Sealing caries in primary molars: randomized control trial, 5-year results.

The Hall Technique (HT) is a method for managing carious primary molars. Decay is sealed under pre-formed metal crowns without any caries removal, tooth preparation, or local anesthesia. The aim of this study was to compare HT clinical/radiographic failure rates with General Dental Practitioners' (GDPs) standard (control) restorations. We conducted a split-mouth, randomized control trial (132 children, aged 3-10 yrs, GDPs n = 17) in Scotland. There were 264 study teeth with initial lesions, 42% of which were radiographically > half-way into dentin, and 67% of which had Class II restorations. Teeth were randomized to HT (intervention) or GDPs' usual treatment (control). Annual clinical/radiographic follow-up data were recorded. Ninety-one patients (69%) had 48 months' minimum follow-up. At 60 months, 'Major' failures (irreversible pulpitis, loss of vitality, abscess, or unrestorable tooth) were recorded: HT, 3 (3%); control restorations, 15 (16.5%) (p = 0.000488; NNT 8); and 'Minor' failures (reversible pulpitis, restoration loss/wear/fracture; or secondary caries): HT, 4 (5%); control restorations, 38 (42%) (p < 0.000001; NNT 3). Overall, there were follow-up data for 130 patients (2-60 mos): 'Major' failures: HT, 3 (2%); control restorations, 22 (17%) (p = 0.000004; NNT 7); and 'Minor' failures, HT, 7 (5%); control restorations, 60 (46%) (p < 0.000001; NNT 3). Sealing in caries by the Hall Technique statistically, and clinically, significantly outperformed GDPs' standard restorations in the long term (Trial registration no. ISRCTN 47267892).

A novel technique using preformed metal crowns for managing carious primary molars in general practice - a retrospective analysis.

BACKGROUND: There is a high level of untreated dental decay in primary teeth in Scotland. Despite evidence for the efficacy of preformed metal crowns (PMCs) for the restoration of primary molars, few are placed in general practice, possibly due to the interventive nature of the clinical procedure. There is, however, a novel way of placing PMCs involving no local anaesthesia, no caries removal and no preparation of the tooth: the Hall technique. AIM: To investigate the survival of carious primary teeth treated with PMCs placed using a novel, simplified method - the Hall technique. SETTING: General dental practice, in Scotland. METHOD: A retrospective analysis of practice records from one general practitioner, from 1988 to 2001. The majority of the 978 PMCs fitted on 259 children, using the Hall technique, were placed when there was clinical evidence of approximal caries into dentine. The Kaplan-Meier approach was used to analyse survival times and the Mantel-Haenszel Log rank test for comparison between tooth types. RESULTS: For all tooth types, the probability of surviving three years without being extracted or the PMC being lost, was 73.4% (95% confidence interval 70.1% to 76.4%), and for five years was 67.6% (95% confidence interval 63.3% to 71.5%). The probability of surviving without extraction alone for three years was 86.0% (95% confidence interval 83.2% to 88.4%), and for five years was 80.5% (95% confidence interval 76.5% to 83.9%). CONCLUSIONS: Hall technique restorations placed on primary molars with decay clinically into dentine, by a single operator in general dental practice, have a similar success rate to some other, more conventional, restorative techniques. The technique requires further evaluation through a prospective randomised control clinical trial before its use could be generally recommended.

An investigation into the bonding of orthodontic attachments to porcelain.

This study assessed bonding of orthodontic brackets to porcelain teeth using two different surface preparation techniques and comparing two bonding systems, Fuji Ortho L.C. and Transbond. Four groups of 20 porcelain premolar teeth were bonded with metal orthodontic brackets (0.022 inch Minitwin, 3M Unitek) according to the following protocol: Transbond with a phosphoric acid etch (group 1), Transbond with a hydrofluoric acid etch (group 2), Fuji Ortho L.C. with a hydrofluoric acid etch (group 3), and Fuji Ortho L.C. with a phosphoric acid etch (group 4). All groups were bonded with a silane coupling agent. The teeth were debonded with an Instron universal testing machine. Bond strength, site of bond failure and adhesive remnant index (ARI) were recorded for each group. Differences between groups were analysed statistically. The composite resin groups (groups 1 and 2) had the highest mean bond strength values at 7.9 and 9.7 MPa, respectively. The resin-modified glass ionomer cement groups (RMGIC; groups 3 and 4) had the lowest mean bond strength values at 6.3 and 1.8 MPa, respectively. The mean bond strength of group 3 was significantly lower than all other groups (P < 0.0001). The Fuji groups had also significantly (P < 0.001) lower ARI scores than the composite groups (groups 1 and 2). Most samples experienced porcelain surface damage, except group 4. In conclusion, the highest bond strength levels were achieved with a conventional composite resin cement (groups 1 and 2). No significant differences in bond strength were found between the hydrofluoric and phosphoric acid etch technique.

