Herodontics - is there a place for maintaining the apparently hopeless tooth?

The population is ageing and people are keeping their own teeth for much longer due in part to the efforts of the dental profession in restoring teeth and reducing the number of teeth being extracted. Along with this there is now an increasing expectation by patients that they will retain their own teeth as they age and that dental practitioners will have the knowledge and skills to help them retain their own teeth. Contemporary restorative materials and techniques have increased the range of options available to assist with maintaining the dentition, and many of these procedures enable minimally invasive and cost effective management of the teeth as an alternative to complex and expensive procedures. This paper discusses the restoration of compromised and failing teeth in the ageing patient, and looks at the various issues facing the ageing dentate patient and the dilemma of when to restore or when to extract. Ultimately it is hoped that maintaining healthy teeth for life may not only improve oral function and quality of life, but may in fact reduce the impact of the physical and psychological aspects of ageing.

Minimum intervention dentistry and the management of tooth wear in general practice.

The incidence of tooth wear, or non-carious tooth surface loss (NCTSL), is increasing and oral rehabilitation of patients with non-carious tooth loss requires strategies that address all the factors relevant to the aetiology and pathogenesis of the condition. The multifactorial nature of tooth wear and the variability in its clinical presentation provides treatment challenges for the clinician and successful management must be more than just restoration. Management must include an appropriate mix of preventive and restorative strategies and an understanding that long-term restorative success is affected by the patient's oral environment, and how diet, lifestyle and medical status can modify this environment. Ultimately, the success of any restorative intervention is very dependent on the stability of the oral environment and the condition of the remaining tooth structure. Minimum intervention dentistry (MID) philosophies are ideally suited to tooth wear cases and an overall MID strategy involving diagnosis, recognition and control of predisposing factors, stabilization of the oral environment, remineralization and restoration of the tooth structure, and ongoing maintenance can be implemented. When restorative treatment is required, contemporary materials and techniques are available that can provide cost-effective and conservative restorative alternatives for patients unable to undergo the complex indirect restorative techniques that are both costly and time consuming to implement. These minimally invasive approaches are not only an economically viable solution, but can provide aesthetic and functional rehabilitation and maintain tooth structure as a precursor to more complex restorative options when required.

Laser-activated fluoride treatment of enamel as prevention against erosion.

BACKGROUND: Erosion is the loss of dental hard tissues from an acidic challenge, often resulting in exposure of dentinal tubules and hypersensitivity to environmental stimuli. Laser-activated fluoride (LAF) therapy with 488nm laser energy has been shown previously to increase the resistance of human enamel and dentine to acid dissolution. The aims of this study were to investigate the action spectrum of LAF in protecting tooth enamel from softening in response to an erosive challenge, and to examine for any temperature change with the treatment. MATERIALS AND METHODS: Buccal and lingual surfaces of extracted sound molar and premolar teeth were used to prepare matched pairs of enamel slabs (N = 10 per group). After application of 1.23% neutral sodium fluoride gel (12 300ppm F ion), slab surfaces were lased with 488, 514.5, 532, 633, 670, 830 or 1064nm wavelength (energy density 15J/cm(-2); spot size 5mm), then exposed to an erosive challenge (1.0M HCI for five minutes). The Vicker's hardness number (VHN) was recorded before fluoride gel application and again following the acid challenge. Negative controls did not receive laser exposure. RESULTS: All wavelengths of laser light examined provided a protective LAF effect against softening, compared with the negative control surfaces. CONCLUSION: From these findings, we conclude that the action spectrum of the LAF effect extends across the visible spectrum, providing protection to dental enamel from an erosive challenge.

Combined CPP-ACP and photoactivated disinfection (PAD) therapy in arresting root surface caries: a case report.

