A case-controlled investigation of risk factors associated with molar incisor hypomineralization (MIH) in 8-12 year-old children living in Chandigarh, India.

PURPOSE: Despite mounting evidence in favour of various perinatal risk factors for occurrence of MIH, verification of these remains doubtful because of lack of documented proof. The present study was aimed at examining the putative risk factors for MIH based on hospital-maintained records assessment. METHODS: A total of 3176, 8-12 year-old children were screened for MIH using EAPD criteria (2003). Of these, risk factor analysis was carried out for 104 MIH affected and 211 non-MIH affected children with complete peri-natal medical records maintained up to 3 year post-birth. Chi-square test was used for risk factor comparison, while significance was assessed using logistic regression. RESULTS: Prevalence of MIH in study population was 11.72% (372/3176). Various pre-natal, natal and post-natal risk factors including intra-uterine growth retardation (6.7 vs. 1.4%); maternal anaemia (10.6 vs. 3.8%) and neonatal jaundice (29.8 vs. 14.2%) were significantly higher in the MIH group. Furthermore, pre-term birth (OR 3.01), low birth weight (OR 2.37), more than three pyrogenic episodes (OR 7.61) and consumption of Amoxicillin Clavulanate (OR 3.01) were significantly associated with higher risk of developing MIH. CONCLUSIONS: Pre and post-natal risk factors showed a moderate to high association for occurrence of MIH although social and nutritional factors had a lesser association.

Oral and maxillofacial surgery patient satisfaction with telephone consultations during the COVID-19 pandemic.

Due to the COVID-19 pandemic most oral and maxillofacial surgical (OMFS) units have moved to conducting patient consultations over the telephone. The aim of this study was to assess patients' satisfaction with telephone consultations during the COVID-19 pandemic. A retrospective survey was conducted of OMFS patients at our hospital who had telephone consultations between 1 April - 8 June 2020. The survey was conducted by independent interviewers and used the Generic Medical Interview Satisfaction Scale (G-MISS) along with a previously published additional questionnaire. Variables recorded included age, gender, theme of consultation, grade of clinician, and type of consultation. Statistical analysis was performed to assess for any differences between patient groups. The records of 150 consecutive patients were reviewed and 135 met inclusion criteria. A total of 109 patients completed the survey giving a response rate of 80.74%. The total G-MISS score for satisfaction was high, which indicates a high level of satisfaction among all patients. We found no statistical difference in satisfaction when comparing patients in terms of gender, age, theme of consultation, or level of clinician. A significant difference was found in compliance levels between review and new patients, with review patients demonstrating higher compliance levels (p=0.004). Overall, 83.48% of patients said they would be willing to have a telephone consultation in future. The majority of patients in this study reported high levels of satisfaction with telephone consultations. New patients reported lower levels of compliance which may suggest this type of consultation is less suited to telephone consultation.

Prevalence, defect characteristics and distribution of other phenotypes in 3- to 6-year-old children affected with Hypomineralised Second Primary Molars.

PURPOSE: To assess the prevalence, severity and defect characteristics of hypomineralised second primary molars in schoolgoing children along with distribution of other phenotypes. METHODS: A total of 3013, 3- to 6-year-old children were examined for the presence of hypomineralised second primary molars (HSPMs) using an adapted version of EAPD Criteria (2003). The molars were evaluated for the presence, location and colour of demarcated opacities along with associated post-eruptive breakdown (PEB) and atypical restorations. A thorough examination of the entire dentition was followed for evaluation of teeth other than primary second molars for the presence of similar hypomineralised defects. Data were analysed using Chi Square, Fisher exact's and Mann-Whitney U tests at α = 0.05. RESULTS: A total of 3013 out of 3200 children were included having a mean age of 4.25 ± 0.5 years and deft of 2.1 ± 0.5. Using the adapted version of EAPD 2003 criteria for MIH, the children were evaluated for the presence of hypomineralised second primary molars, the prevalence of which was found to be 7.9%. Hypomineralisation defects were more commonly observed in the maxillary arch (53.4% vs. 42.8%, p = 0.04) with creamish white opacities involving the buccal and lingual surfaces being the most common defects (43.6%). The mean number of HSPMs per child was 1.9. Other phenotypes included demarcated opacities majorly on primary canines (6.6%) followed by primary first molars (4.6%). CONCLUSIONS: Hypomineralised primary second molars are a fairly common condition affecting approximately 7.9% of the population thus warranting early recognition and management.

