Pulpal space pressure and temperature changes from Nd:YAG laser irradiation of dentin

OBJECTIVES

To investigate pulpal space pressure and temperature after application of Nd:YAG laser, and high-speed diamond bur on dentin surface.

METHODS

One and 3 W Nd:YAG laser and high-speed diamond bur were used to remove dentine from twenty extracted premolars. The pulp chambers were monitored for pressure and temperature changes with a pressure transducer and thermocouple, respectively.

RESULTS

Regardless of the remaining dentin thickness (RDT), laser irradiation and high-speed diamond bur use generated an increase in pulpal space pressure and temperature (ANOVA and Fisher's LSD tests, P < 0.001). Pressure and temperature increased with an increase in laser power. Three-Watt laser irradiation caused greater changes than 1 W (1.75 kPa and 1.31 degrees C, 0.53 kPa and 0.34 degrees C, respectively). Both pulpal space pressure (P < 0.001) and temperature (P < 0.005) increased as the RDT decreased.

CONCLUSIONS

Laser irradiation and the use of a high-speed diamond bur generated an increase in pulpal space pressure and temperature. Pulpal space pressure and temperature increased with an increase in energy density of laser and a decrease in RDT.

Effects of vaginalBrucella ovisinfection of red deer hinds on reproductive performance, and venereal transmission to stags

AIMS

To investigate the effects of vaginal Brucella ovis infection on the reproductive performance of red deer (Cervus elaphus) hinds. To determine whether stags may become infected with B. ovis by venereal transmission from mating infected hinds.

METHODS

Thirty mixed-age red deer hinds serologically negative for B. ovis antibodies were synchronised for oestrus on 22 March 2000. B. ovis was inoculated into the vagina of each hind at oestrus and again, 18 days later. At oestrus, hinds were randomly allocated to six groups, each joined with a 16 month-old red deer stag seronegative for B. ovis, for 55 days. Hinds were blood sampled and scanned for pregnancy using rectal ultrasonography at monthly intervals. Six pregnant and four non-pregnant hinds were slaughtered pre-calving and three hinds were slaughtered post-calving. Reproductive tracts and foetuses were examined grossly, histologically and microbiologically. Calves were identified and blood sampled within 3 days of birth. Hinds and calves were blood sampled in February and May 2001 and vaginal swabs were collected from hinds for B. ovis culture. Blood was collected from stags, 5 and 19 days after mating and semen was collected for B. ovis culture. The 17 remaining hinds were mated in 2001 to two mixed-age wapiti (Cervus canadensis) stags. Both stags were blood sampled after mating. Sera were tested in a B. ovis complement fixation test (CFT) and enzyme-linked immunosorbent assay (ELISA).

RESULTS

All 30 hinds developed B. ovis antibody levels, measurable using either the CFT or ELISA, but these did not remain elevated. There was no evidence of infection, either by gross pathology, histopathology or microbiological culture in the ten hinds or six foetuses slaughtered pre-calving. All remaining 20 hinds produced normal calves, 15 of which survived until weaning. Three hinds experienced dystocia and gave birth to dead calves and two calves died within 4 days of birth. One hind which had dystocia was euthanased. Samples from this hind and from 3/5 dead calves showed no evidence of B. ovis infection. B. ovis was cultured from the vagina of 1/19 hinds 48 weeks after inoculation, at which time B. ovis CFT and ELISA results for this hind were negative. Most calves had B. ovis serum antibodies at 1-3 days of age but levels were negligible when sampled at 10-15 weeks of age. Foetuses and dead calves were all seronegative. Three of the five red deer stags used for mating became infected with B. ovis. The two wapiti stags used to mate the remaining 17 hinds the following year remained seronegative.

CONCLUSIONS

B. ovis is unlikely to have significant detrimental effects on the reproductive performance of red deer hinds. Venereal transmission via the vagina of hinds is a possible route of transmission between stags. It is possible that survival of the organism in the vagina of some hinds could create difficulties in disease control programmes.

CLINICAL RELEVANCE

B. ovis infection of hinds at the time of mating is unlikely to cause significant reproductive losses. Venereal transmission of B. ovis between stags via the hinds may occur when groups of hinds are joined with more than one stag.