A 19-year-old male was referred to the School of Dentistry, University of Queensland for management and treatment of uncontrolled root caries. A total of 12 teeth had non-cavitated root carious lesions requiring treatment. The lesions were treated with a daily application of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP; GC Tooth Mousse) and in-surgery photo-activated disinfection (PAD). Laser fluorescence (KaVo Diagnodent) was used to monitor the changes in the carious lesions. The combination of CPP-ACP and PAD proved to be very effective and holds great potential as a recommended treatment for stabilising root surface caries in the clinical practice.

Laser-activated fluoride treatment of enamel against an artificial caries challenge: comparison of five wavelengths.

BACKGROUND: Laser-activated fluoride (LAF) therapy with 488 nm laser energy has been shown previously to increase the resistance of human enamel and dentine to acid dissolution in laboratory models of dental caries. The aims of this study were to examine whether LAF therapy, conducted using a range of wavelengths in the visible and near infrared regions, can protect human dental enamel from an artificial cariogenic challenge. MATERIALS AND METHODS: Buccal and lingual surfaces of extracted sound, molar and premolar teeth were used to prepare matched pairs of enamel slabs (N=10 per group). After application of neutral sodium fluoride gel (12300 ppm F ion), slab surfaces were lased (energy density 15 J/cm2; spot size 5mm, wavelength 532, 633, 670, 830 or 1064nm), then exposed to an artificial cariogenic challenge for a period of seven days. The Vicker's hardness number (VHN) was recorded before and after laser treatment and again following the cariogenic challenge. Negative controls did not receive laser exposure. RESULTS: All wavelengths of laser light examined provided an effective LAF effect, compared with the unlased negative control surfaces. CONCLUSION: Using this in vitro model, we conclude that the action spectrum of the LAF effect extends across the visible and near-infrared regions of the spectrum.

Bacteria and salivary profile of adolescents with and without cleft lip and/or palate undergoing orthodontic treatment.

BACKGROUND: Patients with cleft lip and/or palate (CL&/P) experience a higher caries prevalence. This study aimed to determine if patients with CL&/P, undergoing and not undergoing orthodontic treatment, have a different salivary biochemical profile and different salivary levels of Mutans Streptococci (MS) and Lactobacilli (LB) compared to patients undergoing and not undergoing orthodontic treatment without CL&/P. METHODS: One hundred and ten subjects aged between 12 and 17 years were recruited into one of four different groups comprising two control groups and two treatment groups. The control groups comprised of subjects with and without CL&/P who were not undergoing orthodontic treatment. The treatment groups comprised of subjects with and without CL&/P undergoing orthodontic treatment. Regular reinforcement of oral hygiene instructions, dietary counselling and debridement, when necessary, were offered to subjects in the treatment groups following their orthodontic adjustment appointments. The salivary secretion time, pH of resting and stimulated saliva, salivary flow rate, buffering capacity, quantity of salivary MS and LB were measured. RESULTS: Subjects with CL&/P undergoing orthodontic treatment at the Children's Oral Health Service tended to present with microbiological and salivary profiles that were less favourable for caries development. There was a significant difference in the percentage of subjects with > or = 10(5) colony forming units (CFU)/mL of MS between the cleft treatment and non-cleft treatment groups. Subjects in the non-cleft treatment group had the highest percentage of subjects (86.7 per cent) with > or = 10(5) CFU/mL of MS whereas subjects in the cleft treatment group had the lowest percentage of subjects (60 per cent) with > or = 10(5) CFU/mL of MS. For LB, there were significantly higher percentages of subjects with > or =10(5) CFU/mL of LB in the non-cleft treatment (76.7 per cent) and cleft treatment (73.3 per cent) groups compared to the non-cleft control (46.7 per cent) and cleft control (40.0 per cent) groups. CONCLUSIONS: Regular oral hygiene reinforcement and dental health education appears to have a positive effect in reducing the percentage of subjects with > or = 10(5) CFU/mL of MS.

'Schools without walls?' Developments and challenges in dental outreach teaching - report of a recent symposium.

