Practitioners' experiences of adolescent suicidal behaviour in peer groups.

WHAT IS KNOWN ON THE SUBJECT?: Group suicidal behaviour can be devastating for all concerned. There is an absence of research on adolescent suicidal group behaviour. The perspectives of practitioners' experiences of these groups are largely lacking from research literature. WHAT THIS PAPER ADDS TO EXISTING KNOWLEDGE?: Practitioners work regularly with suicidal behaviour in adolescent peer groups. Practitioners identify peer relationships in groups as complex, including elements that are both suicide encouraging and preventing. Practitioners identify a range of ways in which young people become involved in suicidal behaviour in groups, including indirectly through risk taking and care-seeking as well as directly suicidal or self-harming. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Assessments of young people should routinely include a focus on the qualities of peer relations, including those in the online/digital realm. Assessments and interventions need to consider the complexity of group relationships and roles, and the multiplicity of factors that can contribute to suicidal behaviour in groups. Interventions that sustain therapeutic connectedness are helpful for taking dynamic/fluctuating risks into account. ABSTRACT: Introduction Group suicidal behaviour by young people can have harmful effects; it may be increasing, influenced by online media and reported increasing self-harm rates; new knowledge and understanding to inform interventions is required. Aim To explore how practitioners experience group suicidal behaviour amongst adolescents, how they assess risks/needs, and how these insights inform understanding about these groups. Method Ten practitioners, including Mental Health Nurses, were interviewed in one multidisciplinary CAMHS, in England. Data analysis was by Thematic Analysis (Braun & Clarke 2006). Results Participants described frequently working with suicidal groups. Roles in groups include suicide encouraging and preventing. Practitioners identify risky and protective connections between young people, online and offline. Clinical tensions include living with suicidal risks, emotional and positional challenges, and getting to grips with digital media. Discussion Peer groups appear to have a larger role in adolescent suicide than recognized to date. Practitioners need to assess young people's roles in groups, their diverse motivations and to understand constantly changing digital media. Implications for practice Assessments of suicide risk for young people should routinely include focus on peer relations including the online/digital realm. Maintaining relationships with vulnerable young people facilitates managing fluctuating risks and understanding different group dynamics.

Occlusal plane discrepancies generated by transverse horizontal axis deviations.

STATEMENT OF PROBLEM: Any deviation from the patient's rotational axis of the mandible during closure and the arc of closure on an articulator has been reported to produce occlusal discrepancies. These discrepancies can affect diagnostic planning procedures and the occlusal relationships of restorations. PURPOSE: This study investigated the magnitude and types of occlusal errors produced by deviations between the patient's transverse horizontal axis and the axle on the articulator. MATERIAL AND METHODS: A simplified monoplane model was diagrammatically analyzed for deviations from the model's true transverse horizontal axis. Axis deviations of 5 mm were used in 8 different directions from the true transverse horizontal axis of the model. Changes in the orientation of the mandibular plane to the maxillary plane were illustrated diagrammatically. These changes were quantified by geometric and trigonometric assessments. RESULTS: All axis deviations produced mandibular plane orientation errors with angular plane malalignment to the maxillary plane on complete closure. These axis deviations also produced anterior-posterior shifting of the mandibular plane relative to the maxillary plane. CONCLUSION: Several different types of planar shifting and angular discrepancies were demonstrated from deviations away from the true transverse horizontal axis.

Evaluation of biomechanical properties of Expanded-Polytetrafluoroethylene Soft Tissue Patch after dorsal implantation in the rat to mimic TMJ lateral reconstruction.

