Anthony J Ireland

An in vivo investigation into bond failure rates with a new self-etching primer system

Self-etching primers have recently been introduced to simplify the orthodontic bonding process. The aim of this study was to compare the effectiveness of such a product with conventional 2-stage etching and priming with 37% o-phosphoric acid and a conventional unfilled primer. Twenty consecutive patients having orthodontic bonds placed were selected to participate in this cross-mouth control study. Diagonally opposite quadrants were randomly allocated to either the self-etching primer group or the conventional etching and priming group. A total of 364 teeth were bonded with a light-cured diacrylate adhesive; bond failures were then monitored over 6 months. There were 20 bond failures (10.99%) in the self-etching primer group and 9 bond failures (4.95%) in the conventional etch and priming group over this period. The results were analyzed with the McNemar test and 95% confidence interval. The difference between the failure proportions was -0.06 with an associated 95% confidence interval of -0.121 to 0.001. This study produced weak evidence to suggest that bond failures with a self-etching primer will be higher than those with conventional etching and priming. This increased likelihood of bond failure must be weighed against the time advantage of the self-etching primer when used at the initial bonding appointment.

Sucking habits in childhood and the effects on the primary dentition: findings of the Avon Longitudinal Study of Pregnancy and Childhood

INTRODUCTIONnMost previous research on non-nutritive sucking habits has been cross-sectional in nature. This study determined the prevalence of non-nutritive sucking habits and the effects on the developing dentition within a longitudinal observational cohort.nnnMETHODSnThe Children in Focus group of the Avon Longitudinal Study of Pregnancy and Childhood study was studied. Questionnaire data on non-nutritive sucking habits were collected on the children at 15 months, 24 months, and 36 months of age. Dental examinations were performed on the same children at 31 months, 43 months, and 61 months of age.nnnRESULTSnAt 15 months, 63.2% of children had a sucking habit, 37.6% used just a dummy, and 22.8% used a digit. By 36 months, sucking had reduced to 40%, with similar prevalence of dummy and digit sucking. Both habits had effects on the developing dentition, most notably in upper labial segment alignment and the development of anterior open bites and posterior crossbites.nnnCONCLUSIONSnThe majority of children had non-nutritive sucking habits up until 24 months of age. Both digit and dummy sucking were associated with observed anomalies in the developing dentition, but dummy-sucking habits had the most profound influence on the anterior and posterior occlusions of the children.

An evaluation of clinicians' choices when selecting archwires.

The aim of this research was to determine the choices made by clinicians with respect to archwires and arch form during the initial and latter stages of orthodontic treatment with fixed appliances. A questionnaire-based study was carried out at Bristol Dental Hospital between November 2005 and March 2006. Questionnaires were distributed within the dental hospital and at local meetings in order to obtain a mixed sample of hospital and practice-based orthodontists. The clinicians asked to complete the questionnaire were consultant orthodontists (n = 37), specialist practitioners (n = 36), senior specialist registrars in orthodontics (n = 10), and dentists with a special interest in orthodontics (n = 17). The questionnaire consisted of two parts: the first was concerned with the initial alignment phase of treatment and the second with the space-closing phase of treatment in premolar extraction cases. The choice of archwires, significance of arch form, and intra-arch dimensions considered important at both stages were assessed. The clinicians were also asked about their usual practice with regard to adaptation of working archwires and the use of study models and symmetry charts. One hundred questionnaires were returned, giving a response rate of 92.6 per cent. The majority of clinicians felt that preservation of the pre-treatment arch form was essential in the latter but not in the early stages of treatment. In particular, conservation of the original intercanine width was considered important. However, there was no uniformity in how arch form should be preserved. Some respondents used study models and symmetry charts as an aid, but even then they were used in different ways. There was no uniformity in the landmarks used when adapting stainless steel archwires to arch form. Therefore, even when clinicians do adapt their archwires carefully with the intention of preserving arch form, are they choosing the correct arch form?

