Effects of zoledronic acid and geranylgeraniol on the cellular behaviour and gene expression of primary human alveolar osteoblasts.

INTRODUCTION: Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a serious complication of bisphosphonate therapy. The mechanism underlying BRONJ pathogenesis is poorly understood. OBJECTIVES: To determine the effects of zoledronic acid (ZA) and geranylgeraniol (GGOH) on the mevalonate pathway (MVP) in osteoblasts generated from the human mandibular alveolar bone in terms of cell viability/proliferation, migration, apoptosis and gene expression. MATERIALS AND METHODS: Primary human osteoblasts (HOBs) isolated from the mandibular alveolar bone were phenotyped. HOBs were cultured with or without ZA and GGOH for up to 72 h. Cellular behaviour was examined using a CellTiter-Blue® viability assay, an Ibidi culture-insert migration assay, an Apo-ONE® Homogeneous Caspase-3/7 apoptosis assay and transmission electron microscopy (TEM). Quantitative real-time reverse transcriptase polymerase chain reaction (qRT2-PCR) was used to determine the simultaneous expression of 168 osteogenic and angiogenic genes modulated in the presence of ZA and GGOH. RESULTS: ZA decreased cell viability and migration and induced apoptosis in HOBs. TEM revealed signs of apoptosis in ZA-treated HOBs. However, the co-addition of GGOH ameliorated the effect of ZA and partially restored the cells to the control state. Twenty-eight genes in the osteogenic array and 27 genes in the angiogenic array were significantly regulated in the presence of ZA compared with those in the controls at one or more time points. CONCLUSION: The cytotoxic effect of ZA on HOBs and its reversal by the addition of GGOH suggests that the effect of ZA on HOBs is mediated via the MVP. CLINICAL RELEVANCE: The results suggest that GGOH could be used as a possible therapeutic/preventive strategy for BRONJ.

An Investigation of the Views of Parents in Otago on Dental Care for Primary School-Aged Children by the Community Oral Health Service Prior to the Introduction of the Hub-Based Clinic System.

BACKGROUND AND OBJECTIVES: Prior to the introduction of the Southern District Health Board's reconfigured Community Oral Health Service in Otago, a project was undertaken with parents to investigate their knowledge, understanding and views of the historical School Dental Service and of the Community Oral Health Service that was being introduced. METHODS: Focus groups were run during 2011 in ten selected schools (parents with children in years 1-8) across two areas in Otago to represent ur ban and rural settings and to represent parents who were already travelling to dental services. RESULTS: Parents valued the traditional School Dental Service in Otago highly, generally agreeing that the service based in schools was accessible and convenient for parents and children. Rural parents who had always taken their children to dental appointments viewed it as a normal process, accepting that there could not be a service located in every school. Parents were aware that facilities were out-of-date. They highlighted the challenges of locating therapists since they started moving from school to school in the later 1990s and felt it was difficult for children seeing different therapists at each recall. There were diverse views on the proposed new system. Some parents felt that school-aged children should go to dental clinics on their own or with peers, while other parents welcomed the opportunity to attend when their child was having health care. CONCLUSION: It appears that the Community Oral Health Services should have an ongoing process to seek the views of parents and children about the service.

The use of radiography in the diagnosis of oral conditions in children and adolescents.

Radiography can serve as a useful aid in the diagnosis of numerous oral conditions, with a place in nearly all of the disciplines of dentistry. As such it can have a beneficial role in caring for the oral health of children and adolescents. The following review discusses the use of radiography in the diagnosis of oral conditions in children and adolescents, with particular reference to the diagnosis of dental caries, dental trauma, growth and development and in other dental scenarios, along with the importance of incidental findings. The risks associated with radiation exposure from the use of radiography are discussed, how these need to be balanced with the possible benefits associated with such use, as well as how risks could be minimised. Summary recommendations are also presented, providing an overview of the use of radiography for oral diagnosis in various clinical scenarios for children and adolescents.

Zoledronic acid and geranylgeraniol regulate cellular behaviour and angiogenic gene expression in human gingival fibroblasts.

