World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.): Third edition of the guideline for evaluating efficacy of anthelmintics in ruminants (bovine, ovine, caprine)

This guideline is aimed at those who are involved in the assessment of anthelmintic efficacy in ruminant livestock species (bovine, ovine and caprine). The intent is to provide a framework that can be adopted worldwide for the testing of anthelmintics in ruminants, such that studies carried out in different countries can be compared and thereby unnecessary duplication can be reduced. Recommendations are made for the selection, housing and feeding of study animals, the type of studies required, the method used to conduct those studies, the assessment of results and the standards for defining anthelmintic efficacy.

The orthodontic condition of children in the United Kingdom, 2003

BACKGROUND

The 2003 Children's Dental Health Survey is the fourth in a series of decennial national children's dental health surveys in the United Kingdom.

AIMS

This paper reports on the orthodontic condition of children aged 12 and 15 years.

METHODOLOGY

A representative sample of children across the UK were invited to participate in a clinical dental examination in school. Two thousand, five hundred and ninety-five 12-year-olds and 2,142 15-year-olds were examined. Current and past orthodontic treatment and type of appliance worn were recorded. Orthodontic treatment need was assessed by the Modified IOTN in those not undergoing treatment. A postal questionnaire sought parents' views on the orthodontic condition of their children and perceived need for treatment.

RESULTS

At age 12, 35% were judged to have an orthodontic treatment need, 57% had no need and 8% were wearing an appliance. The corresponding figures at age 15 were, 21% (need), 65% (no need) and 14% (wearing appliance). A higher proportion of girls (p < 0.05) were wearing an appliance than boys. A greater proportion of 15-year-olds were undergoing treatment than in the 1993 and 1983 surveys and the use of fixed appliances had increased.

CONCLUSIONS

In this representative sample of UK children, one in five were still judged as having an orthodontic treatment need at age 15 years, as determined by the modified index of orthodontic treatment need. However, considerable variation was observed between professional and lay perceptions of need.

The influence of lower face vertical proportion on facial attractiveness

This study investigated the influence of changing lower face vertical proportion on the attractiveness ratings scored by lay people.Ninety-two social science students rated the attractiveness of a series of silhouettes with normal, reduced or increased lower face proportions. The random sequences of 10 images included an image with the Eastman normal lower face height relative to total face height [lower anterior face height/total anterior face height (LAFH/TAFH) of 55 per cent], and images with LAFH/TAFH increased or decreased by up to four standard deviations (SD) from the Eastman norm. All the images had a skeletal Class I antero-posterior (AP) relationship. A duplicate image in each sequence assessed repeatability. The participants scored each image using a 10 point numerical scale and also indicated whether they would seek treatment if the image was their own profile. The profile image with normal vertical facial proportions was rated by the lay people as the most attractive. Attractiveness scores reduced as the vertical facial proportions diverged from the normal value. Images with a reduced lower face proportion were rated as significantly more attractive than the corresponding images with an increased lower face proportion. Images with a reduced lower face proportion were also significantly less likely to be judged as needing treatment than the corresponding images with an increased lower face proportion.

The psychosocial impact of orthognathic surgery: a systematic review

The aim of this study was to review the reported psychosocial benefits of orthognathic surgery. A systematic review of the literature was conducted using MEDLINE (1966 to December 2000), Web of Science (1981 to December 2000), and reference sections of identified articles. We also hand searched key orthodontic, oral surgery, and psychology journals. No language limitations were imposed. Randomized controlled trials, other controlled clinical trials, prospective studies (with or without controls), and retrospective studies (with or without controls) were considered for inclusion. Two reviewers extracted the data and independently assessed the quality of the studies. In all, 29 studies, including a number of prospective and retrospective studies, were identified as relevant. The results of the review indicated that orthognathic patients experience psychosocial benefits as a result of orthognathic surgery, including improved self-confidence, body and facial image, and social adjustment. However, there were wide variations in the study designs and a lack of uniformity in measuring the psychosocial constructs. This made it difficult to quantify the extent and the duration of the psychosocial benefits.

