Root caries prevention via sodium fluoride,chlorhexidine and silver diamine fluoride in vitro

Uncertainty exists as to how to best prevent root caries development. The aim of the present study was to compare sodium fluoride (NaF), chlorhexidine (CHX) and silver diamine fluoride (SDF) varnishes (V) and rinses (R) regarding their caries preventive effect in an artificial caries biofilm model. 140 bovine root dentin samples were cut, polished and embedded. Samples were allocated to seven treatment groups (n = 20/group): Four varnishes (applied once prior biofilm challenge): 38% SDF (SDFV), 35% CHX-varnish (CHXV), 22,600 ppm NaF-varnish (NaFV), placebo-varnish (PV); two rinses (applied once daily during biofilm challenge): 500 ppm NaF solution (NaFR), 0.1% CHX solution (CHXR); one untreated group. Caries was induced in a multi-station, continuous-culture Lactobacillus rhamnosus GG (LGG) biofilm model. Bacteria were inoculated 1 × daily, while 2% sucrose was supplied 8 ×/day followed by artificial saliva for 10 min. After 12 days, mineral loss (ΔZ) was measured in the effect area and adjacent to the varnished areas. Bacterial counts were assessed on de-Man-Rogosa-Sharpe agar. ΔZ was significantly lower in the NaFR group compared with all other groups. Varnishes did not significantly prevent mineral loss in adjacent areas. None of the agents had a significant antimicrobial effect on LGG. Regular fluoride rinses showed highest root caries-preventive effect.     

Effect of sodium,amine and stannous fluoride at the same concentration and different pH on in vitro erosion

Objective

This study aimed to compare the effects 0.5% and 1% sodium, amine and stannous fluoride at different pH on enamel erosion in vitro.

Methods

Bovine enamel samples were submitted to a cyclic de- and remineralisation for 3 days. Each day, the samples were exposed for 120 min to pooled human saliva and subsequently treated with one of the fluoride solutions for 3 min: amine fluoride (AmF, 0.5% and 1% F⁻), sodium fluoride (NaF, 0.5% and 1% F⁻), each at pH 3.9 and 7.0, and stannous fluoride (SnF₂, 0.5% and 1% F⁻), at pH: 3.9. Additionally, two groups were treated with fluoride-free placebo solutions (pH: 3.9 and 7.0) and one group served as control (no fluoridation). Ten specimens each group were inserted in a so-called artificial mouth and eroded six times daily with hydrochloric acid (pH 2.6) for 90 s each intermitted by exposure to artificial saliva (1 h). After 3 days, enamel loss was analyzed profilometrically and evaluated statistically by ANOVA.

Results

Only the acidic 0.5% and 1% SnF₂ and 1% AmF solutions were able to reduce erosive enamel loss significantly, while all other solutions and placebos did not differ significantly from the control. Between the acidic SnF₂ and the 1% AmF solutions no significant differences could be detected.

Conclusion

At the same concentrations, acidic SnF₂ and AmF may be more effective than NaF to protect enamel against erosion.     

Caries-preventive effect of anti-erosive and nano-hydroxyapatite-containing toothpastes in vitro

Objectives

The aim of the study was to investigate the caries-preventive effect of newly developed fluoride and fluoride-free toothpastes specially designed for erosion prevention. The hypothesis was that these products might also show superior caries-inhibiting effect than regular fluoride toothpastes, since they were designed for stronger erosive acid challenges.

Materials and methods

Enamel specimens were obtained from bovine teeth and pre-demineralized (pH = 4.95/21 days) to create artificial caries lesions. Baseline mineral loss (ΔZ_B) and lesion depth (LD_B) were determined using transversal microradiography (TMR). Ninety specimens with a median ΔZ_B (SD) of 6027 ± 1546 vol% × μm were selected and randomly allocated to five groups (n = 18). Treatments during pH-cycling (14 days, 4 × 60 min demineralization/day) were brushing 2×/day with AmF (1400 ppm F⁻, anti-caries [AC]); AmF/NaF/SnCl₂/Chitosan (700 ppm F⁻/700 ppm F⁻/3500 ppm Sn²⁺, anti-erosion [AE1]); NaF/KNO₃ (1400 ppm F⁻, anti-erosion [AE2]); nano-hydroxyapatite-containing (0 ppm F⁻, [nHA]); and fluoride-free toothpastes (0 ppm F⁻, negative control [NC]). Toothpaste slurries were prepared with mineral salt solution (1:3 wt/wt). After pH-cycling specimens presenting lesion, surface loss (mainly by NC and nHA) were discarded. For the remaining 77 specimens, new TMR analyses (ΔZ_E/LD_E) were performed. Changes in mineral loss (ΔΔZ = ΔZ_B − ΔZ_E) and lesion depth (ΔLD = LD_B − LD_E) were calculated.

