Measuring socio-economic inequalities in edentate Scottish adults--cross-sectional analyses using Scottish Health Surveys 1995-2008/09.

OBJECTIVES: To investigate the appropriateness of different measures of socio-economic inequalities, in relation to adult oral health in Scotland, utilizing data from a series of large, representative population surveys. METHODS: The Scottish Health Surveys (SHeS) (1995; 1998; 2003; 2008/09) are cross-sectional national population-based surveys used to monitor health status in those living in private households. The age groups included in this study are as follows: 45-54; 55-64 years: all survey years; 65-74: 1998 onwards; 75+: 2003 onwards. Primary outcome was no natural teeth (edentulism). Three measures of socio-economic position: Occupational social class, Education, Carstairs deprivation score (2001) were used. Simple (absolute/relative differences) and complex measures (Slope Index, Relative Index, Concentration Index and c-index) of inequality were produced for each age group across all four surveys. RESULTS: Simple and complex (absolute) measures of inequality have both demonstrated narrowing disparities in edentulism over time in the 45- to 64-year-old group, a levelling off in those aged 65 and above, and a rise in those aged 75+. Complex relative measures (RII, Concentration Index and c-index), however, show an increasing trend in inequalities over time for all age groups, suggesting that rates of improvement in edentulism rates are not uniform across all social groups. CONCLUSIONS: Simple absolute inequality provides a quick and easy indication of the extent of disparities between extreme groups, whereas complex measures (absolute and relative) consider the gradient in health across all social groups. We have demonstrated that both are useful measures of inequality and should be considered complementary to one another. The appropriate choice of complex measure of inequality will depend on the audience to whom the results are to be communicated. This methodological approach is not confined to oral health but is applicable to other health outcomes that are socially patterned.

An in vitro comparison of four intra-oral ceramic repair systems.

OBJECTIVES: This study evaluated the effect of different surface conditioning methods on the tensile bond strength (TBS) and integrity of the leucite-reinforced glass ceramic (Cerana(®) inserts)-resin composite interface, using four commercially available ceramic repair systems. METHODS: Two hundred extra-large Cerana(®) inserts were mechanically treated and stored in artificial saliva for 3 weeks and subsequently randomly assigned to one of the following ceramic repair systems (n=40/group): Group 1, Ceramic Repair(®) (Ivoclar Vivadent, Liechtenstein); Group 2, Cimara(®) (Voco, Germany); Group 3, Clearfil Repair(®) (Kuraray, Japan); Group 4, CoJet system(®) (3M ESPE, Germany); and Group 5, no surface conditioning and no adhesive system applied: the control group. Subsequently, resin composite material was added to the substrate surfaces and the ceramic-resin composite specimens were subjected to TBS testing. Representative samples from the test groups were subjected to scanning electron microscopy (SEM) to determine the mode of failure. The data were analysed statistically using a one-way multivariate analysis of variance and Kruskal-Wallis test at a 95% confidence interval level. RESULTS: Surface conditioning with the CoJet(®) system resulted in significantly higher bond strength values (5.2 ± 1.1 MPa) than surface conditioning with the other repair systems (p=0.03). The SEM examination of the failed interfaces revealed that all the specimens examined failed adhesively. SIGNIFICANCE: Whilst highest bond strength values were observed with the CoJet(®) system all tested repair systems resulted in relatively weak TBS values and, as a consequence, these repair systems may be indicated only as interim measures.

A comparative in vitro study of two denture cleaning techniques as an effective strategy for inhibiting Candida albicans biofilms on denture surfaces and reducing inflammation.

