Evaluation of Different Preosteotomy Determinants as Affecting the Success of Implant Therapy: A "CBCT"-based Clinical Study.

AIM: The success of implant therapy is of greatest concern for clinicians because a minor negligence can lead to ultimate failure of treatment. However, comprehensive and precise treatment planning can ensure high success rate of implant therapy. Cone-beam computed tomography (CBCT) is an innovation that allows clinicians to explore all related factors in details. This study was conducted to evaluate different preosteotomy determinants as affecting the success of implant therapy in the maxillary anterior region using CBCT. MATERIALS AND METHODS: This study was conducted on 98 partially or complete denture patients willing for artificial replacement of their missing teeth by implant or implant over-denture. Demographic details of participating patients were collected. Furthermore, comprehensive local examination was also done to finalize the site of placement of implant. Cone-beam computed tomography was attempted in all patients for determining accurate implant location, status of bone, and other interrelated determinants of implant success. Cone-beam computed tomography was also prescribed for patients so as to have presurgical idea of implant dimensions as shown in virtual placement of implant. To rule out any interobserver bias, the interpretations of CBCT images were completed by two independent experienced observers. RESULTS: In the 98 studied patients, 61 were males and 37 were females. The study was restricted to the maxillary anterior region only. The studied preosteotomy determinants were available bone height and width in the edentulous region from ridge crest up to the maxillary sinus floor or the nasal fossa floor. A total of 107 implants were placed virtually (on CBCT) in the maxillary anterior region and compared quantitatively in postosteotomy phases. Implant placement sites were the maxillary central incisor region (39), the lateral incisor region (31), and canine (37). Authors also noticed that the relative length and width of virtual implant remained unaffected in 97% of the cases. CONCLUSION: Cone-beam computed tomography showed accurate status of various presurgical determinants like trabeculae, peri-ridiculer pathology, and amount of horizontal and vertical bone losses. Hence, it was further concluded that all these presurgical determinants greatly affect the final success rate of implant therapy. It is therefore deemed necessary to judiciously consider and clinically manage such factors before attempting implant in the maxillary anterior region. CLINICAL SIGNIFICANCE: Presurgical evaluation of factors associated with implant dimensions significantly assists clinicians in deciding the finest treatment option. All additional information provided by CBCT genuinely led to a change in the treatment plan that provides enhanced clinical outcome with lesser postoperative complications. How to cite this article: Jain S, Kapoor K, Sethi K, et al. Evaluation of Different Preosteotomy Determinants as Affecting the Success of Implant Therapy: A "CBCT"-based Clinical Study. J Contemp Dent Pract 2019;20(10):1212-1216.

Pediatric Ventriculoperitoneal Shunts and their Complications: An Analysis.

INTRODUCTION: Ventriculoperitoneal (VP) shunt is the most commonly utilized shunting procedure because of the capacity of the peritoneum to resorb fluid. Initial and subsequent peritoneal catheter placements can be done with relative ease. They are associated with a variety of complications. MATERIALS AND METHODS: The total number of patients operated in the study period was 96. We studied 41 operated patients of VP shunt who had various shunt-related complications and analyzed the predisposing risk factors and spectrum of complications. RESULTS: The mean age was 28 ± 32 months out of which 28 were males and 13 females. The etiology of hydrocephalus was aqueductal stenosis in 18, Arnold Chiari malformation in 10, Dandy-Walker malformation in 2, postmeningitis in 8 (pyogenic in 5 and tubercular in 3), postintraventricular hemorrhage in 2 patients and postencephalocele surgery in 1. CONCLUSION: With this retrospective review of complications of VP shunts, age at initial shunt insertion and the interval between the age of initial shunt placement and onset of complications were the most important patient-related predictors of shunt failure. The different predominant etiological factors responsible for early and late shunt failure were infective and mechanical complications, respectively.

Molecular dissection of a Borrelia burgdorferi in vivo essential purine transport system.

The Lyme disease spirochete Borrelia burgdorferi is dependent on purine salvage from the host environment for survival. The genes bbb22 and bbb23 encode purine permeases that are essential for B. burgdorferi mouse infectivity. We now demonstrate the unique contributions of each of these genes to purine transport and murine infection. The affinities of spirochetes carrying bbb22 alone for hypoxanthine and adenine were similar to those of spirochetes carrying both genes. Spirochetes carrying bbb22 alone were able to achieve wild-type levels of adenine saturation but not hypoxanthine saturation, suggesting that maximal hypoxanthine uptake requires the presence of bbb23. Moreover, the purine transport activity conferred by bbb22 was dependent on an additional distal transcriptional start site located within the bbb23 open reading frame. The initial rates of uptake of hypoxanthine and adenine by spirochetes carrying bbb23 alone were below the level of detection. However, these spirochetes demonstrated a measurable increase in hypoxanthine uptake over a 30-min time course. Our findings indicate that bbb22-dependent adenine transport is essential for B. burgdorferi survival in mice. The bbb23 gene was dispensable for B. burgdorferi mouse infectivity, yet its presence was required along with that of bbb22 for B. burgdorferi to achieve maximal spirochete loads in infected mouse tissues. These data demonstrate that both genes, bbb22 and bbb23, are critical for B. burgdorferi to achieve wild-type infection of mice and that the differences in the capabilities of the two transporters may reflect distinct purine salvage needs that the spirochete encounters throughout its natural infectious cycle.