Modified IOTN: an orthodontic treatment need index for use in oral health surveys

This paper reports the results of a study of the reliability of a modified version of the Index of Orthodontic Treatment Need (IOTN) for use in oral health surveys. Twelve non-specialist dental examiners were trained in the use of the Modified IOTN using a standardised teaching protocol lasting approximately 1.5 hours. Following a school-based calibration exercise it was found that nearly all the examiners achieved either good or excellent agreement (mean Kappa=0.74). The average sensitivity and specificity scores were 0.90 and 0.84, respectively. The Modified IOTN appears to overcome the training and reliability problems that often accompany the use of orthodontic indices by non-specialists in oral health surveys.

Changes in substance P and neurokinin A in gingival crevicular fluid in response to periodontal treatment

BACKGROUND

The study of periodontitis provides a unique model for assessing the involvement of neuropeptides in inflammatory disease.

AIM

To investigate the effects of periodontal treatment, resulting in a return to periodontal health, on the levels of substance P (SP) and neurokinin A (NKA) in gingival crevicular fluid (GCF).

METHOD

We completed a cause of non-surgical treatment for 8 subjects with periodontitis (6 females 2 males, mean age 45.1, range 38-67 years) started a course of non-surgical periodontal treatment. Clinical indices were measured at 2 periodontitis sites at the initial visit and at 8 weeks after the completion of treatment in each subject. A 30-s sample of GCF was collected from each test site using perio paper strips. Each strip was placed into 500 microl of ice cold 0.1 M PBS, pH 7.4, vortex mixed for 30 s, and then stored at -70 degrees C until analysed by radioimmunoassay.

RESULTS

The clinical condition of all test sites improved as a result of the periodontal treatment. The levels (pg/30 s sample) of SP fell from 56.3 (SD 66.0) at the initial visit to 4.2 (3.1) after treatment, p=0.017. The concentration (pg/microl) of SP in GCF fell from 140.6 (175.6) to 24.2 (11.1), p=0.036. The levels of NKA fell from 30.5 (17.1) to 10.6 (4.9), p=0.012 whereas the concentration changed little from 85.4 (43.5) to 61.6 (15.1), p=0.41.

CONCLUSION

The reduction in inflammation resulting from effective periodontal treatment is associated with a reduction in the levels of tachykinins in gingival crevicular fluid.

The influence of dental to facial midline discrepancies on dental attractiveness ratings

This study investigated the perception of discrepancies between the dental and facial midlines by orthodontists and young laypeople. A smiling photograph of a young adult female was modified by moving the dental midline relative to the facial midline. Twenty orthodontists (10 males and 10 females) and 20 young adult laypeople (10 males and 10 females) scored the attractiveness of the smile on the original image and each of the modified images using a 10-point scale. The results showed that the images were scored as less attractive both by the orthodontists and laypeople as the size of the dental to facial midline discrepancy increased. The scores were unrelated to the direction of the midline discrepancy (left or right) or to the gender of the judge. Further analysis revealed that the orthodontists were more sensitive than laypeople to small discrepancies between the dental and facial midline. It was estimated that the probability of a layperson recording a less favourable attractiveness score when there was a 2-mm discrepancy between the dental and facial midlines was 56 per cent.

Predictors of outcome among patients with class II division 1 malocclusion treated with fixed appliances in the permanent dentition

This retrospective study investigated the outcomes achieved in 212 consecutively completed patients with Class II Division 1 malocclusion (overjet > 6 mm). All patients were treated in the permanent dentition with upper and lower fixed appliances. A composite outcome measure was used to identify those cases with an excellent outcome (posttreatment PAR </= 5, posttreatment upper incisor to maxillary plane angle between 104.7 degrees and 115.3 degrees, and anterior movement of the lower incisors </= 2 mm). Logistic regression analysis with patient group as the dependent variable was used to evaluate the predictive value of 32 patient and treatment variables. The three outcome measures (posttreatment PAR score, posttreatment upper incisor inclination, and anterior movement of lower incisors) were ranked and combined to form a single continuous outcome variable. This was used as the dependent variable to carry out further analysis with the linear regression method. Both methods of analysis identified pretreatment overjet and pretreatment upper incisor inclination as significant predictors of outcome. The results revealed that in patients with large overjets an excellent outcome can only be predicted if the upper incisors are very proclined. Every 2 mm increase in overjet (above 4 mm) required approximately a 5 degrees increase in incisor proclination to achieve an excellent outcome.