PURPOSE: Candida albicans is the predominant oral yeast associated with denture-induced stomatitis, and with an increasing population of denture wearers its incidence is increasing. Maintaining good oral and denture hygiene, through chemical and/or mechanical intervention, is essential to reducing this disease. The aim of this study, using a robust adherent C. albicans cell model system, was to evaluate and compare the efficacy of a novel denture cleanser to the efficacy of a commonly used dentifrice coupled with brushing. MATERIALS AND METHODS: Four C. albicans strains isolated from individuals diagnosed as having denture-induced stomatitis, were adhered to denture acrylic resin sections (1 cm(2) by 1 mm thickness) and after 4 hours of growth, challenged daily sequentially for 4 days with a denture cleanser (Polident) or intermittently with denture cleanser (day 1), then dentifrice (Colgate Cavity Protection Toothpaste) and brushing (days 2 and 3) and denture cleanser (day 4). Colony forming units were evaluated for each treatment, as were the levels of regrowth. Scanning electron microscopy (SEM) was also performed. Microbial susceptibility testing and time-kill studies were performed on biofilms. A coculture model was also used to assess interleukin-8 (IL-8) production from treated biofilms. RESULTS: It was shown that sequential treatment with the denture cleanser killed and inhibited regrowth each day. Intermittent treatment showed that viable C. albicans biofilms were only retained rather than being dispersed, which could be visualized by SEM. Time-kill studies demonstrated that the novel denture cleanser was highly active and killed quickly, unlike the dentifrice. IL-8 was expressed in greater levels in 24-hour biofilms than in 4-hour biofilms, but treatment with denture cleanser reduced IL-8 output. CONCLUSIONS: The data indicate that maintaining good oral health for denture wearers requires daily use of a denture cleanser rather than an alternating regimen. The inability of the denture cleanser to sterilize during intermittent treatments demonstrates the difficulty in controlling established biofilm. Moreover, the presence of mature biofilm may result in high levels of inflammation, but this can be controlled through denture cleansing.

The effect of surface conditioning on the bond strength of resin composite to amalgam.

OBJECTIVES: This study evaluated the effect of different surface conditioning methods on the tensile bond strength (TBS) and integrity of the amalgam-resin composite interface, using commercially available restoration repair systems. METHODS: One hundred and sixty Gamma 2 amalgam specimens were stored in artificial saliva for 2 weeks and then randomly assigned to one of the following conditioning groups (n=20/group): Group 1: air abrasion, alloy primer and 'Panavia 21', Group 2: air abrasion and 'Amalgambond Plus', Group 3: air abrasion and 'All-Bond 3', Group 4: diamond bur, alloy primer and 'Panavia 21', Group 5: diamond bur and 'Amalgambond Plus', Group 6: diamond bur and 'All-Bond 3', Group 7: silica coating technique, and Group 8: non-conditioned amalgam surfaces (control group). Subsequently, resin composite material was added to the substrate surfaces and the amalgam-resin composite specimens were subjected to TBS testing. Representative samples from the test groups were subjected to scanning electron microscopy and surface profilometry. The data was analysed statistically with one-way ANOVA and post hoc Tukey's tests (α=0.05). RESULTS: The mean TBS of amalgam-resin composite ranged between 1.34 and 5.13MPa and varied with the degree of amalgam surface roughness and the type of conditioning technique employed. Significantly highest TBS values (5.13±0.96MPa) were obtained in Group 1 (p=0.013). CONCLUSION: Under the tested conditions, significantly greater tensile bond strength of resin composite to amalgam was achieved when the substrate surface was conditioned by air abrasion followed by the application of the Panavia 21 adhesive system. CLINICAL SIGNIFICANCE: Effecting a repair of an amalgam restoration with resin composite via the use of air abrasion and application of Panavia 21 would seem to enhance the integrity of the amalgam-resin composite interface. Clinical trials involving the implementation of this technique are indicated to determine the usefulness of this technique.

Improving mechanical properties of maxillary complete dentures through a bioinspired engineering design.

PURPOSE: This study investigated how ribbed design features, including palatal rugae, may be used to significantly improve the structural performance of a maxillary denture under load. MATERIALS AND METHODS: A computer-aided design model of a generic maxillary denture, incorporating various rib features, was created and imported into a finite element analysis program. The denture and ribbed features were assigned the material properties of standard denture acrylic resin, and load was applied in two different ways: the first simulating a three-point flexural bend of the posterior section and the second simulating loading of the entire palatal region. To investigate the combined use of ribbing and reinforcement, the same simulations were repeated with the ribbed features having a Young modulus two orders of magnitude greater than denture acrylic resin. For a prescribed load, total displacements of tracking nodes were compared to those of a control denture (without ribbing) to assess relative denture rigidity. RESULTS: When subjected to flexural loading, an increase in rib depth was seen to result in a reduction of both the transverse displacement of the last molar and vertical displacement at the centerline. However, ribbed features assigned the material properties of denture acrylic resin require a depth that may impose on speech and bolus propulsion before significant improvements are observed. CONCLUSION: The use of ribbed features, when made from a significantly stiffer material (eg, fiber-reinforced polymer) and designed to mimic palatal rugae, offer an acceptable method of providing significant improvements in rigidity to a maxillary denture under flexural load.