A clinical and radiographic investigation comparing the efficacy of cast metal and indirect resin onlays in rehabilitation of permanent first molars affected with severe molar incisor hypomineralisation (MIH): a 36-month randomised controlled clinical trial.

PURPOSE: Definitive restorative management of young permanent molars affected with severe MIH is still elusive with a dearth of conservative restorative options. The present trial compared the 36 months clinical and radiographic performance of minimally invasive cast metal and indirect resin onlays for rehabilitation of permanent first molars affected with severe MIH. METHODS: In this parallel group open label randomised trial, 42 vital molars affected with severe MIH in 30 children, aged 8-13 years were randomly allocated using stratified permuted block randomization to receive either a cast metal onlay or an indirect composite onlay (n = 21 each). Clinical and radiographic evaluations of these onlays were carried out at 9, 18 and 36 months using the USPHS criteria. Cumulative survival rate as well as the calculated clinical success rates of both types of onlays were also determined. The longevity of onlays was assessed using Kaplan-Meier survival analysis. RESULTS: At 36 months, overall retention rate was found to be 95% with complete elimination of any pre-existing sensitivity. Cumulative survival rates were found to be 95% vs. 100%, p = 0.67, while the calculated clinical success rates were 90% and 85.7% for metal and resin onlays, respectively, with no significant differences (p = 0.76). Mean survival rates based on Kaplan-Meier analysis were determined to be 85% vs. 100% for the metal and composite groups, respectively (p = 0.075). CONCLUSIONS: Irrespective of the type of material used, onlays offer a predictable and conservative restorative alternative for molars affected with severe MIH. CLINICAL TRIAL REGISTRY: The trial is registered under Clinical Trial Registry India (CTRI/2016/10/007379).

Overexpression of succinyl-CoA synthase for poly (3-hydroxybutyrate-co-3-hydroxyvalerate) production in engineered Escherichia coli BL21(DE3).

AIM: This study aims to increase the 3-hydroxyvalerate (3HV) fraction in poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(HB-co-HV)] using succinyl-CoA synthase. METHODS AND RESULTS: Escherichia coli YH090, a polyhydroxyalkonate (PHA)-producing strain, was further engineered for overexpression of succinyl-CoA synthase genes (sucCD), and examined for P(HB-co-HV) copolymer production in the presence of various precursor molecules using mixture analysis. Glycerol, succinate and propionate were screened as important factors for controlling intracellular PHA accumulation and monomer composition. Glycerol concentrations exerted the greatest influence on the overall biomass concentration and the intracellular PHA content, while propionate concentrations in the presence of succinate influenced the 3HV content of the copolymer. Mixture analysis also demonstrated that the engineered strain has the capacity to accumulate up to 80% of its cell dry weight (CDW) as PHA with a variable fraction of 3HV monomer (maximum of 72 wt %) depending on the controlled conditions. CONCLUSIONS: Propionate is the principal precursor for 3HV monomer in P(HB-co-HV) biopolymer and its utilization requires conversion to propionyl-CoA. Engineered E. coli YHY99, overexpressing sucCD genes, leads to an increase of the succinyl-CoA pool, which enhances the conversion rate of propionate by providing a CoA supply to other acyltransferase enzymes that have a role in propionate utilization. SIGNIFICANCE AND IMPACT OF THE STUDY: Engineered E. coli YHY99 was able to utilize propionate with a 4·5-fold increase in rate, as compared to the control strain, and resulted in the synthesis of a copolymer with high 3HV monomer content.

