Andrea Duarte Doetzer

Analysis of Polymorphisms in the Lactotransferrin Gene Promoter and Dental Caries

Regarding host aspects, there has been strong evidence for a genetic component in the etiology of caries. The salivary protein lactotransferrin (LTF) exhibits antibacterial activity, but there is no study investigating the association of polymorphisms in the promoter region of LTF gene with caries. The objective of this study was firstly to search the promoter region of the human LTF gene for variations and, if existent, to investigate the association of the identified polymorphisms with dental caries in 12-year-old students. From 687 unrelated, 12-year-old, both sex students, 50 individuals were selected and divided into two groups of extreme phenotypes according to caries experience: 25 students without (DMFT = 0) and 25 with caries experience (DMFT ≥ 4). The selection of individuals with extreme phenotypes augments the chances to find gene variations which could be associated with such phenotypes. LTF gene-putative promoter region (+39 to −1143) of the selected 50 individuals was analyzed by high-resolution melting technique. Fifteen students, 8 without (DMFT = 0) and 7 with caries experience (mean DMFT = 6.28), presented deviations of the pattern curve suggestive of gene variations and were sequenced. However, no polymorphisms were identified in the putative promoter region of the LTF gene.

Lactotransferrin Gene Polymorphism Associated with Caries Experience

Dental caries is a common multifactorial disease, resulting from the interaction of biofilm, cariogenic diet and host response over time. Lactotransferrin (LTF) is a main salivary glycoprotein, which modulates the host immune-inflammatory and antibacterial response. Although a genetic component for caries outcome has been identified, little is known over the genetic aspects underlying its susceptibility. Thus, the aim of this study was to investigate the association between LTF polymorphisms and caries susceptibility. Six hundred seventy seven 12-year-old students were selected: 346 with (DMFT ≥ 1) and 331 without caries experience (DMFT = 0). Also, individuals concentrating higher levels of disease (polarization group, DMFT ≥ 2, n = 253) were tested against those with DMFT ≤ 1 (n = 424). Along with clinical parameters, three representative LTF tag SNPs (rs6441989, rs2073495, rs11716497) were genotyped and the results were evaluated using univariate and multivariate analyses. Allele A for tag SNP rs6441989 was found to be significantly less frequent in the polarization group, conferring a protective effect against caries experience [AA + AG × GG (OR: 0.710, 95% CI: 0.514-0.980, p = 0.045)], and remained significantly associated with caries protection in the presence of gingivitis (p = 0.020) and plaque (p = 0.035). These results might contribute to the understanding of the genetic control of caries susceptibility in humans.

FasL expression in articular discs of human temporomandibular joint and association with osteoarthrosis

BACKGROUND Apoptosis is a programme of cell death which does not induce an inflammatory response. Recent previous research has suggested a correlation between temporomandibular internal derangement and apoptosis. Fas ligand (FasL) is an apoptosis-inducing factor, known to trigger apoptosis through distinct signal pathways. This study aims to examine, by immunohistochemistry, the expression of FasL in temporomandibular joint (TMJ) articular discs of patients with anterior disc displacement with reduction (ADDwR) and without reduction (ADDwoR) in patients with and without osteoarthrosis (OA). METHODS Forty-two (n = 42) TMJ articular discs were divided into two cut-offs: (i) 8 control, 17 ADDwR, 17 ADDwoR, and (ii) without OA (n = 25) and with OA (n = 17). The area of immunostaining was compared statistically between groups (P < 0.05). RESULTS Statistically significant differences were found in the expression of FasL in TMJ discs between the three groups (P = 0.001). ADDwR presented significant higher FasL expression when compared with ADDwoR (P < 0.001). Significant higher FasL expression was observed in the group without OA (P = 0.001). All patients without OA presented ADDwR, while all the patients with OA presented ADDwoR. CONCLUSION A higher area of in situ immunostaining of FasL was found in temporomandibular discs with reduction, which is the less severe condition. Moreover, a reduced expression of FasL in the discs of patients with osteoarthrosis was found, suggesting that some aspects of apoptosis might underlie the progression of TMJ disorders.

Lactotransferrin Gene (LTF) Polymorphisms and Dental Implant Loss: A Case‐Control Association Study

BACKGROUND Dental implants have been widely used to replace missing teeth, accomplishing aesthetics and function. Due to its large use worldwide, the small percentage of implant loss becomes significant in number of cases. Lactotransferrin (LTF) is a pleiotropic protein, expressed in various body tissues and fluids, which modulates the host immune-inflammatory response and bone metabolism, and might be involved in dental implant osseointegration. Recently, a few studies have been investigating genetic aspects underlying dental implant failure. PURPOSE This case-control study aimed to investigate the association of genetic markers (tag SNPs) in LTF gene and clinical parameters with dental implant loss. MATERIAL AND METHODS 278 patients, both sexes, mean age 51 years old, divided into 184 without and 94 with implant loss, were genotyped for sixteen tag SNPs, representative of the whole LTF gene. Also, clinical oral and systemic parameters were analyzed. Univariate and Multivariate Logistic Regression model were used to analyze the results (p < .05). RESULTS No association was found between the tag SNPs and implant loss in the study population. Clinical association was found with medical treatment, hormonal reposition, edentulism, number of placed implants, plaque, calculus, and mobility. CONCLUSION Clinical variables, but not LTF gene polymorphisms, were associated with implant loss.

