Quaternary low-temperature serpentinization and carbonation in the New Caledonia ophiolite.

The low-temperature alteration (< 150 °C) of ophiolites by infiltrated meteoric waters removes atmospheric CO2 through mineral carbonation and is assumed to generate H2 and possibly CH4 according to so-called serpentinization reactions. This overall alteration pattern is primarily constrained by the chemical composition of alkaline springs that are issued in several ophiolites worldwide. Here we report on the fingerprint, as veinlet mineralization, of the reactive percolation of such meteoric waters in the New Caledonia ophiolite (Massif du Sud). The mineralization which resulted from carbonation and serpentinization reactions, is young (< 2 Ma) and formed at a temperature of ca. 95 °C. It is mainly composed of lizardite, dolomite, magnetite ± pyroaurite. Thermochemical simulation of mineral-water equilibria shows that the percolating aqueous fluid was alkaline and H2 bearing. The δ13C of dolomite is exceptionally high, between 7.1 and up to 17.3‰, and is interpreted as evidence of low-temperature methanogenesis. Overall, the percolating fluid had a chemical composition similar to that of the waters issued today in the (hyper)alkaline springs of the Massif du Sud. The studied veinlets are thus interpreted as a sample of the plumbing system that fed an ancient Quaternary alkaline spring in the area.

Association of onabotulinum toxin A treatment with salivary pH and dental caries of neurologically impaired children with sialorrhea.

BACKGROUND: Sialorrhea is a common manifestation of several neurological disorders. The use of intraglandular onabotulinum toxin A (OBTXA) injection has been recognized to effectively treat sialorrhea. As OBTXA injection reduces salivary flow rate and alters salivary quality, its use may have a detrimental effect on oral health. AIM: To examine the effect of OBTXA injection on caries experience and salivary pH of neurologically impaired children with sialorrhea. DESIGN: Twenty-five children receiving OBTXA treatment and 25 control children were enrolled in the study. Whole saliva was collected to determine salivary pH. All participants underwent an interview on their dietary habits. Dental clinical examinations were carried out to evaluate caries experience and oral hygiene level. RESULTS: Overall, mean salivary pH value was significantly lower in the OBTXA group (6.92 ± 0.77) compared with the control group (7.36 ± 0.70). Caries activity was significantly higher in the OBTXA group (P = 0.01). The regression analyses showed a significant association between OBTXA treatment and salivary pH value (P = 0.03). Results from the logistic regression show that dental caries was significantly associated with OBTXA treatment (OR = 1.73, CI = 1.14-27.3). CONCLUSIONS: The study showed an intricate relationship between OBTXA treatment and oral findings. Hence, special dental care should be given to children receiving OBTXA treatment.

Evaluation of the severity of malocclusions in children affected by osteogenesis imperfecta with the peer assessment rating and discrepancy indexes.

INTRODUCTION: Osteogenesis imperfecta is a heritable disorder affecting bone and tooth development. Malocclusion is frequent in those affected by osteogenesis imperfecta, but this has not been studied in detail. The purpose of this study was to describe and quantify the severity of malocclusions in patients with osteogenesis imperfecta. METHODS: Articulated dental casts were obtained from 49 patients diagnosed with osteogenesis imperfecta (ages 5-19 years; 28 female) and 49 age- and sex-matched control subjects who did not have osteogenesis imperfecta. Both groups were seeking orthodontic treatment. Malocclusions were scored by using the peer assessment rating (PAR) and the discrepancy index (DI). RESULTS: The average United Kingdom weighted PAR scores were 31.1 (SD, 14.5) for the osteogenesis imperfecta group and 22.7 (SD, 10.7) for the control group (P <0.05). The mean United States weighted PAR scores were 32.2 (SD, 15.0) for patients with osteogenesis imperfecta and 21.6 (SD, 9.6) for the controls (P <0.05). The average modified DI scores were 29.8 (SD, 20.2) for the osteogenesis imperfecta group and 12.4 (SD, 6.8) for the control group (P <0.05). Group differences were greatest for lateral open bite (osteogenesis imperfecta group, 7.1; control group, 0.3) for the DI parameters and anterior crossbite (osteogenesis imperfecta group, 13.0; control group, 3.8 [United Kingdom]) for the PAR. CONCLUSIONS: Both the PAR and the DI showed that malocclusions were significantly more severe in patients with osteogenesis imperfecta than in the control group. There was a higher incidence of Class III malocclusion associated with anterior and lateral open bites in patients affected by osteogenesis imperfecta.

Clinical complications in the revascularization of immature necrotic permanent teeth.