Clinically, Gore-Tex Expanded-Polytetrafluoroethylene (E-PTFE) has been used to reconstruct the lateral temporomandibular joint (TMJ) ligament. The purpose of this study was to assess changes in the biomechanical properties of implanted E-PTFE over time with respect to tissue infiltration. Ninety-six specimens of implants were divided into four groups. Group A was the experimental group. Thirty-six autoclave-sterilized specimens were subcutaneously implanted into the backs of 36 rats. The rats were randomly sacrificed at 2 (n = 12), 7 (n = 12) and 12 (n = 12) weeks. The implants were tested for mechanical properties including maximal stress, strain and Young's modulus of elasticity (E) using the servo-hydraulic material testing system (MTS). Group B was the in vitro control group. Thirty-six specimens were placed in tissue culture media at 37 degrees C for a time period equivalent to the experimental group to simulate the effect of a moist, warm environment on biomechanical properties. Group C was the temperature and pressure control group. Twelve specimens were autoclave-sterilized to determine the changes of tensile strength under high temperature and pressure. Control group D (no treatment) was tested to determine the initial tensile strength. The results showed significantly larger maximal stress as well as an increase in E and smaller maximal strain in experimental group A than in control groups B, C and D. There was no significant difference among control groups B, C and D. Histological examination of implants at 12 weeks demonstrated that 0.2-0.3 mm of 1-mm thick implants were occupied by connective tissue from each side. It may be concluded that E-PTFE implants become stronger and less flexible after implantation in vivo.

Masticatory muscle activity assessment and reliability of a portable electromyographic instrument.

STATEMENT OF PROBLEM: Masticatory muscle hyperactivity is thought to produce muscle pain and tension headaches and can cause excessive wear or breakage of restorative dental materials used in the treatment of prosthodontic patients. The quantification and identification of this type of activity is an important consideration in the preoperative diagnosis and treatment planning phase of prosthodontic care. PURPOSE: This study investigated the quantification process in complete denture/overdenture patients with natural mandibular tooth abutments and explored the reliability of instrumentation used to assess this parafunctional activity. MATERIAL AND METHODS: The nocturnal EMG activity in asymptomatic complete denture/overdenture subjects was assessed with and without prostheses worn during sleep. Because of the large variance within and between subjects, the investigators evaluated the reliability of the 3 instruments used to test nocturnal EMG activity in the sample. RESULTS: Electromyographic activity data of denture/overdenture subjects revealed no differences between prostheses worn versus not worn during sleep but demonstrated a very large variance factor. Further investigation of the instrumentation demonstrated a consistent in vitro as well as in vivo reliability in controlled laboratory studies. CONCLUSION: The portable EMG instrumentation used in this study revealed a large, uncontrollable variance factor within and between subjects that greatly complicated the diagnosis of parafunctional activity in prosthodontic patients.

Reliability of an ear-bow arbitrary face-bow transfer instrument.

STATEMENT OF PROBLEM: Accuracy of techniques for recording the orientation of the maxillary arch to the articulation of the temporomandibular joints has been reported. The variability contributed by the dentist and the equipment within a technique may also contribute to technical error. PURPOSE: This study investigated the variability of a group of dentists who used an arbitrary ear-face-bow instrument to mount a maxillary cast. MATERIAL AND METHODS: The same maxillary cast on a single experimental subject was mounted on an articulator with a common arbitrary ear-face-bow instrument. This cast was equipped with 4 reference points for the measurement of changes of spatial orientation of the cast, which were determined through coordinate measurements with a machinist's microscope. A repeated measures analysis of variance was used to determine statistically significant changes in spatial orientation with a Wilks' Lambda test to compare mean values. RESULTS: A confidence interval of 95% demonstrated that any dentist might expect a range of +/-1.2 mm error in using this instrument/articulator combination. The 3 dentists did not demonstrate any significant differences in the spatial orientation of their mountings in the vertical or horizontal directions. However, there were significant differences in their mountings in linear distance changes of the patient's posterior right side. CONCLUSION: A range of inherent error attributable to the operator using this instrument was recorded.

Intrusion phenomenon in combination tooth-implant restorations: a review of the literature.

STATEMENT OF PROBLEM: Controversy regarding the connection of implants to natural teeth in fixed partial dentures has emerged in response to clinical reports of intrusion of the natural teeth. Although theories have been proposed to explain this phenomenon, the cause of the intrusion remains unknown. Numerous longitudinal studies have demonstrated that teeth can be successfully connected to implants. The use of rigid connectors, or nonrigid connectors with the keyway on the implant, are described as mechanisms to prevent intrusion of the natural tooth. PURPOSE: This article reviews the literature that pertains to this subject and includes treatment modalities that may be helpful in preventing intrusion.