Purification and characterization of arylacetonitrile-specific nitrilase of Alcaligenes sp. MTCC 10675.

Arylacetonitrile-hydrolyzing nitrilase (E.C. 3.5.5.5) of Alcaligenes sp. MTCC 10675 has been purified by up to 46-fold to homogeneity and 32% yield using ammonium sulfate fractionation, Sephacryl S-300 gel permeation, and anion exchange chromatography. The molecular weight of the native enzyme was estimated to be 520 ± 60 kDa. The subunit has a molecular weight of 60 ± 14 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimum pH and temperature of the purified enzyme were 6.5 and 50 °C, respectively. The purified arylacetonitrilase has a half-life of 3 H 20 Min at its optimum temperature. The value for Vmax, Km , kcat , and ki of enzyme for mandelonitrile as a substrate was 50 ± 05 µmol/Min/mg, 13 ± 02 mM, 26 ± 03 Sec(-) , and 32.4 ± 03 mM, respectively. Alcaligenes sp. MTCC 10675 arylacetonitrilase amino acid sequence has variations from other reported arylacetonitrilase, namely, A11G, N21H, D149N, S170T, P171R, S179A, Q180N, and S191A, and it has a high thermal stability and catalytic rate as compared with the already purified arylacetonitrilase.

Simultaneous purification of nitrile hydratase and amidase of Alcaligenes sp. MTCC 10674.

Alcaligenes sp. MTCC 10674 has a bienzymatic system for the hydrolysis of nitriles. The nitrile hydratase and amidase have been purified simultaneously to homogeneity using a combination of (NH)4SO4 precipitation, ion exchange chromatography and gel permeation chromatography. Nitrile hydratase and amidase have molecular weight of 47 and 114 kDa, respectively and exist as heterodimer. Optimum temperatures for maximum activity of nitrile hydratase and amidase were 15 °C (2.4 U/mg protein) and 45 °C (2.3 U/mg protein), respectively. Nitrile hydratase showed maximum 7.8 U/mg protein at 50 mM acrylonitrile and amidase has 9.2 U/mg protein at 25 mM propionamide. Nitrile hydratase has Vmax 10 µmol/min/mg and Km 40 mM, while amidase has Vmax 12.5 µmol/min/mg and Km 45.5 mM, respectively. Heavy metal ions Hg2+, Ag+, Pb2+ and Cu2+ were strong inhibitors of nitrile hydratase and amidase activity.

Optimization of arylacetonitrilase production from Alcaligenes sp. MTCC 10675 and its application in mandelic acid synthesis.

Alcaligenes sp. MTCC 10675 has been isolated from soil sample using enrichment method and has nitrilase catalytic system which is highly specific for the hydrolysis of arylaliphatic nitriles. Optimization of culture conditions using response surface methodology and inducer-mediated approach enhanced arylacetonitrilase production significantly (2.4-fold). Isobutyronitrile acted as an effective inducer for the induction of arylacetonitrilase, and it is highly specific for arylacetonitriles (phenyl acetonitrile and mandelonitrile). Arylacetonitrilase has no effect on its relative velocity (V r) up to 20 mM substrate (mandelonitrile) concentration and at 30 mM mandelonitrile, 23.4 % degree of inhibition (I d) was recorded. Half life of arylacetonitrilase of Alcaligenes sp. MTCC 10675 was 27.5 h at 25 °C. Hg(2+), Ag(+), Pb(3+), and Co(2+) were strong inhibitor of arylacetonitrilase activity which resulted into 100 %, 91 %, 84 %, and 83 % inhibition, respectively. Polar protic solvent (dichloromethane, dimethylsulphooxide, and n-butanol) reduce arylacetonitrilase activity up to 80-94 % at 10 % concentration. Alcaligenes sp. MTCC 10675 has higher biocatalytic activity, i.e., 3.9 gg(-1) dcw, which is highest in comparison to till reported organism. Arylacetonitrilase-mediated hydrolysis of racemic mandelonitrile resulted into R-(-) mandelic acid with 99.0 % enantiomeric excess (e.e.).