Results

All toothpastes caused significantly less demineralization (lower ΔΔZ) than NC (p < 0.05, ANOVA) except for nHA. The fluoride toothpastes did not differ significantly regarding ΔΔZ and ΔLD (p > 0.05, ANOVA).

Conclusion/clinical relevance

While both anti-erosive and anti-caries toothpastes reduced mineral loss to a similar extent, the fluoride-free nano-hydroxyapatite-containing toothpaste seemed not to be suitable for inhibition of caries demineralization in vitro.

     

Fluoride toothpaste supplemented with sodium hexametaphosphate reduces enamel demineralization in vitro

Objective

The aim of this study was to evaluate the effect of fluoride dentifrices combined with sodium hexametaphosphate (HMP) on enamel demineralization in vitro.

Material and methods

Enamel bovine blocks were selected by initial surface hardness (SHi) and then divided into five experimental groups (n?=?12): placebo (without fluoride and without HMP); 1100 ppm F (1100F); and 1100F associated with HMP at 0.5 % (1100HMP0.5%), 1 % (1100HMP1%), and 2 % of HMP (1100HMP2%). Blocks were submitted to five pH cycles (demineralizing/remineralizing solutions) at 37 °C. After pH cycling, final surface hardness (SHf), percentage of surface hardness loss (%SH), integrated differential hardness (ΔIH), integrated loss of subsurface hardness (ΔKHN), and enamel firmly bound fluoride (F) were determined. Data were submitted to one-way ANOVA, followed by Student–Newman–Keuls test (p?<?0.05).

Results

Significant differences were observed among all groups regarding %SH and ΔKHN. 1100HMP1% promoted the lowest mineral loss among all groups (p?<?0.001), and led to significantly lower demineralization in the deeper regions of the subsurface lesion when compared with the other HMP-containing toothpastes (p?<?0.001). Significantly higher mineral loss was observed for 1100HMP2% when compared to the other fluoridated dentifrices, mainly in the outer part of the lesion (p?<?0.001). Enamel F uptake was similar for 1100F and 1100HMP1% but significantly reduced for other HMP concentrations.

Conclusion

The supplementation of a 1100-ppm F dentifrice with 1 % HMP promoted a higher inhibitory effect against enamel demineralization when compared to a dentifrice containing the same amount of fluoride in vitro.

Clinical relevance

This dentifrice could potentially be indicated to patients at high risk of caries.

     

Efficacy of the stannous ion and a biopolymer in toothpastes on enamel erosion/abrasion

Objectives

Sn²⁺ has promising erosion-inhibiting properties in solutions, but little is known about respective effects in toothpastes. In addition, biopolymers might have protecting potential. Aim of this study was to investigate the effects of Sn²⁺ in toothpastes and of a biopolymer (chitosan) added to a Sn²⁺ formulation on erosion/abrasion.

Methods

Enamel samples were subjected to cyclic erosion procedures (10 days; 0.50% citric acid, pH 2.5; 6× 2 min/day), and brushing (2× 15 s/day, load 200 g) during immersion in slurries (2 min). The toothpastes were NaF formulations (NaF/1, NaF/2, NaF/3) and Sn²⁺ formulations (NaF/SnCl₂, AmF/SnF₂, AmF/NaF/SnCl₂) and AmF/NaF/SnCl₂ + 0.5% chitosan.Declared concentrations of active ingredients in toothpastes were 1400–1450 μg/g F⁻ and 3280–3500 μg/g Sn²⁺. Negative controls were erosion only and placebo, positive control was a SnF₂ gel. Tissue loss was quantified profilometrically, Sn on enamel surfaces was measured by energy dispersive X-ray spectroscopy.