During the 2004 annual meeting of the International Association for Dental Research, the Education Research Group held a symposium on dental outreach teaching. After a brief introduction, which reviews relevant aspects of the relatively sparse literature, this paper summarises the proceedings, the themes and conclusions that emerged and the research issues that were identified. It aims to describe aspects of current practice around the world and to promote future discussion. Presenters gave details of outreach programmes for dental undergraduates in Australia, Finland, Malaysia (and Southeast Asia), the United Kingdom and the United States. From these presentations four themes emerged. They were: reasons for the introduction of outreach teaching, its perceived beneficial effects, organisational issues, educational issues. The reasons included a recognition of the need to educate dental undergraduates as members of 'care teams' in the environments and communities where they were ultimately like to work and the current shortage of both suitable patients and teachers (faculty) in many dental schools. A wide range of potential benefits and some disadvantages were identified. The organisational issues were, in the main, seen to relate to finance and administration. The educational issues included the need to train and monitor the performance of teachers at outreach clinics and to assess the performance of the undergraduates whilst at the outreach locations. It was concluded that new technology made it easier to teach at a distance and it was possible to create a dental 'school without walls'. It was recognised that few evaluations of dental outreach teaching have been carried out and that there were many research questions to be answered, including: whether it should be a voluntary or compulsory part of the undergraduate curriculum, how long it should last and what type of outcomes should be assessed.

Effects of electrical stimulation of the posterior part of the hypothalamus on the spike activity of neurons in the oral nucleus of the pons.

Chronic experiments were performed on four cats to study evoked spike activity in neurons in the oral nucleus of the pons to electrical stimulation of the posterior hypothalamus in the waking, slow-wave sleep, and paradoxical sleep states. A total of 42% of study neurons were found to respond to stimulation during waking. PS-on and PS-off neurons were identified in the oral nucleus of the pons, along with phasic cells showing bursts of activity during the physical manifestations of paradoxical sleep. Stimulation induced inhibitory responses in PS-on neurons, excitatory responses in PS-off neurons, and excitatory and inhibitory responses in 68% and 32% respectively of phasic neurons. The magnitudes of evoked responses in these neurons changed during the sleep-waking cycle. These data demonstrate the involvement of the posterior hypothalamus in controlling the mechanisms of paradoxical sleep, these mechanisms being located in the oral nucleus of the pons.

Direct restorative materials use in Australia in 2002.

BACKGROUND: This study aimed to determine the reasons for dentists' choice of materials, in particular amalgam and resin composite, in Australia. METHOD: A questionnaire was developed to elicit this information. The names and addresses of 1000 dentists in Australia were selected at random. The questionnaire was mailed to these dentists with an explanatory letter and reply-paid envelope. RESULTS: A total of 560 replies were received. Regarding choice of material, 99 per cent of respondents cited clinical indication as an influencing factor, although patients' aesthetic demands (99 per cent of respondents), patients' wish (96 per cent), patients' financial situation (82 per cent), and lecturers' suggestions (72 per cent) were also reported to influence respondents' choice of materials. Twelve per cent of respondents used composite 'always', 29 per cent 'often', 32 per cent 'sometimes', 23 per cent 'seldom' and 4 per cent 'never' in extensive load-bearing cavities in molar teeth. For composite restorations in posterior teeth, 84 per cent 'always', 'often' or 'sometimes' used the total etch technique, 84 per cent used a thick glass-ionomer layer and 36 per cent never used rubber dam. Fifty-nine per cent of respondents reported a decreased use of amalgam over the previous five years. Sixty-eight per cent of respondents agreed with the statement 'discontinuation of amalgam restricts a dentist's ability to adequately treat patients'. Seventy-five per cent considered that the growth in the use of composites increased the total cost of oral health care. CONCLUSIONS: Of the respondents from Australia 73 per cent place large composite restorations in molar teeth and their choice of material is influenced greatly by clinical indications, and patients' aesthetic demands.

The prevalence of autoantibodies in an elderly sub-Saharan African population.