Airborne particles produced during enamel cleanup after removal of orthodontic appliances

Airborne particles can be produced during enamel cleanup after the removal of fixed orthodontic appliances. Particles with an aerodynamic diameter of less than 2.5 microm, known as PM2.5, can reach the alveoli of the lungs. The aim of this experiment was to qualitatively determine whether such particles are produced during enamel cleanup at the end of orthodontic treatment. Particles were collected and examined under a scanning electron microscope. Aerodynamic diameters of the particles ranged from approximately 2 to 30 microm. X-ray analysis confirmed not only the presence of components of the adhesives being removed, but also tungsten from the bur and tooth enamel. In conclusion, inhalable particles can be produced during enamel cleanup at the completion of orthodontic treatment. Further investigation is required to determine the clinical significance of such particles, how their production can be minimized, and whether even smaller, fine or ultrafine, particles are produced.

Effect of arch form on the fabrication of working archwires.

INTRODUCTIONnPrevious studies have shown that most practitioners plan to maintain intercanine and intermolar widths during orthodontic treatment with fixed appliances. The aim of this study was to determine whether this was put into practice by clinicians during the latter stages of orthodontic treatment with fixed appliances.nnnMETHODSnThis 2-part investigation was a laboratory-based measurement study at Bristol Dental Hospital, United Kingdom, from 2005 to 2007. Using standardized maxillary and mandibular study models with identical intermolar and intercanine widths but with differing degrees of tooth misalignment, 30 clinicians were asked to fabricate final working archwires according to their normal clinical practice. Then the intercanine and intermolar widths of the archwires were measured. In the second part of the study, the same intra-arch dimensions were measured directly from 50 pretreatment and posttreatment patient study models obtained from a subsample of 10 of the clinicians.nnnRESULTSnThe intercanine and intermolar widths measured on the adapted archwires from the standardized study models showed wide variations in the results, even though the intercanine and intermolar widths of the models were identical. Data from 50 treated patients also showed that, in most, there were wide variations in intercanine and intermolar widths between the patients pretreatment and posttreatment study models.nnnCONCLUSIONSnAlthough most clinicians aim to maintain the pretreatment arch form, this study shows that this is often not transferred to clinical practice.

Transition metal salt solutions and anaerobic adhesives in dental bonding

OBJECTIVESnThe objectives of this experiment were twofold. Firstly to determine whether an anaerobic adhesive could be used to bond steel attachments to etched human enamel, following treatment of this surface with various concentrations of copper (II) sulphate solution. Secondly, to determine the effect of 0.05 M solutions of other transition metal sulphates and chlorides on the same bonding process.nnnMETHODSnStainless steel attachments were bonded to human enamel using an anaerobic adhesive. In each case the enamel, which had been ground flat, was etched with 37% o-phosphoric acid and then treated with copper (II) sulphate solution prior to bonding. After bench curing for one hour, the specimens were shear tested to failure, and the load at bebond recorded in each case. The effect of varying the concentration of copper (II) sulphate solution was determined. Following determination of the optimal copper (II) sulphate concentration, the experiment was repeated using the same concentration of various other transition metal sulphates and chlorides.nnnRESULTSnThe results were analysed using mean force to debond (N) and 95% confidence intervals. Kaplan-Meier survival probabilities and log-rank tests were also performed.nnnCONCLUSIONSnUnder the conditions of this experiment the optimal concentration of copper (II) sulphate solution was found to be 0.05 M. Of the various transition metal sulphates and chlorides under test, the sulphates appeared to provide a more active surface for the polymerisation of the anaerobic adhesive than the chlorides. Of the sulphate solutions, the most effective was that of copper.nnnSIGNIFICANCEnAnaerobic adhesives show promise as dental bonding agents capable of bonding metal attachments to enamel following enamel pretreatment with 0.05 M copper (II) sulphate solution.

