Post-mortem enamel surface texture alteration during taphonomic processes—do experimental approaches reflect natural phenomena?

Experimental approaches are often used to better understand the mechanisms behind and consequences of post-mortem alteration on proxies for diet reconstruction. Dental microwear texture analysis (DMTA) is such a dietary proxy, using dental wear features in extant and extinct taxa to reconstruct feeding behaviour and mechanical food properties. In fossil specimens especially, DMTA can be biased by post-mortem alteration caused by mechanical or chemical alteration of the enamel surface. Here we performed three different dental surface alteration experiments to assess the effect of common taphonomic processes by simplifying them: (1) tumbling in sediment suspension to simulate fluvial transport, (2) sandblasting to simulate mechanical erosion due to aeolian sediment transport, (3) acid etching to simulate chemical dissolution by stomach acid. For tumbling (1) we found alteration to be mainly dependent on sediment grain size fraction and that on specimens tumbled with sand fractions mainly post-mortem scratches formed on the dental surface, while specimens tumbled with a fine-gravel fraction showed post-mortem formed dales. Sandblasting (2) with loess caused only negligible alteration, however blasting with fine sand quartz particles resulted in significant destruction of enamel surfaces and formation of large post-mortem dales. Acid etching (3) using diluted hydrochloric acid solutions in concentrations similar to that of predator stomachs led to a complete etching of the whole dental surface, which did not resemble those of teeth recovered from owl pellets. The experiments resulted in post-mortem alteration comparable, but not identical to naturally occurring post-mortem alteration features. Nevertheless, this study serves as a first assessment and step towards further, more refined taphonomic experiments evaluating post-mortem alteration of dental microwear texture (DMT).

Influence of Enamel Exposure to Acidic Drink on Shear Bond Strength of Different Fissure Sealants

In the present study, we evaluated the influence of bovine enamel exposure to acidic drinks (Coca-Cola, Coca-Cola Company, Milano, Italy, pH = 2.37) on shear bond strength of three sealants (Fissurit; Grandio Seal and Admira Fusion—Voco Gmbh, Cuxhaven, Germany). For each sealant, two adhesive techniques were tested to investigate the impact of the adhesive application on shear bond strength of sealants after immersion in acidic drink and in the control: Group 1—Control: enamel surface was not in contact with acid drinks, acid etching application and self-adhesive technique for fissure sealant; Group 2—enamel surface was not in contact with acid drinks, acid etching, and adhesive applications, an etch-and-rinse technique for fissure sealant; Group 3—enamel surface was immersed in acid drink, acid etching application and self-adhesive technique for fissure sealant; Group 4—enamel surface was immersed in acid drink, acid etching, and adhesive applications, an etch-and-rinse technique for fissure sealant. For each specimen, the sealant composite resin was applied to the enamel surface and tested with a universal testing machine. Shear bond strength was measured in MPa and with an optical microscope to determine failure modes, quantified with adhesive remnant index (ARI). Enamel acidification variably influenced bond strength values of the different sealants. When no enamel pretreatment was applied, no significant differences were found among the sealants (p > 0.05). However, the mere application of acid etching without adhesive procedures resulted in lower bond strength (p < 0.001). The acid pretreatment affected significantly the bond strength of all sealants tested (p < 0.001), but no significant differences were recorded between the subgroups.

Examination Of Damage on Enamel Surface Due to Removal of Metal and Ceramic Brackets: A Review

During fixed orthodontic treatment, there is great possibility that the dental enamel could be damaged due to the process of debonding the bracket. Enamel cracks are one of the most common aspects that can develop or increase during debonding. This review aimed to conduct an examination of cracks in the enamel that occur both prior to and following metal or ceramic brackets being debonded.

Examination Of Damage on Enamel Surface Due to Removal of Metal and Ceramic Brackets: A Review

During fixed orthodontic treatment, there is great possibility that the dental enamel could be damaged due to the process of debonding the bracket. Enamel cracks are one of the most common aspects that can develop or increase during debonding. This review aimed to conduct an examination of cracks in the enamel that occur both prior to and following metal or ceramic brackets being debonded.

Efektivitas antibakteri gel chitosan dengan berat molekul berbeda terhadap jumlah koloni bakteri Streptococcus mutans pada permukaan email sekitar braket ortodonti Antibacterial effectiveness of chitosan gel with different molecular weights on the number of Streptococcus mutans colonies in the enamel surface around orthodontic bracket