The effects of increasing the reverse curve of Spee in a lower archwire examined using a dynamic photo-elastic gelatine model

This paper describes the development and testing of a dynamic in vitro photo-elastic model for evaluating the effects of orthodontic mechanics on an entire arch of teeth. A model of a mandibular arch was made and the teeth were embedded in a gelatine material with a high level of mechanical creep which permitted tooth movement in response to orthodontic forces. The excellent photo-elastic properties of this material also facilitated the analysis of the stress distribution around the roots of the teeth. The model of a mandibular arch was used to investigate the tooth movements and stress distributions produced by increasing the reverse curve of Spee in a 0.018 x 0.025-inch stainless steel archwire. The results revealed that a 1-mm reverse curve of Spee increased the arch length by 1.6 mm, but increasing the reverse curve of Spee to 5 mm did not increase arch length further. Photo-elastic analysis showed an increased stress distribution around the roots of the incisors and molars as the reverse curve of Spee was increased in the archwire.

Palatally ectopic canines: closed eruption versus open eruption

This paper reviews the available evidence supporting 2 commonly used methods of surgically exposing palatally ectopic canines. The closed eruption method (a bonded attachment is placed at operation and the palatal flap is sutured back intact) is compared with the open eruption method (a window of palatal mucosa is excised and the canine allowed to erupt naturally). The choice of surgical technique is reviewed in terms of the long-term periodontal implications, the rate of repeat surgery, and treatment time.

Thermal image analysis of electrothermal debonding of ceramic brackets: an in vitro study

This study used modern thermal imaging techniques to investigate the temperature rise induced at the pulpal well during thermal debonding of ceramic brackets. Ceramic brackets were debonded from vertically sectioned premolar teeth using an electrothermal debonding unit. Ten teeth were debonded at the end of a single 3-second heating cycle. For a further group of 10 teeth, the bracket and heating element were left in contact with the tooth during the 3-second heating cycle and the 6-second cooling cycle. The average pulpal wall temperature increase for the teeth debonded at the end of the 3-second heating cycle was 16.8 degrees C. When the heating element and bracket remained in contact with the tooth during the 6-second cooling cycle an average temperature increase of 45.6 degrees C was recorded.

A retrospective comparison of craniofacial form in Northern Irish children with unilateral cleft lip and palate

OBJECTIVE

This study evaluated the craniofacial form of a sample of Northern Irish children with unilateral cleft lip and palate (UCLP). The quality of the outcomes achieved was compared with the outcomes reported for the six centers involved in the European multicenter study (Mars et al., 1992; Mølsted et al, 1992).

DESIGN

Retrospective analysis.

PATIENTS

All children born with complete skeletal UCLP in Northern Ireland during the years 1983 to 1987.

MAIN OUTCOME MEASURES

Cephalometric analysis was used to determine the craniofacial form and soft tissue profile. The quality of the dental arch relationships was independently assessed using the Goslon ranking system.

RESULTS

The sample comprised 25 children with complete skeletal UCLP who had cephalometric radiographs and study casts recorded at a mean age of 9.4 years (range, 8 to 11 years). Cephalometric analysis revealed no important skeletal differences between the Northern Irish UCLP children and the published results from the six Eurocleft centers. The soft tissue profile of the Northern Irish UCLP children was significantly more convex than the soft tissue profile recorded for center D in the Eurocleft study. The Goslon ranking system revealed that 18 (72%) of the Northern Irish UCLP children had good or satisfactory dental arch relationships.

CONCLUSIONS

No clinically important differences were detected between the mean cephalometric skeletal parameters of the Northern Irish UCLP children and those published for the six cleft centers involved in the Eurocleft study. On average, the Northern Irish UCLP children were found to differ significantly from Eurocleft's center D in their soft tissue facial contour and sagittal lip profile. The quality of the dental arch relationships of the Northern Irish sample was between the best and the less good Eurocleft centers.

Clinical assistant training in orthodontics--how effective is it?

OBJECTIVE

To investigate the quantity and the quality of orthodontic treatment carried out by dentists who have completed a 2-year orthodontic clinical assistant training programme.

DESIGN

Retrospective analysis.

SUBJECTS AND METHODS

During a 12-month period the volume of orthodontic treatments completed by 18 dentists who had participated in a clinical assistant training scheme was analysed. Using study models the initial need for treatment and the outcome of treatment of a consecutive sample of each dentist's completed cases were assessed.