An ex vivo assessment of gingivally offset lower premolar brackets.

OBJECTIVES: To compare the force to failure of standard premolar brackets to that of gingivally offset brackets and evaluate the site of bond failure between the two bracket types through the use of the Adhesive Remnant Index (ARI). DESIGN: An ex vivo study. SETTING: Dental Materials Science Laboratory, Dundee Dental School, Dundee. MATERIALS AND METHODS: Forty extracted lower premolar teeth (caries free, extracted as part of orthodontic treatment, all donors living in a non-fluoridated area), divided into two equal size sample groups, as follows: Group 1: Victory Series (3M Unitek, Monrovia CA, USA) lower premolar brackets bonded to buccal surfaces with Transbond XT (3M Unitek, Monrovia CA). Group 2: Victory Series Gingivally Offset Bicuspid Brackets (3M Unitek, Monrovia CA) bonded to buccal surfaces with Transbond XT (3M Unitek, Monrovia CA). Force was applied in the occluso-gingival direction using an Instron Model 4469 Universal Testing Machine (Instron Ltd, High Wycombe, UK) operating at a cross-head speed of 0.5 mm/min and its value at failure determined. Following debond, the site of bond failure and ARI were recorded. OUTCOME: Force to failure, site of bond failure and adhesive remnant index. RESULTS: The Weibull analysis gave higher values for the force to failure at 5% level (200 v. 159 N) and at all other levels of probability of failure for the gingivally offset bracket. The non-parametric survival analysis using Gehan-Wilcoxon tests with Breslow's algorithm (p < 0.0001) showed significant difference in force to failure between bracket types. Chi-square tests showed no significant (p = 0.55) relationship between the site of bond failure and the bracket types. CONCLUSION: Ex vivo testing suggests that there is a significant difference in the force to failure between gingivally offset and standard lower premolar brackets when force application is from an occluso-gingival direction. The site of failure (as given by the ARI) is insensitive to bracket types and force to failure.

An ex vivo assessment of a bonding technique using a self-etching primer.

OBJECTIVE: This study assessed a new self-etch/priming system for use in orthodontic bonding. SETTING: An ex vivo study. METHOD: Three groups of 20 extracted premolar teeth were bonded with metal orthodontic brackets. Group 1 was bonded with Transbond using the conventional technique (control). Group 2 was bonded using the new Transbond-Plus combined etch/primer system to wet enamel and Group 3 to dry enamel. The teeth were debonded using an Instron Universal Testing Machine. The mean debond force was calculated for each group and compared statistically. The teeth were examined under the stereomicroscope to assess the site of debond and adhesive remnant index. RESULTS: Group 2 (etch/primer on wet enamel) had the lowest mean debond value at 5.2 MPa. ANOVA and Tukey tests confirmed that the bond strength results of Group 2 were significantly lower than Groups 1 (P < 0.01) and 3 (P < 0.05). The enamel/resin interface was the commonest site of bond failure for both etch/primer groups (Groups 2 and 3). They had less retained resin and significantly (P < 0.001) lower ARI scores compared with Group 1 (control). CONCLUSIONS: The results of this ex vivo study suggest that the self-etch primer should achieve adequate bond strengths when applied to dry enamel surfaces. In addition there should be less retained resin requiring removal at debond.

Fluoride supplements and changes in tooth decay on the Island of Tristan da Cunha: 1966-1996.

BACKGROUND: The island of Tristan Da Cunha is one of the few examples in the world of a remote enclosed community. The inhabitants of the island were transported to England in 1961 as a result of a volcanic eruption and during their time in England they received a detailed dental health examination. They were later examined back on the island in 1966 by Dr John Fisher and in 1982 a school fluoride supplementation programme was introduced. AIM: The present paper reports the results of the first dental health survey to be carried out on the island since the introduction of a regular school fluoride supplementation programme in 1982. SUBJECTS AND METHODS: A cohort of 6-19-year-old subjects on the island were examined in 1996 using a similar protocol to that which was used by Fisher in the 1966 examination. RESULTS: Comparing the 6-12-year-olds who were caries free in 1966 with those caries free in 1996 using the Chi-squared statistic reveals a statistically significant greater number caries free in the more recent cohort (X2 - 6.0, P- 0.014). For the older age group (13-19 years), a similar comparison reveals a highly statistically significant difference(Z2 - 12.26, P 0.005). CONCLUSIONS: A significant increase in the number of caries free 6-19-year-old children in Tristan Da Cunha between 1966 and 1996 was noted: 1) This is a significant finding in the light of the school fluoride supplementation programme that was introduced on the island in 1982; and 2) Appropriate fluoride supplementation regimes may have conferred a protective effect in a group of children with a cariogenic diet. The paper discusses the significance of this study in the support of fluoridation as a method of reducing the prevalence of dental caries a nd also discusses possibilities for future research on the island of Tristan Da Cunha.