Correction: In Vivo Expression Technology Identifies a Novel Virulence Factor Critical for Borrelia burgdorferi Persistence in Mice.

Analysis of the transcriptome of Borrelia burgdorferi, the causative agent of Lyme disease, during infection has proven difficult due to the low spirochete loads in the mammalian tissues. To overcome this challenge, we have developed an In Vivo Expression Technology (IVET) system for identification of B. burgdorferi genes expressed during an active murine infection. Spirochetes lacking linear plasmid (lp) 25 are non-infectious yet highly transformable.Mouse infection can be restored to these spirochetes by expression of the essential lp25-encoded pnc A gene alone. Therefore, this IVET-based approach selects for in vivo-expressed promoters that drive expression of pncA resulting in the recovery of infectious spirochetes lacking lp25 following a three week infection in mice.Screening of approximately 15,000 clones in mice identified 289 unique in vivo-expressed DNA fragments from across all 22 replicons of the B. burgdorferi B31 genome. The in vivo-expressed candidate genes putatively encode proteins in various functional categories including antigenicity, metabolism, motility, nutrient transport and unknown functions. Candidate gene bbk46 on essential virulence plasmid lp36 was found to be highly induced in vivo and to be RpoS-independent. The bbk46 gene was dispensable for B. burgdorferi infection in mice. Our findings highlight the power of the IVET-based approach for identification of B. burgdorferi in vivo-expressed genes, which might not be discovered using other genome-wide gene expression methods. Further investigation of the novel in vivo-expressed candidate genes will contribute to advancing the understanding of molecular mechanisms of B.burgdorferi survival and pathogenicity in the mammalian host.

In vivo expression technology identifies a novel virulence factor critical for Borrelia burgdorferi persistence in mice.

Analysis of the transcriptome of Borrelia burgdorferi, the causative agent of Lyme disease, during infection has proven difficult due to the low spirochete loads in the mammalian tissues. To overcome this challenge, we have developed an In Vivo Expression Technology (IVET) system for identification of B. burgdorferi genes expressed during an active murine infection. Spirochetes lacking linear plasmid (lp) 25 are non-infectious yet highly transformable. Mouse infection can be restored to these spirochetes by expression of the essential lp25-encoded pncA gene alone. Therefore, this IVET-based approach selects for in vivo-expressed promoters that drive expression of pncA resulting in the recovery of infectious spirochetes lacking lp25 following a three week infection in mice. Screening of approximately 15,000 clones in mice identified 289 unique in vivo-expressed DNA fragments from across all 22 replicons of the B. burgdorferi B31 genome. The in vivo-expressed candidate genes putatively encode proteins in various functional categories including antigenicity, metabolism, motility, nutrient transport and unknown functions. Candidate gene bbk46 on essential virulence plasmid lp36 was found to be highly induced in vivo and to be RpoS-independent. Immunocompetent mice inoculated with spirochetes lacking bbk46 seroconverted but no spirochetes were recovered from mouse tissues three weeks post inoculation. However, the bbk46 gene was not required for B. burgdorferi infection of immunodeficient mice. Therefore, through an initial IVET screen in B. burgdorferi we have identified a novel in vivo-induced virulence factor critical for the ability of the spirochete to evade the humoral immune response and persistently infect mice.

Buccal metastasis in a case of carcinoma breast: A rare case report with review of literature.

INTRODUCTION: Metastatic lesions to oral cavity from distant tumours account for 1% of all oral cavity malignancies. Oral cavity is a rare site of metastasis from the breast. We describe case report of breast cancer patient with metastasis to buccal mucosa. PRESENTATION OF CASE: We report a case of pre-menopausal woman with left side infiltrating ductal carcinoma breast - T4aN1M0. She received three cycles of neo-adjuvant chemotherapy followed by modified radical mastectomy (MRM) and three cycles of adjuvant chemotherapy and loco-regional EBRT. She presented with a lump in region of MRM scar and a painful swelling in the right cheek, one year afterwards. Core needle biopsy from scar site revealed infiltrating ductal carcinoma. CECT revealed a heterogeneous lesion (1.1cm×1.7cm) in right masticator space, which on biopsy revealed metastatic deposit consistent with infiltrating ductal carcinoma. DISCUSSION: Metastatic lesions to oral cavity from distant tumours are uncommon. They mainly involve bony structures. Primary metastases to soft tissues are rare and accounts for 0.1% of oral malignancies. In our case, patient presented with scar recurrence and distant metastasis at an unusual site. Had it not been for scar recurrence, patient might not have presented to the OPD with oral swelling. A high degree of clinical suspicion and previous history of breast cancer led to detection of metastatic deposit. CONCLUSION: Diagnosis of a metastatic lesion in buccal mucosa is challenging and requires a high degree of clinical suspicion.