Results

Loss values (μm) for erosion only and placebo were 14.4 ± 4.5 and 20.2 ± 3.8, respectively, and 4.6 ± 1.9 for the positive control (p ≤ 0.001 each compared to erosion only). The other loss values were: NaF/1 16.5 ± 3.0, NaF/2 14.0 ± 2.7, NaF/3 12.6 ± 3.9, NaF/SnCl₂ 14.7 ± 5.1, AmF/SnF₂ 13.5 ± 4.8, AmF/NaF/SnCl₂ 12.4 ± 4.2, AmF/NaF/SnCl₂ + chitosan 6.6 ± 3.5 (except NaF/1 all p ≤ 0.01 compared to placebo). AmF/NaF/SnCl₂/chitosan was more effective than all other toothpastes (p ≤ 0.01 each). Sn on the enamel surface ranged between 1.3 ± 0.3 and 2.8 ± 0.04 wt.% with no obvious relationship with efficacy.

Conclusions

The NaF and Sn²⁺ toothpastes without chitosan exhibited similar anti-erosion and abrasion-prevention effects. The experimental Sn²⁺ formulation with chitosan revealed promising results similar to those of the positive control.

Clinical significance

NaF toothpastes offer a degree of protection against erosion/abrasion, which is likely sufficient for most subjects with average acid exposures. For patients with initial erosive lesions, however, more effective toothpaste is desirable. The combination of Sn²⁺ and a biopolymer appears promising in this context.     

Age-related changes in the pulp chamber of maxillary and mandibular molars on cone-beam computed tomography images

Objectives

Secondary dentine is laid on pulp chamber walls with increasing age, and decreases pulp chamber size. This study aimed to investigate age estimation on cone-beam computed tomography (CBCT) images for forensic science, and the relationship between age and pulp chamber area of maxillary and mandibular molars.

Methods

We reviewed the CBCT images of 316 first molars in 87 patients with dental lesions. The 87 patients were classified into three groups: younger, 11–28 years; middle-aged, 34–59 years; and older, 60–74 years. The relationship between age and pulp chamber area of maxillary and mandibular molars was evaluated.

Results

The mean pulp chamber area of maxillary molars was 8.4 ± 2.0, 4.4 ± 1.7, and 2.9 ± 0.9 mm² in the younger, middle-aged, and older groups, respectively, (p = 0.028). The mean pulp chamber area of mandibular molars was 10.5 ± 2.3, 6.7 ± 2.2, and 3.7 ± 1.5 mm² in the younger, middle-aged, and older groups, respectively, (p = 0.000). The mean pulp chamber area of mandibular molars was larger than that of maxillary molars in the younger (p = 0.000), middle-aged (p = 0.000), and older (p = 0.094) groups. The mean pulp chamber area of maxillary and mandibular molars was significantly correlated with age [Y = ?0.142X + 11.582 (R ² = 0.586, p = 0.000) and Y = ?0.163X + 14.249 (R ² = 0.609, p = 0.000), respectively].

Conclusions

These findings should be useful for diagnosis and treatment planning in dental practice and age estimation in forensic science.

     

Antimicrobial efficacy and mechanical properties of BAC-modified hard and soft denture liners