The purpose of this case series was to report on the use of a technique of revascularization for necrotic immature permanent teeth, several problems encountered, and solutions to those problems. Eighteen pulp revascularizations were performed in 2009 using the original protocol of revascularization (adapted from the AAE/AAPD joint meeting in 2007 in Chicago). The protocol consisted of opening the canal and disinfecting it with sodium hypochlorite, sealing in a triple antibiotic paste for 2-6 weeks, re-opening, re-irrigating, creating a blood clot in the canal, and sealing with an MTA barrier over the clot. Three problems were encountered during the treatment: (1) bluish discoloration of the crown; (2) failure to produce bleeding; and (3) collapse of the mineral trioxide aggregate (MTA) material into the canal. Modifications to solve these problems included: changing one of the antibiotics, using a local anesthesia without epinephrine, and adding collagen matrix to the blood clot.

Tooth extraction socket healing in pediatric patients treated with intravenous pamidronate.

Osteonecrosis of the jaw (ONJ) has been described as a complication of bisphosphonate therapy in adults. In the present study, we did not find a case of ONJ among 278 pediatric patients who had received intravenous pamidronate during childhood or adolescence.

Bisphosphonates, osteonecrosis, osteogenesis imperfecta and dental extractions: a case series.

Over the past 4 years, numerous cases of osteonecrosis of the jaw in patients treated with bisphosphonates have been reported. Since 1998, children and adolescents with osteogenesis imperfecta have received bisphosphonates to increase their bone density and reduce the incidence of bone fractures. The results have been convincing, but recent reports of osteonecrosis of the jaw have caused great concern when these patients require dental extractions. The dental records of 15 children and adolescents with osteogenesis imperfecta, involving 60 dental extractions, mostly of primary teeth, done between 2001 and 2006, were reviewed. All patients but one had had or were having bisphosphonate treatment at the time of the extractions. No patient developed osteonecrosis. Further studies and data that allow clinicians to design adequate and safe treatment plans for this unique population are needed.

Childhood urine mercury excretion: dental amalgam and fish consumption as exposure factors.

The authors investigated the effect of amalgam fillings and fish consumption on urine mercury level (UHg), in children aged 4-8 years old inclusive. Using a sample of 60 children, we found that children with amalgam fillings had significantly higher UHg levels than children without amalgams (geometric mean=1.412microg Hg/g versus 0.436 microg Hg/g, respectively, P = 0.0001). Subjects with reported higher fish consumption also had significantly higher UHgs (P = 0.004). Univariate analyses provide evidence of an association between elevated UHg level and young age (P = 0.009), short height (P = 0.024), and low weight (P = 0.049) in children with amalgam chewing surfaces. We also found a negative correlation between urine mercury and age (-0.378), height (-0.418), and weight (-0.391). A multiple logistic regression model shows that the presence of amalgam fillings leads to increased odds of high UHg in children (OR=47.18), even after adjusting for high fish consumption (OR=8.66) and height (OR=11.36).

Interproximal contact points and proximal caries in posterior primary teeth.

PURPOSE: The purpose of this study was to investigate the hypothesis that the risk of proximal caries in posterior primary teeth is higher when interproximal contact points are closed than when they are open. METHODS: A cross-sectional study design was used with a sample of 286 children aged 24 to 72 months (mean age 54 months +/- 16 months). Children with any permanent dentition were excluded. Caries (defined as a lesion halfway through enamel or further) was assessed radiographically by a single dentist. The open/closed nature of contact points was assessed by a different dentist through resistance to dental floss. Data concerning known risk factors and indicators for caries were also collected. Analyses were performed at the level of the contact point, comparing the same contact points in different children. Multiple logistic regression was used to asses the relationship between open/closed status and caries status for each posterior contact point. RESULTS: In 7 of the 8 contact points examined, the odds for caries were significantly increased when contact points were dosed. CONCLUSIONS: This research suggests that the risk for proximal caries in the posterior primary dentition is raised if contact points are dosed compared to those that are open.

Association of occlusion with eating efficiency in children with cerebral palsy and moderate eating impairment.

PURPOSE: This study focused on the contribution ofthe dental occlusion to chewing efficiency in a group of children with cerebral palsy (CP). METHODS: Twenty children aged 8.3 +/- 0.9 years participated in this study. Chewing efficiency was measured and biting and drinking skills were noted. Occlusion was determined from extra- and intra-oral photographs and from orthodontic plaster models. RESULTS: Significant correlatons were found between chewing efficiency and age (r:0.6, P=.006) and the total number of posterior teeth (r:0.7, P<.001). A marginally significant negative correlation was found between the total number of teeth and chewing time for the viscous texture (r:-0.4, P=.06). CONCLUSIONS: A possible association between chewing efficiency and occlusal wear may exist, but will need further examination. There was also a higher frequency of drooling (23%) in children who had an open bite compared to those with a normal bite. These results suggested that occlusal problems affected the efficiency of ingestion in children with CP.