The ferrule effect: a literature review

LITERATURE REVIEW

A ferrule is a metal ring or cap used to strengthen the end of a stick or tube. It has been proposed that the use of a ferrule as part of the core or artificial crown may be of benefit in reinforcing root-filled teeth. A review of the literature investigating this effect is presented. The literature demonstrates that a ferrule effect occurs owing to the artificial crown bracing against the dentine extending coronal to the crown margin. Overall, it can be concluded that a ferrule is desirable, but should not be provided at the expense of the remaining tooth/root structure.

Liver copper, selenium and vitamin B12concentrations in farmed and feral red deer (Cervus elaphus)

AIM

To compare liver copper, selenium and vitamin B12 concentrations in red deer of farmed and feral origin.

METHODS

Liver samples were collected from red deer at a South Island deer slaughter premise and a game packing house in November 2000. The site of origin and age of each animal were recorded. A subsample of 107 livers was selected (n=5-10 per site of origin and age category) from farmed deer from central Canterbury, Nelson and Westland, and from feral deer from north, central and south Westland. Samples were analysed for copper, selenium and vitamin B12 concentrations and reported on a wet-matter basis.

RESULTS

Mean liver copper concentrations for farmed and feral yearlings were 267 and 889 micromol/kg, respectively, and for farmed and feral adults were 206 and 677 micromol/kg, respectively. Liver copper concentrations were lower for farmed than for feral deer (p<0.001) and for feral adults than for feral yearlings (p=0.002). Mean liver selenium concentrations in farmed and feral yearlings were 2050 and 1539 nmol/kg, respectively, and in farmed and feral adults were 1938 and 1625 nmol/kg, respectively. Liver selenium concentrations varied significantly between regions and overall, farmed deer had higher liver selenium concentrations than feral deer (p=0.04). Mean liver vitamin B12 concentrations in farmed and feral yearlings were 456 and 742 nmol/kg, and for farmed and feral adults were 428 and 869 nmol/kg, respectively. Liver vitamin B12 concentrations were lower for farmed than for feral deer (p<0.001).

CONCLUSION

Feral deer had higher liver copper and vitamin B12 concentrations and lower liver selenium concentrations than farmed deer in the regions studied.

Complex regional pain syndrome

Complex regional pain syndrome (CRPS), formerly known as reflex sympathetic dystrophy, is a regional, posttraumatic, neuropathic pain problem that most often affects 1 or more limbs. Like most medical conditions, early diagnosis and treatment increase the likelihood of a successful outcome. Accordingly, patients with clinical signs and symptoms of CRPS after an injury should be referred immediately to a physician with expertise in evaluating and treating this condition. Physical therapy is the cornerstone and first-line treatment for CRPS. Mild cases respond to physical therapy and physical modalities. Mild to moderate cases may require adjuvant analgesics, such as anticonvulsants and/or antidepressants. An opioid should be added to the treatment regimen if these medications do not provide sufficient analgesia to allow the patient to participate in physical therapy. Patients with moderate to severe pain and/or sympathetic dysfunction require regional anesthetic blockade to participate in physical therapy. A small percentage of patients develop refractory, chronic pain and require long-term multidisciplinary treatment, including physical therapy, psychological support, and pain-relieving measures. Pain-relieving measures include medications, sympathetic/somatic blockade, spinal cord stimulation, and spinal analgesia.

Advances in health and welfare of farmed deer in New Zealand

New Zealand has lead the world in pastoral farming of red, wapiti and fallow deer since this was first sanctioned in 1970. Among technological advances in deer production systems have been milestones in our understanding of deer health and welfare in an intensive pastoral farming environment, contributed by the combined efforts of veterinary practitioners, producers and researchers. These advances have impacted enormously on the health and wellbeing of New Zealand's farmed deer population, and contribute significantly to the success of deer production systems and the sustainability of the industry's international markets and reputation. These activities have brought local and international distinction upon the veterinary profession in New Zealand, by demonstrating innovation and initiative in establishing a new discipline of veterinary endeavor. This paper briefly reviews the important milestones in veterinary knowledge of capture-stress management, deer mortalities, the key disease syndromes of tuberculosis, yersiniosis, malignant catarrhal fever (MCF), internal parasites, trace elements and miscellaneous conditions, and selected animal welfare issues.