Management of the gingival sulcus in fixed prosthodontics: a literature review and treatment protocol.

This review of the fixed prosthodontics and periodontology literature illustrates the influence of various factors on the health of the periodontium during and after fixed prosthodontic treatment. This article describes four categories of marginal finish lines for fixed prosthodontic restorations relative to the gingival margin and the epithelial attachment. The management of each category from both the periodontal and prosthodontic prespectives is also discussed.

Evaluation of shear stress of the human temporomandibular joint disc.

The aim of this study was to determine the shear stress of the human postmortem temporomandibular joint (TMJ) disc. Correlation of shear stress with age or with the region of the disc was determined. Nine discs were removed unilaterally from postmortem humans, ages 36 to 76 years. Discs were sectioned into lateral (eight), central (eight), and medial (eight) specimens. Each specimen was attached by cyanoacrylate adhesive to a servohydraulic test system apparatus within 48 hours of retrieval. Shear properties were measured under quasistatic conditions with a linear increase of displacement until the specimen failed to maintain maximum resistance to the applied force. The shear moduli were analyzed by means of the Wilcoxon's signed ranks test. The results showed that values of shear moduli on peripheral portions (lateral and medial) were significantly higher than on central portions (P = 0.0013). The correlation between the shear moduli of TMJ discs and age showed a regression slope for shear moduli of -0.326 + 0.031 x age (r = 0.769; P < 0.01). Peripheral portions (lateral and medial) have a higher shear moduli and are stiffer than the central portions of discs and shear moduli or stiffness of TMJ discs increase with age.

Prevalence of temporomandibular disorders (TMD) in children based on physical signs.

Temporomandibular disorders (TMD) are related to the function and integrity of the masticatory system with restricted jaw movement and/or joint clicking or crepitus, for example, dominating the clinical signs of these disorders. The prevalence of TMD signs was examined in non-patient children ages six to twelve (1994 n = 185, 1995 n = 237) by four examiners using standardized techniques. Of significance was the finding that 7.3 percent of the 1994 children had audible joint sounds, while the 1995 examination reported 3 percent. Statistically significant relationships (p < 0.05) between the ages of the subjects and measurements of overbite (p < 0.0001), overjet (p < 0.01), and clicking (p < 0.005) were calculated from the 1994 data, while significant correlations for overbite (p < 0.001) and overjet (p < 0.01), but not clicking were found in the 1995 examination. One study of four- to six-year-old nonpatients reported a higher occurrence of joint sounds (48 percent). This disparity indicates a possible need for standardization of examination techniques specifically targeting joint sounds and their role in TM disorders.

The impact of pre-transplant obesity on renal transplant outcomes.

The impact of obesity on graft survival after renal transplantation continues to be controversial. We have reviewed our experiences with living donor and cadaver transplantation in the current decade, focusing specifically on the impact of obesity on transplant outcome. Preoperative body mass index (BMI, kg/m2) was calculated for all adult renal transplant recipients between January 1990 and December 1995 and was used to classify patients as non-obese, moderately obese or morbidly obese. The effect of the degree of obesity on early and late outcomes after renal transplantation was examined. Three hundred and thirty-three recipients had pre-transplant BMI < 30 (normal or mild obesity), 68 BMI 30-40 (moderate obesity), and 7 BMI over 40 (morbid obesity). There was no correlation between obesity and other demographic factors. Wound infections and delayed graft function occurred more commonly in moderately and morbidly obese than in other cadaver donor recipients. Obese patients gained more weight after surgery and were given lower doses per kilogram of cyclosporine. There was, however, no significant correlation between obesity and graft survival for either cadaver or living donor transplants. Although obese patients have an increased risk of delayed graft function with cadaver donor transplantation, obesity has no discernible impact on either immunologic or overall graft survival with cadaver or living donor transplantation. The impact of moderate obesity on transplant outcome is modest and should not prevent these patients from receiving a transplant.

An evaluation of operator preference of diamond burs in coronal tooth preparation.

