Study on Evolution of Micropipes from Hexagonal Voids in 4H-SiC Crystals by Cathodoluminescence Imaging.

This paper presents an investigation on micropipe evolution from hexagonal voids in physical vapor transport-grown 4H-SiC single crystals using the cathodoluminescence (CL) imaging technique. Complementary techniques optical microscopy, scanning electron microscopy, and energy-dispersive spectroscopy (EDS) are also used to understand the formation mechanism of hexagonal voids along with the origin of pipes from these voids. The ability of CL to image variations along the depth of the sample provides new insights on how micropipes are attached to hexagonal voids that lie deep within the bulk single crystals. CL imaging confirms that multiple micropipes can originate from a single hexagonal void. EDS mapping shows that the inside of the micropipe walls exhibits higher levels of carbon. Investigation of the seed region by optical imaging shows that improper fixing of the seed to the crucible lid is the root cause for the formation of hexagonal voids that subsequently lead to micropipe formation.

Changes in Mandibular Third Molar Angulation in High-anchorage Extraction vs Non-extraction Orthodontic Treatment: A Prospective Study.

AIM AND OBJECTIVE: The study aimed to compare the prospective changes in mandibular third molar angulation in high anchorage cases treated with first premolar extractions vs non-extraction orthodontic treatment. MATERIALS AND METHODS: The sample consisted of 56 nongrowing patients: Group I had 26 patients with a high anchorage requirement who underwent first premolar extractions and group II had 30 patients who underwent non-extraction treatment. Pretreatment, mid-treatment, and posttreatment panoramic radiographs were obtained for group I and pretreatment and posttreatment for group II. Angle between M2 (second molar)-horizontal reference plane (HRP), M3 (third molar)-HRP, and M2-M3 were measured bilaterally. Data were analyzed using Student t test and ANOVA test (p value < 0.05). RESULTS: Statistically significant increase was found between the pretreatment, mid-treatment, and posttreatment values of M2-M3 in group I (p value = 0.02 R and p value = 0.049 L) and between pretreatment to posttreatment values of M2-HRP in group II bilaterally (p value = 0.001). Significant increase was found in the M2-M3 angulations in group II on the right side (p value = 0.036). M3-HRP decreased in group I without reaching statistical significance. No statistically significant intergroup differences were found between the two groups in relation to M2-HRP, M3-HRP, and M2-M3 angulations. CONCLUSION: M2-M3 angulations increased significantly bilaterally in group I and on the right side in group II, indicating worsening of third molar angulation. M3-HRP worsened in group I without reaching statistical significance. Extraction therapy in high anchorage cases does not lead to an improvement in third molar angulation. CLINICAL SIGNIFICANCE: The extraction of first premolars in high anchorage cases does not lead to an improvement in the angulation of mandibular third molars; moreover, the angulation worsened with extraction therapy. Prospective orthodontic patients need to be cautioned against any improvement in mesioangular impaction of mandibular third molars in high anchorage premolar extraction cases.

Effect of socioeconomic, nutritional status, diet, and oral habits on the prevalence of different types of malocclusion in school-children.

OBJECTIVE: Although there have been many reports on the prevalence of malocclusion, there is paucity of data concerning factors associated with it. The present study aimed to study the effects of three environmental factors namely socio-economic status (SES), nutritional status, and oral habits on malocclusion. MATERIAL AND METHODS: A total number of 765 students [Low socio-economic status (LSS; 369 subjects) and High socio-economic status (HSS; 396 subjects)] based on Modified Kuppuswamy scale were examined within the age group of 13- 15 years amongst various government and private schools in Chandigarh, India. A questionnaire was filled up by the subjects, which was followed up with clinical examination using the Dental Aesthetic Index (DAI). Additionally, the provisional diagnosis, retained, transposed teeth, and overbite were estimated. RESULTS: The total prevalence of malocclusion in the population was 49.7%. The prevalence of malocclusion in LSS was found to be 42.90% and in HSS was 57.10% (P: 0.003). The mean DAI score in LSS was 26.011 and in HSS was 27.179. The mean DAI score in soft eaters was 29.527, average eaters was 26.369 and hard eaters was 26.410. CONCLUSION: The total prevalence of malocclusion in Chandigarh was 49.7%. Class I type 1 was the most prevalent type of malocclusion. Adolescents belonging to HSS had more malocclusion as compared to those belonging to LSS. Soft diet caused increased malocclusion. The present study highlighted the effect of diet pattern on the prevalence of malocclusion. (www.actabiomedica.it).

Novel Protocols for the Production of Autologous Blood Concentrates With High Platelet Volume.