A review of tissue reference values used to assess the trace element status of farmed red deer (Cervus elaphus)

AIMS

This paper reviews the principles for the establishment of biochemical reference criteria for assessing the trace element status of farmed livestock and summarises data for copper, selenium, vitamin B12 and iodine for farmed red deer.

COPPER

Enzootic ataxia and osteochondrosis occur when liver copper concentrations are below 60 micromol/kg fresh tissue, and serum copper concentrations are below 3-4 micromol/l. Growth responses to copper supplementation have been equivocal when blood copper concentrations were 3-4 micromol/l, but were significant when mean blood copper concentrations were 0.9-4.0 micromol/l. No antler growth or bodyweight response to copper supplementation was observed when blood ferroxidase levels averaged 10-23 IU/l (equivalent to serum copper concentrations of 6-13 micromol/l) and liver copper concentrations averaged 98 mumol/kg fresh tissue. These data suggest that 'deficient', 'marginal' and 'adequate' ranges for serum copper concentrations should be 5, 5-8, and 8 micromol/l, respectively, and those for liver copper concentrations should be 60, 60-100, and 100 micromol/kg, respectively.

SELENIUM

White muscle disease has been reported in young deer with blood and liver selenium concentrations of 84-140 nmol/l and 240-500 nmol/kg fresh tissue, respectively. No growth-rate response to selenium supplementation occurred in rising 1-year-old deer when blood selenium concentrations were less than 130 nmol/l, the range in which a growth-rate response would be expected in sheep. VITAMIN B12: Vitamin B12 concentrations in deer are frequently below 185 pmol/l without clinical or subclinical effects. No growth response was observed in young deer with vitamin B12 concentrations as low as 75-83 pmol/l. A growth response to cobalt/vitamin B12 supplementation occurs in lambs with serum vitamin B12 concentrations 336 pmol/l.

CONCLUSIONS

Data that can be used to establish reference ranges for assessing trace element status in deer are limited. More robust reference values for farmed red deer need to be established through further studies relating biochemical data to health and performance.

Risk factors for dystocia in farmed red deer (Cervus elaphus)

OBJECTIVE

To analyse data from a study of deer herd health and productivity to identify potential risk factors for the occurrence of dystocia.

DESIGN

A 2-year longitudinal observational study of 14 red deer farms was carried out in New Zealand. About 2700 hinds were monitored each year for individual characteristics including body condition score (BCS), and reproductive performance. Grazing and calving management practices were recorded. During calving, farmers recorded calving difficulties (dystocia) that needed human assistance or caused the death of the hind. Risk factors potentially affecting the occurrence of dystocia were identified and analysed by multivariable statistical techniques.

RESULTS

The percentage of hinds with dystocia was 0.52% (95% CI 0.32 to 0.78). Hinds with a post-winter BCS over 3.5 were 2.7 times as likely to experience dystocia as hinds scoring 3.5 or less. Given the same BCS class, bodyweight gain in late pregnancy was associated with an increased risk of dystocia. Grazing steep paddocks in the last trimester of pregnancy decreased the risk of dystocia in hinds with a BCS over 3.5.

CONCLUSIONS

The risk of dystocia on red deer farms may be reduced if key individual animal, management and environmental factors are optimal.

Disease and mortality on red deer farms in New Zealand

A longitudinal observational study of 15 red deer farms was carried out in New Zealand for two years from March 1992. The deer were monitored for performance and health problems, and farm management practices were recorded. Numbers at risk were 4,683 hind-years, 2,459 stag-years and 3,202 weaner-years. The numbers of primiparous and adult hinds at risk of losing their progeny by weaning were 653 and 3,364, respectively. Where possible, postmortem examinations were carried out, and organs were sampled for histological and microbiological investigation. Rates of mortality varied with season with most stag and hind deaths in winter and weaner deaths in autumn and winter. Overall mortality rates were 1.77, 2.60 and 5.87 per 100 deer-years for hinds, stags and weaners, respectively. Malignant catarrhal fever accounted for 0.53 stag and 0.17 hind deaths per 100 deer-years at risk Misadventure, including broken bones, accounted for 15.4 per cent of weaner mortalities, or 0.53 weaner mortalities per 100 weaner-three months in autumn. Yersiniosis was confirmed in 18.6 per cent of weaner deaths, or 1.09 weaners per 100 weaner-years during the first six months after weaning, but was also suspected but unconfirmed in a further 41 per cent of weaner mortalities. Overall, 17 per cent of yearling hinds, and 9.2 per cent of adult hinds lost their progeny between pregnancy diagnosis in June and weaning in March. One outbreak of osteochondrosis was recorded. Mortality rates varied between farms and many mortalities were preventable.