MAIN OUTCOME MEASURES

IOTN and PAR indices used by expert examiners.

RESULTS

The median number of cases treated by the dentists was 37 with a range of 2 to 488. No significant predictive variables were associated with the higher volume operators. Of the 166 orthodontic cases evaluated 72.9% had a definite dental health need for orthodontic treatment. Following treatment the mean post-treatment PAR score for the whole sample was 9.2 (median = 8.0). Thirteen (72%) of the dentists had an average post-treatment PAR score of 10 or less.

CONCLUSIONS

The outcomes achieved by the Northern Irish clinical assistants were similar to those reported for other clinical assistant schemes. A significant proportion of the dentists treated a relatively low volume of patients and two of the dentists treated a very high volume of cases.

Equity and orthodontic treatment: a study among adolescents in Northern Ireland

This epidemiological study investigated the reasons why children in Northern Ireland who need orthodontic treatment do not receive treatment even when it is provided free by the state. A total of 1584 15- and 16-year-olds were examined in 23 high schools with the Index of Orthodontic Treatment Need. The characteristics of the adolescents who had received orthodontic treatment were compared with those who had a definite need for treatment and yet did not receive treatment or advice. One in 10 of the adolescents examined had an unmet need for orthodontic treatment. Logistic regression analysis was used to assess the influence of 11 variables including socioeconomic status, religion, and standard of dental health on the uptake of orthodontic care. This analysis revealed that the only significant predictors of whether an adolescent received orthodontic treatment was the dental attendance pattern of the adolescent, the adolescent's dental health, and the dental attendance pattern of the adolescent's mother. Those adolescents who had good dental health, who regularly attended a dentist, and whose mother regularly attended a dentist were more likely to receive orthodontic treatment.

Bonding to molars--the effect of etch time (an in vitro study)

This study evaluated the effect of etch time on the shear bond strength obtained when bonding to the buccal enamel of first molar teeth. Recently extracted first molar teeth were etched with 37 per cent phosphoric acid gel for 15, 30 and 60 seconds. Preformed cylinders of Concise composite resin were then bonded to the buccal surfaces of the molar teeth. After storage in water for 24 hours at 37 degrees C, the specimens were debonded in a direction parallel to the buccal surface. Examination of the shear bond strengths showed significant differences in shear bond strength between 15 and 30 seconds (P < 0.01) and between 15 and 60 seconds (P < 0.001). Weibull analysis revealed that the probability of bond survival increased as etch time increased, however, the difference between 30 and 60 seconds was not statistically significant. The results indicate that, despite current recommendations of a 15-second etch for premolars, canines and anterior teeth, an etching time of at least 30 seconds should be used when bonding to the buccal surfaces of first molars. A further increase in etching time to 60 seconds produces no significant increase in bond strength.

Treatment outcome for a sample of patients with Class II division 1 malocclusion treated at a regional hospital orthodontic department

This retrospective study assessed the outcome of orthodontic treatment of 264 patients with Class II division 1 malocclusion (overjet greater than 6 mm). The sample comprised patients who had completed their fixed appliance orthodontic treatment at a regional hospital orthodontic unit in the Republic of Ireland. The PAR Index (Peer Assessment Rating) was used to evaluate treatment outcome using before and after treatment study casts. The results revealed that treatment for this particular type of malocclusion was highly effective with a very few patients failing to benefit from their orthodontic treatment.

A field trial of an orthodontic treatment need learning package for general dental practitioners

OBJECTIVE

To evaluate whether GDPs using an index of Orthodontic Treatment Need (IOTN) learning package in a practice setting referred (or treated) more patients with a definite need for orthodontic treatment.

DESIGN

A randomised controlled trial.

SUBJECTS AND METHODS

20 GDPs (test group) used the package when selecting patients for orthodontic care during normal dental practice. A control group of 20 GDPs did not use the package. Over a 12-month period impressions were taken by the participating GDPs of all patients selected for orthodontic treatment, either referred to another practitioner or to be treated by the GDP.

MAIN OUTCOME MEASURE

IOTN used by two expert examiners.