Autologous blood concentrates (ABCs), specifically platelet-rich plasma (PRP), were originally discussed in the literature more than 60 years ago. Since then, protocols to fabricate PRP from patient-derived blood have steadily evolved with the aim of creating better products with more effective clinical results. Key to the protocol evolution has been the development of ABCs with higher concentrates of platelets and other blood components that enhance soft- and hard-tissue healing and, hence, regeneration. The authors present a protocol for obtaining high-platelet-concentration PRP and autogenous thrombin. This fifth-generation protocol allows PRP to be attained with a platelet concentration six times higher than that which is present in the original clot. This double-centrifugation PRP protocol is relatively simple and inexpensive, as it does not require special equipment or advanced technical knowledge by the practitioner and can readily be conducted in a private dental clinical setting.

Cadent iTero's digital system for dental impressions: the end of trays and putty?

Because conventional dental impression methods often are imprecise and subject to guesswork, and because these methods often are uncomfortable for the patient and expensive for the practitioner, the Cadent iTero system was created to help reduce or eliminate those negative aspects of dental impressions. The system's enhanced visualization and real-time analytical tools enable clinicians to adjust measurements before completing the intraoral digital scanning of dental patients. And because the iTero technology lends itself for use with all restorative procedures and materials via a network of dental laboratory partners, implantologists as well as other dentists interested in quality production of restorations can lower costs while assuring precise and patient-pleasing results.

Imaging modalities for dental implants: DEXIS digital radiography.

DEXIS intraoral radiography provides clarity of image, a software interface that is intuitive and easy to use, and a flexibility that allows it to network reliably with a practice's existing computer systems. For oral implantology in particular, which is highly dependent on the proper preoperative treatment planning and appropriate radiographic evaluation of the edentulous ridge, modem imaging techniques such as those provided by DEXIS are facilitating the trend toward the nonspecialist place-ment of implants. DEXIS can be used effectively to assess the quantity and quality of the bone present and to visualize the location and relationships between critical internal anatomic structures for implant placement. The company's patented PerfectSize intraoral sensor replaces traditional intraoral X-ray film, providing images that are particularly useful as adjuncts to implant planning and placement.

Dental implant imaging: TeraRecon's Dental 3D Cone Beam Computed Tomography System.

Early in the development of implant technology, conventional dental imaging techniques were limited for evaluating the patient for implant surgery. During the treatment-planning phase, the recipient bed is routinely assessed by visual examination and palpation, as well as by periapical and panoramic radiology. These two imaging modalities provide a two-dimensional image of the mesiodistal and occlusoapical dimensions of the edentulous regions where the implants might be placed. When adequate occlusoapical bone height is available for endosteal implants, the buccolingual width and angulation of the available bone are the most important criteria for implant selection and success. However, neither buccolingual width nor angulation can be visualized on most traditional radiographs. Although clinical examination and traditional radiographs may be adequate for patients with wide residual ridges that exhibit sufficient bone crestal to the mandibular nerve and maxillary sinus, these methods do not allow for the precise measurement of the buccolingual dimension of the bone or assessment of the location of unanticipated undercuts. Because of these concerns, it is necessary to view the recipient site in a plane through the arch of the maxilla or mandible in the region of the proposed implants. Implant surgeons soon recognized that, for the optimum placement of implants, cross-sectional views of the maxilla and mandible are the ideal means for providing necessary preoperative information. For complex cases where multiple implants are required or where anatomical measurements are crucial, but also increasingly for more routine cases, more and more clinicians are recommending CT scan imaging procedure such as that offered by TeraRecon's Dental CBCT system. Because of its ability to reconstruct a fully three-dimensional model of the maxilla and mandible, CBCT provides a highly sophisticated format for precisely defining the jaw structure and locating critical anatomic structures. CBCT scans, in conjunction with software that renders immediate treatment plans using the most real and accurate information, provide the most precise radiographic modality currently available for the evaluation of patients for oral implants.

Analyzing dental occlusion for implants: Tekscan's TScan III.

Though no single, specific occlusal pattern has been developed that is ideal for oral implantology, research suggests some general criteria for deciding on a particular occlusal pattern that will help reduce cuspal interferences and lessen horizontal or lateral forces on the fixtures. Anticipated occlusal and chewing forces need to be taken under consideration for any implant-supported prosthesis. In addition, opposing dentition, as well as potential parafunctional mandibular movements, should be noted. Tekscan's T-Scan Occlusal Analysis System can help clinicians meet the needs of their patients for reliable measurements of occlusal biting forces. The T-Scan III System is Tekscan's most recent attempt to help dental clinicians obtain consistent and useful occlusal data for the placement, analysis, and repair of dental implants.