The effect of oscillation and low seating forces on pulpward pressure transmission and seating during crown cementation: a laboratory study

PURPOSE

This study investigated the effects of low seating force (5 N) with and without oscillation on pulpward pressure transmission during crown cementation.

MATERIALS AND METHODS

Thirty human premolars received standardized complete-crown preparations. They were randomly allocated into three experimental groups of ten: group 1 = 100-N static load; group 2 = 5-N static load; and group 3 = 5-N load with oscillation. Crowns were constructed of base-metal alloy and attached to a purpose-built loading device. Pulpal pressures were recorded using a 0- to 104-kPa pressure transducer that was connected via the sectioned root of the premolar to the pulp chamber, which was perfused with saline driven by nitrogen gas at 83 kPa until a steady rate was achieved. The crowns were cemented using zinc phosphate cement, and postcementation elevations were measured with a linear variable differential transformer. An amalgam condenser provided oscillation for 1 minute.

RESULTS

The pulpal pressures were: group 1 = 455 Pa; group 2 = 26 Pa; and group 3 = 76 Pa. The postcementation crown elevations were: group 1 = -48 microm; group 2 = 362 microm; and group 3 = 26 microm.

CONCLUSION

Acceptable crown seating can be obtained using low force (5 N) combined with oscillation, and lower pressure pulses are generated compared to using high force (100 N) alone.

Evaluation of techniques for lignocaine hydrochloride analgesia of the velvet antler of adult stags

AIM

To evaluate the effectiveness of various routes of administration and doses of local anaesthetic (LA) to provide analgesia of the velvet antler of adult stags.

METHODS

In Experiment 1, antlers from 50 red deer stags, >or=2-years-old were allocated to 1 of 4 treatment groups (n = 25 antlers/group) to receive injections with 2% lignocaine hydrochloride as follows: High-dose (1 ml/cm pedicle circumference) or Low-dose ring-block (0.4 ml/cm pedicle circumference) or; High-site or Low-site regional nerve block (5 ml per site, both of which included the auriculopalpebral nerve). An electrical stimulus was applied before application of LA and then each min for up to 4 min after LA injection. If no response was observed, analgesia was tested with a saw cut. If no response occurred, the antler was cut at that time. If the animal responded, a further wait time was applied until 4 min had elapsed, at which time observations ceased. In Experiment 2, 10 primary and 50 re-growth antlers were given a High-dose ring-block and tested with a saw cut after 1 min (n = 30) or 2 min (n = 30). If no response occurred, the antler was removed. If a response occurred, further 1-min wait periods were applied.

RESULTS

In the High-dose ring-block and High-site nerve-block groups, 24/25 and 21/25 antlers were removed without response by 2 min, compared with 20/25 and 15/25 antlers in the Low-dose ring-block and Low-site nerve-block groups, respectively. The High-dose ring-block provided more effective analgesia after 3 min than the Low-dose ring-block, as assessed by the number of stags that did not respond to the electrical stimulus (p = 0.008), or subsequent antler removal (p = 0.050). The numbers of antlers removed without response after 1 or 2 min were greater using the High-site nerve-block than the Low-site nerve-block (p = 0.002 and p = 0.037, respectively). In all but the High-dose ring-block group, at least 1 stag required further LA after 4 min, before antler could be humanely removed. In Experiment 2, stags reacted to a saw-cut test on 6/30 antlers, 1 min after a High-dose ring-block, compared with 1/30 antlers after 2 min (p = 0.051).

CONCLUSION

The High-dose ring-block produced the most effective and rapid analgesia.

CLINICAL RELEVANCE

A High-dose ring-block with a 2-min wait period should be the preferred method for achieving local analgesia for velvet antler removal.

