Oral Mesenchymal Stem/Progenitor Cells: The Immunomodulatory Masters.

Oral mesenchymal stem/progenitor cells (MSCs) are renowned in the field of tissue engineering/regeneration for their multilineage differentiation potential and easy acquisition. These cells encompass the periodontal ligament stem/progenitor cells (PDLSCs), the dental pulp stem/progenitor cells (DPSCs), the stem/progenitor cells from human exfoliated deciduous teeth (SHED), the gingival mesenchymal stem/progenitor cells (GMSCs), the stem/progenitor cells from the apical papilla (SCAP), the dental follicle stem/progenitor cells (DFSCs), the bone marrow mesenchymal stem/progenitor cells (BM-MSCs) from the alveolar bone proper, and the human periapical cyst-mesenchymal stem cells (hPCy-MSCs). Apart from their remarkable regenerative potential, oral MSCs possess the capacity to interact with an inflammatory microenvironment. Although inflammation might affect the properties of oral MSCs, they could inversely exert a multitude of immunological actions to the local inflammatory microenvironment. The present review discusses the current understanding about the immunomodulatory role of oral MSCs both in periodontitis and systemic diseases, their "double-edged sword" uniqueness in inflammatory regulation, their affection of the immune system, and the underlying mechanisms, involving oral MSC-derived extracellular vesicles.

Lesion-Specific Language Network Alterations in Temporal Lobe Epilepsy.

BACKGROUND AND PURPOSE: Temporal lobe epilepsy, structural or nonlesional, may negatively affect language function. However, little is known about the lesion-specific influence on language networks. We hypothesized that different epileptogenic lesions are related to distinct alterations in the functional language connectome detected by fMRI. MATERIALS AND METHODS: One hundred one patients with epilepsy due to mesiotemporal sclerosis (21 left, 22 right), low-grade mesiotemporal tumors (12 left), or nonlesional temporal lobe epilepsy (22 left, 24 right) and 22 healthy subjects performed 3T task-based language fMRI. Task-based activation maps (laterality indices) and functional connectivity analysis (global and connectivity strengths between language areas) were correlated with language scores. RESULTS: Laterality indices based on fMRI activation maps failed to discriminate among patient groups. Functional connectivity analysis revealed the most extended language network alterations in left mesiotemporal sclerosis (involving the left temporal pole, left inferior frontal gyrus, and bilateral premotor areas). The other patient groups showed less extended but also predominantly ipsilesional network changes compared with healthy controls. Left-to-right hippocampal connectivity strength correlated positively with naming function (P = .01), and connectivity strength between the left Wernicke area and the left hippocampus was linked to verbal fluency scores (P = .01) across all groups. CONCLUSIONS: Different pathologies underlying temporal lobe epilepsy are related to distinct alterations of the functional language connectome visualized by fMRI functional connectivity analysis. Network analysis allows new insights into language organization and provides possible imaging biomarkers for language function. These imaging findings emphasize the importance of a personalized treatment strategy in patients with epilepsy.

Effect of total sonicated Aggregatibacter actinomycetemcomitans fragments on gingival stem/progenitor cells.

BACKGROUND: Aggregatibacter-actinomycetemcomitans (A.actinomycetemcomitans) are strongly associated with localized-aggressive-periodontitis (LAgP). The study's aim was to test for the first time the effect of total sonicated A.actinomycetemcomitans-bacterial-fragments on gingival mesenchymal stem/progenitor cells' (G-MSCs) proliferation and regenerative gene expression in-vitro. MATERIAL AND METHODS: G-MSCs were isolated, characterized, expanded and stimulated by total sonicated A.actinomycetemcomitans-bacterial-fragments (0 (negative-control), 15, 60, 120 and 240µg/ml; serovar-b; n=6/group). Cellular proliferation and NF-κß (NFKB1), Alkaline Phosphatase (ALPL), Collagen-I (COL1A1), Collagen-III (COL3A1), Osteonectin (SPARC) and Osteopontin (SPP1) m-RNA expression were assessed via reverse-transcription-polymerase-chain-reaction (RT-PCR) at 24, 48 and 72 hours and CFUs-ability evaluated at twelve days. RESULTS: G-MSCs demonstrated stem/progenitor cells' characteristics. A.actinomycetemcomitans-bacterial-fragments (up to 72 hours) resulted in marked G-MSCs' proliferation over-time (p<0.001) and elevated NFKB1 (p=0.017), COL1A1 (p=0.025), SPARC (p=0.025), decreased ALPL (p=0.017), with no significant differences for COL3A1 and SPP1 expression or stimulation times (p>0.05; Friedman-test). Longer-term stimulation for twelve days reduced G-MSCs' CFUs. CONCLUSIONS: Sonicated A.actinomycetemcomitans-bacterial-fragments' exert beneficial short-term effects on G-MSCs' proliferative and non-mineralized tissue forming aptitude. Results shed new light on the importance of periodontal treatment for LAgP patients, using power driven sonic/ultrasonic devices, which, in addition to reducing the subgingival microbial load, produces cell-stimulatory A.actinomycetemcomitans-bacterial-fragments, with positive attributes on tissue reparative/regenerative responses of tissue resident stem/progenitor cells in their niche.

