Markers for implant placement in CBCT: a technical overview.

Cone beam computer tomography (CBCT) is becoming a more accessible modality of imaging within dentistry. It has particular application in the diagnostic treatment planning for dental implant placement. The use of radiographic surgical stents with CBCT can help to provide important information about bone position and therefore placement of implants and final restorations. This article looks at a novel technique, which allows a variety of different marker positions that can be quickly and easily placed and removed. It allows the use of a current prosthesis that can be adapted to act as a surgical stent during CBCT.

Insulin resistance in obese Zucker rat (fa/fa) skeletal muscle is associated with a failure of glucose transporter translocation.

The genetically obese Zucker rat (fa/fa) is characterized by a severe resistance to the action of insulin to stimulate skeletal muscle glucose transport. The goal of the present study was to identify whether the defect associated with this insulin resistance involves an alteration of transporter translocation and/or transporter activity. Various components of the muscle glucose transport system were investigated in plasma membranes isolated from basal or maximally insulin-treated skeletal muscle of lean and obese Zucker rats. Measurements of D- and L-glucose uptake by membrane vesicles under equilibrium exchange conditions indicated that insulin treatment resulted in a four-fold increase in the Vmax for carrier-mediated transport for lean animals [from 4.5 to 17.5 nmol/(mg.s)] but only a 2.5-fold increase for obese rats [from 3.6 to 9.1 nmol/(mg.s)]. In the lean animals, this increase in glucose transport function was associated with a 1.8-fold increase in the transporter number as indicated by cytochalasin B binding, a 1.4-fold increase in plasma membrane GLUT4 protein, and a doubling of the average carrier turnover number (intrinsic activity). In the obese animals, there was no change in plasma membrane transporter number measured by cytochalasin B binding, or in GLUT4 or GLUT1 protein. However, there was an increase in carrier turnover number similar to that seen in the lean litter mates. Measurements of GLUT4 mRNA in red gastrocnemius muscle showed no difference between lean and obese rats. We conclude that the insulin resistance of the obese rats involves the failure of translocation of transporters, while the action of insulin to increase the average carrier turnover number is normal.

Na- and Cl-dependent glycine transport in human red blood cells and ghosts. A study of the binding of substrates to the outward-facing carrier.

Na- and Cl-dependent glycine transport was investigated in human red blood cells. The effects of the carrier substrates (Na, Cl, and glycine) on the glycine transport kinetics were studied with the goal of learning more about the mechanism of transport. The K1/2-gly was 100 microM and the Vmax-gly was 109 mumol/kg Hb.h. When cis Na was lowered (50 mM) the K1/2-gly increased and the Vmax-gly decreased, which was consistent with a preferred order of rapid equilibrium loading of glycine before Na. Na-dependent glycine influx as a function of Na concentration was sigmoidal, and direct measurement of glycine and Na uptake indicated a stoichiometry of 2 Na:1 glycine transported. The sigmoidal response of glycine influx to Na concentration was best fit by a model with ordered binding of Na, the first Na with a high K1/2 (greater than 250 mM), and the second Na with a low K1/2 (less than 10.3 mM). In the presence of low Cl (cis and trans 5 mM), the K1/2-gly increased and the Vmax-gly increased. The Cl dependence displayed Michaelis-Menten kinetics with a K1/2-Cl of 9.5 mM. At low Cl (5 mM Cl balanced with NO3), the glycine influx as a function of Na showed the same stoichiometry and Vmax-Na but a decreased affinity of the carrier for Na. These data suggested that Cl binds to the carrier before Na. Experiments comparing influx and efflux rates of transport using red blood cell ghosts indicated a functional asymmetry of the transporter. Under the same gradient conditions, Na- and Cl-dependent glycine transport functioned in both directions across the membrane but rates of efflux were 50% greater than rates of influx. In addition, the presence of trans substrates modified influx and efflux differently. Trans glycine largely inhibited glycine efflux in the absence or presence of trans Na; trans Na largely inhibited glycine influx and this inhibition was partially reversed when trans glycine was also present. A model for the binding of these substrates to the outward-facing carrier is presented.

