Poster 2156, Sprache: Englisch
Objectives: The aim of the present study was to investigate straightening of curved root canals after the engine-driven nickel-titanium systems Hero (Micro Mega), Revo-S (Micro Mega), Twisted Files (Kerr Endodontics), and Mtwo (VDW) were used for root canal preparation.
Methods: A total of 60 root canals in extracted human teeth with a curvature of at least 25° were prepared. In each case, 15 canals were randomly assigned and prepared with the Hero 642 System (H), the Revo-S System (R), the Twisted File System (T), and the Mtwo System (M) according to the manufacturer's instructions. The sequence for strongly curved canals, respectively wide canals was used. The degree of straightening was evaluated by superimposition of standardised digital x-ray images taken before and after root canal preparation. These images were generated from X-rays of 2 planes which were at an angle of 90° to each other.
Results: The statistical analysis showed a significant influence of the rotary systems used to straighten the root canals (p< 0.001, ANOVA). For the four-test series, the following straightenings were evaluated (mean values and standard deviations in °): H: 4.78±3.24, R: 7.67±5.04, T: 5.07±2.91 and M: 4.23±3.72. Pairwise comparison showed significantly higher straightening in specimens treated with Revo-S (R) compared to the other systems (p≤0.05, Tukey's Test). The comparison of straightening within the other groups H, T, and M showed no significant differences (p>0.05, Tukey's Test).
Conclusions: Regarding the limitations of an in vitro study, it can be concluded that all root canal preparation systems were associated with canal straightening, while Revo-S significantly showed the strongest straightening.
Schlagwörter: root canal treatment, rotary NiTi system, straightening, endodontics, engine-driven preparation devices
Poster 2167, Sprache: Englisch
Introduction: The purpose of this clinical study was to evaluate the dentoalveolar changes due to unilateral maxillary molar distalization and to determine side effects using a 3-dimensional intraoral scanning method.
Methods: The study group comprised 30 patients (mean age: 19.8 years) with a Class II molar relationship. All patients were treated with the iPANDA for unilateral and bilateral maxillary molar distalization. Three-dimensional models were obtained before and after distalizaion. Digital models were superimposed using surface-to-surface matching of the palatal area, which included the midpalatal screws of iPANDA and rugae as a reference area. Molar movement was measured on the superimposed maxillary arches before and after distalization.
Results: A Class I molar relationship was obtained in an average 5 months, with a movement rate of 0.6 mm per month. In the sagittal plane, the first molars showed a mean linear movement of 1.2 ± 0.7 mm and the average molar inclination was 4.22 ± 3.41°. In the vertical plane, the first molars showed slightly intrusion, with a mean value of 0.7 mm ± 1.3 mm. In the transverse plane, rotation of the first molars was 1.70 ± 3°.
Conclusions: Through support from midpalatal miniscrews, the maxillary first molars were effectively distalized without anchorage loss. Furthermore, movement was observed in all three dimensions.
Schlagwörter: Distalization, iPanda, miniscrew
Poster 2169, Sprache: Englisch
Introduction: Proliferative activity of periodontal ligament (PDL) cells decrease with age in an animal model. Furthermore, human PDL is less cellular in adults than in children. However, there is no quantitative human PDL assessment related to the effect of age on PDL cell proliferation under different durations of orthodontic load.
Aim of Study: To determine the differences in proliferative activity of PDL cells on the root surface of orthodontic loading teeth between younger and older groups in different loading periods.
Materials and Methods: Fifty-eight patients, requiring premolar extraction for orthodontic treatment, were divided into two groups: younger group (age15-20) and older group (age>20). For loading, 0.016-inch improved super-elastic nickel-titanium alloy wires were used. One of their maxillary first premolars was loaded for one, two, four, six, or eight weeks, whereas the contralateral premolar was not loaded as a control. Premolar extractions were performed, and the extracted premolars were fixed with 10% buffered formalin and stained with toluidine blue. Digitised images were taken under a stereomicroscope, and the percentage of stained PDL was analysed. Differences in the percentage of stained PDL between loaded and unloaded teeth for the different durations of load were analysed using the independent t-test. P-values less than 0.05 were considered statistically significant.