Assessing Corticospinal Tract Asymmetry in Unilateral Polymicrogyria.

BACKGROUND AND PURPOSE: Asymmetry of the corticospinal tract in congenital lesions is a good prognostic marker for preserved motor function after hemispherectomy. This study aimed to assess this marker and provide a clinically feasible approach in selected cases of unilateral polymicrogyria. MATERIALS AND METHODS: Corticospinal tract asymmetry of 9 patients with unilateral polymicrogyria substantially affecting the central region was retrospectively assessed on axial T1WI and DTI. Volumes of the brain stem and thalamus and DTI parameters of the internal capsule were measured. Two neuroradiologists independently rated the right-left asymmetry at 4 levels along the corticospinal tract. DTI tractography was used to determine the motor cortex within polymicrogyria, with task-based functional MR imaging available in 3/9 cases. RESULTS: Visual assessment of the brain stem asymmetry showed excellent correlation with quantitative measures on both T1WI and color-coded DTI maps (P = .007 and P = .023). Interrater reliability regarding structural and DTI-based corticospinal tract asymmetry was best at the midbrain (Cohen κ = 0.77, P = .018). Three patients underwent functional hemispherectomy with postsurgical stable motor function, all showing marked corticospinal tract asymmetry preoperatively. Following the DTI-based corticospinal tract trajectories allowed identifying the presumed primary motor region within the dysplastic cortex in 9/9 patients, confirmed by functional MR imaging in 3/3 cases. CONCLUSIONS: Visual assessment of corticospinal tract asymmetry in unilateral polymicrogyria involving the motor cortex is most reliable with T1WI and color-coded DTI maps at the level of the midbrain. Pronounced asymmetry predicts preserved motor function after hemispherectomy. DTI-based tractography can be used as a guidance tool to the motor cortex within polymicrogyria.

The effectiveness of a dentifrice without sodium lauryl sulphate on dental plaque and gingivitis - a randomized controlled clinical trial.

OBJECTIVES: The purpose of the study was to evaluate the effect on dental plaque and gingivitis of a dentifrice without sodium lauryl sulphate (SLS) compared to two SLS-containing dentifrices. MATERIAL AND METHODS: For this double-blind, parallel study, 90 volunteers having moderate gingival inflammation (≥40%) were randomly divided among three groups: one group using non-SLS dentifrice containing enzymes, colostrum and low concentrations of zinc and two control groups each using different SLS-containing dentifrices. Dental plaque scores (Turesky modification of Quigley & Hein) and gingivitis scores (Bleeding On Marginal Probing) were assessed at baseline, after 2 and 4 weeks. RESULTS: Eighty-nine participants provided evaluable data. A slight decrease in gingivitis scores was observed for all groups over 4 weeks, which was statistically significant for the non-SLS group. Mean values for dental plaque scores did not show major differences over 4 weeks. For both parameters, no significant differences between groups could be observed at any time point. Patient appreciation was in favour of the SLS groups especially regarding the foaming effect. CONCLUSION: No significant differences could be observed with respect to the effect on plaque and gingivitis between SLS-containing and SLS-free dentifrice containing enzymes, colostrum and low concentration zinc. Patients enjoyed the duration of taste and the 'foaming effect' of SLS-containing dentifrices better.

