Prophylactic application of antibiotics selects extended-spectrum ß-lactamase and carbapenemases producing Gram-negative bacteria in the oral cavity.

Prophylactic administration of broad-spectrum antibiotics in surgery can change the oral microbiome and induce colonization of oral cavity with Gram-negative bacteria including multidrug (MDR) or extensively drug resistant (XDR) organisms which can lead to lower respiratory tract infections. The aim of the study was to analyse the Gram-negative isolates obtained from oral cavity of the mechanically ventilated patients in ICUs, after prophylactic application of antibiotics and their resistance mechanisms and to compare them with the isolates obtained from tracheal aspirates from the same patients. The antibiotic susceptibility was determined by broth dilution method. PCR was applied to detect genes encoding ß-lactamases. Marked diversity of Gram-negative bacteria and resistance mechanisms was found. High resistance rates and high rate of blaCTX-M and carbapenemase encoding genes (blaVIM-1 , blaOXA-48 ) were found among Klebsiella pneumoniae. Pseudomonas aeruginosa was found to harbour blaVIM and in one strain blaPER-1 gene, whereas Acinetobacter baumannii produced OXA-23-like and OXA-24/40-like oxacillinases and was XDR in all except one case. All XDR isolates belong to international clonal lineage II (IC II). The main finding of the study is that the prophlylactic application of antibiotics in surgery intensive care units (ICUs) is associated with the colonization of oral cavity and lower respiratory tract with Gram-negative bacteria. The identity of Gram-negative bacteria in oral cavity reflected those found in endotracheal aspirates leading to conclusion that oral swab as non-invasive specimen can predict the colonization of lower respiratory tract with resistant Gram-negative organisms and the risk for development of ventilator-associated pneumonia.

Development of a valid and reliable instrument for the assessment of quality of life in parents of children with clefts.

PURPOSE: Orofacial clefts are the most common congenital malformations that affect craniofacial structures. Studies show that they have a major influence on psychological development of the patient, and on their families. A review of the literature showed a lack of specific questionnaires for children and their parents. This study investigated the impact of orofacial clefts in children on the quality of life of their parents. In addition, the results of the treatment and the quality of work of the health team members involved in this process were evaluated. MATERIALS AND METHODS: For the purpose of this study, an original questionnaire was made to analyse the effect of orofacial clefts in children who had undergone surgery on the quality of life of 73 of their parents. The questionnaire consisted of 28 simple statements, which were evaluated with a 5-degree Likert scale (from 1-fully disagree to 5-fully agree), did not require any specific additional clarification, and were easy to complete. RESULTS: Analysis of areas of the questionnaire that applied to the parents, resulted in two subscales, parental social health and child social health, which had satisfactory Cronbach's coefficients (0.907 and 0.897, respectively). However, some issues had a relatively poor coefficient of internal consistency, which justified their expulsion from the final model of the parent questionnaire. CONCLUSION: The questionnaire developed for this study comprised two subscales concerned with the social health of parents/respondents and the social health of adolescents, as perceived by the parents. It was a valid and reliable instrument, and it showed satisfactory quality of life for parents of adolescents with clefts.

Efficacy of removal of cariogenic bacteria and carious dentin by ablation using different modes of Er:YAG lasers.

The primary objective of this in vitro study was to evaluate the efficiency of removal of cariogenic bacteria and carious dentin by ablation using two lasers: fluorescence-feedback controlled (FFC) Er:YAG laser and different pulses of Er:YAG laser based on variable square pulse technology (VSPt). The secondary objective was to measure the temperature during laser ablation of carious tissue. Seventy-two extracted human molars were used in this study. Sixty teeth with carious dentin were randomly divided into four experimental groups according to the treatment for caries removal: group 1: 400 µs (FFC group); group 2: super short pulse (SSP group, 50 µs pulse); group 3: medium short pulse (MSP group, 100 µs pulse); group 4: short pulse (SP group, 300 µs pulse) and one positive control group with no treatment. Twelve teeth without carious lesion were used as a negative control group. After caries removal, swabs were taken with cotton pellets and real-time PCR analysis was performed. During caries ablation, a thermal infrared camera was used to measure the temperature changes. In all experimental groups, specimens were free of bacterial contamination after the treatment. In the SSP, MSP and SP groups, temperatures measured during caries ablation were significantly higher compared to temperatures in the FFC group (P<0.001). In this in vitro study, laser treatment for removal of carious dentin and cariogenic bacteria was an efficient treatment modality without causing excessive temperatures that might adversely affect pulp vitality.