The effect of venting on pulpward pressure transmission and seating on crown cementation: a laboratory study

Measurable hydraulic forces towards the pulp chamber can occur whilst cementing a crown. This study investigated the effect of crown venting and the use of two different seating forces (100 and 2. 5 N) on pulpward pressure transmission. Forty single-rooted premolar teeth were collected from patients requiring extractions for orthodontic reasons. A standardized crown preparation was made and impressions taken to construct individual base-metal alloy crowns. The teeth were divided into four groups based on the type of crown (vented or non-vented) and force used (100 or 2.5 N). The teeth mounted on a specially constructed stand and connected to a 0-104 kPa pressure transducer. The pulp chamber was perfused with saline driven by nitrogen gas at 83 kPa for up to 2 h until a steady state perfusion rate was achieved. Crowns were cemented to the teeth on a uniaxial seating device using zinc phosphate cement. Simultaneous recordings of both pressure pulse and seating discrepancies were recorded. The 40-fold increase in seating force from 2.5 to 100 N resulted in a significant increase (P<0.001) in pulpward pressure in both vented and non-vented crowns. Seating was also significantly improved for the vented crowns regardless of which force was used. Venting had no significant effect on pulpward pressure transmission. It was concluded that a significant relationship existed between seating force and pulpward pressure transmission. Venting improved crown seating but did not have a demonstrable effect on pulpward pressure transmission.

Attempted transmission ofBrucella ovisbetween red deer stags by successive grazing or adjacent-paddock grazing

AIM

To determine whether Brucella ovis can be transmitted from stag to stag by successive grazing of infected and noninfected stags in the same paddock, or by grazing infected and non-infected stags in adjacent paddocks.

METHODS

Six red deer stags (Cervus elaphus) were artificially infected with B. ovis and 5 were confirmed to be shedding the organism in their semen. Infected stags alternated paddocks, and therefore grazing and wallows (successive grazing), once or twice weekly with 6 non-infected stags from 3 March to 18 August, 1999. Direct contact between the 2 groups of animals was prevented. The 2 groups alternated paddocks 32 times. Six other non-infected stags were grazed in a paddock adjacent to the infected stags throughout this period, separated by a standard deer fence. Non-infected stags were blood sampled at 2to 6-week intervals to test for B. ovis antibodies using a complement fixation test and an enzyme linked immunosorbent assay.

RESULTS

No stag from either non-infected group became infected with B. ovis.

CONCLUSIONS

The risk of stags becoming infected with B. ovis by successive grazing of the same paddock as, or by grazing in paddocks adjacent to, infected stags appears to be low. We conclude from this result, and similar experimental evidence and experience of this disease in sheep, that transmission of B. ovis requires animals to be grazed or confined together in a way that allows direct contact between animals.

CLINICAL RELEVANCE

It is likely that infected and non-infected stags can be managed on the same property without transmission occurring between the groups, provided that they do not come into direct contact with one another.

A survey of the distribution and types of full crowns prescribed in Melbourne, Australia

The full crowns made by 11 commercial dental laboratories in Melbourne, Australia, were surveyed over a two-month period. The survey was designed to find which teeth were crowned and what types of full crowns were prescribed. Maxillary central incisors were found to be the most frequently crowned teeth (15.6 per cent) and porcelain-fused-to-metal crowns were the most commonly prescribed type of crown (82.9 per cent). This study may form a baseline with which other Australian studies may be compared and contrasted.

A randomized, placebo-controlled study of outpatient premedication for bone marrow biopsy in adults with lymphoma