Bristle splaying and its effect on pre-existing gingival recession-a 12-month randomized controlled trial.

OBJECTIVE: The link between bristle splaying and gingival recession is unclear. METHODS: In a 12-month, parallel group, randomized, controlled clinical trial, 110 systemically healthy participants with pre-existing gingival recessions (pre-GR) were assigned to brush their teeth with either a manual (MT) or a powered toothbrush (PT). Every 3 months, toothbrushes and brush heads were replaced. Wear was measured using the Bristle-Splaying-Index (BSI), matched between groups and correlated to the change of pre-GR. RESULTS: Data from 109 subjects (PT, 55; MT, 54) were analyzed. The overall mean BSI was found to be significantly lower (p < 0.001) in the PT group (median 5.5; second and third quartile 1.9-10.0) as compared to the MT group (21.5; 15.0-30.5). After 12 months, pre-GR decreased significantly in the PT group (∆0.2 ± 0.1 mm; p < 0.001) and remained stable in the MT group (∆0.1 ± 0.1 mm; p > 0.05). In the MT group, higher BSI values were associated with a higher risk for increasing or stable recession over 12 months: odds ratio (95 % CI) = 27.9 (1.7; 452.9); p = 0.019. CONCLUSION: After a mean using time of 3 months, the PT group demonstrated a lower BSI than the MT group, and the greater bristle splaying was associated with a higher risk of increased (or stable) GR in subjects using a MT but not a PT. CLINICAL RELEVANCE: Compared to a manual toothbrush, powered toothbrushes seem to be utilized with less force and can be considered safe to use in patients with pre-existing gingival recession.

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.

[Prevention and Information for Patients Undergoing Periodontal Treatment: Potentials for Improvement from the Patients' Perspective]. / Prävention und Aufklärung im Rahmen der Parodontitisbehandlung: Verbesserungspotenziale aus Patientensicht.

2 334 patients from 29 dental practices took part in a written survey on their experiences with dental treatment in general as well as treatment of periodontal disease (response rate 80.8%). 72.6% of all participating patients fully agreed that they could recommend their dentist to their friends. 63.6% of patients undergoing treatment of periodontitis (N=328) rated this treatment as "excellent". However, for important aspects (prevention, patient information, treatment) potentials for improvement became obvious. 43.7% of patients treated for periodontitis were not completely satisfied with information on how this disease develops; 40.7% saw potentials for better information on preventive care (dental-hygiene, nutrition). An even higher percentage of patients actually not treated for periodontitis was interested in more information on prevention (51.4%). The results of the survey show that dentists should offer information and exercise on how to prevent periodontal desease more actively. There is a lack of research on the present state of affairs and potentials for improvement concerning treatment and prevention of periodontitis including the patients' perspective.

The effect of various model parameters on enamel caries lesions in a dose-response model in situ.

OBJECTIVES: The aim of this exploratory double-blinded, randomized, cross-over, in situ study was to compare the effects of various model parameters ('intervention', 'brushing', 'position') on enamel caries lesions in a dose-response model. METHODS: In each of four experimental legs of four weeks 16 participants wore intraoral mandibular appliances with four 'plaque-retaining' and four 'easily cleanable' positioned pre-demineralized bovine enamel specimens in the vestibular flanges mimicking proximal and buccal surfaces, respectively (n=512). The four randomly allocated interventions (either application only or brushing) included the following dentifrices: AlF3 1360ppmF(-)+chlorhexidine 0.05% (Lacalut aktiv, LA1360), NaF 1,450ppmF(-)(Blend-a-Med ProExpert), NaF 500ppm F(-) and 0ppm F(-) as negative control (NC) (both experimental, based on Blend-a-Med ProExpert). RESULTS: Differences in integrated mineral loss (ΔΔZ) and lesion depth (ΔLD) were calculated between values before and after the in situ period using transversal microradiography. Significant differences for ΔΔZ [adjusted mean (95% CI))] were found between NC, NaF500 and LA1360for both 'plaque-retaining' [-1830 (-2371;1289); -986 (-1530;442); -2 (-548;544)vol%×µm] as well as 'easily cleanable' specimens [-399 (-682; -116); -391 (-672; -110); -16 (-302;270)vol%×µm]. Values for NaF1450 revealed a similar dose-response as LA1360.Values for LA1360 and NaF1450 did not differ significantly (p>0.05; ANCOVA). CONCLUSION/CLINICAL SIGNIFICANCE: The design of the present in situ study was able to reveal a fluoride dose-response to hamper further demineralization of enamel specimens for 'easily cleanable' and 'plaque-retaining' sites being brushed or not. Particularly 'plaque-retaining' sites seem to be recommendable for measuring potential anticaries efficacy in situ.