The mevalonate pathway (MVP) and the anti-angiogenic effect of bisphosphonates have been shown to play a role in the pathogenesis of bisphosphonate-related osteonecrosis of the jaw (BRONJ). This study determined the effect of the bisphosphonate, zoledronic acid and the replenishment of the MVP by geranylgeraniol on human gingival fibroblasts. Cell viability, apoptosis, morphological analysis using transmission electron microscopy, and gene expression for vascular endothelial growth factor A, bone morphogenic protein 2, ras homologue gene family member B, epiregulin and interferon-alpha were conducted. Results showed cellular viability was decreased in the presence of zoledronic acid and the co-addition of zoledronic acid with geranylgeraniol restored cell viability to control levels. Caspase 3/7 was detected in zoledronic-acid-treated cells indicating apoptosis. Transmission electron microscopy revealed dilation of the rough endoplasmic reticulum with zoledronic acid and the appearance of multiple lipid-like vesicles following the addition of geranylgeraniol. Zoledronic acid significantly (P < 0.05, FR > ± 2) up-regulated vascular endothelial growth factor A, bone morphogenic protein 2, ras homologue gene family member B and epiregulin at one or more time points but not interferon-alpha. Addition of geranylgeraniol resulted in a reduction in the expression of all five genes compared with zoledronic-acid-treated human gingival fibroblasts. The study concluded geranylgeraniol partially reversed the effects of zoledronic acid in human gingival fibroblasts both at the cellular and genetic levels, suggesting the regulation of these genes is mediated via the mevalonate pathway.

Management of the pulp in primary teeth--an update.

Management of the pulpal tissue in primary teeth is a clinical challenge facing dental practitioners on a regular basis. This article reviews the most common treatments used at the present time in the management of the pulp in deciduous teeth. It gives an overview of treatment options and the indications and contra-indications for the different treatment modalities. The evidence behind the medicaments used, their actions and success rates are discussed. Practical guidelines for choosing to retain or extract deciduous teeth and management of the primary tooth pulp with different clinical presentations are discussed. Areas of future research are highlighted.

Fluoridation and dental caries severity in young children treated under general anaesthesia: an analysis of treatment records in a 10-year case series.

OBJECTIVE: To compare the severity of dental caries in the primary dentitions of children under 7 years (who received comprehensive restorative treatment under general anaesthesia, GA) from an optimally fluoridated area (0.85 ppmF) and a low-fluoride area (approximately 0.1 ppmF). RESEARCH DESIGN: Consecutive clinical case series: clinical details (diagnoses and the treatments provided) were recorded for children who had received comprehensive dental care under GA between 2000 and 2009. Age, gender, ethnicity, socio-economic status and fluoridation status (determined from the residential address) were also recorded. RESULTS: Of the 1396 treated children, 55.7% came from fluoridated areas and 52.5% were male. On average, children from low-fluoride areas were 2.4 months younger and presented with more decayed deciduous teeth than those from fluoridated areas (4.9 and 3.9 teeth respectively; p<0.0001). For each tooth type, the mean number of carious teeth at presentation was greater among the children from low-fluoride areas. In the multivariate model, the number of deciduous teeth affected by caries was lower among older children, those residing in a fluoridated area and among those seen after 2001. It was higher among those not living in high-SES areas. CONCLUSIONS: Children with severe dental caries had statistically significantly lower numbers of lesions if they lived in a fluoridated area. The lower treatment need in such high-risk children has important implications for publicly-funded dental care.

Dental trauma experience and oral-health-related quality of life among university students.

BACKGROUND: This study aimed to investigate the impact of self-reported dental trauma on oral-heath-related quality of life (OHRQoL) of young adults and determine whether personality characteristics influenced how it was reported. METHOD: A cross-sectional study was carried out using a sample of 435 university students. A questionnaire sought data on previous dental trauma. OHRQoL was assessed using the short-form of the oral health impact profile (OHIP-14); the outcome being one or more impacts occurring 'fairly often'/'very often'. Personality was assessed using the Positive and Negative Affect Scale (PANAS). RESULTS: The participation rate was 87.2%. Dental trauma experience was reported by 110 participants (25.3%), and 242 (55.6 %) indicated previous dental caries experience. Among those with dental trauma history, one or more OHIP-14 impacts was reported by 29.1% (with 21.2% among those with no history). Impact prevalence was higher among those who had previous dental caries experience (29.8%) than among those who had not (14.7%; P < 0.001). Higher PANAS negative affect scores were observed among those reporting one or more OHIP-14 impacts (P < 0.001). CONCLUSION: While dental trauma does not appear to have a negative impact on OHRQoL in young adults, past dental caries experience does. Negative emotionality influences self-reported oral health.