The outpatient bone marrow biopsy and aspiration (BMBA) procedure performed with local anesthetic is often poorly tolerated in adults. This prospective, randomized, placebo-controlled, double-blind trial was designed to determine whether oral (p.o.) lorazepam and hydromorphone reduces pain and anxiety during BMBA. Eligible patients had lymphoma, had no prior BMBA, and were > or = 18 years old. Since patients had bilateral BMBA, each served as their own control. Patients were stratified by anxiety level using the Spielberger Trait Anxiety Scale and randomized to: A) placebo for the first BMBA and 2 mg lorazepam and 2 mg hydromorphone p.o. for the contralateral BMBA, or B) placebo for both BMBAS. Changes in pain and anxiety experienced between the first and second BMBA were measured by the Visual Analogue Scale (VAS) and the Spielberger State Anxiety Scale at the time of the BMBA and 24 hours later. Twenty-seven patients were enrolled and 25 were evaluable; there were 17 males and eight females. The median age was 57 years (range, 28-79 years). Overall, BMBA was reported as painful in both arms, with a median VAS pain score after the second BMBA of 3.9 (scale, 0-10) for arm A and 5.8 for arm B (P = 0.21). There was no difference in the change in pain, anxiety, or recalled anxiety between treatment arms (all P values > 0.05). The difference in the change in recalled pain was of borderline significance (P = 0.07) and consistent with benzodiazepine-induced anterograde amnesia.

Effect of forage legumes containing condensed tannins on lungworm (Dictyocaulus sp.) and gastrointestinal parasitism in young red deer (Cervus elaphus)

To investigate the effect of feeding forage legumes containing condensed tannins (CT) on internal parasitism, red deer calves were fed either lucerne (Medicago sativa; 0.1 per cent CT), birdsfoot trefoil (Lotus corniculatus; 1.9 per cent CT) or sulla (Hedysarum coronarium; 3.5 per cent CT) and trickle-infected with deer-origin gastrointestinal nematode and lungworm (Dictyocaulus sp.) larvae for 5 weeks, then slaughtered at 7 weeks. There was a significant negative linear relationship between dietary CT concentration and abomasal nematode burdens. No significant differences in faecal egg counts, lungworm burdens or voluntary feed intake were found. Deer fed sulla had higher liveweight gain, carcass weight and carcass dressing-out percentage, higher serum total protein and albumin concentration and lower serum gastrin concentration and faecal lungworm larval count, compared with lucerne-fed deer. Inclusion of sulla in diets for young red deer may reduce the impact of internal parasites and/or reduce the dependence on anthelmintic treatment.

Fracture strength of all-ceramic crowns with varying core elastic moduli

The aim of this study was to investigate the fracture strength of aluminous porcelain jacket crowns on core structures with different elastic moduli. Forty standardized aluminous porcelain jacket crowns were fabricated and divided into four groups. Each crown was luted with zinc phosphate cement onto a master die with a known elastic modulus, and loaded until failure occurred. The fracture load was shown to increase with increasing elastic modulus of the core. Analysis of data by ANOVA revealed a significant difference (p < 0.05) between the four groups. The results suggested that core elastic modulus may have an influence on the fracture resistance of aluminous porcelain jacket crowns, and it may be appropriate to recommend the use of high modulus metals for core placement on teeth to be restored with all-ceramic crowns.

Reproductive performance of farmed red deer (Cervus elaphus) in New Zealand: V. Mob and individual-hind risk factors associated with calf rearing to weaning

A 2-year longitudinal observational study of 15 red deer farms was carried out in New Zealand from March 1992. Both years combined, 3364 adult and 653 yearling hinds were diagnosed pregnant in June by ultrasound scanning and monitored for reproductive success up to weaning. At weaning, pre-rut at approximately 100 days after calving, udders were palpated or observed by the farmer and hinds were categorised as lactating (wet) indicating survival of calf, or not lactating (dry). Farm management practices during calving and early lactation were recorded. Analysis of risk factors associated with progeny survival was done using path analysis (separately for adult and yearling hinds). Adult hinds >3 years old at calving, conceiving before 1 May and having a body-condition score >2 in September had 2.8, 2.4 and 2.9 times significantly higher odds of rearing a calf to weaning than other hinds, respectively. Adult hinds had about 5 times lower odds of rearing a calf to weaning when they were mixed with mature stags during calving. When farmers visited calving paddocks and checked for calving problems, adult hinds had 1.7 times higher odds of rearing a calf to weaning. When the farmer entered calving paddocks at least every second time they observed the hinds, yearling hinds had a twice higher odds of rearing a calf up to weaning. Sunny weather and high maximum temperatures were positively and negatively associated, respectively, with the probability of an adult hind being in lactation at weaning.