Survival characteristics of 771 resin-retained bridges provided at a UK dental teaching hospital.

OBJECTIVE: To analyse the factors affecting the clinical performance and those influencing the survival of resin-retained bridgework provided at a UK dental teaching hospital between 1994 and 2001. DESIGN: A prospective analysis of restorations provided at a single centre using case notes with all patients invited for review to corroborate findings. SETTING: Department of Restorative Dentistry, University of Bristol Dental Hospital and School, Bristol, United Kingdom. SUBJECTS AND METHODS: Between January 1994 and December 2001, data regarding 1,000 consecutive resin-retained bridges provided at Bristol Dental Hospital and School were recorded. Data was available for 805 patients at the time of the study. Following invitation, 621 patients attended for a review appointment. Life table and Kaplan-Meir survival analysis were carried out for all restorations provided. RESULTS: The five-year and ten-year survival rates estimated by the life-table method are 80.8% (95% confidence interval 78.0-83.6%) and 80.4% (95% confidence interval 77.6-83.2%) respectively. The median survival cannot be estimated for this study as the survival probability remains above 80% even at the longest follow-up. Analysis of clinical variables influencing survival revealed that design of the restoration and experience of the operator providing the restoration were significant factors. Resin-retained bridges made with minimal tooth preparation are shown to be superior in terms of longevity than those for which other types of tooth preparation is made. Patient satisfaction with their treatment was high.

Skeletal muscle plasma membrane glucose transport and glucose transporters after exercise.

Recent reports have shown that immediately after an acute bout of exercise the glucose transport system of rat skeletal muscle plasma membranes is characterized by an increase in both glucose transporter number and intrinsic activity. To determine the duration of the exercise response we examined the time course of these changes after completion of a single bout of exercise. Male rats were exercised on a treadmill for 1 h (20 m/min, 10% grade) or allowed to remain sedentary. Rats were killed either immediately or 0.5 or 2 h after exercise, and red gastrocnemius muscle was used for the preparation of plasma membranes. Plasma membrane glucose transporter number was elevated 1.8- and 1.6-fold immediately and 30 min after exercise, although facilitated D-glucose transport in plasma membrane vesicles was elevated 4- and 1.8-fold immediately and 30 min after exercise, respectively. By 2 h after exercise both glucose transporter number and transport activity had returned to nonexercised control values. Additional experiments measuring glucose uptake in perfused hindquarter muscle produced similar results. We conclude that the reversal of the increase in glucose uptake by hindquarter skeletal muscle after exercise is correlated with a reversal of the increase in the glucose transporter number and activity in the plasma membrane. The time course of the transport-to-transporter ratio suggests that the intrinsic activity response reverses more rapidly than that involving transporter number.

Multiple atresias in a low-birth-weight twin.

This report describes a case of 16 small bowel atresias in a twin who was born at 31 weeks' gestation, weighing 1,690 g. All atresias and intestinal segments of 5 cm or less in length were resected, resulting in nine primary anastomoses, preserving 75% (107 cm) of his initial small bowel length. The baby went home on full oral feedings after 10 weeks. Multiple anastomoses in the low-birth-weight neonate can be tolerated with the functional benefit of maximal bowel length. The time taken to tolerate feedings appears to be independent of the number of anastomoses. Vascular anastomoses associated with monochorionic twinning may place both fetuses at risk of intestinal atresia in the event of an ischemic insult, either concurrently or with the demise of one affecting the other. Prenatal ultrasound scan appears to be useful for monitoring the evolution of intestinal atresia. However, the risks of extreme prematurity preclude the delivery of the affected baby at the time of initial diagnosis, and as yet it is unknown whether early delivery will alter the number, type, or prognosis of multiple atresias.

A review of pediatric cases of urinary tract calculi.