Spontaneous regression of a congenital epulis in a newborn.

A 3 day old girl presented with lobulated mass protruding from her mouth. The mass was clinically diagnosed as a congenital epulis. The child had no airway obstruction and was able to feed well. A conservative treatment was proposed with monthly follow up appointments to monitor the lesion. After 10 months the lesion completely regressed and the eruption of maxillary anterior teeth remained unaffected

An isobutyronitrile-induced bienzymatic system of Alcaligenes sp. MTCC 10674 and its application in the synthesis of α-hydroxyisobutyric acid.

Alcaligenes sp. MTCC 10674 was isolated as acetone cyanohydrin hydrolyzing bacterium from soil of orchid gardens of Himachal Pradesh. Acetone cyanohydrin hydrolyzing activity of this organism comprised nitrile hydratase and amidase activities. It exhibited higher substrate specificity towards aliphatic hydroxynitrile (acetone cyanohydrin) in comparison to arylaliphatic hydroxynitrile. Isobutyronitrile (40 mM) acted as a carbon source as well as inducer for growth of Alcaligenes sp. MTCC 10674 and expression of acetone cyanohydrin hydrolyzing activity. Optimization of culture condition using response surface methodology increased acetone cyanohydrin hydrolyzing activity by 1.3-fold, while inducer mediation approach increased the activity by 1.2-fold. The half life of this enzyme was 25 h at 15 °C. V max and K m value for acetone cyanohydrin hydrolyzing enzyme was 0.71 µmol mg(-1) min(-1) and 14.3 mM, when acetone cyanohydrin was used as substrate. Acetone cyanohydrin hydrolyzing enzyme encountered product inhibition and IC50 and K i value were calculated to be 28 and 10.2 mM, respectively, when product α-hydroxyisobutyric acid was added in the reaction. Under optimized reaction conditions at 40 ml fed batch scale, 3 mg dcw ml (-) resting cells of Alcaligenes sp. MTCC 10674 fully converted 0.33 M acetone cyanohydrin into α-hydroxyisobutyric acid (1.02 g) in 6 h 40 min. The characterization of acetone cyanohydrins hydrolyzing activity revealed that it comprises bienzymatic nitrile hydrolyzing system, i.e. nitrile hydratase and amidase for the production of α-hydroxyisobutyric acid from acetone cyanohydrin and maximum 70 % yield is being reported for the first time.

Access to primary dental care for cleft lip and palate patients in South Wales.

AIM: To determine the provision of NHS primary dental care for children with cleft lip and/or palate in South Wales and the ease of accessing this dental care. METHOD: A postal questionnaire was sent to all cleft lip and/or palate patients under the age of 18 (n = 750) in South Wales. The questionnaire identified patients' medical history, episodes of dental emergency, distance from home to dental surgery and ease of accessing primary dental care. To increase the response rate a second questionnaire was posted to non-responders. RESULTS: The response rate was 49% (368/750). The majority of patients (92%, n = 340) attended a dentist. Over 17% (n = 61) had suffered an episode of dental emergency. About 63% (n = 240) lived within 5 miles of their primary dental care provider, and 13% (n = 66) lived more than 10 miles away. Other medical problems were found in over 30% (n = 111) of the sample. Parents of 39% (n = 107) found it difficult or impossible to access a local NHS dentist. CONCLUSION: Many children with cleft lip and/or palate find it difficult or impossible to access NHS primary dental care. Shortcomings in the services provided to this high risk group have been highlighted. Further research is needed at national levels to evaluate the extent of the shortcomings and propose methods to overcome them.

Microscopic observation of kinetic molecular sieving of hydrogen isotopes in a nanoporous material.