Epilepsy surgery: recent advances in brain mapping, neuroimaging and surgical procedures.

The general principle of epilepsy surgery is to achieve seizure freedom without causing any neurological deficit that would outweigh the clinical benefit. To achieve this, the epileptogenic zone, which is the part of the brain responsible for seizure generation, as well as the anatomic location of the eloquent cortex must be precisely identified in order to spare those functions during excision of the epileptogenic tissue. Major technical advances over the last decade have continuously contributed to increase our ability to map the brain and identify these critical areas. These technologies and innovations that can be routinely used today include non-invasive studies such as magnetoencephalography (MEG), functional MRI (fMRI), simultaneous EEG-fMRI, and nuclear medicine based methods like PET and SPECT as well as invasive studies through chronically implanted electrodes. Electrodes can be either placed subdurally via burr holes and craniotomies or within the brain parenchima via frame-based and frameless stereotactic methods. Apart from a continuous change in these insertion techniques, the most valuable advances here include recordings on high frequency bandwidth (100-600 Hz EEG) that are capable to delineate high-frequency oscillations (HFOs). These HFOs have been recognized as a biomarker for epileptogenic tissue. All of these technical advances have made epilepsy surgery a truly multidisciplinary field and surgeons have to be able to understand and interpret all of the gathered data. Moreover, this development has influenced surgical approaches and techniques and epilepsy surgery today includes a wide variety of procedures. These can be subdivided into resective, disconnective and neuromodulation procedures and vary from a small, targeted lesionectomy to disconnection/resection of one entire hemisphere. This review will give an overview of the available surgical techniques today and will focus on how the technical advances enable us to map the brain and delineate the critical areas.

Influence of using different bonding systems and composites on the margin integrity and the mechanical properties of selectively excavated teeth in vitro.

OBJECTIVES: Selective (incomplete) caries excavation reduces the risk of pulpal complications, but might compromise the properties of teeth or restorations. Different restorative approaches might be required after selective instead of complete excavation. We compared margin integrity, micro-leakage and fracture resistance of selectively excavated and differently restored premolars in vitro. METHODS: In 72 extracted human premolars, artificial residual lesions were induced on pulpo-axial walls of standardized cavities. Teeth were restored using one of three bonding systems (OptiBond FL, Clearfil SE Bond, G-aenial Bond) and a fibre-enforced (EverX) or standard hybrid composite resin (Filtek Z250). After thermo-mechanical cycling, groups (n = 12) were compared regarding their gingivo-cervical margin integrity (proportion of acceptable margins), microleakage depth, and fracture resistance, with statistical evaluation using generalized linear modelling. RESULTS: Margin integrity was significantly influenced by the bonding system (p < 0.001), but not by the composite (p = 0.105). Proportions of acceptable margins were increased in teeth restored with OptiBond FL (median [25th/75th percentiles]: 93 [78/100%]) or Clearfil SE (82 [60/94]%) compared with G-aenial Bond (43 [15/74%]; p < 0.05). Neither bonding systems nor composites significantly influenced leakage depth in enamel (p = 0.749/0.569) or dentine (p = 0.112/0.909). Fracture resistance was significantly influenced by bonding system (p = 0.008) and composite (p = 0.001), and was higher in teeth restored using OptiBond FL (mean [SD]: 1210 [336]N) compared with Clearfil SE (1007 [208]N) or G-aenial Bond (1023 [281]N, p < 0.05), and using EverX (1182 [314]N) instead of Filtek Z250 (979 [228]N; p < 0.01). CONCLUSIONS: Bonding systems which perform well in completely excavated teeth also yielded good results for selectively excavated teeth in vitro. Using fibre-enforced composites to restore selectively teeth increased fracture resistance. CLINICAL SIGNIFICANCE: Bonding systems which perform well in completely excavated teeth are also suitable for restoring selectively excavated teeth. Using fibre-enforced composites seems suitable for increasing the fracture resistance of selectively excavated teeth and their restorations.

