Mechanism of enamel damage in the grooves of molars during mastication

BACKGROUND

During mastication, molars are subjected to heavy stress. However, a full explanation of the effects of physiological loads on tooth structures is lacking.

OBJECTIVES

The study aimed to determine stress in molars and identify the mechanism of enamel damage in the grooves of the teeth during computer-simulated mastication.

MATERIAL AND METHODS

The study was carried out using the finite element method (FEM). A three-dimensional (3D) model of the first mandibular molar and of the crown of the opposing maxillary tooth was created. A food bite was introduced between the antagonistic teeth. The mastication cycle of the bolus was computer-simulated. The equivalent stress in the enamel and dentin of the mandibular molar was calculated according to the modified von Mises (mvM) criterion.

RESULTS

During the simulated chewing activity, the highest equivalent mvM stress and tensile stress concentrated on the molar enamel around the central groove and the foramen cecum. The value of the equivalent mvM stress was close to the tensile strength of the enamel. According to the mvM criterion, the enamel in these areas was exposed to destruction, which coincided with the occurrence of class I caries.

CONCLUSIONS

During mastication, significant tensile and mvM stress concentrates on the mandibular molar enamel around the central groove and the foramen cecum. High stress in these areas may cause prism microfractures and facilitate the bacterial penetration of the enamel.

Comparative scanning electron microscope analysis of the enamel of permanent human, bovine and porcine teeth

Background

Bovine and porcine teeth are often used in in vitro experiments as substitutes of human teeth.

Objectives

The aim of the present study was to perform a comparative analysis of enamel morphology of permanent human, bovine and porcine teeth under the scanning electron microscope.

Methods

As many as 10 human, 10 bovine, and 10 porcine teeth were studied. All the teeth were sectioned and the halves were randomly divided into 2 groups according to the examined tissue (vestibular enamel at the mid-height of the dental crown and in the cervical area). Human and bovine enamel was etched for 15 sec and porcine enamel for 30 sec. The scanning electron microscope analysis was performed. The length and width of enamel prisms were determined with the “Met-Ilo” 1.1 computer program.

Results

All enamel samples revealed the same etching pattern—Silverstone's type 2. Bovine enamel showed a similar porosity and the amount of interprismatic enamel compared to human enamel while the amount and width of interprismatic enamel bands in porcine enamel were evidently greater. The shape of the porcine prisms was visually similar to human prisms, although dimensions were significantly different. However, bovine prisms differed in form and appeared to be distinctly elongated.

Conclusions

Reported findings indicate that the results of experimental studies carried out on bovine and porcine enamel should not be compared with the results obtained on human enamel.

Evaluation of dental status and effectiveness of treatment among children and adolescents in the reference groups aged 6, 12, and 18 years from Skierniewice and its region in 2017-2020

INTRODUCTION

Dental caries is a transmissible chronic disease of dental hard tissues. To monitor the course of carious process, age reference groups were designated which are subject to regular dental check-ups. The groups include children aged 6, 12, and 18 years as well as adults at the age of 35-44 and 55-64 years.

AIM

The aim of the study was to evaluate the state of dentition and effectiveness of treatment among children and adolescents in the reference groups aged 6, 12, and 18 years from the town of Skierniewice and its region in the years 2017-2020.

MATERIAL AND METHODS

The study included 385 children and adolescents from the reference groups. Dental examination was carried out in the dental office of the Ogrodowa Medical Centre in Skierniewice. Dental caries intensity expressed by the the DMFT index, and its particular components, D, M, and F (D- the mean number of teeth with caries (decayed), M- teeth extracted (missing), and F- filled) as well as the dental caries treatment index DTI (F/(D+F)) were determined according to sex.

RESULTS

Distribution of the DMFT index components was very similar in children aged 6 years and in 18-year-old adolescents. The D component constituted half the DMF index (50.7% in 6-year-olds and 52.4% in 18-year-olds), the M component values were lowest (16.1% and 12.3%, respectively) while the F component accounted for slightly more than 1/3 of the whole value (33.2% and 35.3%, respectively). In 12-year-olds, the D component value was 68.4% of the DMF index, the M component accounted for only a few percent (4.5%) and the F component was 27.1%. The DTI value was 0.40 for 6-year-olds and 18-year-olds and appeared to be significantly higher than in the group of 12-year-olds (0.3).