Assessment of efficacy of two chlorhexidine mouthrinses on oral hygiene and gingival health in adolescents wearing two types of orthodontic brackets.

OBJECTIVE: To investigate the efficacy of two formulations of chlorhexidine 0.2% (CHX) mouthrinses in terms of oral hygiene and gingival health status in adolescents with fixed orthodontic appliances wearing two different types of brackets during 18 weeks. STUDY POPULATION AND METHODOLOGY: Eighty subjects were randomly divided into two equal groups according to brackets type: (i) metal-stainless steel, (ii) ceramic. Four weeks after the placement of the fixed orthodontic appliances the subjects from each group were randomly allocated into two equal subgroups and were provided with two different mouthrinses for 14 days: (i) alcohol-free CHX, (ii) CHX with antidiscoloration system (CHX-ADS). Assessment was carried out according to gingival index (GI) and oral hygiene index-simplified (OHI-S) performed prior to the placement of the appliance (t1 ), 6 weeks (t2 ), and 18 weeks (t3 ) after the placement. To analyse the data, two-way mixed model MANOVA. Pearson correlations, one-way ANOVA and Independent Samples t test were conducted. RESULTS: Statistically significant decrease in GI and OHI-S indices after 6 weeks and then increase after 18 weeks for all groups was found. Both GI and OHI-S values were lower in subjects wearing ceramic brackets, with statistically significant difference for GI after the usage of the mouthrinse for 14 days, at t2 (P<.05). CONCLUSION: The results revealed that the ceramic brackets as well as usage of CHX-ADS resulted in improved gingival status.

Efficacy of removal of cariogenic bacteria and carious dentin by ablation using different modes of Er: YAG lasers

The primary objective of this in vitro study was to evaluate the efficiency of removal of cariogenic bacteria and carious dentin by ablation using two lasers: fluorescence-feedback controlled (FFC) Er:YAG laser and different pulses of Er:YAG laser based on variable square pulse technology (VSPt). The secondary objective was to measure the temperature during laser ablation of carious tissue. Seventy-two extracted human molars were used in this study. Sixty teeth with carious dentin were randomly divided into four experimental groups according to the treatment for caries removal: group 1: 400 µs (FFC group); group 2: super short pulse (SSP group, 50 µs pulse); group 3: medium short pulse (MSP group, 100 µs pulse); group 4: short pulse (SP group, 300 µs pulse) and one positive control group with no treatment. Twelve teeth without carious lesion were used as a negative control group. After caries removal, swabs were taken with cotton pellets and real-time PCR analysis was performed. During caries ablation, a thermal infrared camera was used to measure the temperature changes. In all experimental groups, specimens were free of bacterial contamination after the treatment. In the SSP, MSP and SP groups, temperatures measured during caries ablation were significantly higher compared to temperatures in the FFC group (P<0.001). In this in vitro study, laser treatment for removal of carious dentin and cariogenic bacteria was an efficient treatment modality without causing excessive temperatures that might adversely affect pulp vitality.

Chronology, dynamics and period of permanent tooth eruption in Zagreb children (Part II).

The aim of the present paper is to determine the beginning, order, median time, termination, dynamics, continuity and intensity of the permanent tooth eruption, as well as its calendar, in a sample of Zagreb children. The study included 2768 children (1398 boys and 1370 girls). All subjects were classified in one-year age groups. The continuity of tooth eruption occurs from 5.1 years to 14.97 years, i.e., for a period of 9.87 years. Each particular tooth has its own dynamics of eruption (V5-V95) which on the average amounts to 4.25 years. The continuity of eruption is 10.1 years in boys and 9.8 years in girls. The dynamics of eruption is 4.15 years in boys and 4.35 years in girls. A certain asymmetry in eruption has been described.