Results: The percentage of PDL cell proliferation was significantly greater in the younger group than in the older group after loading for short durations (one to two weeks) (p
Schlagwörter: Proliferative activity, PDL cell proliferation, orthodontic loading
Poster 2171, Sprache: Englisch
The current pocket money trends among school children are steeply increasing. The children receiving pocket money indulge in unhealthy habits. Access to pocket money by children has a direct influence on sweet snacking and junk food consumption. This unhealthy habit has gigantically leaped forward nowadays in school-aged children, leading to bitter consequences for their oral hygiene. There is a wide availability of fast food in nearby school areas, with prices within the range of pocket money. The pocket money trend turns out to be a risk factor for dental caries. This e-poster represents a questionnaire-based survey conducted among school children to show the implications of pocket money related to oral health in paediatric dentistry.
Schlagwörter: caries, children and pocket money
Poster 2179, Sprache: Englisch
Objectives: The purpose was to gain an overview of the oral health status of Ghanaian pre-school and school-aged children in rural and urban areas between the ages of 3 and 12 years in the southern area of the country. The study was carried out in 2017 and focused on identifying differences between these areas in terms of caries prevalence.
Methods: The study was designed as a socio-epidemiological cross-sectional survey to include Ghanaian children and young adolescents between 3 to 4, 6 to 7, and 12 to 13 years of age. The participants were recruited from nurseries and schools in Accra (Greater Accra Region), representing urban and Kpando (Volta Region), representing rural areas of Ghana. The dental examination was conducted according to WHO criteria by one standardised investigator. The total number of decayed, missing, and filled primary teeth (dmft) for 3, 4, 6, and 7-year-olds or permanent teeth (DMFT) for 12 and 13 year-olds were recorded.
Results: A total number of 313 children (165 urban, 148 rural) were included and examined. The distribution of participants according to age was as follows: 3 to 4 years (n=62), 6 to 7 years (n=47) and 12 to 13 years (n= 73). The average dmft among 3 to 4-year-old children was 0.9 in urban and 1.5 in rural areas, and among 6 to 7-year-olds 0.8 and 1.4, respectively. The average DMFT among 12 to 13-year-old adolescents was 0.9 and 0.3 respectively.
Conclusions: The average dmft/DMFT-scores of Ghanaian children and adolescents ranges between 0.3 and 1.5. Whereas children from rural areas in the age groups 3 to 4 and 6 to 7 years consistently had fewer caries than those from urban areas, in contrast, adolescents in urban areas had a lower DMFT than those in rural areas.
Schlagwörter: oral health, caries, Ghana, DMFT, children
Poster 2180, Sprache: Englisch
Objectives: The aim of the study was to evaluate microtensile bond strength of a universal adhesive (Futurabond U, Voco GmbH, Germany) in self-etch and etch-and-rinse mode on human enamel and dentin compared with established systems. Additionally, the influence of an oxalate-containing desensitiser was evaluated.
Methods: 180 human third molars were included. Standardised enamel and dentin specimens were prepared. 15 enamel and dentin samples each were assigned to one of the following experimental groups: Enamel groups: 1: Futurabond U, etch & rinse; 2: Futurabond U, self-etch; 3: Futurabond® DC; 4: Solobond M. Dentin groups: 5: Futurabond U, etch & rinse; 6: Desensitizer, Futurabond U, etch & rinse; 7: Futurabond U, self-etch; 8: Desensitizer, Futurabond U, self-etch; 9: Futurabond DC; 10: Desensitizer, Futurabond® DC; 11: Solobond M; 12: Desensitizer, Solobond M. The oxalate-containing desensitiser was applied in advance to the dentin samples. The adhesives were applied according to the manufacturer's instructions. After polymerization of the composite microtensile bond strength values were determined using a universal testing machine (Zwick Z 005).