Phosphoric acid and copper (II) sulphate as a combined etchant and activator prior to the use of an anaerobic adhesive

OBJECTIVESnPrevious work has shown that steel attachments can be bonded to etched human enamel using anaerobic adhesives, following treatment with a solution of 0.05M copper (II) sulphate. The objectives of this experiment were to determine whether simultaneous etching and activation could be performed with a combined solution of o-phosphoric acid and copper (II) sulphate.nnnMETHODnStainless steel attachments were bonded to human enamel using an anaerobic adhesive. In each case the enamel was etched and activated using a solution of 37% o-phosphoric acid containing various concentrations of copper (II) sulphate. After bench curing for one hour, the specimens were shear bond tested to failure and the load at debond recorded in each case. Following determination of the optimum copper (II) sulphate concentration the experiment was repeated, but this time the acid was made into a gel using colloidal silica. The effect of rinse time after etching was also investigated with the gel.nnnRESULTSnThe results were analysed using mean force to debond (N) and 95% confidence intervals. Kaplan-Meier survival probabilities and log rank tests were also performed. Under the conditions of this experiment the optimum concentration of copper (II) sulphate was found to be 1M. When the acid was made into a gel the optimum rinsing time was found to be 60s.nnnSIGNIFICANCEnThis experiment demonstrates that steel attachments can be bonded to enamel using anaerobic adhesives where the enamel has been simultaneously etched and activated. A combined o-phosphoric acid and copper (II) sulphate solution or gel can be used, but a conventional etch pattern is not produced.

Phosphoric acid and various transition metal salt solutions as a combined etchant and activator prior to the use of an anaerobic adhesive

OBJECTIVESnThe objectives of this experiment were to determine whether various transition metal salts in 37% o-phosphoric acid could both activate and etch an enamel surface prior to the use of an anaerobic adhesive.nnnMETHODnStainless steel attachments were bonded to human enamel using an anaerobic adhesive. In each case, the enamel was etched and activated using a solution of 37% o-phosphoric acid containing various transition metal sulfates and chlorides. After bench curing, the specimens were shear bond tested to failure and the load at debond recorded in each case.nnnRESULTSnThe results were analyzed using mean force to debond (N) and 95% confidence intervals. Kaplan-Meier survival probabilities and log-rank tests were also performed.Conclusions. Under the conditions of this experiment, the sulfate and chloride of copper in acid were the most effective etching/activating solutions. There was no significant difference in the mean force to debond between the copper (II) sulfate and copper (II) chloride. The chloride in acid was, however, the only one of the two to produce a conventional etch pattern on the surface of the enamel.nnnSIGNIFICANCEnIt is possible to render the enamel surface both retentive and active towards anaerobic adhesives, such that relatively unreactive substrates can be bonded to enamel using such adhesives.

Treatment outcome for children born with cleft lip and palate.

In the management of children born with orofacial clefting there is a danger that the information on genetic and environmental influences together with data emerging from randomized controlled trials are divorced from the current reality of clinical care. It is important that treatment outcomes are constantly reviewed as new evidence unfolds but for many children born with a cleft, basic care will be more rapidly improved through examination of quality of outcomes than the higher level scientific exploration of gene-environment interactions and clinical trials. There are good examples of how scrutiny of outcomes has led to changes in service and an improvement of care. These changes have subsequently improved outcomes. These examples will be explored in some depth as well as the outcomes that are seen as relevant to carers and users. Finally the need to determine the influence of genetics and environments on outcomes is seen as the ultimate goal of total care. If we are clear as to how outcomes might be improved for an individual then reference to genetic determinants will provide a bespoke care pathway for surgical interventions, speech and language therapy, psychological and educational support as well as many other areas. This will however require a detailed longitudinal cohort study of all phenotypes to understand the gene-environment interactions, individual development and treatment outcomes. Thus, outcomes can be used to define service and policy, drive scientific investigation, but most importantly improve the care of those children born with a cleft.