Defective dental restorations: to repair or not to repair? Part 2: All-ceramics and porcelain fused to metal systems.

UNLABELLED: With the increasing use of ceramics in restorative dentistry, and trends to extend restoration longevity through the use of minimal interventive techniques, dental practitioners should be familiar with the factors that may influence the decision either to repair or replace fractured metal-ceramic and all-ceramic restorations and, also, the materials and techniques available to repair these restorations. This second of two papers addresses the possible modes of failure of ceramic restorations and outlines indications and techniques in this developing aspect of restoration repair in clinical practice. CLINICAL RELEVANCE: The repair of metal-ceramic and all-ceramic restorations is a reliable low-cost, low-risk technique that may be of value for the management of loss or fracture of porcelain from a crown or bridge in clinical practice.

Defective dental restorations: to repair or not to repair? Part 1: direct composite restorations.

UNLABELLED: The presentation of patients with failing dental restorations that exhibit minor defects is a common clinical situation in everyday dental practice. The repair of such restorations, rather than replacement, is increasingly considered to be a viable alternative to the replacement of the defective restoration. This first of two papers considers indications and techniques for the repair of defective direct composite restorations. It is possible that some dental practitioners are unaware of the option of repair rather than replacement of composite restorations. This article provides an overview of contemporary knowledge and understanding of restoration repair in the clinical management of defective composite restorations. CLINICAL RELEVANCE: A sound understanding of the indications, benefits and techniques of direct composite restoration repair could allow the longevity of the existing restoration to be extended without unnecessarily sacrificing healthy tooth structure.

Two- and three-dimensional accuracy of dental impression materials: effects of storage time and moisture contamination.

Dental impression materials are used to create an inverse replica of the dental hard and soft tissues, and are used in processes such as the fabrication of crowns and bridges. The accuracy and dimensional stability of impression materials are of paramount importance to the accuracy of fit of the resultant prosthesis. Conventional methods for assessing the dimensional stability of impression materials are two-dimensional (2D), and assess shrinkage or expansion between selected fixed points on the impression. In this study, dimensional changes in four impression materials were assessed using an established 2D and an experimental three-dimensional (3D) technique. The former involved measurement of the distance between reference points on the impression; the latter a contact scanning method for producing a computer map of the impression surface showing localised expansion, contraction and warpage. Dimensional changes were assessed as a function of storage times and moisture contamination comparable to that found in clinical situations. It was evident that dimensional changes observed using the 3D technique were not always apparent using the 2D technique, and that the former offers certain advantages in terms of assessing dimensional accuracy and predictability of impression methods. There are, however, drawbacks associated with 3D techniques such as the more time-consuming nature of the data acquisition and difficulty in statistically analysing the data.

The prevalence of dental, facial and head injuries sustained by schoolboy rugby players. A pilot study.

AIM: The aim of the study was to determine the prevalence of dental, orofacial and head injuries and of mouthguard use among schoolboy rugby players. MATERIALS AND METHODS: All members of the first and second XV rugby squads at three secondary schools (two in England and one in Australia) were included in the study. All participants answered a questionnaire that sought information regarding dental, orofacial and head injuries. Statistical differences between groups were determined using chi-square tests for categorical variables and Kruskal-Wallis tests for discrete (count) variables. RESULTS: One hundred and seventy-eight completed questionnaires were returned (100% response rate). One hundred and twenty-five (70%) players reported having sustained at least one injury (range 1-4). Facial injuries were common. Dental injuries were the most prevalent injury: 46 (26%) were reported. Fractured teeth were reported by 20 (11%) players, and avulsed teeth by 7 (4%). There was evidence of a difference between schools in the prevalence of injured players (P=0.014), but among those reporting injuries, there was no difference between schools in the number of injuries (P=0.95). All players said that they used a mouthguard regularly. CONCLUSIONS: Dental, orofacial and head injuries were commonly reported. Dental injuries were the most prevalent type of injury. All players used mouthguards regularly.