Relationship between laser fluorescence and enamel hypomineralisation.

OBJECTIVES: To study the relation between the mechanical properties of hypomineralised enamel, and its laser fluorescence (LF). METHODS: Five extracted teeth with molar-incisor hypomineralisation (MIH) were sectioned longitudinally through the defects and polished to prepare the hypomineralised enamel for testing. Hardness (H) and elastic modulus (E) of enamel were measured using nanoindentation. Measurement recording started from the cervicoenamel junction and proceeded occlusally in increments of 200 microm. Laser fluorescence readings were taken along the same line and at the same sites using a DIAGNOdent pen. RESULTS: H, E, and LF readings from cervical enamel were within the expected range for normal sound enamel. After log transformation of the H and E measurements to allow for linear correlation analysis, there was a significant and moderately strong inverse correlation between LF and H or E samples (r (between specimens)=0.59, r (between specimens)=0.39, respectively; p<0.001). CONCLUSIONS: This study shows that, in the absence of dental caries, increased DIAGNOdent readings can indicate enamel hypomineralisation. While the increased LF readings in carious enamel are thought to be related to the presence of caries bacterial metabolites, the increased readings in hypomineralised enamel may be related to proteins in the hypomineralised enamel and/or light scattering by the inhomogeneous enamel.

Effects of environmental tobacco smoke on the oral health of preschool children.

AIMS: This study investigated the association between the prevalence of oral health problems (caries, gingivitis, mucosal pigmentation and enamel defects in one to 5 year-old children exposed and not exposed to environmental tobacco smoke before and/or after birth. Exposure to environmental tobacco smoke (ETS) in childhood may have significant health effects. METHODS: A structured questionnaire was used to collect data on a child's current and previous illnesses, oral health behaviours, dietary habits, parental smoking behaviours and parents' dental history. The intraoral examination recorded dental caries (dmfs), enamel defects, gingival health, melanin pigmentation and soft tissue health. Stimulated saliva was collected. Total sIgA levels were quantified using indirect competitive ELISA with a SalimetricsTM kit. RESULTS: The 44 children (aged 15-69 months) recruited were divided into two groups: ETS and non-ETS (control). There were 22 children in each: 16 who were exposed to ETS during and after gestation were identified as the ETSB subgroup. Participants exposed to ETS were more likely to have had upper respiratory tract and middle ear infections during the neonatal period and had higher mean dmft, mean dmfs, mean percent of surfaces with demarcated opacities and mean GI than the non-ETS participants. The children exposed to ETS before and after birth had the highest occurrence of enamel opacities showed a higher risk for dental caries even though more children in this group used the recommended fluoride toothpaste (1000 ppm fluoride). Mothers who smoked either never breastfed their children or breastfed their children for less than the recommended period of 6 months. Children exposed to ETS were shown to have higher mean total sIgA (µg/ml) than the children in the control group. CONCLUSIONS: Associations between ETS exposure before and after gestation and oral health, including salivary changes in young children were shown in the present study. Dental health professionals should include a question about household smoking in children's dental histories, which would allow opportunities to discuss the impact of smoking on child oral health. Longitudinal oral health studies should include a history of maternal smoking during pregnancy and afterwards.

Total fluoride intake in children aged 3 to 4 years--a longitudinal study.