This study investigated the antimicrobial efficacy and mechanical strength of hard and soft denture liners modified with benzalkonium chloride (BAC). The specimens (1 mm thickness, 8 mm diameter) were prepared by mixing 0.5, 1, 2 and 5 wt% BAC with soft (Sofreliner Medium, Tokuyama) and hard (Rebase II, Tokuyama) denture liners (n = 5/group). BAC was not added to the controls. Candida albicans ATCC 28366 (A ₅₅₀ = 0.5) and Streptococcus mutans Ingbritt suspensions (A ₅₅₀ = 0.35) were pipetted onto the specimens, and incubated for 4 h. The viable cells were collected, and determined by plate-culturing (CFU). The tests were repeated after the specimens were soaked in distilled water for 7 days. The mechanical strengths were evaluated by tear and 4-point flexural strength tests for soft and hard liners, respectively. The data were analyzed with ANOVA and Tukey’s HSD tests at p = 0.05. C. albicans viability was lost in all groups of BAC-modified soft liners (p < 0.001), and S. mutans viability was reduced (p < 0.01), except of soaked BAC 0.5 wt% group (p > 0.05). For the hard liner, BAC 5 wt% killed the C. albicans and S. mutans cells both before and after soaked in water (p < 0.001). BAC 2 wt% showed comparable tear strength with the soft liner control (p > 0.05). BAC did not reduce the flexural strength of the hard liner (p > 0.05), except of BAC 5 wt% group (p < 0.01). BAC can be a promising agent reducing the C. albicans and S. mutans viability on the soft and hard denture liner surfaces.     

Effect of a chitosan additive to a Sn2+-containing toothpaste on its anti-erosive/anti-abrasive efficacy—a controlled randomised in situ trial

Objectives

It is well known that Sn²⁺ is a notable anti-erosive agent. There are indications that biopolymers such as chitosan can enhance the effect of Sn²⁺, at least in vitro. However, little information exists about their anti-erosive/anti-abrasive in situ effects. In the present in situ study, the efficacy of Sn²⁺-containing toothpastes in the presence or absence of chitosan was tested.

Methods

Ten subjects participated in the randomised crossover study, wearing mandibular appliances with human enamel specimens. Specimens were extraorally demineralised (7 days, 0.5 % citric acid, pH?2.6; 6?×?2 min/day) and intraorally exposed to toothpaste suspensions (2?×?2 min/day). Within the suspension immersion time, one half of the specimens were additionally brushed intraorally with a powered toothbrush (5 s, 2.5 N). Tested preparations were a placebo toothpaste (negative control), two experimental toothpastes (F/Sn = 1,400 ppm?F^?, 3,500 ppm Sn²⁺; F/Sn/chitosan = 1,400 ppm?F^?, 3,500 ppm Sn²⁺, 0.5 % chitosan) and an SnF₂-containing gel (positive control, GelKam = 3,000 ppm Sn²⁺, 1,000 ppm?F^?). Substance loss was quantified profilometrically (μm).

Results

In the placebo group, tissue loss was 11.2?±?4.6 (immersion in suspension) and 17.7?±?4.7 (immersion in suspension?+?brushing). Immersion in each Sn²⁺-containing suspension significantly reduced tissue loss (p?≤?0.01); after immersion in suspension?+?brushing, only the treatments with GelKam (5.4?±?5.5) and with F/Sn/chitosan (9.6?±?5.6) significantly reduced loss [both p?≤?0.05 compared to placebo; F/Sn 12.8?±?6.4 (not significant)]

Conclusion

Chitosan enhanced the efficacy of the Sn²⁺-containing toothpaste as an anti-erosive/anti-abrasive agent.

Clinical relevance

The use of Sn²⁺- and chitosan-containing toothpaste is a good option for symptomatic therapy in patients with regular acid impacts.     

Sustained release of calcium hydroxide from poly(<Emphasis Type="SmallCaps">dl</Emphasis>-lactide-co-glycolide) acid microspheres for apexification

Calcium hydroxide (CH) loaded poly(dl-lactide-co-glycolide) acid (PLGA) microspheres (MS) might be used for apexification requiring a sustained release of Ca²⁺. The aim of this study was to formulate and characterize CH-PLGA-MS. The CH-loaded MS were prepared by either oil-in-water (O/W) or water-in-oil/in-water (W/O/W) emulsion solvent evaporation technique. MS produced by the O/W technique exhibited a larger diameter (18.63 ± 7.23 μm) than the MS produced by the W/O/W technique (15.25 ± 7.37 μm) (Mann–Whitney U test P < 0.001). The CH encapsulation efficiency (E _e) and Ca²⁺ release were calculated from data obtained by absorption techniques. Ca²⁺ release profile was evaluated for 30 days. To know the E _e, the CH-loaded MS were dissolved in 1 M NaOH to release all its content and a Ca²⁺ colorimetric marker was added to this solution. The reagent marked the Ca²⁺ in blue color, which was then measured by a UV–Vis system (650 nm). The percentage of E _e was calculated on the basis of the theoretical loading. The E _e of the O/W-produced MS was higher (24 %) than the corresponding percentage of the W/O/W-produced MS (11 %). O/W- and W/O/W-produced MS released slower and lower Ca²⁺ than a control CH paste with polyethylene glycol 400 (Kruskal–Wallis test). O/W-produced MS released higher Ca²⁺ than W/O/W-produced MS (statistically significant differences; P < 0.05). In conclusion, the CH-PLGA-MS were successfully formulated; the technique of formulation influenced the size, encapsulation efficiency and release profile. The MS were better sustained release system than the CH paste.     