RESULTS

Among the patients selected for orthodontic treatment by the test group there were more patients with a definite objective need for orthodontic treatment (78.1% versus 62.5% in the control group). After adjustment for potential confounding variables, the odds on a patient selected by a test group dentist being in definite need were 2.24 (95% CI 1.25, 4.01) more than the odds on a patient selected by a control group dentist (P = 0.007).

CONCLUSIONS

Use of the IOTN learning package by GDPs would reduce the proportion of patients selected for orthodontic treatment with low or moderate objective need.

An investigation of tooth size in Northern Irish people with bimaxillary dental protrusion

This study examined tooth size in a sample of thirty Northern Irish people with bimaxillary dental protrusion. The mesiodistal diameters of all permanent teeth (excluding second and third molars) were measured. The tooth sizes were compared with a control group who did not have bimaxillary dental protrusion. The results revealed that, on average, tooth size for the overall maxillary and mandibular dentition was 5.7 per cent larger in the bimaxillary sample than in the control sample.

The incidence of bacteremia after orthodontic banding

This investigation assessed the incidence of bacteremia after orthodontic banding. Thirty adult volunteers with good oral health, who were not at risk from bacterial endocarditis, were included in this study. An orthodontic band was placed on a first molar of each subject. Venous blood samples were taken before, and 1 to 2 minutes after the molar band was fitted. Microbiologic tests performed on the blood samples revealed a comparatively low incidence of bacteremia (10%) after orthodontic banding.

Training dental nurses in the use of the PAR Index: a pilot study

This paper reports the results of a PAR Index training and calibration course organized for dental nurses. Using a similar contact teaching time to that normally employed when training orthodontists, approximately one-quarter of the dental nurses were successfully calibrated in the use of the PAR Index.

The effect of etch duration on the microstructure of molar enamel: an in vitro study

This in vitro study evaluated the influence of varying etch time on the microstructure of molar buccal enamel. The buccal surfaces of four groups of extracted first molar teeth were etched for 15, 30, 45, and 60 seconds. The etch patterns obtained were photographed with a scanning electron microscope and rated with a 3-grade scale. The 15-second etch time failed to produce any optimal etch patterns. The best etch patterns were found in molars etched for 60 seconds.

Ankylosis: an orthodontic problem with a restorative solution

This case illustrates a restorative approach using adhesive techniques to overcome the aesthetic and functional problems associated with infraclusion of a mandibular canine tooth resulting from ankylosis. In this case a diagnosis of ankylosis was confirmed after 3 months of fixed appliance orthodontic therapy failed to extrude the tooth.

An investigation of the association between overjet size, lip coverage, and traumatic injury to maxillary incisors

This study investigated the association between overjet size and lip coverage when assessing the likelihood of traumatic injury to maxillary incisors. Eleven-hundred-and-thirty-seven 11- and 12-year-olds were examined in school for traumatic injury to their maxillary incisors. The size of overjet and the adequacy of lip coverage of the maxillary incisors was assessed for each child. One-hundred-and-sixty-seven (15 per cent) had experienced traumatic injury to their maxillary incisors. Both increased overjet and inadequate lip coverage of the maxillary incisors were found to be significant risk factors. However, inadequate lip coverage was the single most important independent predictor of traumatic injury (P < 0.001), with a relative odds ratio of 2.62. The results suggest that much of the predictive value of increased overjet may be explained by inadequate lip coverage.

Pilot study of an orthodontic treatment need learning package for general dental practitioners

This pilot study evaluated an Index of Orthodontic Treatment Need Learning Package which was developed for use by general dental practitioners. Fifty-seven dentists participated in a randomised controlled trial which involved assessing the need for orthodontic treatment among two representative samples of 16 study casts. All the dentists assessed the first set of study casts without any aids or assistance. During the assessment of the second set of study casts one group of dentists used an IOTN Learning Package in the form of a poster, another group used an IOTN Learning Package in the form of a booklet, and the remaining group acted as a control and did not use any Learning Package. The results reveal that compared with the control dentists, the dentists using the IOTN poster and the IOTN booklet had, respectively, 1.8 and 2.6 fewer errors when assessing aesthetic need and 2.0 and 2.1 fewer errors when assessing dental health need.