Several previous studies using food consumption tables or diet records have estimated that children aged 1 to 12 years resident in fluoridated (1 ppm) areas receive, on average, between 0.05 and 0.07 mg fluoride/kg body weight from foods and drinks alone. In this study, the duplicate-diet approach, which is a more accurate method of determining nutrient intake, was used to determine if levels of fluoride intake from foods and drinks are similar to those estimated from food consumption tables or diet records. Duplicate portions of all foods and drinks consumed over 24 hours by 66 children aged 3 to 4 years resident in fluoridated and low-fluoride areas of New Zealand were collected on three separate days over a period of 12 months and analyzed for fluoride. Fluoride intake from the use and ingestion of toothpastes and fluoride supplements was also determined for each child. It was hypothesized that the total amount of fluoride received by children in low-fluoride areas from diet, toothpastes, and fluoride supplements was similar to that received by children in fluoridated areas from diet and toothpastes. The mean fluoride intake from foods and drinks alone in the low-fluoride areas was 0.008 +/- 0.003 mg/kg body weight (0.15 +/- 0.06 mg/day; n = 34) and in the fluoridated areas was 0.019 +/- 0.009 mg/kg body weight (0.36 +/- 0.17 mg/day; n = 32). The mean fluoride intake from foods and drinks and toothpastes in the low-fluoride areas was 0.027 +/- 0.012 mg/kg body weight (0.49 +/- 0.25 mg/day) and in the fluoridated areas was 0.036 +/- 0.015 mg/kg body weight (0.68 +/- 0.27 mg/day). Fluoride intake from diet alone did not exceed 0.04 mg/kg body weight (0.74 mg/day), and fluoride intake from diet and toothpaste did not exceed 0.07 mg/kg body weight (1.31 mg/day). The results suggest that levels of fluoride intake from foods and drinks alone as estimated by the duplicate-diet approach are much lower than previously estimated from food consumption tables or diet records. It was calculated that if all children in the low-fluoride areas were to take currently recommended dosages of fluoride tablets, which have been based on dietary surveys and diet records, then the total fluoride intake of some children in the low-fluoride areas would exceed that of their counterparts in the fluoridated areas. The results suggest that currently recommended dosages of fluoride tablets need to be further reduced if dental fluorosis in children is to be avoided.

An investigation of the disposal of dental clinical waste in Bangkok.

This study investigated the disposal of clinical waste within dental surgeries in Bangkok, Thailand and followed the waste trail to the rubbish tips. A questionnaire was sent to all dental practices in the Bangkok Metropolitan Area. The response rate was 57.7 per cent. At the same time, rubbish collectors and scavengers were interviewed to see if they encountered clinical dental waste. Few dentists complied with all recommendations for the disposal of waste. Most waste was disposed of into the domestic rubbish stream. Rubbish collectors and scavengers knew what dental rubbish looked like and some had had needle-stick injuries. Although recommendations can be made to the dental profession to alter their behaviour, real improvement is unlikely without changes to legislation and social policy.

Risk indicators for tooth wear in New Zealand school children.

AIM: To investigate the prevalence and severity of tooth wear in the primary dentition of a representative sample of New Zealand school children and relate these to possible risk factors. DESIGN: A cross-sectional study. SETTING: Primary schools in Dunedin, New Zealand. PARTICIPANTS: 104 children of both sexes, aged between 5 and 8 years, randomly selected. METHODS: Clinical examinations of the buccal, occlusal/incisal and lingual surfaces of deciduous canines and molars. MAIN OUTCOME MEASURE: Degree of wear and the presence of dentinal cupping of teeth. Information on weaning and consumption of fruit-based drinks at bed time, frequency of consumption of fruits, yoghurt, pickled foods, fizzy and fruit-based drinks. RESULTS: The prevalence of tooth wear was similar in boys and girls and there were no significant differences between sides of the arches. A high percentage (82%) of children had at least one primary tooth with dentine exposed. While maxillary canines showed the greatest prevalence of dentine exposed, maxillary molars displayed the greatest prevalence of cupping. Severe tooth wear was less prevalent among children weaned after 12 months (14.3%) than those weaned earlier (27.9% P < 0.01). There were no statistically significant associations between wear and the consumption of fruit, yoghurt, pickled foods, fizzy drinks or fruit-based drinks. CONCLUSIONS: Tooth wear associated with dentine exposure is common in 5-8 year old children. This is not significantly associated with dietary factors, but appears to be related to early weaning from the breast.

Effectiveness of electronic dental anesthesia for restorative care in children.

The effectiveness of electronic dental anesthesia (EDA) for pain control during restorative procedures was compared with local anesthetic injection (LA) in 32 children aged 6 to 12 years. Each child selected had two antimere primary or permanent molars requiring similar-sized Class I or Class II restorations. The pain levels during restorative treatment were assessed using a visual analogue scale. Heart rates and behavior were also recorded. A crossover design was used with each child acting as his/her own control. The results showed that overall, EDA was less effective than LA for cavity preparation. The reported pain scores for EDA were higher in permanent teeth for the deeper cavities, and with one of the operators. The pre- or post-treatment anxiety scores were not found to differ significantly between the two restorative appointments. However, children with the highest pretreatment scores were more likely to report higher pain scores with EDA. Despite this, 63% of the children preferred EDA to LA. Dental anxiety, cavity depth, the tooth being treated, and operator attitude may also be important factors in determining the success of EDA.