Socioeconomic inequality and caries: a systematic review and meta-analysis.

Dental caries is the most prevalent disease worldwide, with the majority of caries lesions being concentrated in few, often disadvantaged social groups. We aimed to systematically assess current evidence for the association between socioeconomic position (SEP) and caries. We included studies investigating the association between social position (determined by own or parental educational or occupational background, or income) and caries prevalence, experience, or incidence. Risk of bias was assessed using the Newcastle-Ottawa Scale for observational studies. Reported differences between the lowest and highest SEP were assessed and data not missing at random imputed. Random-effects inverse-generic meta-analyses were performed, and subgroup and meta-regression analyses were used to control for possible confounding. Publication bias was assessed via funnel plot analysis and the Egger test. From 5539 screened records, 155 studies with mostly low or moderate quality evaluating a total of 329,798 individuals were included. Studies used various designs, SEP measures, and outcome parameters. Eighty-three studies found at least one measure of caries to be significantly higher in low-SEP compared with high-SEP individuals, while only 3 studies found the opposite. The odds of having any caries lesions or caries experience (decayed missing filled teeth [DMFT]/dmft > 0) were significantly greater in those with low own or parental educational or occupational background or income (between odds ratio [95% confidence interval] = 1.21 [1.03-1.41] and 1.48 [1.34-1.63]. The association between low educational background and having DMFT/dmft > 0 was significantly increased in highly developed countries (R (2) = 1.32 [0.53-2.13]. Publication bias was present but did not significantly affect our estimates. Due to risk of bias in included studies, the available evidence was graded as low or very low. Low SEP is associated with a higher risk of having caries lesions or experience. This association might be stronger in developed countries. Established diagnostic and treatment concepts might not account for the unequal distribution of caries (registered with PROSPERO [CRD42013005947]).

miR-200a-mediated suppression of non-muscle heavy chain IIb inhibits meningioma cell migration and tumor growth in vivo.

miR-200a has been implicated in the pathogenesis of meningiomas, one of the most common central nervous system tumors in humans. To identify how miR-200a contributes to meningioma pathogenesis at the molecular level, we used a comparative protein profiling approach using Gel-nanoLC-MS/MS and identified approximately 130 dysregulated proteins in miR-200a-overexpressing meningioma cells. Following the bioinformatic analysis to identify potential genes targeted by miR-200a, we focused on the non-muscle heavy chain IIb (NMHCIIb), and showed that miR-200a directly targeted NMHCIIb. Considering the key roles of NMHCIIb in cell division and cell migration, we aimed to identify whether miR-200a regulated these processes through NMHCIIb. We found that NMHCIIb overexpression partially rescued miR-200a-mediated inhibition of cell migration, as well as cell growth in vitro and in vivo. Moreover, siRNA-mediated silencing of NMHCIIb expression resulted in a similar migration phenotype in these cells and inhibited meningioma tumor growth in mice. Taken together, these results suggest that NMHCIIb might serve as a novel therapeutic target in meningiomas.

Comparison of triclosan and stannous fluoride dentifrices on parameters of gingival inflammation and plaque scores: a systematic review and meta-analysis.