Pendahuluan: Chitosan merupakan bahan alami, bersifat antibakteri, dan dapat dibentuk menjadi gel sehingga berpotensi sebagai agen profilaksis terhadap Streptococcus mutans, penyebab demineralisasi email. Lesi white spot merupakan salah satu risiko penggunaan alat ortodonti cekat. Berat molekul merupakan salah satu faktor yang memengaruhi efektivitas antibakteri chitosan, namun hubungannya masih memberikan hasil yang inkonsisten. Penelitian ini bertujuan menganalisis perbedaan efektivitas gel chitosan dengan berat molekul berbeda terhadap jumlah koloni bakteri Streptococcus mutans pada permukaan email sekitar braket ortodonti. Metode: Penelitian ini menggunakan metode eksperimen laboratoy dengan menggunakan 24 sampel gigi dengan braket dioles gel chitosan A (50-80 kDa), gel chitosan B (50-150 kDa), gel chitosan C (190-310 kDa), dan gel kontrol klorheksidin diglukonat 0,2% (CHX) masing-masing 6 sampel. Seluruh sampel diinkubasi dalam biakan Streptococcus mutans secara bertahap, 10 μl suspensi dari plak yang terbentuk pada sampel dibiakkan untuk memperoleh koloni pada biakan agar. Data dianalisis dengan uji one-way ANOVA dan Least Significant Difference (LSD). Hasil: Jumlah koloni bakteri Streptococcus mutans setelah aplikasi gel chitosan A, B, C, dan gel klorheksidin diglukonat 0,2% (CHX) didapatkan sebesar 10,05x106 CFU/ml; 9,72x106 CFU/ml; 10,96x106 CFU/ml; dan 4,35x106 CFU/ml sehingga tidak terdapat perbedaan bermakna jumlah koloni bakteri Streptococcus mutans antara ketiga kelompok gel chitosan (p>0,05) dan terdapat perbedaan jumlah koloni bakteri Streptococcus mutans yang bermakna antara ketiga gel chitosan dengan gel kontrol (p<0,05). Simpulan: Efektivitas antibakteri gel chitosan dengan berat molekul berbeda terhadap jumlah koloni bakteri Streptococcus mutans pada permukaan email sekitar braket ortodonti adalah sama besar, namun lebih rendah daripada efektivitas antibakteri gel klorheksidin diglukonat 0,2% pada studi ini.Kata kunci: berat molekul; braket ortodontik; kitosan; email; Streptococcus mutans ABSTRACTIntroduction: Chitosan is a natural ingredient, antibacterial, and can be formed into a gel so that it has the potential as a prophylactic agent against Streptococcus mutans, the cause of enamel demineralization. White spot lesions are one of the risks of using fixed orthodontic appliances. Molecular weight is one factor that affects the antibacterial effectiveness of chitosan, but the relationship still gives inconsistent results. This study aimed to analyze the differences in the effectiveness of chitosan gels with different molecular weights on the number of Streptococcus mutans bacteria colonies on the enamel surface around orthodontic brackets. Methods: This study used an experimental laboratory method using 24 dental samples with brackets smeared with chitosan A gel (50-80 kDa), chitosan B gel (50-150 kDa), chitosan C gel (190-310 kDa), and chlorhexidine control gel. digluconate 0.2% (CHX) each of 6 samples. All samples were incubated in Streptococcus mutans culture in stages, 10 l suspension of the plaque formed on the samples was cultured to obtain colonies on agar cultures. Data were analyzed by one-way ANOVA and Least Significant Difference (LSD). Results: The number of Streptococcus mutans colonies after application of chitosan gel A, B, C, and 0.2% chlorhexidine digluconate (CHX) gel was 10.05x106 CFU/ml; 9.72x106 CFU/ml; 10.96x106 CFU/ml; and 4.35x106 CFU/ml, so that there was no significant difference in the number of Streptococcus mutans colonies between the three chitosan gel groups (p>0.05) and there was a significant difference in the number of Streptococcus mutans bacteria colonies between the three chitosan gels and the control gel (p<0.05). Conclusions: The antibacterial effectiveness of chitosan gel with different molecular weights on the number of Streptococcus mutans bacterial colonies on the enamel surface around orthodontic brackets was simi-lar but lower than the antibacterial effectiveness of 0.2% chlorhexidine digluconate gel.Keywords: molecular weight; orthodontic bracket; chitosan; enamel; Streptococcus mutans

Study of the effect of using a hard toothbrush with a high abrasive toothpaste according to profilometry data

Compliance with oral hygiene is an important aspect of the prevention of dental diseases. But an uncontrolled choice, the use of improperly selected home hygiene products can lead to a number of complications, for example hyperesthesia of dentin. An important aspect of the choice of home hygiene products is their effect on the hard tissues of the tooth.Aim. To study in the experiment the effect of a hard toothbrush with a high level of abrasiveness of a toothpaste on the change in the enamel surface according to profilometry data.Materials and methods. Using the device for cleaning teeth, a study was carried out on the roughness of the surface if the enamel of the sample. In research were used the first 3 molars removed for periodontal indications, of which 3 samples of 1×1 cm were prepared. The measurements were carried out using a Senso neox profilometer (Sensofar) with a 3D magnification of 150 at the following time intervals: initial condition of the tooth, 1 week, 1 month, 6 months, 1 year.Conclusion. When using a hard toothbrush together in combination with a highly abrasive paste, the optimal combination time is not more than 6 months. Further, there is an increase in roughness of enamel surface.

Shear bond strength of orthodontic tubes bonded directly with composite resin reinforcement on the enamel surface

To evaluate the shear bond strength and the fracture type of orthodontic tubes bonded directly with composite resin throughout the enamel surface. 30 bovine teeth were cut into 3 slices with 5 mm each and embedded in PVC pipes with acrylic resin exposing the buccal face. Subsequently, the teeth were submitted to conventional bonding techniques. Natural Ortho resin was applied for direct bonding of Edgewise Standard orthodontic tubes (Morelli®) and light-cured for 20s. A different viscosity resin was chosen and light-cured for 40s to reinforce the tube surface. The samples were divided into the following groups: Orthodontic tube with direct bonding without reinforcement (CONTROL), Tube with Natural Ortho resin + Reinforcement (NO + NO), Tube with Natural Ortho resin + Reinforcement with Flow resin (NO + FL). These were submitted to shear bond strength; immediate and 1-year aging fracture analysis after simulated through thermocycling. In the shear bond strength test, the group of orthodontic tubes that were directly bonded with Natural Ortho resin and reinforced (NO + NO) showed greater strength results after 24 hours and 1 year with values of (p=0.0225) and (p=0.0273). It was statistically differentto the NO + FL and CONTROL reinforced groups. In the fracture analysis, the NO +NO group was classified immediately as composite cohesive, and mixed failure after aging by thermocycling. The addition of a composite resin layer on the surface of the directly bonded orthodontic tube improved bond strength. The reinforcement must be carried out in regular consistency and the use of Flow resin is not indicated.