Guided bone regeneration in standardized calvarial defects using beta-tricalcium phosphate and collagen membrane: a real-time in vivo micro-computed tomographic experiment in rats

Guided bone regeneration (GBR) procedures using graft materials have been used for reconstruction of osseous defects. The aim of the present in vivo micro-computed tomographic (µCT) and histologic study was to assess in real time the bone regeneration at GBR sites in standardized experimental calvarial defects (diameter 3.3 mm) using β-tricalcium phosphate (β-TCP) with and without collagen membrane (CM). A single full-thickness calvarial defect was created on the left parietal bone in young female Wistar albino rats (n = 30) weighing approximately 300 g and aged about 6 weeks. The animals were randomly divided into three groups for treatment, based on calvarial defect filling material: (1) control group (n = 10); (2) β-TCP + CM group (n = 10); (3) β-TCP group (n = 10). Real-time in vivo µCT analyses were performed immediately after surgery and at 2, 4, 6 and 10 weeks to determine the volume and mineral density of the newly formed bone (BVNFB, MDNFB) and remaining β-TCP particles (VRBP, MDRBP). The animals were killed at 10 weeks and calvarial specimens were evaluated histologically. In the control group, MDNFB increased significantly at 6 weeks (0.32 ± 0.002 g/mm³, P < 0.01) compared to that at baseline. In β-TCP + CM group, BVNFB (1.10 ± 0.12 mm³, P < 0.01) and MDNFB (0.13 ± 0.02 g/mm³, P < 0.01) significantly increased at the 4th week than baseline. In the β-TCP group, BVNFB (1.13 ± 0.12 mm³, P < 0.01) and MDNFB (0.14 ± 0.01 g/mm³, P < 0.01) significantly increased at 6 weeks compared to that at baseline. Significant reduction in VRBP was neither seen in the β-TCP + CM group nor in the β-TCP group. While in the β-TCP + CM group MDRBP was reduced significantly at 6 weeks (0.44 ± 0.9 g/mm³, P < 0.01) from baseline (0.98 ± 0.03 g/mm³), similar significant reduction in MDRBP from baseline (0.92 ± 0.07 g/mm³) was seen only at 10 weeks (0.45 ± 0.06 g/mm³, P < 0.05) in the β-TCP group. Histologic findings at 10 weeks revealed greater amount of NFB with osteocytes in the matrix, in the β-TCP + CM group than in the β-TCP group. Biomechanical assessment of NFB for hardness (H) and elastic modulus (E) revealed significantly higher values for the β-TCP + CM group (H = 612.6 ± 4.28 Mpa; E = 13.57 ± 0.07 Gpa) when compared to those of the control (H = 192.1 ± 4.93 Mpa; E = 6.76 ± 0.04 Gpa) and the β-TCP groups (H = 241.9 ± 6.29 Mpa; E = 4.34 ± 0.06 Gpa). In conclusion, based on real-time assessment, NFB is formed in calvarial defects as early as 4 weeks following GBR with β-TCP + CM as compared to 6 weeks when β-TCP alone was used.     

A new method for the evaluation of the accuracy of full-arch digital impressions in vitro

Objectives

Introducing a new approach to evaluate the accuracy of digital impression methods for full-arch scans, avoiding “best-fit alignment.”