A retrospective review was performed of the records of 93 children with urinary tract calculi treated during a 10-year period (1983 to 1992). Two distinct groups of patients were identified. One group comprised 63 Aboriginal children, mainly from the northern region of Western Australia, who presented at a young age (average, 2.8 years) with urinary tract infections and failure to thrive. The other group comprised of 30 non-Aboriginal children, mainly from the metropolitan region, who presented at an older age (average, 6.7 years) with abdominal and flank pain. Calculi were located in the upper urinary tract in 85 children (91.4%) and in the bladder in eight (8.6%). Most patients underwent open surgical procedures for removal of their calculi, and the overall success rate was 86%. In recent years, percutaneous nephrolithotomy has been used successfully in selected patients with renal pelvic calculi. This method seems to be the trend for the future.

Primary obstructive megaureter.

Twenty-three children with primary obstructive megaureters presented between 1978 and 1988 to the Princess Margaret Hospital for Children in Perth. Twenty-eight ureters were treated. Urinary infections were the presenting feature in 14 children. The obstructive segment was transvesically excised. Histopathologic examination of the distal, intramural ureter showed fibromuscular disarray with a relative increase in fibrous tissue and reduction of musculature in all specimens. Twenty-two ureters were tapered by excision and all 28 were reimplanted using an antireflux technique. Seventeen children were followed for an average of 3 years. Seven children showed renal growth, reduction in ureteric size by greater than 2 cm, improvement in glomerular filtration rate by more than 10%, no obstruction on reflux, and no infections in postoperative period. Four children showed all the above but suffered one or more infections after the operation. Of the remaining 6 children, 3 had postoperative obstruction and 3 had vesicoureteric reflux.

Diagnosis, management, and outcome of cervicofacial teratomas in neonates: a Childrens Cancer Group study.

The management of cervicofacial teratomas in neonates is often complicated and may result in significant morbidity and death. A Childrens Cancer Group (CCG) retrospective study was conducted to evaluate a multiinstitutional experience with the treatment of these extremely rare neoplasms. Twenty neonates with cervicofacial teratomas, presenting from 1971 to 1994, were identified from nine CCG institutions. Fourteen neonates had cervical teratomas, and six had orofacial teratomas. There were 12 males and eight females. A diagnostic prenatal ultrasound examination was performed in six cases. Life-threatening airway obstruction occurred in seven infants (35%) in the early postnatal period. Two neonates died in the delivery room without ever having their airway secured. Two other infants with a prenatal diagnosis survived only because tracheostomies were performed by pediatric surgeons who were in the delivery room. Three other patients were orally intubated, one after sustaining hypoxic cardiac arrest. Eighteen infants had their primary tumor excised. Three patients required tracheostomy. After resection, two patients had evidence of unilateral recurrent laryngeal nerve injury, and two required prolonged thyroid hormone replacement. Histological examination showed eight mature and seven immature teratomas. Four infants (20%) clearly had malignant lesions. Pulmonary metastases occurred in two patients and contributed to one late death at 6 months of age. The overall survival rate was 85%, and the mean follow-up period was 5 years (range, 2 months to 16 years). Twelve of 17 surviving patients (70%) have had an excellent functional and cosmetic outcome. Four children have varying degrees of developmental delay and mental retardation. Hypoxia at birth was believed to have contributed to these problems in two cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Button wires in the treatment of mandibular fractures.

Button wiring has been used as an alternative to eyelet wiring in the Department of Oral and Dental Surgery of Birmingham General Hospital since 1977. This clinical update reviews 65 patients with mandibular fractures in which button wires were utilised in their treatment.

Grand multiparity: a reappraisal of the risks.

An excellent maternal and perinatal outcome is reported in a group of grand multipara of low socioeconomic status. These observations on a group of patients who are traditionally considered to be high risk show that in a healthy population with access to modern medical care and hospital delivery, a favorable outcome can be achieved despite a low socioeconomic or refugee status.

Obstetric outcome among Vietnamese refugees in Hong Kong: an age-matched case-controlled study.