Three postgraduate prosthodontic students served as clinicians/evaluators in a study rating their preferences for three different diamond cutting instruments from three manufacturers. Each evaluator prepared the axial walls of complete veneer crowns on extracted molar teeth and then ranked their preference of the instruments. To prepare nine teeth, each of the three instruments was used in random order and without knowledge of the specific manufacturer. The methodology for analyzing the evaluators' preferences and the results are discussed.

Masticatory muscle pain before, during, and after treatment with orthopedic protraction headgear: a pilot study.

Protraction headgear has been used in conjunction with a palatal expansion appliance to correct Class III malocclusion with maxillary deficiency and/or mandibular prognathism. In general, 800 gm of orthopedic force is used to protract the maxilla, and 75% of this force is transmitted to the temporomandibular joint (TMJ) area via the mandible. The effect of this heavy intermittent force on the TMJ has not been reported in the literature. The objectives of this study were to determine the level of masticatory muscle pain and EMG activity in patients treated with maxillary protraction headgear. Ten patients with skeletal Class III malocclusion whose treatment plan called for maxillary protraction headgear treatment participated in this study. Nocturnal masticatory muscle activity was determined using a portable electromyographic (EMG) recording device. Subjects wore the EMG device 14 nights before treatment, 14 nights during treatment, and 14 nights 1 month after active treatment. Masticatory muscle pain level was determined by muscle palpation, scored on a scale of 0 to 3 each period, according to the method of Gross and Gale. The examiner followed a sequence outlined by Burch to examine the masticatory muscles. Results showed no significant differences for masticatory muscle activities before, during, and after treatment. Only a few patients experienced level 1 masticatory pain during treatment. None of the patients experienced masticatory muscle pain 1 month after treatment. These results demonstrate no significant increase in masticatory muscle activity or muscle pain associated with orthopedic treatment using maxillary protraction headgear.

Meningitis in infancy caused by Pasteurella multocida.

A high proportion of household pets are colonised by Pasteurella multocida. The organism can be transmitted to humans by contact with animal saliva and is a recognised, although rare, cause of meningitis in infancy. Intimate contact between infants and family pets should be discouraged.

Reliability and validity of instrumentation used to record nocturnal clenching and/or grinding.

Nocturnal clenching and grinding can be recorded with a portable electromyograph unit and a standard cassette tape recorder, which registers the clenching episodes on a cassette tape. The information can then be coded by a new instrument, called a Pulse Identifier, that subsequently transfers the data to a polygraph chart recorder. This study evaluated the reliability and validity of the Pulse Identifier when interfaced with other instruments that measure nocturnal clenching/grinding. A known number of clenching incidents over a baseline period of time were evaluated by three "blind" scores. The results demonstrated an interscorer reliability coefficient of 0.99 and a validity coefficient of 0.99.

Evaluation of variables associated with the transverse horizontal axis.

The effect of transverse horizontal axis deviations on the vertical and horizontal orientation of maxillary and mandibular members was investigated on a laboratory articulator model. Twelve axis deviations (+30, +25, +20, +15, +10, +5, -5, -10, -15, -20, -25, and -30 mm groups) within a 55 mm dimension model were evaluated. Three trials at each transverse horizontal axis deviation demonstrated significant changes in maxillomandibular orientation after mounting the mandibular member with a standardized intermember mounting record. A linear regression analysis produced an equation for predictive interpolation of anterior-posterior shift as a result of axis deviations from +30 to -30 mm.

Evaluation of the accuracy of cast reorientation to a surveyor by prosthodontic residents.

This study investigated the accuracy of a group of evaluators in reestablishing the orientation of a tripoded master cast to a surveyor instrument. Three prosthodontic residents served as evaluators to reestablish the tilt of a previously tripoded cast with three known reference coordinates. The distance from the known to the reference point was recorded for the three points in four trials by a judge with a machinist height gauge. Analysis of variance revealed a significant difference between the evaluator cast position and the known reference position. The investigation demonstrated +/- 0.2 mm errors at each of the three locations; 0.3-degree angulation errors occurred in reestablishing the tilt of the master cast in relation to the surveyor.