Healing in smokers versus nonsmokers: survival rates for sinus floor augmentation with simultaneous implant placement.

PURPOSE: Evidence suggests that smoking is detrimental to the survival of dental implants placed in grafted maxillary sinuses. Studies have shown that improving bone quantity and quality, using rough-surfaced implants, and practicing good oral hygiene may improve outcomes. In this prospective study, the long-term survival rates of implants placed simultaneously with sinus grafting in smokers and nonsmokers were compared. MATERIALS AND METHODS: Implants with roughened surfaces were immediately placed into maxillary sinus grafts in patients with 1 to 7 mm of residual bone. A total of 2132 simultaneous implants were placed into the grafted sinuses of 226 smokers (627 implants) and 505 nonsmokers (1505 implants). A majority of the patients received a composite graft consisting of 50% autogenous bone. In both smokers and nonsmokers, approximately two thirds of the implants had microtextured surfaces; the remainder had hydroxyapatite-coated surfaces. The implants were restored and monitored during clinical follow-up for up to 9 years. RESULTS: Cumulative survival of implants at 9 years was 97.9%. There were no statistically significant differences in implant failure rates between smokers and nonsmokers. DISCUSSION: Implant survival was believed to depend on the following aspects of the technique used: creation of a large buccal window to allow access to a large recipient site; use of composite grafts consisting of at least 50% autogenous bone; meticulous bone condensation; placement of long implants (i.e., 15 mm); use of implants with hydroxyapatite-coated or microtextured surfaces; use of a membrane to cover the graft and implants; antibiotic use and strict oral hygiene; use of interim implants and restricted use of dentures; and adherence to a smoking cessation protocol.

Predictability of simultaneous implant placement in the severely atrophic posterior maxilla: A 9-year longitudinal experience study of 2132 implants placed into 731 human sinus grafts.

PURPOSE: One-stage implant placement in the grafted maxillary sinus has traditionally been limited to patients with at least 5 mm of residual bone to ensure complete implant stabilization. The aim of this prospective study was to determine the long-term survival rates of implants with roughened surfaces placed immediately into maxillary sinus grafts in patients with 1 to 5 mm of residual bone. MATERIALS AND METHODS: A total of 2132 microtextured screw-type (n=1374) or hydroxyapatite-coated cylinder-type (n=758) implants were immediately placed into the grafted sinuses of 731 patients. The implants were restored and monitored for up to 9 years of clinical follow-up. RESULTS: Cumulative survival at 9 years was 97.9% (n=2091 implants); 20.4% of the implants were placed in 1 to 2 mm of residual bone. DISCUSSION: Initial implant stability and parallelism were achieved through a combination of meticulous condensation of the particulate bone graft material around the implants, the frictional interface of the roughened implant surfaces and the host tissues, and selection of an appropriate graft material. CONCLUSIONS: Simultaneous implant placement into sinus floor grafts can be a predictable treatment option for patients with at least 1 to 2 mm of vertical residual bone height when careful case planning and meticulous surgical techniques are used.

Facilitators of and barriers to accessing clinical prevention services for the South Asian population in Surrey, British Columbia: a qualitative study.

BACKGROUND: British Columbia falls short in uptake of recommended clinical prevention services, with even lower rates among immigrant populations. This study explored facilitators of and barriers to uptake of clinical prevention services among people from South Asia, who represent 31% of the population in Surrey, British Columbia. METHODS: We used a qualitative descriptive approach and employed vignettes in a focus group setting to elicit perspectives of South Asian people on accessing clinical prevention services. Participants aged 40 years or more were recruited between October 2014 and February 2015 from health care and community settings such as older-adult housing, day programs and health education events. Letters of introduction to the study were provided in English or Punjabi or both to all potential participants. We conducted qualitative content analysis of the results. RESULTS: Sixty-two South Asian adults (36 women and 26 men) aged 40-87 years participated in 1 of 8 focus groups in health care or community settings. Facilitators of and barriers to accessing clinical prevention services were noted at the patient, primary care provider and health care system levels. Facilitators at the patient level included taking ownership over one's health, health literacy and respecting the provider's advice; barriers included fear of the diagnosis, death and/or procedures, perceived low risk of disease or utility of the intervention, and side effects of procedures. Provider factors centred on a trust-based patient-provider relationship, strong communication and adequate time during visits. Health care system factors included such facilitators as processes to routinely offer prevention services as part of other health care or social services, systems that encourage prevention-oriented family practice and services at low or no cost to the patient. INTERPRETATION: Our findings validate previously identified facilitators of and barriers to accessing preventive care for immigrant populations. However, the results suggest that system-level factors influencing the duration of primary care visits may have a more salient impact on uptake of clinical prevention services in this population.