OBJECTIVE: To systematically review the literature to compare the efficacy of triclosan (Tcs) and stannous fluoride (SnF) dentifrices on parameters of gingivitis and plaque scores. MATERIALS AND METHODS: Medline, EMBASE and Cochrane Central Register of Controlled Trials were searched up to March 2013 to identify appropriate studies. Studies regarding self-performed manual brushing by adults with a minimum 4 weeks of follow-up were included. Primary outcomes were parameters of gingivitis. Secondary outcome was plaque score. RESULTS: Of 55 publications, 11 met the eligibility criteria. Additionally, four unpublished papers were added after contacting the manufacturers of the leading brands. In total, 15 studies [10 medium term and five long term (>6 months)] were processed for data analysis. There was no difference in gingival index (or its modification) between the two types of dentifrice [DiffM-0.04, 95% confidence interval CI (-0.11; 0.04); P = 0.34]. The change in the average gingival bleeding score was significantly in favour of SnF [DiffM0.02, 95% CI (0.01; 0.02); P < 0.00001]. Plaque scores demonstrated a statistical significant difference in favour of Tcs, according to Quigley-Hein Plaque Index (Q&H PI; DiffM-0.29, 95% CI [-0.45; -0.13]; P = 0.0004), but there was no difference according to Rustogi Modified Navy Plaque Index (RMNPI) [DiffM-0.09, 95% CI (-0.01; 0.18); P = 0.07]. Long-term results supported these findings. CONCLUSIONS: In the context of inconclusive results for the primary outcome variable of gingival health, it can be concluded that there was a minor and most likely clinically insignificant difference between Tcs- and SnF-containing dentifrices. Meta-analysis of plaque score reduction was also inconclusive; whereas Tcs was more effective when assessed by the Q&H PI, it was not when scored with the RMNPI.

Marginal integrity and secondary caries of selectively excavated teeth in vitro.

OBJECTIVES: Selective caries removal involves sealing of carious dentine beneath restorations, which might decrease their marginal integrity and increase the susceptibility for secondary caries and microleakage. The present study compared these marginal characteristics of restorations in selectively and completely excavated teeth. METHODS: In 32 premolars, shallow and deep artificial lesions were created on pulpo-axial walls of mesial-distal-occlusal cavities, with mesial and distal margins located in enamel and dentine, respectively. Demineralised dentine was either removed or left before adhesively restoring the teeth (n=8), which were then submitted to thermo-mechanical cycling. The integrity of gingivo-cervical margins was assessed using scanning electron microscopy. In half of each margin, caries was induced adjacent to restorations using a continuous-culture biofilm model, and resulting lesions were evaluated using transversal microradiography. The other half of each margin was used to assess microleakage. RESULTS: Integrity or microleakage of margins located in enamel did not differ significantly between groups, and bacterial biofilms did not induce distinct caries lesions in enamel. Dentinal margins in teeth with deep compared with shallow lesions showed a significantly higher proportion of marginal imperfections, gaps and microleakage (p≤0.05, Mann-Whitney/χ(2)-test). In contrast, neither marginal integrity nor microleakage differed significantly between completely and selectively excavated teeth (p>0.05). Dentinal mineral loss adjacent to restorations did not differ significantly between groups (p>0.80). CONCLUSIONS: The marginal characteristics of restorations were affected by the depth of sealed or excavated lesions, but not by the performed caries excavation. This study did not find selective excavation detrimental for restoration integrity in vitro. CLINICAL SIGNIFICANCE: Selective excavation of deep lesions was shown to reduce pulpal risks, whilst leaving caries beneath restorations is feared to compromise the marginal characteristics of the subsequently placed restoration. Based on the present in vitro study, such assumptions cannot be supported.

Radiopaque Tagging Masks Caries Lesions following Incomplete Excavation in vitro.

One-step incomplete excavation seals caries-affected dentin under a restoration and appears to be advantageous in the treatment of deep lesions. However, it is impossible to discriminate radiographically between intentionally left, arrested lesions and overlooked or active lesions. This diagnostic uncertainty decreases the acceptance of minimally invasive excavation and might lead to unnecessary re-treatment of incompletely excavated teeth. Radiopaque tagging of sealed lesions might mask arrested lesions and assist in discrimination from progressing lesions. Therefore, we microradiographically screened 4 substances (SnCl2, AgNO3, CsF, CsCH3COO) for their effect on artificial lesions. Since water-dissolved tin chloride (SnCl2×Aq) was found to stably mask artificial lesions, we then investigated its radiographic effects on progressing lesions. Natural lesions were incompletely excavated and radiopaque tagging performed. Grey-value differences (△GV) between sound and carious dentin were determined and radiographs assessed by 20 dentists. While radiographic effects of SnCl2×Aq were stable for non-progressing lesions, they significantly decreased during a second demineralization (p < .001, t test). For natural lesions, tagging with SnCl2×Aq significantly reduced △GV (p < .001, Wilcoxon). Tagged lesions were detected significantly less often than untagged lesions (p < .001). SnCl2×Aq was suitable to mask caries-affected dentin and discriminate between arrested and progressing lesions in vitro. Radiopaque tagging could resolve diagnostic uncertainties associated with incomplete excavation.