CONCLUSIONS

There is an urgent need for monitoring the dental status, professional caries prevention, and conservative treatment of teeth in children and adolescents of the Skierniewice region.

The influence of tobacco smoking on dental periapical condition in a sample of an adult population of the Łódź region, Poland

OBJECTIVES

Epidemiological studies show that apical periodontitis (AP), alongside tooth decay, is the most common oral disease. The aim of the study was to evaluate the influence of smoking on the prevalence of AP in the population of the Łódź region, Poland.

MATERIAL AND METHODS

The study involved 815 first-time, randomly selected patients reporting to the Central Teaching Hospital of the Medical University of Lodz. The studied group was a systematic sample of the population admitted for treatment in 2016. The study consisted of a questionnaire and a radiological part. Each patient filled out a questionnaire containing demographic data, and an interview regarding smoking and diabetes. The radiological part of the study included the analysis of panoramic radiographs which showed the periapical status, and the presence and quality of root canal treatment.

RESULTS

Teeth with AP were observed more frequently in patients addicted to tobacco either at the time of the study or in the past (group 1) - 7.2% than in people who had never smoked (group 2) - 5.2% (p < 0.0005). In the teeth without root canal treatment, AP was observed more frequently in group 1 - 3.5% than in group 2 - 1.9% (p < 0.0005). A statistically significant difference was found in the percentage of endodontically treated teeth between group 1 and group 2 (10.7% vs. 9.6%) (p = 0.017). However, no difference was observed in the frequency of AP in the endodontically treated teeth in both groups (37.6% vs. 35.8%) (p = 0.451).

CONCLUSIONS

Smokers are a group facing an increased risk of AP and, therefore, there is a need for an early detection and treatment of caries and its complications in this group of patients. The multifactorial etiology of AP indicates the necessity to undertake further studies on the effect of smoking on the periapical status. Int J Occup Med Environ Health. 2020;33(1):45-57.

Effect of health promoting behaviours on caries prevalence in children aged 1-3 years from the Skierniewice region

BACKGROUND

Health promoting behaviours have a decisive effect on the development and cours of caries at any age.

OBJECTIVES

The aim of the study was to investigate the correlation between health promoting behaviours and the state of dentition in children aged 1-3 years by determining the child's age, the cause of the first visit at the dental office and evaluating the relationship between the intensity of dental caries and the frequency of oral hygiene practices as well as the consumption of sweet foods.

MATERIAL AND METHODS

The study was conducted among 204 children aged 1-3 years from the town of Skierniewice and its vicinity, who visited the Dental Clinic at the Ogrodowa Medical Centre in Skierniewice in the years 2019 and 2020. The study consisted of two parts: a questionnaire and clinical examination.

RESULTS

In the entire study group, active caries was found in 65.2% of children. Most of the children came for the first time to the dentist at the age of 3 years (37.5%), and the least number of them in the first year of age (22.6%). There was no significant correlation observed between the purpose of the visit (adaptation, check-up and treatment, pain) and the child's age (p> 0.05). The majority of children (67.6%) cleaned their teeth twice a day; and the value of their dmf index (2.00 ± 0.88) was significantly lower compared to those brushing teeth once a day: in the morning (2.82 ± 1.01) or in the evening (2.89 ± 0.93) (p <0.001). Only 8.8% of children did not eat sweets at all, while more than half (58.8%) consumed them more than once a day. The dmf index value significantly (p<0.001) increased with the frequency of sweets consumption from 0.37 ± 0.08 - never, through 1.73 ± 0.86 - once a day, to 2.99 ± 1.03 - often.

CONCLUSIONS

The results of our study showed that health-promoting measures have a significant impact on the dental state of children aged 1-3 years.

Bond strength of Biodentine to a resin-based composite at various acid etching times and with different adhesive strategies

BACKGROUND

Biodentine® is a bioactive calcium silicate-based material, with better strength parameters, an easier application method and a shorter setting time than mineral trioxide aggregate (MTA). The bond strength between Biodentine and the composite material is essential for the durability of the layered restoration.