Results: Significantly higher values could be found for Futurabond U in the etch-and-rinse mode (21.45 MPa) compared to the self-etch mode (16.09 MPa) on enamel. Compared to the other two adhesives, no significant differences could be detected. The additional application of the oxalate-containing desensitiser in the case of dentin samples did not show any significant difference in the etch-and-rinse mode. For groups in self-etch mode, the desensitiser application resulted in significantly reduced tensile bond strength values compared to groups without desensitiser application.
Conclusions: Regarding the limitations of an in-vitro study, it can be concluded that Futurabond U has very promising results on enamel and dentin compared to the established adhesives. The influence of an oxalate-containing desensitiser on the adhesion is only visible in the case of the self-etch application mode.
Schlagwörter: desensitising, microtensile bond strength, universal adhesive, self-etch, etch-and-rinse
Poster 2181, Sprache: Englisch
The purpose of this study was to determine the correlation between the number of fungiform papillae on the tongue and the occurrence of dental caries in 18-21 year-olds. One hundred and fifteen undergraduate students of K.L.E Society's Institute of Dental Sciences participated in this cross-sectional study. The subjects were selected by simple random sampling. The data on brushing habits, ethnicity, socio-economic status, and taste preferences were collected by a self-administered questionnaire, and the DMFT index of all subjects was recorded by a single examiner. Based on the DMFT index, the individuals were categorised into low caries (0-5), moderate caries (6-9), and high caries (≥10) groups. The fungiform papillae were identified using Brilliant Blue FCF (E133) dye, which was applied on the anterior part of the tongue on a 6mm diameter circular area. The area was photographed with a digital camera, and these photographs were used to quantify the fungiform papillae. In this study we established a relationship between fungiform papillae count and caries experience in different caries groups.
Schlagwörter: fungiform papillae, caries experience
Poster 2185, Sprache: Englisch
Pericoronal radiolucencies with calcifications can be due to dentigerous cysts, adenomatoid odontogenic tumour, calcifying epithelial odontogentic cyst and tumour, cemento ossifying fibroma, odontomas, etc. Here is a case of a 13-year-old male, who presented with swelling of the lower jaw. Radiograph revealed a pericoronal radiolucent lesion with respect to an impacted mandibular canine.
Diagnosis of pericoronal radiolucencies correctly is sometimes challenging for an oral radiologist. This poster attempts to discuss the differential diagnosis of such pericoronal radiolucent lesions that must be considered while making the diagnosis and treatment planning.
Schlagwörter: Ameloblastic fibrodentinoma, dentinoma, fibroameloblastic dentinoma, odontogenic tumour, calcifications
Poster 2190, Sprache: Englisch
Introduction: The presence of a certain zone of attached gingiva (AG) is essential for maintenance of gingival health, prevention of soft tissue recession, and unaltered levels of the connective tissue attachment. In a clinical study by Lang and Loe, it was demonstrated that in areas with less than 1mm of attached gingiva, inflammation persisted despite optimal plaque control. The earliest documented surgical techniques to increase the width of AG were the push-back procedure, the vestibular extension technique, an apically repositioned flap, and an autogenous free gingival graft. Later, Carnio et al. found that a modification of the apically repositioned flap is an effective method to increase both keratinised and attached tissue width.
Platelet-rich fibrin (PRF) is a natural fibrin-based healing biomaterial. It encourages angiogenesis, immunity, epithelisation, and is used to shield open wounds, thereby promoting faster healing and soft tissue maturation.
Objective: Taking into consideration the advantages of PRF, it was assumed that the combination (MARF+PRF) therapy might be a beneficial modality in patients with Miller's class III and IV recession over single/ multiple adjacent teeth.
