British Journal of Orthodontics, Vol. 26, No. 1, 15-19,
March 1999
© 1999 British Orthodontic Society
Assessment of Clinical Case Presentations for the Membership in Orthodontics, Royal College of Surgeons of England 1995, 1996
R. T. Lee, D.Orth., M.Orth R.C.S., F.D.S.R.C.S and
V. Crow, M.Orth., M.Sc., F.D.S.R.C.S.
Royal London Hospital, London, U.K.
J. A. Dickson, D.Orth., M.Orth., M.Sc., F.D.S.R.C.S.
Cheltenham Hospital, U.K.
C. Daniels, B.D.S., F.D.S.R.C.S.
Cardiff Dental School, Cardiff, U.K.
Correspondence: Mr R. T. Lee, Department of Orthodontics, Royal London Hospital,
London E1 1BB, U.K.
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Abstract
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The cases presented and treated at successive examinations by the candidates for the Membership
Examination in Orthodontics in 1995 and 1996 at The Royal College of Surgeons of England,
were of a very high standard and demonstrated a wide range of treatment modalities. All cases
had fixed appliances, predominantly with pre-adjusted Edgewise appliances. IOTN confirmed
that most cases were in great need of treatment, with PAR scores showing them to be treated to a
high standard.
Key words: Assessment, Case Presentations, M. Orth.
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Introduction
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The Membership in Orthodontics of the Royal College of Surgeons of England is taken after a
minimum of 2 years 9 months of recognized specialty training in orthodontics and is awarded to
the successful candidates after completing 3 years training. An essential element of the
examination is the presentation of the case records of three completed cases. It is necessary that
these cases have been treated entirely by the candidates and these cases should represent the best
efforts of the candidates during the training programme. It is expected that the cases will have
been supervised closely during the training of the specialist, and therefore a high standard of
treatment and case records is required.
It was considered appropriate therefore to evaluate the nature and variation of cases being
treated, and the quality of the results of these presentations on two consecutive years, 1995 and
1996. The objective was to establish an insight on the standards of the cases to enable
comparison in future years or in other examinations.
There are three cases presented by each of the candidates at the examination. These cases were
assessed by two independent assessors not involved in the examination, and the nature of the
treatment recorded. It was decided to use indices to record, first, the nature of the malocclusion
being treated by the candidates, and secondly, the quality of the result and degree of
improvement achieved.
The Index of Orthodontic Treatment Need (Dental Health Component) described by Brook and
Shaw (1989
) is an accepted means of identifying those patients who
would most benefit from orthodontic treatment. There are five grades for the Dental Health
Component (DHC) with Grade 5 indicating a great need for treatment and Grade 1 indicating no
need for treatment. Generally, cases with Grades 4 and 5 are objectively regarded as being in the
greatest need of treatment.
The Peer Assessment Rating (PAR) is a mechanism devised to assess the degree of
improvement achieved from orthodontic treatment (Richmond et al., 1992a,b). The concept is to assign a score to various occlusal traits
which make up a malocclusion.
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Method and Materials
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The case presentation folders and study casts presented by each candidate were independently
scored, for PAR and IOTN, by two assessors. They had been trained and calibrated in the use of
the indices.
In July 1995, of the 19 candidates, a total of 55 case presentation folders were available for
assessment. IOTN, and pre- and post-treatment PAR scores were measured independently by the
two assessors. In June 1996 there were 20 candidates and 56 case presentations were scored for
IOTN and PAR, by the same two examiners as for the 1995 examination.
In addition, a third assessor recorded the type of malocclusion, extraction pattern, and appliance
systems used during treatment.
The instructions to candidates outlined that marks would be awarded for:
- the severity of the case and the difficulty of the treatment;
- the quality of the result obtained and the candidates understanding of the treatment undertaken.
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Results
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The number of case presentations in each of the five categories of IOTN is shown in Table 1. In 1995, 80 per cent of the cases were IOTN 4 and 5, and 96 per cent in
1996. The range and means of the PAR values in Table 2a, in both years,
show marked consistency. The number of cases shown to be `greatly improved'
in Table 2b is extremely high.
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TABLE 1 Index of Orthodontic Treatment Need (Dental Health Component) for case
presentations in July 1995 and June 1996
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TABLE 2 Range, means, percentage change, and mean reduction in
Peer Assessment Rating for case presentations in July 1995 and June 1996
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The malocclusion types of the cases are shown in Table 3. The
extraction pattern in Table 4 is such that 77 per cent of cases in 1995 and
66 per cent in 1996 were extraction cases, with almost 80 per cent of these involving premolar
extraction's, although only a limited number involved extraction of four first premolars.
The range of malocclusion types is illustrated by two cases. In case number 23 (1995) the IOTN
is 5i with a pretreatment PAR score of 50 (Figure 1 a-e) and end of
treatment score of 4 (Figure 2a-e). The change in PAR score would be
considered `greatly improved'. Case number 15 (1996) required the extraction of
four first molars and fixed appliances. This case has a low IOTN of 2 with pretreatment PAR
score of 26 (Figure 3 a-e) and end of treatment score of 3 (Fig. 4 a-e). The change in PAR of 23 is also `greatly improved'
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Table 5 shows that 89 per cent of cases in 1995 and 88 per cent in 1996
had pre-adjusted (`Straight Wire') fixed appliances. Functional appliances were
used in combination with fixed in 14 per cent in 1995 and 19 per cent in 1996.
