from subjects producing short sentences and orofacial nonspeech movements in the scanner. Using pauses or silent intervals in volume acquisition and block designs, results from individual subjects result in robust activation without motion-induced signal artefact. This approach is an efficient method for studying the neural basis of spoken language production and the effects of speech and language disorders using fMRI.