The ranking of dental aesthetics

This study examined the effectiveness of three different aesthetic ranking systems. The Aesthetic Component of the Index of Orthodontic Treatment Need (10 photographs), a numerical scale illustrated with three photographs and a numerical scale with only two photographs were assessed. Ten general dental practitioners ranked the attractiveness of dentitions using each aesthetic scale. A greater tendency to underscore was detected when the dentists used the two-photograph scale. Reducing the number of photographs in the aesthetic scale did not significantly improve the dentists ability to rank dental aesthetics.

Calibration of dentists in the use of occlusal indices

Dentists' opinions as to both need for and outcome of orthodontic treatment show wide variation. Within the profession there is an opportunity to reduce subjective bias and standardise criteria by the use of occlusal indices. The results of this study demonstrate that a group of dentists can easily be trained to record the Aesthetic and Dental Health Components of the Index of Orthodontic Treatment Need and the PAR index to a satisfactory level.

The influence of social class, gender, and peers on the uptake of orthodontic treatment

The accurate prediction of the future demand for orthodontic treatment requires an understanding of the factors which influence the uptake of orthodontic treatment. This paper examines the influence of social class, gender, and peer group on the uptake of orthodontic treatment. A representative random sample comprising five-hundred-and-forty 15- and 16-year-old adolescents were interviewed in school. The results indicate that familiarity with orthodontic appliances among a subject's peer group has a greater influence on the uptake of orthodontic treatment than the subject's social class or gender.

Self-perception of malocclusion among adolescents

This study investigated the self-perception of malocclusion among 506 15 and 16-year-old children. The Aesthetic Component of the Index of Orthodontic Treatment Need was used to allocate each subject to 'no aesthetic need' for treatment, 'borderline aesthetic need', or 'definite aesthetic need' for treatment subgroups. The results indicate that adolescents who were scored by a trained examiner (using IOTN) as having similar dental aesthetics have similar perceptions of their malocclusion irrespective of their gender or social background.

A comparison of orthodontic screening methods used in school dental inspections

The validity of two currently used orthodontic screening programmes was investigated and compared to an objective measure of need for orthodontic treatment. The results indicate that existing orthodontic screening methods underestimate the numbers of children with severe malocclusions. The use of a more objective measure of orthodontic treatment need is recommended.

Effectiveness of a personalised referral letter following orthodontic screening

No data exist on the usefulness of orthodontic screening in guiding those children who need orthodontic treatment towards professional advice. This study evaluated the effectiveness of a personalised referral letter following an orthodontic screening programme employing an objective measure of treatment need, the Index of Orthodontic Treatment Need (IOTN). Out of a total sample of 924 children aged 11-12 yr, 201 were in need of orthodontic treatment and no orthodontic treatment was planned. From this subsample test and control groups matched for sex, socio-economic background, dental disease and aesthetic impairment were created. Following screening, the parents of the test group only were sent a specific orthodontic referral letter. The dental practitioners of the children in the test and control groups were contacted during a follow-up investigation carried out 8 months later, this revealed that significantly more children entered orthodontic treatment pathways from the test group. This study demonstrated that a screening programme, using IOTN as a screening test, and a referral procedure which provided parents with specific information were successful in guiding over one third of children with a need for orthodontic treatment towards orthodontic advice.

The need for orthodontic treatment in the child population of the United Kingdom

The effective management of a public dental health system requires accurate data on the needs of the population. Previous assessments of the levels of orthodontic treatment need in populations, by both epidemiologists and orthodontists, vary considerably. This paper presents the findings of two independent investigations into orthodontic treatment need in the United Kingdom using the Index of Orthodontic Treatment Need (IOTN, Brook and Shaw, 1989). The results indicate that approximately one-third of 11-12-year-olds were in objective need of orthodontic treatment. The basis for allocation to the treatment need groups was similar in both studies, as were the proportions of the most severe occlusal traits.

Residual orthodontic treatment need in a sample of 15- and 16-year-olds

This study investigated the residual unmet orthodontic need, both normative and perceived, in young adults who had passed the age at which orthodontic treatment would have normally commenced. A total of 506 15- and 16-year-olds attending eight secondary schools were screened by a single trained examiner using the 'Index of Orthodontic Treatment Need' (IOTN). There were 154 (30.4%) subjects classified as being in need of orthodontic treatment using IOTN and 82 of these (16% of the sample) were found to be in need of orthodontic treatment but had no recollection of orthodontic treatment ever being discussed with them. Children with malocclusion, who had received no orthodontic advice, came from across the range of socio-economic groups, were more likely to be male, and were less likely to be happy with their appearance than their unaffected peers.