An ex vivo assessment of a resin-modified glass ionomer cement in relation to bonding technique.

OBJECTIVE: This study assessed a resin modified glass ionomer bonding system, Fuji ortho L.C. using different bonding techniques and compared it with a composite control (Transbond). DESIGN: Ex vivo study. Twenty extracted premolar teeth in each group were bonded as follows: (i) Group 1 Control (Transbond); (ii) Group 2 Fuji ortho L.C. without an etch procedure/wet enamel surface; (iii) Group 3 Fuji ortho L.C. without an etch procedure/dry enamel surface; (iv) Group 4 Fuji ortho L.C. using a conventional acid etch technique. OUTCOME: Shear bond strength, site of bond failure and adhesive remnant index. RESULTS: Brackets bonded as recommended by the manufacturer (Group 2) have significantly (p < 0.001) lower bond strengths compared with the control (Group 1). Bonding with an etch technique (Group 4) will significantly (p < 0.001) increase the bond strength compared with the other Fuji groups. All the Fuji groups tended to fail at the enamel/resin interface with lower ARI scores compared with the control. CONCLUSION: The lower bond strength of Fuji ortho L.C. would limit its use as a routine bonding agent. When bonded with an acid etch technique, the bond strength may be sufficient for low loading situations such as the upper anterior teeth.

Scope of the OSCE in the assessment of clinical skills in dentistry.

INTRODUCTION: The objective structured clinical examination (OSCE) is now an accepted tool in the assessment of clinical skills in dentistry. There are however no strict or limiting guidelines on the types of scenario that are used in the OSCE examinations and experience and experimentation will inevitably result in the refinement of the OSCE as a tool for assessment. AIM: The aim of this study was to compare and contrast different types of clinical operative skills scenarios in multi-station OSCE examinations. METHODOLOGY: Student feedback was obtained immediately after the sitting of an OSCE examination on two different occasions (and two different cohorts of students). The same questionnaire was used to elicit the responses. RESULTS: The questionnaire feedback was analysed qualitatively with particular regard to student perception of the usefulness and validity of the two different kinds of OSCE scenarios. CONCLUSIONS: OSCE scenarios which involve phantom heads are perceived to lack clinical authenticity, and are inappropriate for the assessment of certain clinical operative skills. While the OSCE is useful in the examination of diagnostic, interpretation and treatment planning skills, it has apparent limitations in the examination of invasive operative procedures.

An investigation into the use of a structured clinical operative test for the assessment of a clinical skill.

AIM: This study was designed to investigate the level of agreement between a group of assessors observing students undertaking a structured clinical operative test. METHOD: 3 assessors agreed a series of criteria to assess the performance of undergraduate students in the recording of a dental impression. Guidelines for assessing whether the students adequately performed in relation to each criteria were also agreed. Following preliminary validation between the assessors, 2 assessors independently scored the performance of each student by reference to the agreed criteria, and the levels of agreement between assessors were compared. The 3 assessors worked in pairs with each other on three groups of students who were in the early stages of their clinical course. RESULTS: A total of 39 clinical dental students were assessed in the recording of a dental impression. The 3 pairs of assessors had satisfactory levels of agreement in the study with similar judgements being made on 90% or more of the 12 criteria assessed. Some differences existed between the pairs of assessors. Certain criteria were more easily judged than others and this was reflected in the level of agreement seen. For over 90% of the criteria, positive assessments were made by each of the 3 assessors, and although there were minor variations between the pairs of assessors, this may have reflected the ability of the groups of students studied. CONCLUSION: The study showed that different assessors were generally able to make agreed judgements on performance criteria in a structured clinical operative test. In setting up performance assessment it is necessary to have close collaboration between assessors to make clearly defined criteria so that judgements are not too subjective. Furthermore, for the assessment of more complex clinical skills, great care is needed in assembling criteria that can be used reproducibly, and sufficient preparation time for the assessors is critical.

The effect of wavelength, bandwidth, and probe design and position on assessing the vitality of anterior teeth with laser Doppler flowmetry.