The obstetric performance of 308 Vietnamese refugees is compared with that of 308 age-matched Hong Kong Chinese patients. Vietnamese women were of higher parity and had an increased incidence of late booking and unreliable dates. Significant differences were found in the incidence of previous termination of pregnancy, iron-deficiency anemia, parasitic infestation, tuberculosis (TB) and syphilis. There was no significant difference in the mean birthweight between the two groups. However, there were twice as many low birthweight (less than 2500 g) infants amongst the Vietnamese whereas the Chinese patients had a higher incidence of macrosomic (greater than 4 kg) infants. There were no perinatal deaths and no significant perinatal morbidity.

Adhesive techniques.

This paper describes the use of adhesive techniques to restore teeth previously affected by tooth surface loss so avoiding the need to remove sound tooth tissue.

Progress of infants fed Karitane Milk Food compared with those on breast or homogenised milk.

A study was made of three groups of babies, one breast fed, one having Karitane Milk Food, the third homogenised milk. Blood sodium and urea were measured in the neonatal period. The urea levels were significantly higher in babies having homogenised milk compared with those fed Karitane or breast milk. Haemoglobin was measured in the neonatal period, and at 3, 6, 10 1/2 and 18 months. At six months, haemoglobin levels were significantly higher in Karitane milk fed than in homogenised milk fed babies. Serum cholesterol and triglyceride were measured in cord blood, and at 6 and 18 months of age. Serum triglyceride levels in babies on Karitane Milk Food were significantly higher than those on homogenised milk. Increments in weight, height and head circumference were compared. Karitane milk fed babies gained significantly more weight than breast fed between three and six months of age.

Retrospective survey of resin-retained cast-metal palatal veneers for the treatment of anterior palatal tooth wear.

Anterior palatal tooth wear is easily recognized, but its precise pathogenesis remains unknown. Treatment of this condition with cast-alloy palatal veneers used in combination with an adhesive cement is described. Forty-eight patients, aged 11 to 71, were treated with a total of 210 cast metal veneers over a period of 56 months. Twenty-three of the restorations failed, resulting in an overall success rate of 89%. All failures were confined to 13 patients. A glass polyalkenoate cement was less effective than a chemically active resin composite luting agent. Nickel-chromium veneers cemented with activated resin composite recorded a survival probability of 0.74 at 56 months. Adhesive cast-alloy veneers provided a useful method of restoring maxillary anterior teeth affected by acid erosion.

A teaching strategy for identifying values: a clinical experience with the homeless.

Beginning baccalaureate students recorded their thoughts, feelings, and observations after participating in a clinical experience with the homeless. A content analysis protocol was used to uncover the meaning of the encounter. The findings suggest that assigning students to a homeless clinic is one way to help students identify professional values, such as altruism, equality, and human dignity.

The use of adhesive restorations in the management of localised anterior toothwear.

Toothwear appears to be increasingly common, particularly in the younger age groups, and will often require restorative intervention to provide satisfactory appearance and function. Well established conventional restorative techniques can be relatively complex and time-consuming and as a consequence may not be accessible for many patients. This paper, with the help of the literature, discusses the alternative application of a variety of adhesive materials and techniques used in the restoration of moderate to severe anterior toothwear.

The replacement of missing maxillary central incisor teeth incorporating a midline diastema with a fixed-fixed resin-retained bridge.

The replacement of maxillary central incisor teeth with the maintenance of a midline diastema can create considerable problems for the restorative dental surgeon. This case report illustrates the treatment of such a case using a fixed-fixed resin-retained bridge with a modified palatal connector. Alternative treatment options are discussed.

An immediate resin-bonded bridge using the natural tooth.

Missing anterior teeth are commonly replaced immediately with partial dentures, but this may cause embarrassing problems and a poor aesthetic appearance. This paper describes a technique for replacing anterior teeth using the natural tooth as a pontic with a resin-bonded cast metal framework. The main advantage of this technique is that a fixed restoration is provided on the same day as the tooth is removed, providing a major psychological benefit to the patient and maintaining the aesthetics. The short-term results are promising- and recent advances in adhesive dentistry mean that the long-term result should be equally as good.

Hypodontia: 2. The management of severe hypodontia.

The management of severe lack of teeth in the dental arch presents the clinician with a number of difficulties. In this paper, the second in a series on hypodontia, the problems are outlined and suggestions made as how best to overcome them.