Enhanced detection of host response antibodies to Borrelia burgdorferi using immuno-PCR.

Lyme disease is the fastest-growing zoonotic disease in North America. Current methods for detection of Borrelia burgdorferi infection are challenged by analysis subjectivity and standardization of antigen source. In the present study, we developed an immuno-PCR (iPCR)-based approach employing recombinant in vivo-expressed B. burgdorferi antigens for objective detection of a host immune response to B. burgdorferi infection. iPCR is a liquid-phase protein detection method that combines the sensitivity of PCR with the specificity and versatility of immunoassay-based protocols. Use of magnetic beads coated with intact spirochetes provided effective antigen presentation and allowed detection of host-generated antibodies in experimentally infected mice at day 11 postinoculation, whereas host-generated antibodies were detected at day 14 by enzyme-linked immunosorbent assay (ELISA) and day 21 by immunoblotting. Furthermore, magnetic beads coated with recombinant B. burgdorferi in vivo-expressed antigen OspC or BmpA demonstrated positive detection of host-generated antibodies in mice at day 7 postinoculation with markedly increased iPCR signals above the background, with the quantification cycle (C(q)) value for each sample minus the mean background C(q) plus 3 standard deviations (ΔC(q)) being 4 to 10, whereas ΔC(q) was 2.5 for intact spirochete-coated beads. iPCR demonstrated a strong correlation (Spearman rank correlation = 0.895, P < 0.0001) with a commercial ELISA for detection of host antibodies in human Lyme disease patient sera using the B. burgdorferi VlsE C6 peptide. In addition, iPCR showed potential applicability for direct detection of spirochetes in blood. The results presented here indicate that our iPCR assay has the potential to provide an objective format that can be used for sensitive detection of multiple host response antibodies and isotypes to B. burgdorferi infection.

Borrelia burgdorferi harbors a transport system essential for purine salvage and mammalian infection.

Borrelia burgdorferi is the tick-borne bacterium that causes the multistage inflammatory disease Lyme disease. B. burgdorferi has a reduced genome and lacks the enzymes required for de novo synthesis of purines for synthesis of RNA and DNA. Therefore, this obligate pathogen is dependent upon the tick vector and mammalian host environments for salvage of purine bases for nucleic acid biosynthesis. This pathway is vital for B. burgdorferi survival throughout its infectious cycle, as key enzymes in the purine salvage pathway are essential for the ability of the spirochete to infect mice and critical for spirochete replication in the tick. The transport of preformed purines into the spirochete is the first step in the purine salvage pathway and may represent a novel therapeutic target and/or means to deliver antispirochete molecules to the pathogen. However, the transport systems critical for purine salvage by B. burgdorferi have yet to be identified. Herein, we demonstrate that the genes bbb22 and bbb23, present on B. burgdorferi's essential plasmid circular plasmid 26 (cp26), encode key purine transport proteins. BBB22 and/or BBB23 is essential for hypoxanthine transport and contributes to the transport of adenine and guanine. Furthermore, B. burgdorferi lacking bbb22-23 was noninfectious in mice up to a dose of 1 × 10(7) spirochetes. Together, our data establish that bbb22-23 encode purine permeases critical for B. burgdorferi mammalian infectivity, suggesting that this transport system may serve as a novel antimicrobial target for the treatment of Lyme disease.

Molecular characterization of the Borrelia burgdorferi in vivo-essential protein PncA.

The conversion of nicotinamide to nicotinic acid by nicotinamidase enzymes is a critical step in maintaining NAD(+) homeostasis and contributes to numerous important biological processes in diverse organisms. In Borrelia burgdorferi, the nicotinamidase enzyme, PncA, is required for spirochaete survival throughout the infectious cycle. Mammals lack nicotinamidases and therefore PncA may serve as a therapeutic target for Lyme disease. Contrary to the in vivo importance of PncA, the current annotation for the pncA ORF suggests that the encoded protein may be inactive due to the absence of an N-terminal aspartic acid residue that is a conserved member of the catalytic triad of characterized PncA proteins. Herein, we have used genetic and biochemical strategies to determine the N-terminal sequence of B. burgdorferi PncA. Our data demonstrate that the PncA protein is 24 aa longer than the currently annotated sequence and that pncA translation is initiated from the rare, non-canonical initiation codon AUU. These findings are an important first step in understanding the catalytic function of this in vivo-essential protein.