OBJECTIVES: To investigate the effect of four variables: wavelength (633 nm and 780 nm), bandwidth filter (3 kHz, 15 kHz, 22 kHz), probe fibre separation (250 microns) and 500 microns) and distance of the probe from the gingival margin (2-3 mm and 4-5 mm) when assessing the vitality of anterior teeth with a laser Doppler flowmetry system. DESIGN: Split-mouth cohort clinical trial. SETTING: Childrens dental clinic, Glasgow Dental Hospital and School. SAMPLE AND METHODS: Sample included 11 non-vital maxillary incisors with necrotic pulps in 10 patients (mean age 12.25 years old). Recordings were taken from the non-vital tooth and from a vital maxillary incisor from the same patient, using all 24 combinations of the recording variables listed above. The vital/non-vital ratios of the signals from the 11 pairs of teeth were calculated and discriminant analysis applied to the data. RESULTS: Of the variables investigated, the combination of a 633 nm laser source with a 3 kHz bandwidth filter using a probe with a 500 microns fibre separation placed 2-3 mm from the gingival margin was the most reliable, with 10 out of a possible 11 true positives for pulpal necrosis, no false positives, and one equivocal diagnosis, and was the only combination that recorded a smaller blood flow from the non-vital tooth compared with the vital control tooth for all 11 pairs of teeth investigated. CONCLUSIONS: It was concluded, therefore, that laser Doppler flowmetry can be of use in assessing the vitality of anterior teeth and that this is the preferred combination of recording variables for further investigations.

A comparison of laser Doppler flowmetry with other methods of assessing the vitality of traumatised anterior teeth.

Laser Doppler flowmetry is a non-invasive electrooptical technique which allows the semi-quantitative recording of pulpal blood flow. This study aimed to determine the reliability (measured as the sensitivity and specificity) of laser Doppler flowmetry as a method of assessing the vitality of traumatised anterior teeth, and to compare it with standard pulpal diagnostic tests. Recordings of pulpal blood flow were taken from 67 non-vital anterior teeth (55 patients), where the pulpal status was confirmed by pulpectomy. For comparison, recordings were also taken from 84 vital anterior teeth (84 patients). Analysis of the recordings allowed diagnostic criteria to be developed which gave the technique a sensitivity and specificity of 1.0 for this sample. None of the other standard pulpal diagnostic methods tested was as reliable. This was usually due to low sensitivities, which ranged between 0.92 for sensibility testing with ethyl chloride down to 0.36 for periapical radiolucency and 0.16 for a history of pain. Laser Doppler flowmetry was found to be a reliable method of assessing the pulpal status of traumatised anterior teeth, although it is technique-sensitive and time-consuming to use.

Stability of bimaxillary osteotomy following surgical correction of class II skeletal deformities: a two-centre study.

This study compares the stability following bimaxillary osteotomy for correction of class II skeletal deformities between two groups of patients. One group (15 patients) were treated at Canniesburn Hospital, West of Scotland Regional Plastic and Maxillofacial Unit, UK. The other group (15 patients) were treated at Ann Arbor Michigan University Hospital, USA. All cases were treated by Le Fort I maxillary advancement/impaction and bilateral sagittal split advancement osteotomy. In all cases Le Fort I maxillary osteotomy was more stable than sagittal split advancement osteotomy. The maxilla stayed within 1 mm of its immediate postoperative position. The average mandibular advancement in Canniesburn cases was 6 mm and about 4 mm in Michigan cases. During surgery the condyles were displaced about 2 mm posteriorly in Canniesburn cases, but remain in their anatomic position in Michigan cases. At 6 months following surgery, Canniesburn patients showed a clockwise mandibular relapse. This increased both the mandibular plane angle and ramus angle by 2.7 degrees and 2.9 degrees respectively. The mandible settled posteriorly 1.7 mm and inferiorly 1.5 mm. In Michigan cases the mandible stayed within 1 mm of its immediate postoperative position. The difference in mandibular relapse between the two groups was statistically significant (P < 0.05). The differences in the stability between the two groups are investigated and the theories of mandibular relapse following sagittal split osteotomy are discussed.

Defining, conferring and assessing the skills of the dentist.

The task facing educators in dentistry is never an easy one. It is an area where as many questions as answers arise. This paper looks at how the skills that a dentist needs can be defined and the best way to confer them.

Differentiation between cleft lip with or without cleft palate and isolated cleft palate using parental cephalometric parameters.