Second molar extraction in the treatment of lower premolar crowding

Thirty-four children with lower premolar crowding were treated by extraction of second molars. Thirteen cases had mechanical lower arch treatment started not less than 6 months after extractions. The remainder had no treatment in the lower arch. The change in premolar crowding was measured, and the reasons why spontaneous alignment occurred in some cases and not in others were examined.

Orthodontic headgear related to allergic contact dermatitis: a case report

A case is reported of a 13-year-old girl who developed a facial rash shortly after orthodontic headgear was fitted. Patch testing revealed that she was strongly allergic to nickel and also allergic to cobalt and chrome. A diagnosis of allergic contact dermatitis was made. Painting the metal buckle of the cervical strap with polyurethane paint prevented further development of her rash, while allowing her orthodontic treatment to progress.

Surgical and orthodontic management of compound odontoma

Practitioners should always consider the possibility of an odontoma when the eruption of teeth is delayed. The authors report an example of compound odontoma associated with delayed eruption of incisor teeth, and describe the surgical and orthodontic management of the case.

Measurement of class specific antibody against cryptosporidium in serum and faeces from experimentally infected calves

Anti-cryptosporidium antibody levels were measured in serum and faeces of experimentally infected calves. In serum, IgG was detectable six days after infection and remained elevated throughout infection. IgA and IgM in serum showed little change. IgG, IgA and IgM levels all rose in the faeces five or six days after infection and reached a peak between days 8 and 14 after infection and then declined.

Experimental concurrent infection of cattle with Ostertagia ostertagi and Salmonella dublin

Six seven-month-old Friesian steers were given 8.1 X 10(9) Salmonella dublin orally. Four had been infected with third stage larvae of Ostertagia ostertagi on four occasions over the previous three months. All became pyrexic and excreted S dublin in the faeces for eight to 15 days. Intravenous injection of 8.7 X 10(8) S dublin six weeks later produced similarly mild effects in parasitised and control animals alike. Two parasitised animals stopped excreting S dublin after three and five weeks respectively; the other four were still excreting regularly when killed eight weeks after intravenous infection. S dublin was recovered from the carcases of all six. O ostertagi, unlike Fasciola hepatica, did not increase susceptibility to S dublin or predispose to prolonged infection.

Fasciola hepatica: migration of newly excysted juveniles in resistant rats

Using transmission and scanning electron microscopy, the early migration of juvenile Fasciola hepatica was examined in naive and resistant rats. In naive rats, the migration of flukes to the peritoneal cavity was uneventful. In resistant rats, flukes were rapidly coated with antibody whilst still in the gut lumen and a proportion of the flukes were unable to penetrate the intestinal wall. Those that did penetrate were unharmed as they crossed the gut wall, but on entering the peritoneal cavity they were coated with antibody and host cells including eosinophils, neutrophils, macrophages, and mast cells. Eosinophils were seen degranulating onto the fluke surface, and this appeared to result in the erosion of the tegumental syncytium.

Fasciola hepatica: the flukicidal effect of some anaesthetics and analgesics in common use

The anaesthetic halothane and the sedative xylazine were shown to have anthelmintic properties in rats against the liver fluke Fasciola hepatica. Flukes in rats treated with the local anaesthetic lignocaine or the anaesthetic/analgesic ketamine were unaffected.

Fasciola hepatica: development of the tegument of normal and gamma-irradiated flukes during infection in rats and mice