What can be done when asymptomatic patients discover they have Brugada syndrome? A case report of Brugada syndrome

Brugada syndrome is an inherited cardiac disorder associated with a specific electrocardiographic pattern, involving ST segment elevation in leads V1 to V3. When not spontaneously terminated, it can lead to ventricular fibrillation and sudden death. We present a case report of a young male whose brother suffered a sudden cardiac arrest while playing soccer. A novel mutation c.2678G>A was detected on the gene SCN5A through molecular diagnosis. The mutation was shown to be present in the individual, his daughter and his other brother. For patients with previous ventricular fibrillation and/or syncope, implantable cardiac device (ICD) is recommended. However, how can patients without symptoms but with a clear diagnosis prevent cardiac arrest?

Operative management of idiophatic myositis ossificans of lateral pterygoid muscle

INTRODUCTION Myositis ossificans (MO) is characterized as heterotopic bone formation within muscle. MO rarely occurs in the head and neck region. Excision of the heterotopic bone is the standard treatment. This report summarizes a case of a 12-year old female with MO involving the lateral pterygoid muscle. The heterotopic bone was excised using an intraoral incision. Despite intensive physical therapy, the operation failed as evidenced by new bone formation in the area within three weeks of the operation. PRESENTATION OF CASE A twelve years old female patient presenting with mouth opening of 10 mm, no facial asymmetry, and no jaw joint pain or other symptoms. Computer tomography (CT) exam was requested and revealed calcification of the left lateral pterygoid muscle. No other masticatory or head muscles showed any signs of calcification. The calcified muscle was completely removed beyond the ossified segment and a 35 mm mouth opening was achieved immediately after the procedure. One month after total bone structure removal (first surgery) the patient could not open her mouth anymore due to a significant calcified mass. DISCUSSION The surgical technique used in this case avoided invasive gap arthroplasty to access lateral pterygoid muscle and anaesthetic scarring formation, by using an intraorally incision accessing the muscle directly. The authors of these study did not see any relation with the condylar dislocation that the patient had five years prior to the pathology, and they could not find any real cause for the myositis ossificans of lateral pterygoid muscle. CONCLUSION The outcome of the surgical procedure was not successful, perhaps due to the expression of the disease, indicating the need to further physiologic and genetic studies to elucidate the aetiology of MO as well as to provide directions to an adequate treatment choice for such cases.

Expression of MMP-13 in Human Temporomandibular Joint Disc Derangement and Osteoarthritis

Abstract Objective: MMP-13 performs digestion of collagen, which is a primary component of the temporomandibular joint (TMJ) articular disc. This study evaluated the expression of MMP-13 in patients with anterior disc displacement with (ADDwR) and without reduction (ADDwoR), and in the presence of TMJ osteoarthrosis. Methods: Thirty-nine human temporomandibular joint disc samples were collected and divided in two ways: ADDwR (21 samples), ADDwoR (10 samples), and a control group (8 samples); and with osteoarthrosis (10 samples) and without osteoarthrosis (29 samples). Immunostaining of the TMJ discs was statistically compared between the groups. Results: There was no statistically significant difference for the area of MMP-13 immunostaining between the control group, ADDwR, and ADDwoR, nor between groups with and without osteoarthrosis. Conclusion: This study suggests MMP-13 is not significantly involved in collagen degradation in human TMJ disc displacement or osteoarthrosis.

Immunohistochemical expression of TLR-4 in temporomandibular joint dysfunction

Abstract Objective Toll-like receptor 4 (TLR-4) is a transmembrane protein involved in the innate immune system and has been implicated in the pathogenesis of temporomandibular joint dysfunction (TMD). The purpose of this study was to histologically examine the level of expression of TLR-4 relative to severity of TMD. Methods Thirty-one human TMJ disc samples were immunostained for TLR-4 and evaluated for intensity of stain. Among the samples, 8 were control samples, 16 were from patients with anterior disc displacement with reduction (ADDwR), and 7 were from patients with anterior disc displacement without reduction (ADDwoR). Results There was no statistically significant difference in intensity of stain between groupings (p = 0.673). Conclusions The results indicate a negative correlation between TMD and the expression of TLR-4.

Clinical aspects and polymorphisms in the LTA, TNFA, LTB genes and association with dental implant loss

BACKGROUND This study shows the relationship between host factors and environmental factors in the influence of susceptibility to loss of dental implants. PURPOSE The aim of this study was to investigate the association of clinical aspects and tag SNPs of the genes LTA, TNFA, and LTB with dental implant loss. MATERIALS AND METHODS The subjects consisted of 244 patients, divided into two groups: control group (C)-163 individuals who did not lose any implants, being in function for at least 6 months; and study group (S)-81 individuals who had lost at least one implant. DNA was collected from saliva, and the genotypes were determined by real time PCR. Univariate and multivariate analysis were employed p < .05. RESULTS After multivariate analysis, dental implant loss remained associated with the presence of teeth (p = .011), a larger amount of placed implants (p = .001), and allelle C of rs2009658 of the LTA gene (p = .006). For the other tag SNPs of these studied genes, there was no association between the groups C and S with dental implants loss. CONCLUSION Presence of teeth, number of placed implants and allele C of rs2009658 of LTA gene were associated with implant loss.

Erupted Complex Odontoma Mimicking a Mandibular Second Molar

Odontoma was first described as a distinguished lesion by Broca in 1866. It is considered a hamartoma or a benign tumor containing enamel, dentin, pulp and cementum, and account for 22% of all comprising odontogenic tumors [1]. According to the classification of the World Health Organization (WHO, 2005), there are two types of odontoma: compound odontoma and complex odontoma (CO), the first being twice as common as the latter. Compound odontoma resembles a tooth (or multiple tooth-like mass composing the lesion), as the complex odontoma contains tooth tissues in a disorganized manner.