Cariogenic effects of probiotic Lactobacillus rhamnosus GG in a dental biofilm model.

Probiotic bacteria have been suggested to inhibit Streptococcus mutans (SM) and thus prevent dental caries. However, supporting evidence is weak and probiotic species might be cariogenic themselves. Thus, we compared and combined the probiotic Lactobacillus rhamnosus GG (LGG) with SM and analysed the resulting mineral loss (ΔZ) in dental tissues. We simulated three biofilm compositions (SM, LGG, SM × LGG), two lesion sites (smooth enamel, dentin cavity) and two nutrition supply frequencies (twice/day, 6 times/day) in a multi-station, continuous-culture biofilm model. A total of 240 bovine enamel and dentin samples were cut, polished and embedded. All experimental procedures were performed in independent duplicates, with 10 samples being allocated to each group for each experiment (final sample size n = 20/group). Biofilms were cultured on the specimens and supplied with 2% sucrose medium and artificial saliva in consecutive pulses. After 10 days, ΔZ and bacterial numbers were assessed. SM × LGG biofilms caused significantly increased ΔZ compared with SM or LGG biofilms (p < 0.01, Mann-Whitney test), and ΔZ was significantly increased in dentin cavities compared with smooth enamel lesions (p < 0.01). Bacterial numbers did not significantly differ between biofilms of different species (p > 0.05, ANOVA). Frequent nutrition supply significantly increased bacterial numbers (p < 0.01). Biofilms in dentin cavities compared to smooth enamel harboured significantly more bacteria (p < 0.05). LGG induced mineral loss especially in dentin cavities and under highly cariogenic conditions. LGG did not have inhibitory effects on SM, but rather contributed to the caries process in vitro.

Comparison of sealant and infiltrant penetration into pit and fissure caries lesions in vitro.

OBJECTIVES: The aim of this in vitro study was to evaluate the penetration of an infiltrant and a sealant, when applied as recommended, into fissure caries lesions. METHODS: The fissure systems of extracted human teeth were classified according to the international caries detection and assessment system (ICDAS, codes: 0, 1, 2). Within each ICDAS-code ten teeth were either etched with 37% H3PO4-gel for 60s and subsequently sealed ('Fissure Sealing'; Helioseal; Ivoclar Vivadent) or etched with 15% HCl-gel for 120s and subsequently infiltrated ('Resin Infiltration'; Icon; DMG). Additionally, ten teeth with ICDAS-code 2 were etched with 37% H3PO4-gel for 120s and infiltrated ('Soft-Etch-Infiltration'). Specimens were cut perpendicular to their surfaces, polished, and confocal microscopic images were obtained. Lesion depths (LDmax) and penetration depths (PDmax) were measured and percentage penetration was calculated as PPmax=PDmax/LDmax×100. RESULTS: Baseline LDmax [median (interquartile range)] for ICDAS-code 2 lesions was 1192 (805-1512)µm. In ICDAS-code 2 lesions PPmax was significantly higher for specimens treated with 'Resin Infiltration' [41 (30-78)%] compared to 'Soft-Etch-Infiltration' [11 (0-21)%] or 'Fissure Sealing' [5 (0-9)%] (p<0.05; Mann-Whitney test). PPmax did not differ significantly between groups in ICDAS-code 0 and 1 lesions (p>0.05). CONCLUSION: The fissure sealant when applied after etching with H3PO4-gel only penetrates superficially into non-cavitated fissure caries lesions. Penetration of an infiltrant is superior in particular after etching with HCl-gel. CLINICAL SIGNIFICANCE: Compared with sealing, infiltration of fissure caries lesions leads to more deeply infiltrated lesions, which might in turn result in superior abilities to hamper caries progression.