Materials and methods

A lower jaw model with a straight metal bar between the second molars of both quadrants was directly digitized using an intraoral scanner (True Definition, TRD, n?=?12) and indirectly digitized (D810, CON, n?=?12) after impression and plaster cast. A dataset of the bar from a coordinate measuring machine served as reference (REF). Datasets obtained from test groups were analyzed using inspection software to determine the aberration of the bar length, the linear shift (in X-, Y-, Z-axis) and the angle deviation (α _overall, α _coronal, α _horizontal) caused by the digitalization method. Mann–Whitney U and unpaired two-sample Student’s t test were implemented to detect differences. The level of significance was set at 5 %.

Results

Concerning the bar length, no significant differences were found between groups. In view of the linear shift, CON showed significantly higher values than TRD in Y-axis (p?=?0.003) and in Z-axis (p?=?0.040). Regarding the angle measurement, TRD showed significant smaller values than CON for α _overall (p?=?0.006) and for α _coronal (p?=?0.005).

Conclusions

This in vitro study shows that intraoral scanning systems seem to show the same or even higher accuracy than the conventional impression with subsequent indirect digitalization.

Clinical relevance

Intraoral scanners have proven excellent accuracy for single teeth or small spans. However, insufficient data is available about their accuracy for full-arch scans. The presented new approach seems to be suitable to precisely analyze differences in the accuracy of different digitalization methods without using best-fit alignment.

     

Correlation between resonance frequency,insertion torque and bone-implant contact in self-cutting threaded implants

The aim of this study was to evaluate the correlation between resonance frequency analysis (RFA) values and the histomorphometric bone-implant contact (BIC) immediately after insertion of the implant. Additionally, it was examined to define which extent peak insertion torque (PIT) was correlated with the latter measurements. 15 Xive^® S plus root from dental implants were inserted in fresh porcine frontal bones. The insertion torque was measured with the Kavo Intrasurg 300 surgical unit. RFA connector was coupled to the implants and the mean value of 20 consecutive RFA measurements was calculated via Osstell^® ISQ device. The implants were removed with the adjacent bone with a band saw. The blocks were processed for undecalcified histology. Two perpendicular longitudinal middle sections of the implant were made and stained with toluidine blue and the BIC was assessed by histomorphometry. The correlation coefficient (Spearman) between RFA and BIC was R = 0.579 (p = 0.026, F test). The correlation between PIT and BIC (0.33, p > 0.05) and PIT and RFA (0.153, p > 0.05) was not statistically significant. The present data confirmed a moderate and statistically positive correlation between RFA and BIC. No correlation between BIC and PIT and PIT and RFA was observed. Further studies considering different bone qualities would be beneficial in understanding the relation between RFA and BIC.     

Influence of the bleaching interval on the luminosity of long-term discolored enamel-dentin discs

Objectives

The aim of this study is to investigate the influence of changing the sodium perborate-tetrahydrate (PBS-4) at a 4-day interval versus no change after 16 days of internal bleaching.

Materials and methods

Two hundred and ten bovine enamel-dentin discs were discolored for 3.5 years with 14 different endodontic materials. All groups with a discoloring index of ?E _(mean) ≥ 5.5 were included in the present investigation: ApexCal (APCA), MTA white + blood (WMTA+BL), Portland cement + blood (PC+BL), blood (BL), MTA gray (GMTA), MTA gray + blood (GMTA+BL), Ledermix (LED), and triple antibiotic paste containing minocycline (3Mix). Fourteen specimens of each group were randomly assigned into two treatment groups: (1) no change of the PBS-4 (n = 7); (2) change of the PBS-4 every 4 days (n = 7). Color measurements were taken at 10 different time intervals and the L*a*b* values were recorded with a spectrophotometer (VITA Easyshade® compact).

Results

In the group 3Mix, significantly better results were achieved by changing the bleaching agent every 4 days (P = 0.0049; q = 0.04), while the group WMTA+BL indicated better results by no change of the bleaching agent (P = 0.0222, q = 0.09). All remaining groups showed no statistical difference between the two treatment procedures.

Conclusions

Moderate discolorations can be successfully treated without changing the bleaching agent over a period of 16 days. Changing the sodium perborate-tetrahydrate every 4 days is preferred in case of severe discolored enamel-dentin discs only.