In the present prospective, census-based study we have investigated the prevalence of organ-specific and non-organ-specific autoantibodies (AAb) in 152 unselected Cameroonians aged 60 years and older living in the community. AAb were detected in 49% of the participants. Non-organ-specific AAb (47%) predominated over organ-specific AAb (7%). Anti-TPO, anti-Tm, anti-Tg and anti-PC AAb were completely absent. RF was the most frequent AAb, being found in 57 (38%) cases. The prevalences of anti-SMA and RF were significantly higher in women than in men (respectively, P=0.023 and P=0.016). Higher serum concentrations of gammaglobulins were accompanied by a higher prevalence of RF (P < 0.0001) and a lower prevalence of ANA (P=0.036). The overall prevalence of AAb was higher in the filaria-infected (60%) compared to the non-infected (42%) participants (P=0.046). There was no significant influence of the vitamin D status, number of pregnancies, physical activity or medication use on the prevalence of AAb. In this study a heterogeneous pattern for the presence of the various AAb was found. Some AAb, which are commonly encountered in other studies on elderly subjects, were completely absent in this population. This diversified pattern of AAb prevalence therefore argues in favour of exogenous influences in the occurrence of AAb in elderly populations.

Pulpal heat changes with newly developed resin photopolymerisation systems.

Composite resin is a widely-used direct tooth coloured restorative material. Photoactivation of the polymerisation reaction can be achieved by visible blue light from a range of light sources, including halogen lamps, metal halide lamps, plasma arc lamps, and Light Emitting Diode (LED) lights. Concerns have been raised that curing lights may induce a temperature rise that could be detrimental to the vitality of the dental pulp during the act of photoactivation. The present study examined heat changes associated with standardised class V restorations on the buccal surface of extracted premolar teeth, using a curing time of 40 seconds. The independent effects of type of light source, resin shade, and remaining tooth thickness were assessed using a matrix experimental design. When a conventional halogen lamp, a metal halide lamp and two different LED lights were compared, it was found that both LED lamps elicited minimal thermal changes at the level of the dental pulp, whereas the halogen lamp induced greater changes, and the metal halide lamp caused the greatest thermal insult of all the light sources. These thermal changes were influenced by resin shade, with different patterns for LED versus halogen or halide sources. Thermal stress reduced as the remaining thickness of tooth structure between the pulp and the cavity floor increased. From these results, it is concluded that LED lights produce the least thermal insult during photopolymerisation of composite resins.

The surface effect of dentifrices.

The aim of this study was to evaluate clinically three commercially available dentifrices and to determine any surface effects on tooth or gingival surfaces. Sixty-four participants were included in this study and were allocated randomly to one of four treatment groups by an independent person to ensure the investigators were unaware of the brushing material used. All toothbrushes and dentifrices were distributed by this independent person. The treatment groups were: Group 1--brush with water; Group 2--brush with Colgate (Baking Soda and Peroxide); Group 3--brush with Macleans (Whitening); Group 4--brush with Colgate (Sensation Whitening). All participants were requested to brush both morning and evening in their customary fashion using only the designated toothpaste, or water, for four weeks. All participants were required to use the same toothbrush type. No other oral hygiene products such as mouth rinses or dental floss were used during the trial period. Prior to commencement of the brushing period, all participants received a full clinical examination recording the status of the soft and hard tissues including a gingival index (Löe and Silness) to record gingival condition. A polyvinyl siloxane impression was taken of the six anterior teeth and gingival tissues at the commencement of the trial. After four weeks, a second full clinical examination was made and further silicone impressions were taken of the anterior teeth. All impressions were cast in epoxy resin for investigation with light and electron microscopy. Participants were also asked to answer a questionnaire relating to the toothpaste used. The results of this study indicated that no significant clinical differences were recorded for any dentifrice or water and there was no significant difference in gingival index scores over the four week period. Patient responses to each dentifrice varied according to individual patient preferences and expectations and no consistent findings could be determined. Light and electron microscopy indicated that tooth and gingival surface changes that occurred over the four week period with any of the dentifrices were similar to, and not significantly different from, changes seen with the use of water alone. These results indicate that none of the dentifrices tested was harmful to teeth or soft tissues.