Assessment of agreement between observer 1 and observer 2 for the Dental Health Component
of IOTN, was tested using the kappa statistic (Cohen, 1960). According
to Cohen the coefficient k is the proportion of agreement after chance agreement is
removed from consideration. An unweighted kappa statistic was deemed to be appropriate for
this study.
The kappa statistic (Table 6a) for observers 1 and 2 in 1995 is
0•96. This is considered to be an excellent agreement between the two observers. The value
of k in 1996 was 0•80 which is considered a substantial agreement.
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TABLE 6 Observer agreement for IOTN in 1995 and 1996 using kappa (k) statistic and
correlation coefficients for pretreatment, post-treatment and change in PAR. Paired t-tests
applied to test significant differences in PAR
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Assessment of the PAR scores for the two observers were tested using intra-class correlation
coefficients shown inTable 6b. The pretreatment PAR score correlation
coefficients in both years show good agreement between the observers. The post-treatment
correlation coefficients show only a moderate agreement and a statistically significant difference.
This may be explained by the relatively narrow range of post-treatment values, which, in turn,
will highlight small differences between the observations.
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Discussion
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The dental health component of IOTN indicated that 81 per cent of the cases presented in 1995
and 96 per cent in 1996 had a definite need for treatment. In 1995, 16 per cent had a
`borderline need', whereas in 1996 this was lower (4 per cent). This compares
favourably
with Shaw et al. (1991) who showed that 74•4 per cent of
222 patients referred to a hospital unit were in grades 4 and 5, and 19•7 per cent in grade 3.
The IOTN and PAR do not necessarily reflect the difficulty of treatment. The case presentation in
1995 with IOTN of 2 (Fig. 3,4), required
extraction of all first molars and is likely to have required considerable skill in producing a good
result.
A change in PAR of more than 22 points is considered to be greatly improved and 82 per cent of
the cases in 1995, and 90 per cent in 1996 were judged to be in this category. The mean
percentage reduction in PAR was high at 84 per cent and this compares very favourably with the
personal audit carried out by Richmond (1993), who achieved a reduction
of 74 per cent. The mean post-treatment PAR score of 4 (1995 and 1996) is also lower than the
mean score of 7 presented by Richmond in 1993. In a survey of specialist practitioners, by Kelly
and Springate (1996), a mean PAR reduction of 89 per cent was greater
than the candidates presented for the membership examination. However, it would appear the
specialist practitioner cases were only scored by a single individual and so possibly subject to
bias. The specialist practitioners had a mean pretreatment score of 26•6 compared to 37 for
the examination cases, which suggests that the examination cases were of far greater complexity.
A post-treatment PAR score of 4 would be equivalent to a centre line discrepancy of a quarter to
a half lower incisor width. The worst post-treatment PAR score of 11 (1995) would approximate
to a residual overjet of 4 mm and an increased overbite of greater than two-thirds coverage of the
lower incisors.
In 1995 and 1996, more than three-quarters of the cases underwent extractions, with 79 per cent
being premolars in 1995 and 78 per cent in 1996. The remaining extractions involved
combinations of premolars, molars, and only one case with upper second molars alone. All cases
had a fixed phase of treatment, using pre-adjusted systems (SWA) in 49 cases in 1995 (89 per
cent) and 50 cases (88 per cent) in 1996. Begg and Tip Edge accounting for five of the cases in
1995 and four cases in 1996. Functional appliances were used in a multi-phased treatment
approach with headgear and fixed appliances often following the functional appliance treatment.
In both years 9 per cent of cases involved osteotomies, with four of the surgical cases in 1995
and three in 1996 requiring bimaxillary procedures.
It should be remembered that these cases represent the best efforts of supervised postgraduate
trainees who in the main have little or no previous personal experience of complex orthodontic
treatment.
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Conclusions
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The case presentations were of a high standard and demonstrated a wide range of treatment
modalities. Premolar extraction's and pre-adjusted fixed appliances were the main type of
treatment. The clinical need for treatment, as shown by IOTN, was high and the vast majority of
cases were treated to a high standard.
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Acknowledgments
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We wish to express our thanks to Dr A. Linney of the Medical Physics Department of University
College London Hospitals for his help with statistical analysis. Thanks also to Ms H. Illing and
Mr D. Morris for giving permission to present clinical material.
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References
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Brook, P. H. and Shaw, W. C. (1989) The development
of an index for orthodontic treatment priority, European Journal of Orthodontics, 11, 309–332.[Abstract/Free Full Text]
Cohen, J. (1960) A coefficient of agreement for nominal
scales, Educational and Psychological Measurement, 20, 37–46.
Kelly, B. M. and Springate, S. D. (1996) Specialist
orthodontics in the General Dental Services, British Dental Journal, 180, 209–215.[Medline]
Richmond, S. (1993) Personal Audit in Orthodontics, British Journal of Orthodontics, 20, 135
–145.[Abstract]
Richmond, S., Shaw, W. C., O'Brien, K. D.,
Buchanan, I. B., Jones, R., Stephens, C. D., Roberts, C. T., Andrews, M. (1992a) The development of the PAR index, European Journal of Orthodontics, 14,125
–139.[Abstract/Free Full Text]
Richmond S., Shaw W. C. and Roberts, C. T. (1992b)
The PAR index (Peer Assessment Rating): methods to determine outcome of orthodontic
treatment in terms of improvement and standards, European Journal of Orthodontics, 14, 180–187.[Abstract/Free Full Text]
Shaw, W. C., Richmond, S, O'Brien, K. D., Brook
P. H. (1991) Quality control in Orthodontics: indices of treatment need and
treatment standards, British Dental Journal, 170, 107–112.[Medline]
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Abstract
Introduction