Restoration of primary anterior teeth with composite crowns.

For children with extensive caries of primary teeth, or with deformed or traumatised teeth, restoration with composite using a crown form gives excellent results. Strength is gained by full crown coverage. The aesthetics are very acceptable. The technique also allows primary teeth to be modified to resemble permanent teeth when these are missing and the primary teeth are being kept until more definitive treatment is provided. Caries is usually well controlled, and space loss due to further tooth breakdown is avoided.

Proposal 3: Is a coordinated and effective approach to work force planning, education, and research possible? Part II: The interdependence of research, education and the oral health work force.

Undoubtedly, to achieve the goals set for oral health in New Zealand, representative leadership is essential for effective coordination of work force planning, education, and research. It is to be hoped that, from discussion and debate, this Forum will be able to make suggestions or recommendations for a structure that can be developed to allow the appropriate representation and leadership to drive research and work force planning for the provision of oral health care in New Zealand.

Jaw and tooth abnormalities detected on panoramic radiographs in New Zealand children aged 10-15 years.

Panoramic radiographs of 1,608 children and adolescents aged 10 to 15 years (797 males and 811 females) were reviewed to determine the prevalence of tooth and jaw abnormalities. Abnormalities were detected on 21 percent of the radiographs (23 percent females and 17.3 percent males); 879 teeth were diagnosed with abnormalities on 331 radiographs. The more common abnormalities were malpositioned teeth, missing teeth, misshaped teeth, and teeth with hypoplastic appearance. Bony abnormalities and growth problems were detected in a few radiographs. This study demonstrates the value of panoramic radiography in detecting or confirming dental abnormalities, and supports recommendations on the use of panoramic radiography to aid in the assessment of dental development.

Prevalence of marginal alveolar bone loss in children referred for treatment to the Paediatric Clinic at the School of Dentistry, University of Otago.

Proximal contact loss due to caries may contribute to the appearance of marginal alveolar bone loss (ABL) in the deciduous dentition. Children referred for treatment to the School of Dentistry, University of Otago, usually have special problems related to caries or management, or both, and the aim of the study was to determine the prevalence of marginal ABL in children treated in this clinic, and to compare it with that found in a previous study in a random sample of New Zealand 5-year-olds. Posterior bite-wing radiographs of 187 children, aged 4 to 14 years, were selected for examination. A total of 1,523 sites, from the distal of the deciduous cuspids to the mesial of the deciduous second molar or the first permanent molar if present, were examined. ABL was recorded when there was complete absence of the lamina dura and the distance from the cemento-enamel junction to the crest of the alveolar bone was > 2 mm. ABL was found in 20.8 percent of the children; 31.9 percent of these sites were adjacent to extensive proximal caries; 83.3 percent were in the maxilla, and 95.8 percent were between deciduous teeth. The youngest age at which ABL was found was 5 years. Among the children with ABL, 48.7 percent had ABL in more than one site. Comparison of the prevalence of ABL at age 5 in the present study (19.2 percent) with the one previously reported for a random population (2.1 percent), suggested that, because of the special characteristics of the children attending the University clinic, students are exposed to an exaggerated image of caries and periodontal diseases in children.

Comparison of the cariogenicity of some processed cheeses.

AIM: Cheeses have been investigated for their potential cariogenicity in several studies and have been shown to produce little change in the resting pH in dental plaque and little or no demineralisation of enamel in most intra-oral cariogenicity studies. The aim of the present study was to investigate the cariogenicity of four processed cheese formulations. METHODS: Enamel demineralisation was measured intra-orally in bovine enamel, and aliquots of 10g of each test cheese were used to assess plaque pH using the plaque harvesting technique after the San Antonio criteria. In a second experiment, the same cheeses were assessed for their effects on enamel using the intra-oral cariogenicity test (ICT) with bovine enamel. RESULTS: None of the four cheeses caused pH drops below the critical pH and two of the cheeses raised the pH slightly. The effects on pH were all significantly different from those of the sucrose saliva control. None of the cheeses produced microhardness changes that were statistically significantly different from the saliva control. CONCLUSION: None of these cheeses as tested were found to lead to acidogenicity and by inference to be cariogenic. They were therefore deemed to be safe for teeth when used as a food.