The effect of fissure morphology and pretreatment of the enamel surface on penetration and adhesion of fissure sealants.

Fissure sealants have been used successfully as a means of preventing fissure caries. This effectiveness is directly related to sealant retention and retention is dependent upon a meticulous method of application. The aims of this study were to determine if sealant adhesion and penetration were affected by the variation in preparation of the enamel surface, or by pretreatment of the enamel surface with dentine adhesive systems, in fissures of varying morphology. Non-carious posterior teeth were visually examined and sorted according to fissure type, classified as shallow, deep or intermediate. Occlusal fissures were sealed using one of six methods, thermocycled for 200 cycles between 5 and 55 degrees C, in artificial saliva, then placed in a 1.5% procion orange dye for 3 min. Teeth were sectioned bucco-lingually and examined with a light microscope for (i) penetration of the sealant into the fissure pattern and (ii) adhesion of the sealant. All sealant techniques employed in this study adapted well to the enamel surface as the 1.5% procion Reactive orange dye failed to penetrate any of the sealed tooth sections. Shallow fissures were well obturated in both lateral and vertical dimensions. Sealants adapted well to the vertical walls at the orifice of deep fissures but generally failed to penetrate into the deeper aspects. Reducing the etching period with 37% phosphoric acid resulted in increased voids between the sealant and enamel surface and poorer adaptation to the vertical walls. The addition of dentine adhesive systems, Scotchbond Multi-Purpose and All-Bond 2, enhanced the vertical penetration of the sealant, particularly in deep fissures. It is proposed that the dentine adhesive systems may improve the retention rate of sealants in deep fissures particularly if the fissure is not completely dry prior to resin placement.

The effect of a vital bleaching technique on enamel surface morphology and the bonding of composite resin to enamel.

This study examined the effect of a nightguard vital bleaching procedure on enamel surface morphology and the shear bond strength of a composite resin luting cement to enamel. Extracted human teeth were bleached for 1 week using a vital bleaching product. Control teeth were brushed with a fluoride toothpaste and processed similarly to the bleached teeth, however the bleaching product was substituted with artificial saliva in the night guards. Teeth were stored in artificial saliva for 24 h, 1, 6 or 12 weeks and then examined for any surface changes using light and scanning electron microscopy. The effect of etching surfaces with 37% phosphoric acid was examined at the scanning electron microscope level. The shear bond strength of composite resin luting cement to both buccal and lingual surfaces of bleached and control teeth was determined. Light microscopy investigation suggested the bleaching process resulted in a loss of mineral from enamel which was evident 24 h after bleaching and was sustained following 12 weeks storage in artificial saliva. Scanning electron microscopy showed a definite change in the surface texture of the bleached enamel surface. Acid etching of the bleached enamel surface produced loss of prismatic form and the enamel appeared overetched. The mean shear bond strength between composite resin luting cement and etched enamel tended to be lower for bleached enamel surfaces, however no significant difference in shear bond strength was noted between control and experimental groups. The results of this study suggest that bleaching resulted in changes to the surface and subsurface layers of enamel. Although surface changes were observed in the etched enamel, the shear bond strength of composite resin luting cement to etched bleached enamel appeared to be clinically acceptable.

A laboratory investigation of a composite resin/dentine bonding agent mixture used as a root canal sealer.