OBJECTIVES

The objective of this study was to evaluate the bond strength of Biodentine to a resin-based composite at various acid etching times and with different adhesive strategies.

MATERIAL AND METHODS

In the 1st part of the experiment, the specimens were divided into 2 groups: the adhesive was applied in the total-etch (TE) and self-etch (SE) techniques. In the TE group, 37% orthophosphoric acid was applied after 30 s (TE 30) and 240 s (TE 240). In the SE group, the SE system was applied for 30 s (SE 30) and 240 s (SE 240). In the 2nd part, the SE systems Clearfil® SE Bond and Clearfil S3 Bond Plus were evaluated (the CSE and CS3 groups, respectively). In each group, the adhesive system was applied in 1 (the CSE 1 and CS3 1 subgroups) or 2 layers (the CSE 2 and CS3 2 subgroups). The specimens were subjected to a shear bond strength (SBS) test in a universal testing machine.

RESULTS

Shear bond strength was higher after a prolonged etching procedure in the TE (TE 30: 2.51 MPa, TE 240: 9.39 MPa) and SE techniques (SE 30: 5.92 MPa, SE 240: 7.89 MPa). A statistically significant influence was detected in relation to 30 s of surface preparation time for Clearfil S3 Bond Plus (p < 0.001). Greater bond strength was revealed after the application of 1 layer of the Clearfil S3 Bond Plus single-bottle system (CS3 1: 6.42 MPa).

CONCLUSIONS

The SBS of Biodentine to the composite depends on both the etching time and the mode of application of the adhesive systems. Higher bond strength was obtained for the SE adhesive in a shorter application time.

Evaluation of the preventive and therapeutic programme implementation “Let’s take care of a healthy smile” among 17- and 18-year-old adolescents in the city of Skierniewice in 2018

AIM

The aim of the study was to evaluate the results of the preventive and therapeutic programme addressed to adolescents aged 17 and 18, based on a comparison of the state of dentition prior to and after the completion of the programme.

MATERIAL AND METHODS

All 44 adolescents from the City of Skierniewice and the surrounding area who applied for enrolment were included in the programme. Based on clinical examination, the prevalence of active caries, caries intensity expressed by mean values of the DMFT (decayed, missing, filled teeth) Index including D, M, and F components and the Dental Treatment (DT) Index F/(D + F) were assessed. All parameters were presented according to sex.

RESULTS

Active caries was observed in 34 (77.3%) patients. Caries was more frequently detected in boys (82.6%) than in girls (71.4%). The value of the Caries Intensity Index, DMF, equalled 12.05 and was significantly higher (p<0.01) in boys than in girls: 13.73 ± 3.63 and 10.06 ± 3.42. In the examined group of 17- and 18-year-olds, the mean number of decayed teeth D (6.31) had the highest mean value, followed by the mean number of filled teeth F (4.26), the mean number of extracted (missing) teeth M (1.48) being the lowest. The values of the F Index were statistically significantly higher (t=2.570; p=0.0195) in boys as compared to girls (5.26 ± 2.69 vs. 3.13 ± 2.83). Mean value the Dental Treatment (DT) Index (F/D+F) appeared to be higher in the group of boys than in girls: 0.431 ± 0.182 and 0.358 ± 0.126, respectively. After the completion of the programme, all adolescents studied achieved the value of the Dental Treatment Index equalling 1

CONCLUSIONS

Dental examination qualifying 17- and 18-year old adolescents in Skierniewice to the preventive and therapeutic programme detected numerous foci of active caries. Implementation of the programme allowed to effectively treat the teeth of the adolescents participating in the project and to develop proper hygiene and dietary habits.

Diagnostic value of cone beam computed tomography for recognition of oblique root fractures: An in vitro study

BACKGROUND

Diagnosis of tooth root fractures is based on radiographic examination, which is not reliable in the case of oblique root fractures.

OBJECTIVES

The aim of the study was to evaluate the efficacy of cone beam computed tomography (CBCT) imaging of oblique root fractures.