Clinical relevance

This approach may offer a reduced number of clinical appointments and a secondary cost reduction to the patient.

     

44Ca doped remineralization study on dentin by isotope microscopy

Objective

The dental caries is developed as a result of an alternative course of mineral gain and loss. In order to distinguish between intrinsic Ca (tooth-derived mineral) and extrinsic Ca (solution-derived mineral) uptakes, a ⁴⁴Ca doped pH-cycling was performed using ⁴⁴Ca (a stable calcium isotope) remineralization solution.

Effect of enamel sealants on tooth bleaching and on the color stability of the result

The purpose of this in vitro study was to evaluate the effect of enamel sealants on bleaching of natural teeth by use of 40 % hydrogen peroxide in a dental surgery. The color stability of the results from bleaching was, furthermore, determined 10 months after the bleaching procedure. In a standardized setting, four sealants (Pro Seal^®, Light Bond? Sealant, Protecto^®, and Clinpro? XT Varnish) were applied to and removed from human teeth in accordance with the manufacturer’s instructions. Natural teeth served as medium; half of the teeth were sealed and the others served as controls. Hydrogen peroxide gel (40 %; Opalescence Boost; Ultradent Products, South Jordan, UT, USA) was used as bleaching agent. Color measurement was performed with a spectroradiometer (Photoresearch PR670) before the bleaching process (T1) and 24 h (T2) and 10 months (T3) after bleaching. The spectroradiometer results were expressed by use of the Commission Internationale de l’Éclairage (CIE) L*a*b* color notation. The L*, a*, and b* values of the sealed and the unsealed surfaces were not significantly different at any time during the study (p > 0.05), irrespective of the sealant used. Ten months after the bleaching process, mean L*, a*, and b* values were lower than at 1-day post-bleaching; the mean value of ΔE between 1-day post-bleaching and 10 months post-bleaching was 2.46 (±3.1). The results of the study suggest that the effectiveness of professional tooth whitening is not appreciably affected by the application of the four sealants tested.     

Effects of adrenaline on circulatory dynamics and cardiac function in rats administered chlorpromazine

We aimed to elucidate changes in circulatory dynamics and cardiac function during concomitant use of chlorpromazine (CPZ) and adrenaline (AD). An arterial line and left intraventricular pressure–volume measurement catheter were inserted in rats. CPZ 10 mg/kg was administered to the left great adductor muscle, followed by normal saline (NS) or AD 50 μg/kg through the tongue 20 min later. End-diastolic volume (V _ed), end-systolic pressure (P _es), stroke volume (SV), stroke work (SW), end-systolic volume elastance (E _es), systolic blood pressure (SBP), diastolic blood pressure (DBP), and pulse rate (PR) were measured. Following AD administration, V _ed significantly decreased at 2–4 and 10 min than that in control rats; P _es significantly decreased at 1 min; E _es significantly increased from 2 to 10 min; SV did not change significantly, and SW significantly reduced at 1 and 2 min; SBP and DBP were lower at 1–3 min than in the control; and PR increased at 10 min. These findings suggest that when AD-containing local anesthetics are administered during dental treatment of patients taking CPZ, there is a risk of a temporary drop in blood pressure. However, the blood pressure is recovered a few minutes later by the increase in afterload and the myocardial contractile force.     

The effectiveness of dentifrices without and with sodium lauryl sulfate on plaque,gingivitis and gingival abrasion—a randomized clinical trial

Objectives

The aim of this study was to compare the efficacy of a dentifrice without sodium lauryl sulfate (SLS) to a dentifrice with SLS in young adults aged 18–34 years on gingivitis.

Material and methods

One hundred twenty participants (non-dental students) with a moderate gingival inflammation (bleeding on probing at 40–70 % of test sites) were included in this randomized controlled double blind clinical trial. According to randomization, participants had to brush their teeth either with dentifrice without SLS or with SLS for 8 weeks. The primary outcome was bleeding on marginal probing (BOMP). The secondary outcomes were plaque scores and gingival abrasion scores (GA) as well as a visual analogue scale (VAS) score at exit survey. Baseline and end differences were analysed by univariate analysis of covariance (ANCOVA) test, between group differences by independent t test and within groups by paired sample t test.