A model for study of lungworm (Dictyocaulus sp.) and gastrointestinal nematode infection in young red deer (Cervus elaphus)

A model of sub-clinical parasitism in young red deer, using concurrent trickle infections of lungworm (Dictyocaulus sp.) and mixed gastro-intestinal (GI) nematodes of deer-origin was evaluated. 20 parasite-free deer calves were artificially reared indoors from 4 days of age. A further five calves were naturally reared on pasture with their dams, treated with anthelmintic and brought indoors at 3-4 months. At 4-4.5 months of age they were individually housed and allocated to five groups (n=5). Groups were dosed 3 x per week, for 9 weeks with 0, 100 and 500, 200 and 1000 (2 groups), 400 and 2000 infective larvae of lungworm and mixed GI nematodes, respectively, cultured from deer faeces. Liveweight and voluntary feed intake measurements and faecal and blood samples were taken weekly. In the fourth week following cessation of trickle infection, deer were euthanased and lung and GI nematodes recovered. Both lungworm and GI nematode infections became patent at Week 4 of infection. Maximum group arithmetic mean faecal egg counts were 100-190 epg. Maximum group arithmetic mean faecal lungworm larval counts were 58-123 lpg. Group arithmetic mean nematode counts at slaughter ranged from 439-806 for GI nematodes and 31-73 for lungworm, respectively. Despite low nematode counts, reduced liveweight gain, voluntary feed intake and serum albumin concentration, elevated serum pepsinogen, gastrin and globulin concentrations and elevated peripheral eosinophil counts and slight haemoconcentration, but no clinical signs, were observed. The reduction in liveweight gain was related to the reduction in voluntary feed intake (r2=0.83; p<0.088). Naturally-reared deer had similar liveweight gains, voluntary feed intake and nematode counts to artificially-reared deer. Thus, methods of infection to produce concurrent sub-clinical lungworm and GI nematode burdens for study of sub-clinical parasitism in young deer have been defined.

A new imaging technique for measuring the surface strains applied to dentine

OBJECTIVES

To investigate possible variation in directional material properties of dentine in relationship to tubule orientation using a new optical imaging technique.

METHOD

The optical imaging technique records photometrically a grid pattern formed by using a transmission electron microscope grid as a template on the polished surface of the dentine. The grid pattern is silhouetted onto the sample surface using standard techniques. Compression (c) and diametral compression (dc) tests were undertaken using a servo hydraulic testing machine (MTS model 810) acting on rectangular blocks of dentine with dimensions 1.5 x 1.0 x 1.0 mm (for c) and cylindrical samples with dimensions 2.1 mm in diameter and 1-1.5 mm thick (for dc), respectively. The samples were cut using a diamond wheel and miniature lathe and the cut surfaces polished. Images due to a changing load profile were captured and stored as digitised files on a computer for later analysis. The precision is mainly determined by the pixel resolution of the charged-coupled device camera.

RESULTS

Preliminary results show the value of elastic modulus of dentine (10.4 +/- 2.9 GPa) to be similar to those previously reported in the literature. Very small localised strains at the surface of a sample can be observed qualitatively and measured quantitatively by reference to the line spacing (approximately 85 microns). Maximum strength varied with tubule orientation and (compressive/tensile) stress.

CONCLUSION

Very small samples of dentine may be investigated for strain in more than one direction using the imaging technique described. These results may be more appropriate for finding relative directional change rather than obtaining the elastic properties of the dentine.

Angular asymmetries of the human face

PURPOSE

The determination of an acceptable occlusal plane is essential for the development of esthetic prosthodontic restorations. However, since most faces are not symmetric, a method was developed for measuring facial angular asymmetry, i.e., the divergence from the vertical or horizontal of the line joining the midpoint of the intercanthal line and the philtrum of the lip, the interpupillary line, the intermeatal line, the lip commissure line, and the intercuspid line.

MATERIALS AND METHODS

Standardized frontal images (mouth closed, smiling, and biting on a wooden spatula) of 100 subjects were taken using a digital camera. These images were downloaded into a computer, and the angles between the various facial lines and the horizontal were measured. The subjects were grouped by sex, age, and history of trauma and orthodontic treatment.

RESULTS

No statistically significant differences were found between the mean values for each group.