MATERIAL AND METHODS

Twenty-four bovine incisors were used in the study. They were randomly divided into 2 groups: an experimental group with artificially created oblique root fractures and a control group without fractures. The teeth underwent a CBCT evaluation with a CS 9300 cone-beam scanner (Carestream, Rochester, USA) using a 5 × 5 cm field of view with the resolution up to 90 μm, and a dental radiography. The specimens were examined by 2 observers with different job experience.

RESULTS

In the CBCT scans, fracture lines were detected in 95.8% of cases (the 1st observer made a proper diagnosis in 100% of cases and the 2nd in 91.7%). Fracture lines were identified on radiographs in 33.3% of roots (the 1st observer was able to see the lines in 41.7% of cases and the 2nd in 25%). The inter-observer agreement was very high (the kappa coefficient for CBCT scans was 1.00 and 0.88 for radiographs). The best diagnostic value was recorded for contiguous slices.

CONCLUSIONS

Cone beam computed tomography with a small field of view and high resolution significantly surpasses radiographs in effective imaging of oblique tooth root fractures and should be the method of choice in the diagnosis of these fractures.

Influence of infiltration technique and selected demineralization methods on the roughness of demineralized enamel: An in vitro study

BACKGROUND

The decalcification of enamel leads to an increase in tissue roughness. The development of carious lesions may be halted or these lesions may heal, which results in a smoother surface.

OBJECTIVES

The objective of the study was to assess the impact of selected agents on the roughness of demineralized enamel on the smooth surfaces of teeth.

MATERIAL AND METHODS

A total of 25 samples with exposed enamel surfaces were examined in the study. The samples were randomized into groups and they were exposed to a demineralizing solution, after which the following agents were applied: Icon (Ic), Elmex gel (El), GC Tooth Mousse (TM), Colgate Total (K+) - a positive control group, and distilled water as a negative control group (K-). The impact of selected agents on the roughness of demineralized enamel was assessed with a profilometer. The parameters Ra, Rz and Rq were analyzed.

RESULTS

Following infiltration and demineralization, the Ra coefficient declined in groups Ic, TM, K+ and K-, Rz decreased in groups Ic, TM and Rq was lower in groups Ic, TM and Kafter using agents when compared with demineralization. The lowest Ra, Rz and Rq values, i.e. the highest degree of surface smoothness, were observed in group Ic. An increase in all coefficients (Ra, Rz and Rq) was noted in group El.

CONCLUSIONS

Demineralized enamel can be smoothed out through the one-time application of Icon resin or the long-term application of GC Tooth Mousse. The least effective agents turned out to be those with a high fluoride content.

Evaluation of dental state in 6-year-old children from the Skierniewice region

INTRODUCTION

Caries is a social disease and a serious problem, especially in the childhood. The effects of untreated caries can cause not only disorders of the stomatognathic system, but also have a negative impact on the overall health and development of the child

THE AIM OF THE STUDY

The aim of this study was to evaluate the state of dentition of 6-year-old children from the Skierniewice region

MATERIALS AND METHODS

A total of 140 children (6-year-old) were included to the study - 74 from a small town (Skierniewice) and 66 from a village. Caries prevalence, caries intensity (dmf, DMF) and dental treatment index (DTI) were assessed. The results were analyzed statistically

RESULTS

The caries prevalence in the study group was 88.6%. The caries intensity in the deciduous dentition (dmf) was statistically significantly higher (p=0.021) in rural areas (7.45) than in the city (6.32). The mean dmf value was mainly determined as the number of filled teeth. In permanent dentition, higher values of DMF were found in children from rural areas (2.30) than urban areas (1.93). The dental treatment index for the deciduous dentition amounted to 0.67 and for the permanent dentition to 0.4. Both for deciduous and permanent teeth, this index was higher in urban than rural children

CONCLUSIONS

High rates of caries prevalence and intensity in 6-year-old children from the Skierniewice region confirm that caries is still a serious problem, especially in the village. The high value of the treatment index for deciduous dentition demonstrates the efficacy of treatment in this field. It is necessary to carry out preventive programs and make parents aware that they should early take care of their children’s dentition

Evaluation of the Erosive Potential of Selected Isotonic Drinks: In Vitro Studies

BACKGROUND

Isotonic drinks are an important component of the diet of athletes. Sports drinks cause the body to maintain proper hydration and supplement minerals which are lost in sweat during excessive exercising. Aside from the benefits of isotonic drinks, it is important to be aware of the harmful effects of citric acid within the products, which could cause enamel erosion.