Results

BOMP improved within groups from on average 0.80 at baseline to 0.60 in the group without SLS and to 0.56 in the group with SLS. No statistical difference for BOMP, plaque and gingival abrasion was found between both groups. VAS scores for taste, freshness and foaming effect were significantly in favour of the SLS-containing dentifrice.

Conclusion

The test dentifrice without SLS was as effective as a regular SLS dentifrice on gingival bleeding scores and plaque scores. There was no significant difference in the incidence of gingival abrasion.

Clinical relevance

In patients diagnosed with gingivitis, a dentifrice without SLS seems to be equally effective compared to a dentifrice with SLS and did not demonstrate any significant difference in gingival abrasion. In patient with recurrent aphthous ulcers, the absence of SLS may even be beneficial. However, participants indicate that they appreciate the foaming effect of a dentifrice with SLS more.

     

Prevalence and location of accessory foramina in the human mandible

Objective

This study aimed to radiographically assess the prevalence and location of accessory foramina in the human mandible using helical computed tomography (CT) images and three-dimensional reconstructions.

Methods

Helical CT images from 24 males and 22 females aged 66–88 years (mean age: 73.7 ± 5.3 years) were observed. Each image was assessed in the three anatomical planes, and three-dimensional reconstructions were performed with Amira 5.6 software.

Results

All subjects (n = 46) presented at least one accessory foramina. A lingual foramen was the most frequently observed foramen and present in 96 % (n = 44) of subjects. Mandibular anterior nutrient canals were clearly observed in 72 % (n = 33) of subjects (71 %, n = 17, of males; 73 %, n = 16, of females). A retromolar foramen was present in 17 % (n = 8) of subjects (21 %, n = 5, of males; 14 %, n = 3, of females). A double mental foramen (DMF) was present in only one subject (2 %). Fifty percent (n = 23) of subjects presented one or more inferior retromental foramen (IRF). No significant correlations were observed between prevalences of accessory foramina and sex.

Conclusions

The lingual foramen can be considered a constant finding, and mandibular anterior nutrient canal foramina and IRF were present in the majority of subjects. Retromolar foramina and DMF were less common but can be associated with anesthetic failures and oral surgery complications. Three-dimensional reconstructions provided better understanding of the locations of foramina and their interrelations with the anatomy of the jaw.

     

Detection of subgingival periodontal pathogens—comparison of two sampling strategies

Objective

The aim of the study is to compare detection frequency of periodontal pathogens in patients with aggressive/severe chronic periodontitis using pooled plaque samples from the deepest pockets per quadrant/per sextant.

Methods

In 100 patients with aggressive/chronic periodontitis, subgingival plaque was sampled from the deepest pockets per quadrant (MT4) and per sextant (MT6). Plaque samples were taken using two sterile paper points simultaneously. One paper point from each pocket was pooled with the three other paper points of the pockets (MT4). Subsequently, the remaining four paper points were pooled with two paper points from the deepest pockets from the two remaining sextants (MT6). The content of each vial was analyzed with nucleic-acid based methods for Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Porphyromonas gingivalis, Treponema denticola, Prevotella intermedia, Parvimonas micra, Fusobacterium nucleatum, Campylobacter rectus, Eubacterium nodatum, Eikenella corrodens, and Capnocytophaga sp.

Results

The detection frequency of A. actinomycetemcomitans (MT4/MT6) at 22/24 %, T. forsythia at 93/96 %, P. gingivalis at 78/79 %, T. denticola at 88/90 %, P. intermedia at 40/46 %, P. micra at 75/79 %, F. nucleatum at both 99 %, C. rectus at 84/89 %, E. nodatum at 62/65 %, E. corrodens at 80/87 %, and Capnocytophaga sp. at 49/58 % was higher with MT6 than with MT4. None of these differences were statistically significant.

Conclusion

The detection frequency of the investigated periopathogens was statistically insignificant higher with the sampling method MT6 compared with MT4.

Clinical relevance

In daily dental practice, the plaque sampling of the deepest pockets per quadrant seems to be sufficient.