Energy absorption and hardness of chair-side denture soft lining materials.

The purpose of this study was to evaluate the hardness and energy absorption properties of four commercially available chairside silicone denture soft lining materials and to compare their properties with those of a heat-polymerized silicone denture liner. The denture lining materials investigated were four auto-polymerising silicone soft liners (GC Reline Soft, Ufigel SC, Elite Soft Relining and Tokuyama Sofreliner S) and a heat-polymerised silicone liner (Molloplast B). The soft liners were processed according to manufacturers' instructions. The specimens for hardness testing were 38 x 38 x 3 mm. The specimens for energy absorption test were 10 x 10 x 3 mm. In each test ten samples of each material were tested. There was strong evidence that Tokuyama Sofreliner S and, to a lesser extent, Ufigel SC, were less stiff and more resilient than Molloplast B. There was also strong evidence that both GC Reline Soft and Elite Soft Relining were harder than Molloplast B, while Ufigel SC and Tokuyama Sofreliner S were softer In conclusion differences existed between hardness and energy absorption properties of the soft lining materials.

The opinions of manufacturers of resin-based composite materials towards the repair of failing composite restorations.

AIM: To investigate the opinions of manufacturers of resin-based composite (RBC) towards the repair of their materials. METHODS: Representatives of 20 manufacturers of RBC were electronically mailed a questionnaire seeking information on aspects of the repair of direct composite restorations. RESULTS: The response rate was 100%. The findings indicated that although the majority of respondents regarded repair as a viable option for managing failing direct RBC restorations, marked variations were found to exist regarding recommendations for and contra-indications to performing repairs of RBC restorations. CONCLUSIONS: Within the limitations of the current study, the following conclusions can be drawn: (1) the majority of manufacturers of RBC materials are aware and in favour of repair as opposed to replacement of defective composite restorations; (2) there is a need for manufacturers to produce guidelines for repair of their materials; and (3) there is a need for robust randomised controlled dental practice-based clinical studies in the field of repair of composite restorations.

A pilot study of the prevalence of orofacial and head injuries in schoolboy cricketers at eight private schools in England and Australia.

AIMS: The aims of this pilot study were to determine the prevalence of head, face and dental injuries sustained by schoolboys while playing cricket and to compare the prevalence of those injuries in England and Australia. METHODS: A questionnaire that determined distribution and prevalence of orofacial injuries sustained when playing cricket was distributed to all players (n=411) who played cricket in four private schools in England and four private schools in Australia. There was a 100% response rate. RESULTS: Fifty subjects (24.1%) from English schools and 52 subjects (25.5%) from Australian schools reported injury/injuries to the head, face and teeth. Australian cricketers reported more injuries per player. The distribution of injuries between the two countries was similar. Sixteen players had sustained loosened or broken teeth. Two players reported avulsed teeth. CONCLUSION: It was concluded that there was a high prevalence of head and orofacial injuries among the schoolboy cricketers but relatively few dental injuries. The distribution of types of head, face and dental injury in England and Australia were similar.

The prevalence of orofacial pain and tooth fracture (odontocrexis) associated with SCUBA diving.

AIM: To assess the prevalence of orofacial complications associated with SCUBA (self-contained underwater breathing apparatus) diving. Main outcome measures were prevalence of orofacial pain and odontocrexis. METHOD: Two hundred divers at four dive centres on the north-east coast of Australia were asked to complete a questionnaire that requested information regarding diving experience and facial pain and dental symptoms experienced during diving. RESULTS: One hundred and twenty-five completed questionnaires were returned (63% response rate). The prevalence of reported orofacial pain was 44%. Twenty-one per cent reported toothache, 27% sinus pain, 16% jaw pain, and 12% other pain. The prevalence of odontocrexis was less than 1%. Less than 1% had lost a filling when diving. No divers reported a crown or bridge being dislodged during diving. CONCLUSION: Among those who returned questionnaires, orofacial pain in divers was common and odontocrexis was rare.

Differential adhesion of Streptococcus gordonii to anatase and rutile titanium dioxide surfaces with and without functionalization with chlorhexidine.