Rats and mice were infected with either normal metacercariae or metacercariae gamma-irradiated at 3 krad. or 4 krad. Flukes were recovered at various times after infection and their teguments examined using a transmission electron microscope. In normal flukes, the secretory granules T0, T1 and T2 were all seen during tegumental development. The teguments of flukes from mice developed faster than the corresponding teguments in rats. T0 granules were present from day 0 to day 10 post-infection (p.i.) in mouse flukes and from day 0 to day 14 p.i. in rat flukes. T1 granules first appeared in mouse flukes by day 4 p.i. but not until day 8 p.i. in rat flukes. T2 granules were seen in mouse flukes 2 days p.i. but not before 6 days p.i. in rat flukes. gamma-Irradiation at 4 krad prevented normal tegumental development in flukes from both rats and mice. T0 granules were present at all times in flukes from either host. T1 granules were produced in mouse flukes but their appearance was delayed until day 6 p.i. No significant production of T2 granules occurred in flukes from either host. Parasite survival was also affected by gamma-irradiation and none of the flukes reached maturity. Flukes from rats died between 10 and 21 days p.i. and flukes from mice died between 14 and 28 days p.i. gamma-Irradiation of metacercariae at 3 krad. had an extremely variable effect on subsequent tegumental development in both rats and mice. Some flukes developed normally, some showed development associated with gamma-irradiation at 4 krad, whilst some showed intermediate development.

Fasciola hepatica: attempts to immunise rats and mice with metabolic and somatic antigens derived from juvenile flukes

Attempts were made to vaccinate rats and mice against Fasciola hepatica using either somatic or metabolic antigens derived from juvenile flukes between 10 and 16 days old. None of the regimes tried induced a good resistance to subsequent infection, though metabolic antigens derived from 13-14-day-old flukes when injected subcutaneously into rats with adjuvant did produce some protection to challenge.

Fasciola hepatica: antibody coating of juvenile flukes in the intestinal lumen of resistant rats

Newly excysted juvenile Fasciola hepatica, when placed in isolated loops of intestine prepared in previously infected rats, acquired a surface covering of rat immunoglobulin. IgG, IgA, IgE and IgM were all involved. This immunoglobulin coating was sloughed off when the flukes were maintained in vitro for three hours.

Fasciola hepatica: a technique for the study of gut penetration by juvenile flukes

A method using light and electron microscopes is described which is suitable for the examination of gut penetration by juvenile Fasciola hepatica. It involved the ligation of small sections of the small intestine of rats and the introduction of artificially excysted flukes into these gut loops. By restricting the area of infection in this way it was possible to either recover flukes from the gut lumen or to prepare ultrathin sections for electron microscopy of flukes penetrating the gut wall. In addition, flukes were recovered from the body cavity at various times after preparation of loops in resistant and naive rats. It was found that more flukes reached the body cavity in naive rats than in resistant rats, demonstrating a resistance to infection in the gut loops of sensitized rats.

The development and survival of Trichuris suis ova on pasture plots in the south of England

Pasture plots in the south of England were contaminated each month throughout 1975 with pig faeces containing Trichuris suis ova. At regular intervals thereafter, soil samples were taken, the T suis ova extracted and their state of development noted. Depending on the time of year that the plots were contaminated, ova required between 62 and 90 weeks to complete their development to the infective stage. Little or no development occurred during winter. Once the infective stage was reached, the ova survived for at least two years. Samples taken from the plots at various depths demonstrated that T suis ova did not rapidly leach through the soil but were still available to grazing pigs up to two and a half years later. The early developmental stages of ova appeared to be more susceptible to desiccation than those that had developed to the blastula stage or beyond.

Concurrent daily infection of calves with Fasciola hepatica and Ostertagia ostertagi

Three groups of calves were infected daily with either 1500 Ostertagia ostertagi larvae, 20 Fasciola hepatica metacercariae, or 1500 O ostertagi plus 20 F hepatica metacercariae. Weekly measurements were taken of calf weight, faecal egg output, plasma concentrations of albumin, plasma activities of sorbitol dehydrogenase, gamma glutamyl transpeptidase and pepsinogen and standard haematological indices. Calves were killed either 10 or 21 weeks after daily infections began. F hepatica infection had little influence on the size and structure of the O ostertagi worm population or vice versa. Mean worm burdens found at 20 weeks in those animals infected with both F hepatica and O ostertagi were 293 flukes and 20,641 nematodes. While this level of infection is similar to that seen in the disease complex in the field, there was no evidence of clinical disease or any difference in weight gain between the groups in this experiment. Factors other than additive worm burdens are obviously important for the expression of disease under field conditions.

The destruction of pig helminth ova and larvae in a slurry treatment process

It was established that a thermophilic system for the treatment of pig slurry at 55 degrees C rapidly killed the free living stages of three common pig parasites. This treatment could be beneficially incorporated in any pig slurry recycling process, whether to land or to animals.