We report quasielastic neutron scattering studies of H2-D2 diffusion in a carbon molecular sieve, demonstrating remarkable quantum effects, with the heavier isotope diffusing faster below 100 K, confirming our recent predictions. Our transition state theory and molecular dynamics calculations show that while it is critical for this effect to have narrow windows of size comparable to the de Broglie wavelength, high flux requires that the energy barrier be reduced through small cages. Such materials will enable novel processes for kinetic molecular sieving of hydrogen isotopes.

Child protection: training and experiences of dental therapists.

OBJECTIVE: To identify the training in, experience of and barriers to reporting child abuse among dental therapists in the UK. DESIGN: Postal survey. SUBJECTS AND METHODS: A postal questionnaire was sent to all practising dental therapists (DTs) in the UK registered with the GDC (n = 851) in October-December 2007. RESULTS: A response rate of 49% (n = 420) was achieved; 24 (5.7%) questionnaires were incomplete and excluded. One hundred and ninety-three respondents (48.7%) had qualified in the last 10 years. One hundred and forty-seven (37.1%) recalled undergraduate training; 248 (62.6%) had received training since qualifying; 66 (16.6%) recalled no child protection training. Overall child abuse had been suspected by 135 (34%) DTs, while 72 (18%) had suspected but not referred the case. CONCLUSIONS: The majority of dental therapists (83%, n = 330) have received training in child protection. Overall, 34% (n = 135) have suspected child abuse and 83% (n = 112) of these DTs recorded their suspicions in the patient record. In line with current guidance, most DTs would discuss a case with another dentist.

On the strength of the hydrogen-carbon interaction as deduced from physisorption.

We deduce a new value for the potential well depth for the C-H2 interaction on the basis of experimental validations of isotherms of H2 and D2 predicted using independently characterized microstructural parameters. We use two carbons, one an activated carbon fiber whose structure has been recently characterized by us (Nguyen, T. X.; cohaut, N.; Bae, J.-S.; Bhatia, S. K. Langmuir 2008, 24, 7912) using hybrid reverse Monte Carlo simulation (HRMC) and the other the commercial Takeda 3A carbon molecular sieve whose pore size distribution is determined here from the 273 K CO2 adsorption isotherm. The conventional grand canonical Monte Carlo simulation technique incorporating a semiclassical Feynman and Hibbs (FH) potential approximation (FHGCMC) as well as path integral Monte Carlo calculations is employed to determine theoretical adsorption isotherms. It is found that curvature enhances the well depth for the LJ C-H2 interaction by a factor of 1.134 over that for a flat graphite surface, consistent with our recent study (Nguyen, T. X.; cohaut, N.; Bae, J.-S.; Bhatia, S. K. Langmuir 2008, 24, 7912). A value of the C-C well depth of 37.26 K, used for estimating the C-H2 well depth in conjunction with the Berthelot rules, with the Steele C-C well depth used for interaction with heavier gases (Ar, CO2 and CH4), leads to excellent agreement with experimental isotherms in all cases.

Characterization and adsorption modeling of silicon carbide-derived carbons.

We present characterization results of silicon carbide-derived carbons (Si-CDCs) prepared from both nano- and micron-sized betaSiC particles by oxidation in pure chlorine atmosphere at various synthesis temperatures (600-1000 degrees C). Subsequently, the adsorption modeling study of simple gases (CH4 and CO2) in these Si-CDC samples for a wide range of pressures and temperatures using our Finite Wall Thickness model [Nguyen, T. X.; Bhatia, S. K. Langmuir 2004, 20, 3532] was also carried out. In general, characterization results showed that the core of Si-CDC particles contains predominantly amorphous material while minor graphitization was also observed on the surface of these particles for all the investigated synthesis temperatures (600-1000 degrees C). Furthermore, postsynthetic heat treatment at 1000 degrees C for 3 days, as well as particle size of precursor (betaSiC) were shown to have slight impact on the graphitization. In spite of the highly disordered nature of Si-CDC samples, the adsorption modeling results revealed that the Finite Wall Thickness model provides reasonably good prediction of experimental adsorption data of CO2 and CH4 in all the investigated Si-CDC samples at the temperatures of 273 K, 313 K, and 333 K for a wide range of pressure up to 200 bar. Furthermore, the impact of the difference in molecular size and geometry between analysis and probing gases on the prediction of the experimental adsorption isotherm in a disordered carbon using the slit-pore model is also found. Finally, the correlation between compressibility of the Si-CDC samples under high pressure adsorption and their synthesis temperature was deduced from the adsorption modeling.