The objective of this project was to determine the effectiveness of a dentine bonding agent, in conjunction with a composite resin, to act as an endodontic sealing material. The effectiveness was compared with that provided by a conventional sealer (AH26) by measuring dye penetration into the root canal. Two obturation techniques were used with each sealer; the single gutta-percha point technique, and lateral condensation with multiple gutta-percha points. Lateral condensation with the conventional sealer was found to be the superior procedure, by producing the least amount of linear leakage (coronally from the apex) on average. However, the single point technique with the composite resin/dentine bonding agent sealer provided the greatest number of 'no leakage' samples. Scanning electron microscope investigation of obturated roots revealed the presence of resin tags in dentine tubules only in those samples where the composite resin/dentine bonding agent sealer was used. The short working time provided by the composite resin/dentine bonding agent sealer prevented successful obturation using lateral condensation. The provision of an extended working time composition for this sealer may produce more favourable results in obturation with lateral condensation.

Physiological root resorption of primary molars.

Physiological root resorption of primary molars was assessed using bitewings and orthopantomograms. Thirty-six per cent of teeth examined demonstrated reduced root resorption of one or more roots. Excepting the lower first primary molar, the present study recorded a relatively high incidence of uneven root resorption during the exfoliative process, particularly evident for the upper second primary molar. Discrepancy in size between the premolar and its predecessor, as well as the position of the developing permanent tooth in relation to primary root structure influences the pattern of root resorption. Therefore, constant monitoring of teeth demonstrating uneven resorption is required to avoid the complications associated with over-retained teeth.

The relationship between Ki-67 labeling and mitotic index in gliomas and meningiomas: demonstration of the variability of the intermitotic cycle time.

The monoclonal antibody (mAb) Ki-67 is a marker for the growth fraction (GF) of tumor cells. The exact relationship between the Ki-67 labeling index (LI) and the conventional diagnostic criterion of the proliferative activity of brain tumors, the mitotic index (MI), is unknown except for some general references. On serial frozen sections Ki-67 LI and MI were determined in nearly identical areas of 32 glioblastomas, 20 grade III astrocytomas, 21 grade II astrocytomas and 20 selected cases of meningioma. The data not only clearly showed different median values of LI and MI for the various malignancy grades, but also similar regression coefficients for each glioma type. A non-linear relationship between the two indices was found for all glioma cases with high significance and high correlation coefficient; (LI) = 5.6 (MI)0.59. This results from differing intermitotic cycle times, the variability of which can be estimated from the data given.

The floor of the pulp chamber following pulpotomy.

The purpose of this study was to investigate the incidence of pulpal floor damage caused by operator error in a standard pulpotomy exercise, and to determine if this damage produced significant changes in dentin morphology and thickness at the base of the pulp chamber. One hundred and fourteen primary molar teeth were utilized in this study, 61 having pulpotomies and the remainder untreated. The dentin thickness in the furcation was measured on all the teeth and the pulpal floor morphology was examined using both light and scanning electron microscopy. The difference in thickness of dentin in the furcation of pulpotomized and non-pulpotomized teeth was not statistically significant. Less than fourteen per cent of pulpotomized teeth showed damage to the pulpal floor and this damage was only minimal in all cases. This study therefore suggests that damage to the pulpal floor during preparation is unlikely to be a factor contributing to failure of pulpotomies.

Efficiency of glass ionomer cement linings in preventing microleakage under Class V composite resin restorations.

The ability of glass ionomer linings to aid in the prevention of microleakage under Class V composite resin restorations has been investigated. A conventional glass ionomer lining (Ketac-bond) and two light cured linings (Vitrabond and Timeline) were evaluated with respect to their ability to reduce microleakage. Seventy two Class V cavities were restored either by a bulk fill or incremental fill technique, and following restoration, half the teeth were thermocycled in artificial saliva. Dye penetration, using a Procion orange dye was recorded along the gingival dentine wall and at the occlusal enamel margin for all teeth. The results showed significant differences in leakage along the gingival dentine wall between the various linings under all conditions. Vitrabond produced significantly less leakage than Ketac bond which in turn produced significantly less leakage than Timeline. Significant differences in microleakage were noted between the thermocycled and non-thermocycled groups. Little or no significant differences in leakage were shown between the bulk filled and incremental filled teeth.