The majority of dental implants are composed primarily of titanium and have an outer layer of titanium dioxide. Crystalline titanium dioxide most commonly exists in one of the two structures, anatase and rutile, and both of these have been observed on commercially available dental implants. Early implant failure can be associated with postoperative infection due to implant contamination during or immediately after surgery. The impetus of this study was to investigate whether functionalization of anatase and rutile titanium dioxide surfaces with chlorhexidine-reduced subsequent colonization of the surface by Streptococcus gordonii. Exposure to 100 mg x L(-1) chlorhexidine for 60 s resulted in a fivefold reduction in S. gordonii coverage on anatase and a twofold reduction on rutile. This may be related to a preferential adsorption of chlorhexidine to anatase compared with rutile. The reduction in bacterial coverage was not due to desorption of chlorhexidine into solution. More bacteria were observed on anatase than rutile surfaces without chlorhexidine functionalization, indicating that crystal structure may have a significant effect on bacterial colonization. In conclusion, functionalization with chlorhexidine reduced bacterial coverage on titanium dioxide surfaces, and anatase surfaces may be more amenable to such treatment than rutile.

Denture cleansers, soft lining materials and water temperature: what is the effect?

AIM: To investigate the effect of water temperature, in association with four denture cleansers, on the colour and surface roughness of five soft lining materials. METHOD: Two silicone soft lining materials (Molloplast B and Sofreliner) represented the heat-cured, laboratory-based and chairside materials that are available. The wide range of chairside, acrylic resin-based, temporary soft lining materials was represented by Coe-Soft, Viscogel and Eversoft. An alkaline hypochlorite (Dentural) and three effervescent peroxide solutions with a range of active pH values (Steradent Active Plus, pH 6; Steradent Extra Strength, pH 3; Superdrug Fresh, pH 11) were selected as the cleansers. The denture cleansers were used at two temperatures: 55 degrees C (manufacturers' recommended temperature) and 80 degrees C. The colour of the specimens was evaluated using a colorimeter and the surface roughness was assessed using a three-dimensional, non-contact surface profilometer. This study reported on the effect of using both the higher temperatures and the recommended temperature on the colour and roughness of permanent and temporary soft lining materials. RESULTS AND CONCLUSION: The results of the study showed that the temperature of the water used with denture cleansers might have a detrimental effect on the colour and surface roughness of some permanent and temporary soft lining materials.

The staggered installation of dental implants and its effect on bone stresses.

PURPOSE: The aim of this study was to investigate the effect of offsetting the middle or peripheral implant on the compressive stress values in the crestal bone around the neck of the dental implant. MATERIALS AND METHODS: Three finite element models describing three titanium implants installed in quadrilateral pieces of bone was executed. A 2-mm nickel chromium superstructure representing a bridge was modeled over the implant abutments. In model 1, implants were installed along a straight line. Model 2 had the middle implant installed outside the line connecting the two peripheral implants buccally. Model 3 had the mesial implant installed out of alignment. Six 100-N loads were modeled on top of the mesial and middle implants of the three models individually. Loads 1 and 2 were directed vertically on the mesial and middle implants, while loads 3 and 4 represented the horizontal loads in the buccal direction. Loads 5 and 6 were directed mesially on the mesial and central implants. Maximal compressive stress levels in the crestal bone of the three models were then investigated. RESULTS: The results demonstrated that offset implant installation revealed slightly lower bone stresses under buccally or lingually directed horizontal forces. Slightly higher bone stresses under vertical loads were observed. Horizontal mesial or distal loads resulted in slightly higher bone stresses than those caused by buccal or lingual loading. CONCLUSIONS: The in-line implant alignment clearly had the safest compressive stress outcome on the surrounding structure under vertical loads. Under buccolingual loads, implant alignment with peripheral offset would have, relatively, the safest compressive stress outcome on bone.

The effects of polishing methods on surface morphology, roughness and bacterial colonisation of titanium abutments.