CONCLUSION

Asymmetry of the face can be measured using digital camera imaging and computer analysis. A range of facial asymmetries that can influence the choice of occlusal plane during prosthodontic treatment exists. Thus, the use of an occlusal plane parallel to the ala tragus and interpupillary lines, as often advocated by prosthodontists, may result in less than ideal esthetics in the final restoration.

The effects of oscillating forces upon the flow of dental cements

The aim of this study was to evaluate the effect of oscillating forces upon the flow of five dental cements. A laboratory investigation was carried out using a crown and die. It showed that the application of oscillating forces improved the flow of the tested dental cements when combined with low static loads and wide crown-die separations. The oscillating forces enhanced the late, particle-dominated phase of cement flow. Further investigations characterised the nature of the oscillating forces applied in this experiment and revealed yield stress behaviour shown by one cement.

Complex Regional Pain Syndrome-Reflex Sympathetic Dystrophy

Complex regional pain syndrome-reflex sympathetic dystrophy (CRPS/RSD) is a complex pain-dysfunction syndrome of unknown cause that typically affects a single extremity. Changes are usually more marked peripherally. There are no generally accepted clinical diagnostic criteria or laboratory studies for CRPS/RSD; our current state of knowledge allows the diagnosis to be made only on clinical grounds. Clinical suspicion should be raised if pain and disability are greater than would usually be expected as a result of the original incident, if recovery is slower than expected, and if autonomic changes are prominent in the affected extremity. The pain associated with the condition may be sympathetically maintained, sympathetically independent, or both. No evidence-based treatment regimens for CRPS/RSD are available. Treatment of the individual patient is empiric and uses symptomatic techniques that seem logical or that have been proven to be effective in other conditions. The sympathetic nervous system makes an unknown contribution to CRPS/RSD, but it is not known whether this is a cause or an effect of the pain. Psychological and psychiatric changes are probably secondary rather than etiologic. Treatment should be immediate, aggressive, and directed toward restoration of full function of the extremity. Various analgesic techniques may be necessary to permit the patient to comply with the rehabilitation program. This program is best carried out in a comprehensive interdisciplinary setting, with a primary emphasis on functional restoration.

Routes and doses of lignocaine hydrochloride for analgesia of the velvet antler of stags

AIM

To evaluate the effectiveness of various routes of administration and doses of local anaesthetic to provide analgesia of the velvet antler of young stags.

METHODS

In study 1, in which an electrical stimulus was used, 64 l-year-old male red and red X wapiti deer with velvet antler lo-30 cm long, were randomly allocated to one of ten treatments with four treatments/animal, and 23 or 24 antlers/treatment. Treatments delivered included three control groups, three local anaesthetic (2% lignocaine HCL) doses delivered by ring block (5, 10 or 15 ml per pedicle), and a high or low regional block with or without an auriculopalpebral nerve block (5 ml per site). An electrical stimulus was applied before and 1,2,4 and 8 minutes after local anaesthetic treatments and to controls, at an increasing voltage until a response was observed. The voltage and animal responses were recorded. In Study 2 the same seven local anaesthetic treatments (16-I 8 antlers/treatment) were evaluated using 58 of the stags from Study 1 when antlers were ready for removal, but a saw cut was used as the test stimulus. A test cut was applied to the antler I,2 and 4 minutes after application of local anaesthetic. If no response was observed, the antler was removed at that time.

RESULTS

In Study 1, major dose and treatment effects were significantly different (p < 0.05) with the outcome variable being whether or not the deer responded. No stags given the high dose ring block responded to electrical stimulation 1 minute after treatment, one responded at 2 minutes, and none responded at 4 or 8 minutes. At least one animal responded after all other treatments at all time intervals. More deer responded after the low regional block than the high regional block, and there was a lower response rate when the auriculopalpebral nerves were anaesthetised. In Study 2, no deer responded 2 minutes after the medium dose ring block treatment. Three of 18 stags receiving the high dose ring block still responded after 2 minutes, and one responded after 4 minutes. Responses occurred to all other treatments at each time, with some deer requiring further administration of local anaesthetic before antler removal, even with the four minute waiting period.

CONCLUSION

Ring blocks produced more consistent analgesia of the velvet antler than regional nerve blocks. The high dose ring block produced analgesia faster and more effectively than lower doses, and the regional nerve blocks were more effective when the auriculopalpebral nerve was blocked.