Dental Evidence in Forensic Identification - An Overview, Methodology and Present Status.

Forensic odontology is primarily concerned with the use of teeth and oral structures for identification in a legal context. Various forensic odontology techniques help in the identification of the human remains in incidents such as terrorists' attacks, airplane, train and road accidents, fires, mass murders, and natural disasters such as tsunamis, earth quakes and floods, etc. (Disaster Victim Identification-DVI). Dental structures are the hardest and well protected structures in the body. These structures resist decomposition and high temperatures and are among the last ones to disintegrate after death. The principal basis of the dental identification lies in the fact that no two oral cavities are alike and the teeth are unique to an individual. The dental evidence of the deceased recovered from the scene of crime/occurrence is compared with the ante-mortem records for identification. Dental features such as tooth morphology, variations in shape and size, restorations, pathologies, missing tooth, wear patterns, crowding of the teeth, colour and position of the tooth, rotations and other peculiar dental anomalies give every individual a unique identity. In absence of ante-mortem dental records for comparison, the teeth can help in the determination of age, sex, race/ethnicity, habits, occupations, etc. which can give further clues regarding the identity of the individuals. This piece of writing gives an overview of dental evidence, its use in forensic identification and its limitations.

Enamel hypoplasia and its role in identification of individuals: A review of literature.

Identification of individuals is the mainstay of any forensic investigation especially in cases of mass disasters when mutilated remains are brought for examination. Dental examination helps in establishing the identity of an individual and thus, has played a vital role in forensic investigation process since long. In this regard, description on the role of enamel hypoplasia is limited in the literature. The present article reviews the literature on the enamel hypoplasia and discusses its utility in forensic identification. Enamel hypoplasia is a surface defect of the tooth crown caused by disturbance of enamel matrix secretion. Enamel defects can be congenital or acquired. In cases of mass disasters, or when the body is completely charred, putrefied and mutilated beyond recognition, the unique dental features can help in identification of the victims.

Lateralization of the inferior alveolar nerve with simultaneous implant placement: a modified technique.

PURPOSE: Several nerve repositioning techniques have ben presented in the literature, each with limitations. This article presents a new technique involving the use of 2 osteotomies, with minimizes particularly the potential duration of sensory disruption and the risk of nerve paresthesia and inadvertent nerve transection or compression. MATERIALS AND METHODS: Ten patients ranging in age from 47 to 67 years were selected for nerve lateralization utilizing the modified technique. A total of 23 cylindrical implants were placed. An average follow-up period was 29.8 months. RESULTS: Of the 10 patients, 4 experienced total return of sensation within 3 to 4 weeks. One patient experienced complete recovery at 6 weeks. DISCUSSION: Creating 2 osteotomies as described minimizes the chances for postoperative neuropraxia and nerve paresthesia or anesthesia. CONCLUSION: When there is moderate-to-severe bone resorption of the mandible posterior to the mental foramen, repositioning the inferior alveolar nerve using both an anterior and posterior osteotomy allows for more bone to accommodate ideal placement and greater length of implant.

Comparison of the dental arch changes in patients with different malocclusions.

AIMS AND OBJECTIVES: To evaluate the pre-treatment and post-treatment dental arch changes in both upper and lower arches in orthodontic patients treated with extraction of first premolar teeth. SUBJECTS AND METHODS: Measurements were made on casts of 50 post treated cases in the age group of 12-30 years for individual tooth measurements, width of the arches (inter-incisal, inter-canine, inter-premolar and inter-molar) arch length (both right and left sides, anterior segment, posterior segment and total arch length for both for the maxillary and mandibular dental casts. STATISTICAL ANALYSIS USED: Kolmogorov-Smirnov test for Normality, Regression Analysis was done as variables were tested and proved to follow normality. Statistical software  Statistical Package for the Social Sciences version 18 (SPSS Inc.; Chicago, Illinois, USA) was used for data analysis. Descriptive statistics and paired t-tests were used to compare the changes in the Class I and Class II div 1 groups. RESULTS: There was a significant increase in the inter-incisor and inter-canine width post-treatment in the Class I and Class II div 1 subjects in the upper arch but no significant change in inter-incisor width in the lower arch in class I subjects. A significant decline in the inter-molar arch width in both the groups were seen. The inter-premolar arch width declined significantly in Class I cases while it increased significantly in Class II div 1 subjects. There was a significant increase in anterior arch length and a significant decrease in posterior arch length in all subjects. CONCLUSIONS: The findings of this original clinical research should significantly help the orthodontists in orthodontic treatment planning in patients requiring extractions of premolars.