Bacterial colonisation of exposed implant and abutment surfaces can lead to peri-implantitis, a common cause of oral implant failure. When an abutment becomes exposed in the oral environment the typical recommendation is to debride it, to obtain a smoother surface which might be expected to reduce bacterial colonisation. The aim of this study was to evaluate, in vitro, a conventional polishing protocol (PP1) and a simplified polishing protocol (PP2), suggested to have advantages over PP1. The surface morphology and roughness of titanium abutments were characterised at each stage of polishing, and adhesion of oral bacteria was evaluated, using atomic force microscopy, environmental scanning electron microscopy and optical profilometry. PP1 and PP2 methodologies resulted in indistinguishable surface finishes, with fewer scratches than the unmodified surface, and equal roughness values. PP2 resulted in less disruption and less removal of surface material. Early biofilm formation by Streptococcus mutans was reduced on surfaces polished using PP2, but not PP1. Biofilms of Actinomyces naeslundii were more extensive on polished abutment surfaces. Simplified protocol PP2 may be preferable to conventional protocol PP1, since less material is removed, and there is less chance of rough areas remaining. Polishing, however, does not necessarily reduce oral bacterial colonisation.

The introduction of a new assessment system in restorative dentistry: the undergraduate and patient experience.

In 2000, the University of Bristol Dental School Division of Restorative Dentistry carried out a review of the assessment methods used within the undergraduate programme. Following this review, a number of key recommendations were made and the system of formative assessment within the division was changed. Audits were conducted immediately prior to the introduction of the new system and 2 years after it had been introduced, the results of these audits are presented. There was no change in the number of failed appointments between the initial audit and the second audit. There was a reduction in the number of patients treated by more than one student from 25% to 14% (approximating to 3% if student withdrawal from the course is taken into account). The length of time taken to complete treatment reduced between the two audits with more than half of all patients having their treatment completed within 3 months of their initial examination in the second audit. Ninety-five percent of treatment plans were completed in the second audit compared with only 62% in the first audit. In the second audit, the outstanding 5% of cases were signed off as incomplete for satisfactory reasons by the member of supervisory staff (e.g. patients who had moved away or were discharged due to poor attendance). Student comments were mostly positive, the small number of negative comments related to some students being confused by the paperwork in the new system. The overall process has been an extremely positive experience which has resulted in an assessment system with increased clarity which appears to have reduced the stress levels reported by the undergraduate students on the programme and improved the quality of patient care within restorative dentistry.

Osteomyelitis and pathological mandibular fracture related to a late implant failure: a clinical report.

This clinical report describes an unusual consequence of peri-implantitis and subsequent implant failure in a 72-year-old man. Following uneventful implant removal, osteomyelitis developed at the implant site, which subsequently weakened the mandible sufficiently for a pathological fracture to occur. The patient was treated successfully by use of an intensive oral hygiene regime, antibiotics, and conservative management. The consequences and management of implant failure are discussed, as well as issues relating to the management of osteomyelitis and pathological bone fracture.

A comparison of two methods of enhancing implant primary stability.

BACKGROUND: Surgical technique and implant design have an effect on the primary stability of oral implants, which in turn increases resistance to implant micromotion during healing. PURPOSE: This study was designed to compare the parameters associated with implant insertion using two different methods of enhancing implant primary stability and to identify any relationship between these parameters and changes in the stability of implants during the initial 6-month healing period following implant insertion. A comparison was made between two methods of enhancing primary implant stability: method 1, standard Brånemark System implants (Nobel Biocare AB, Gothenburg, Sweden) inserted with a technique designed to enhance primary stability, and method 2: Brånemark Mk IV implants (Nobel Biocare AB) inserted according to the manufacturer's instructions. MATERIALS AND METHODS: Thirteen patients were selected for inclusion in the study. A total of 42 implants were placed. Insertion torque data were recorded, and bone quality at the implant site was assessed at implant insertion. Resonance frequency analysis measurements were taken at implant insertion as well as at second-stage surgery 6 months later. RESULTS: A statistically significant difference was recorded between the mean maximum insertion torque for type 4 bone and bone types 2 and 3. No significant difference was recorded between bone types 2 and 3. A significantly lower resonance frequency value was seen for standard implants placed into type 4 bone (p < .05). Across all implant types a significant difference in the energy required when inserting implants into type 4 bone and bone types 2 and 3 was seen. A significantly lower mean energy requirement was seen between the Mk IV implants placed into type 4 bone and the other combinations of implant types and bone. CONCLUSIONS: Within the limitations of this study, the results agree with the manufacturer's claim that when compared with standard implants, the design of the Mk IV implant increases implant primary stability with a reduction in the energy imparted into the bone at the implant site.