Materials and methods: A total of 6 teeth were treated in 3 systemically healthy patients (1 male, 2 females; age range- 21-38). Subjects were non-smokers with an inadequate zone of attached gingiva (0.5-2.0mm) and minimal sulcus depth with no bone dehiscence. All the clinical parameters, namely width of attached gingiva, keratinised tissue, marginal tissue recession, and probing depth, (PD) were measured on the mid-buccal aspect of the treated teeth using a UNC-15 probe. Measurements were taken at baseline (immediately before surgical treatment) and 6 months after surgery. When measuring the apico-coronal dimension of KT, an iodine solution was used to visualise the mucogingival junction. The width of attached gingiva was determined by subtracting the PD from the apico-coronal height of KT. Marginal tissue recession was regarded as the distance between the cemento-enamel junction and the gingival margin. Following local anaesthesia, a single horizontal incision parallel to the mucogingival junction was given in keratinised tissue. It is a bevelled incision which allows a coronal portion of gingiva to remain intact in its original position and prevents recession and alveolar bone loss. The mesiodistal extension of the horizontal incision depends on the number of teeth involved and should be extended at least one half tooth mesial and distal to the area where augmentation is required; this allows apical repositioning of the flap without requiring vertical incisions. A spilt-thickness flap was elevated and PRF membrane prepared using a table-top centrifugation machine at 3000 rpm for 10 minutes. The flap was moved apically, PRF membrane placed, and simple interrupted bioabsorbable suturing was done.
Results and conclusions: Treatment with this procedure resulted in an increase in width of both keratinised gingiva and attached gingiva. Gingival recession decreases at 4 treated areas, which may be the result of creeping attachment. In view of the above findings, it may be concluded that (MARF+PRF) may be used as an alternative to other procedures such as FGG with reliable results and minimal patient discomfort.
Schlagwörter: Attached gingiva, aesthetics, fibrin, gingival recession, mucogingival surgery, wound healing
Poster 2198, Sprache: Englisch
Summary & Conclusion: This unpretentious investigation actually shows that wear of titanium can occur in human bone simply due to implant insertion. Though wear is extremely limited in human donor bone and of little clinical relevance, further long-term investigations regarding aspects of bio-tribocorrosion in dental implants are needed. The risk of prolonged inflammation during osseointegration is considered to be extremely low, and therefore titanium implants are a safe and predictable therapeutic option. This investigation was financially supported by DGZMK, the Oral Reconstruction Foundation, and Thommen.
Introduction: In orthopaedics, wear of titanium endo-prosthesis components is an increasing problem, especially in hip prostheses. Inflammation and tissue degeneration make surgical revisions risky and unfavourable. As approximately one million dental implants are inserted every year in Germany alone, side-effects like multi-etiological peri-implantitis or titanium incompatibility have become more frequent. This study was motivated by the need to prevent disturbance of osseointegrative healing of implants after insertion due to phagocytosis of nano-particles, which may cause activation of prolonged tissue inflammation with a subsequent higher risk of implant loss or activation of multi-etiological peri-implantitis.
Methods: Human donor bone of D1 quality (Os femoris) was cut to appropriate size and 6 Conelog implants (Camlog) of 3.8mm diameter (3 implants of osseointegrative surface and 3 of smooth surface, Figure 3) together with 6 Thommen implants of 4mm diameter (3 implants of osseointegrative surface and 3 of smooth surface, Figure 2) were inserted with a maximum torque of 20Ncm. Afterwards, the bone cavity was opened and investigated for titanium wear. Scanning electron microscopy and energy dispersive X-ray spectroscopy were used to detect nano-particles. Statistical analysis was performed using ANOVA.
Results: The occurrence of titanium was very limited. Therefore, the size of particles could not be measured. Overall, 150 sites in 12 implants were analysed (average of 12.5 sites per implant). In total, the measurements of 37 sites produced positive detection of small traces of titanium (0.016 – 0.364 wt.%). No differences were found regarding the surface morphology or type of manufacturer, but remarkably there were differences in the sub-groups (Figure 4). There was a statistically significant difference between smooth and osseointegrative surface in Camlog implants (p=0.0161) as well as a marginal significance between smooth surface implants of Thommen and Camlog (p=0.0826). No difference was found in smooth and osseointegrative Thommen implants (p=0.696).
Schlagwörter: titanium, nano-particles, human donor bone, Camlog, Thommen