The influence of tooth wear on root canal dimensions.

The objective was to investigate the relations between tooth wear and root canal dimensions. The experimental group comprised 100 cuspids (canines), 50 of which had advanced abrasion and 50 were without it The dimensions of root canal were investigated at the light microscope level in order to define their vestibulo-oral and mesio-distal diameters in all three thirds. In the groups of teeth without abrasion the MD diameters of root canaliculi in their cervical thirds were greater than in the teeth with advanced abrasion. In the apical third the MD diameters of canaliculi were highly variable in teeth with no signs of abrasion. In the group of teeth with abrasion the MD and VO diameter values of the cervical thirds were significantly smaller than in the group of teeth without abrasion. In the mid-thirds the values of MD diameters were highly variable in the group of teeth with abrasion, whereas the VO diameter values were much greater than in the teeth without abrasion. As regards to the apical thirds, the VO diameter values were greater than in the control teeth. The data presented herewith contribute to better knowledge about tooth wear and are highly useful in restorative and reconstructive dental procedures.

Prevalence and intraoral distribution of dentin hypersensitivity among students.

The exposed dentin which is the result of the consequence of the enamel loss (by erosion, abrasion, attrition), gingival recession or periodontal therapy, as well as anatomic defects often as its result has dentinal hypersensitivity. The purpose of this work is to examine the frequency of dentinal hypersensitivity in relation to the subjective estimation of the examined persons and objectively, by intraoral examination. Forty persons, students from the School of dentistry of average age of 22.35 years were tested and analysed. Subjective data are achieved by the method of questionnaire while the objective ones by pulling the probe in the area of the tooth neck for the purpose of mechanical testing and by air syringe for the cold stimulus. The results show that the clinical hypersensitivity amounts 52.5% in relation to the subjective data 32.5%. The duration of hypersensitivity amounts in average 18 months and the strongest way of its demonstration is the cold and mechanical stimulus. The half of the examined brush their teeth twice a day out of which 72.5% do that by the half hard nylon brush, and the percentage of teeth with cuneiform defects amounts to 4.45. The often phenomenon of dentin hypersensitivity already among the young underline the need of preventive action and removing the damaging factors which contribute to the start of hypersensitivity of the nude dentin.

A biomechanical analysis of deformation and strain on lower jaw model.

Forces, occurring as result of orthodontic appliances, present a guiding system which controls force activity during the growth and development of lower jaw. By qualitative photoelasticimetric analysis author decided to evaluate the influence of extension apparatus to the lower jaw. The concentration and stress distribution, intensity and force direction on contacts with insert (extensor device) were analysed on araldyte lower jaw models. Three different loadings 41.0, 57.4 and 73.8 N under four different loading conditions with and without the correction appliance were used. The results of investigation indicated that the force created by the orthodontic appliance is correct at the beginning. The change from surface contact to linear and punctual contact increased the static moment and local stress, resulting in new regional conditions.

Effect of unilateral function on craniofacial growth.

The present study is aimed at experimental research of the effects of functional matrices upon the formation of functional units. The sample consisted of 15 experimental dogs (five dogs per each experiment) and five controls. Three experiments were carried out: neurectomy of the right mandibular nerve, circumvention of the right nostril and enucleation of the right eyeball. The results showed no statistically significant difference between age and animal sacrifice time interval. The controls manifested the significant differences in the length, breadth and height of the upper mandibular body consistent with their natural asymmetry. Neurectomy of the right mandibular nerve did not manifest statistically significant differences whereas the sample was too small, animal sacrifice time interval too short and passive movements of that mandibular side were still present after the operation. Circumvention of the right nostril revealed in the nasal opening breadth, which for the very nature of the operation and only a partial exclusion of the right side function could have been anticipated. Enucleation of the right eyeball eliminated the visual function in the right face causing changes in the midface, i. e. in the breadth and height of the nostril. The findings confirmed the initial assumption on the correlation between the removal of potential growth factors and increase of the opposite face parameters. The changes were most prominent in the mid of the head which can be related to its developmental and structural features.