Case report: segmental odontomaxillary dysplasia--a rare disorder.

BACKGROUND: Segmental odontomaxillary dysplasia (SOD) is a rare developmental disorder of the maxilla characterised by abnormal growth and maturation of bone, teeth and gingival of the affected segment. Due to the rarity of the disorder, the full range of clinical manifestations is unknown. Since there are concerns that cases may be subject to misdiagnosis, this report aims to increase awareness of the condition among paediatric dentists. CASE REPORT: A 7-year-old boy was initially referred regarding failure of eruption of maxillary primary molars. Characteristic clinical and radiographic findings led to the diagnosis of SOD. Interestingly, the patient presented with unilateral ectopic eyelashes, a finding previously unreported in association with this condition. TREATMENT: Reassurance was provided regarding the benign nature of the condition. While no active intervention was needed at the time of diagnosis, close monitoring is essential. Future management may require surgical, orthodontic and prosthetic input. FOLLOW-UP: A period of four years elapsed between initial presentation of the condition and its definitive diagnosis. No significant increase in the unilateral maxillary swelling was noted. The patient will continue to be monitored on a regular basis. CONCLUSION: SOD is a rare cause of facial asymmetry. Prompt diagnosis can reassure both patient and healthcare professionals. Reporting of cases is encouraged to help determine the full range of clinical manifestations and establish a management protocol.

Anomalous transport in molecularly confined spaces.

We develop a novel theory to predict the density dependence of the diffusivity of simple fluids in a molecularly sized nanopore with diffusely reflecting walls, incorporating nearest neighbor intermolecular interactions within the framework of the recent oscillator model of low density transport arising from this laboratory. It is shown that when the pore width is about two molecular diameters, at sufficiently high densities these interactions lead to a repulsive inner core, as a result of which the diffusing molecules undergo more frequent reflections at the wall. This leads to a reduction in diffusivity with increase in density, which is consistent with molecular dynamics simulation results, and contrasts with the behavior in larger pores where the transport coefficient has previously been shown to increase with increase in density due to viscouslike intermolecular interactions. At low densities the behavior is opposite, with the inner core becoming more attractive with increase in density, which can lead to an increase in diffusivity. The theory consistently explains molecular dynamics simulation results when the inhomogeneous pair distribution function of moving particles in the pore is axially periodic, suggesting concerted motion of neighboring molecules. It is also shown that a potential of mean force concept is inadequate for describing the influence of intermolecular interactions on transport.

A heterogeneous model for gas transport in carbon molecular sieves.

A dual resistance model with distribution of either barrier or pore diffusional activation energy is proposed in this work for gas transport in carbon molecular sieve (CMS) micropores. This is a novel approach in which the equilibrium is homogeneous, but the kinetics is heterogeneous. The model seems to provide a possible explanation for the concentration dependence of the thermodynamically corrected barrier and pore diffusion coefficients observed in previous studies from this laboratory on gas diffusion in CMS. The energy distribution is assumed to follow the gamma distribution function. It is shown that the energy distribution model can fully capture the behavior described by the empirical model established in earlier studies to account for the concentration dependence of thermodynamically corrected barrier and pore diffusion coefficients. A methodology is proposed for extracting energy distribution parameters, and it is further shown that the extracted energy distribution parameters can effectively predict integral uptake and column breakthrough profiles over a wide range of operating pressures.