OBJECTIVE: The purpose of this study was to identify and compare lateral cephalometric measurements in noncleft parents of children with cleft palate (CP) and cleft lip (CL), and cleft lip and palate (CLP). The hypothesis was that discriminant analysis would enable identification of morphometric features that predispose to orofacial clefting and that differ for CP, CL, and CLP and are unevenly distributed within parental pairs. DESIGN: This was a prospective, parametric analysis. SETTING: The study was conducted by the Department of Dental Health, University of Dundee, and the Department of Statistics, University of Glasgow, Scotland. SUBJECTS: From a completely ascertained sample of 286 children with cleft lip and/or palate born in the West of Scotland between January 1, 1980, and December 31, 1984, a sample of 83 parents of children with non-syndromic clefts volunteered for lateral cephalometric examination. METHODS: Thirty-seven cranial and 99 facial landmarks were identified and 37 linear, angular, and area parameters were used to describe the craniofacial skeleton. Analysis of variance was used for a three-way comparison of CL/CLP/CP, and stepwise discriminant analysis was used to determine which variables discriminate best between cleft lip with or without cleft palate [CL(P)] and isolated cleft palate (CP) parents. RESULTS: There were no significant differences whatsoever in the craniofacial morphology between the parents of children with CL and CLP, but differences were found between the CL(P) and CP groups. The most significant of these were in mandibular length, ramus length, mandibular area, and cranial area. Mandibular ramus length alone discriminated between the two groups in 71.4% of CP and in 62.5% of CL(P) cases, while separate analysis of fathers and mothers showed that ramus length and cranial height together reliably distinguish between mothers in 75% of CP and 80% of CL(P) cases. CONCLUSIONS: Previous studies suggests that unaffected parents with non-syndromic children with cleft lip and/or palate have differences in their craniofacial morphology when compared to the general population. This study indicates that these morphologic features differ for CP and CL(P).

Stability of sagittal split advancement osteotomy: single- versus double-jaw surgery.

The effect of Le Fort I maxillary impaction on the stability of the sagittal split advancement osteotomy is debatable. The aim of this study was to compare the stability of mandibular advancement in two groups of patients: those that had simultaneous Le Fort I maxillary impaction and sagittal split advancement osteotomy and those that had only sagittal split advancement osteotomy. Lateral cephalograms taken immediately after surgery, 6 months postoperatively, and at 1-year follow-up were used in the assessment. In addition to routine cephalometric analysis, the Euclidean Distance Matrix method was also used. The magnitude of mandibular relapse was similar in both groups in the form of mandibular clockwise rotation and posterior settling. The mandible rotated by 2.2 degrees in the single-jaw surgery group and 2.5 degrees in the bimaxillary osteotomy group. The mandible settled posteriorly by 1.0 degree in the single-jaw surgery group and 1.2 degrees in the bimaxillary osteotomy group. The differences were not statistically significant. In all the patients, Le Fort maxillary osteotomy was more stable than was mandibular advancement. The counter-clockwise rotation of the distal mandibular segments and the distraction of the condylar segments during surgery were responsible for mandibular relapse.

A comparison of the Index of Orthodontic Treatment Need applied clinically and to diagnostic records.

The Index of Orthodontic Treatment Need was applied clinically to a group of patients and later to study models and photographs taken at that same visit. Examiner reliability and agreement between the information obtained clinically and from diagnostic models was high. There was however, poor agreement for the Aesthetic component scored from photographs, when compared with scores recorded clinically or from models.

Acute-phase proteins in gingival crevicular fluid during experimentally induced gingivitis.

The dynamics of four acute-phase proteins were investigated in gingival crevicular fluid (GCF) during the course of a 21 day experimental gingivitis study. These acute-phase proteins were the protease inhibitors alpha 2-macroglobulin (alpha 2-M) and alpha 1-antitrypsin (alpha 1-AT) and the iron-binding proteins transferrin (TF) and lactoferrin (LF). 6 healthy volunteers ceased all oral hygiene procedures for 3 weeks. GCF was sampled at seven day intervals from two sites per subject by paper strips for 30 s during the experimental gingivitis period and for two additional weeks after the reinstitution of oral hygiene. The mainly serum derived alpha 2-M, alpha 1-AT and TF exhibited very similar dynamics which reflects their common origin in GCF. Their levels increased significantly from baseline and remained high for at least one week after the reinstitution of oral hygiene measures (repeated measures MANOVA; alpha 2-M: p = 0.015; alpha 1-AT: p = 0.012; TF: p = 0.02). This probably reflects increased vascular permeability in the gingivae and, to a lesser degree, local production by gingival inflammatory cells. In contrast to the serum derived acute-phase proteins, the neutrophil derived LF rose significantly from baseline (repeated measures MANOVA; p = 0.001) but dropped rapidly after the reinstitution of oral hygiene measures. This could be because dental plaque was removed and thus neutrophil chemotactic agents in the crevice were decreased.