OBJECTIVES

The aim of the study was to evaluate the erosive potential of sports drinks using confocal scanning laser microscopy (CLSM).

MATERIAL AND METHODS

The studies measured the change of surface roughness of the dental enamel after etching using Isostar, Powerade and Gatorade drinks, and Fortuna orange juice. Measurements were repeated after 1, 2 and 3 h of exposure to the selected liquid. The evaluation of calcium compound contents was carried out using the complexonometric method.

RESULTS

The surface roughness measurements of dental enamel showed that the lowest values of the parameters Ra and Rz were obtained for Isostar and orange juice. The research of the calcium content in the selected beverages showed the highest value in Isostar (320.0 mg/L) and the lowest in Powerade (40.0 mg/L) and Gatorade (21.0 mg/L).

CONCLUSIONS

Our study confirms that Isostar is the safest sports drink, among the analyzed beverages, for athletes, because it causes the least erosive changes in dental enamel. It is recommended to supplement beverages to reduce their potential for erosion using calcium compounds.

A comparative study of two different regression methods for radiographs in Polish youngsters estimating chronological age on third molars

AIM

The aim of this study was to establish a third molar developmental database to model dental age of Polish youngsters, to investigate the rating level of the scores when dividing a year interval into a quarter of a year and to examine sex differences, left-right and upper-lower jaw asymmetry.

MATERIAL AND METHODS

A cross-sectional sample of 1048 orthopantomograms of 644 females and 404 males aged between 12 and 26 years was investigated using the scoring system of Gleiser and Hunt modified by Köhler. Reference tables according to age were split in a whole year and in quarters of a year using descriptive statistics. The various developmental stages between males and females were analyzed with a paired t-test and the cusum method. Differences in mineralization between the quadrants were analyzed with a two-factor ANOVA and the Duncan post hoc test. The single quadratic and support vector regression were performed to describe the relationship between score and age.

RESULTS

Dividing age classes in quarters of a year discriminated better between individuals provided that there is a sufficient sampling size for all age classes. The mineralization tempo occurred significantly at a faster rate in males. The maturational events in the upper arch developed significantly at earlier ages for both genders. Obtained chronological age had nearly the same standard error of estimate when calculated with both regression methods.

DISCUSSION AND CONCLUSION

Comparing the results of the present study with those of other population groups suggests that there are differences in the ageing process of the wisdom tooth. This is the first database of Polish youngsters (15-24 years) with their respective regression equations to yield age estimations.

Radiographic features and outcome of root canal treatment carried out in the Łódź region of Poland

AIM

The aim of this study was to assess the radiographic features and factors affecting the long-term results of root canal treatment in the Lódź region of Poland.

METHODOLOGY

Three hundred and fifty-five periapical radiographs of previously endodontically treated teeth (282 root-filled teeth and 73 teeth with pulpotomy) from 236 patients were evaluated in the study. The patients were aged from 15 to 76 years and randomly selected amongst subjects referred to the Institute of Dentistry. Medical University of Lódź and two private dental practices. The radiographs were examined by the authors according to criteria proposed by De Cleen et al. (1993) using an illuminated viewbox in a dark room. The Fisher's exact test was used to compare the frequencies in teeth groups.

RESULTS

Amongst root-filled teeth, 49% were adequately filled within 0-2 mm of the radiographic apex. Periapical radiolucencies were observed in 25% of root-filled teeth. Teeth without periapical pathosis were more often filled within 0-2 mm of the apex (59%) than teeth with pathosis (17%). Teeth were most often adequately filled (64%) in patients attending the Institute of Dentistry. In patients attending the dental outpatients' departments, 71% of teeth were inadequately filled. Amongst the teeth treated with pulpotomy, 67% had a periapical radiolucency.

CONCLUSION

The radiographic technical quality of the root canal treatment was associated with the outcome that root fillings of adequate standard were associated with health more often than inadequate root fillings. Pulpotomy was associated with periapical disease in the majority of cases.