Biological effects of low-level laser irradiation (LLLI) on stem cells from human exfoliated deciduous teeth (SHED).

OBJECTIVES: To investigate the effects of low-level laser irradiation (LLLI) on viability/proliferation, migration, osteo/odontogenic differentiation, and in vitro biomineralization of stem cells from human exfoliated deciduous teeth (SHED). MATERIALS AND METHODS: SHED cultures were established by enzymatic dissociation from pulps of deciduous teeth. SHED were irradiated with a diode laser (InGaAsP; 940 nm; 0.2 W, continuous mode) at energy fluences 4, 8, and 16 J/cm2 in the dark, while non-irradiated SHED served as control. Cell viability/proliferation was evaluated by MTT assay and cell mobilization by Transwell™ migration assay. Expression of osteo/odontogenesis-related genes (ALP, BMP-2, BGLAP, DSPP, MSX2, RUNX2) was assessed by real-time PCR, while in vitro biomineralization by Alizarin Red staining. Statistical analysis was performed by two-way ANOVA and Tukey's post hoc tests (*p < 0.05, **p < 0.01). RESULTS: Statistically significant stimulation of cell viability/proliferation was observed at all energy fluences, reaching the highest effect for the 4 and 16 J/cm2. Although the 8 J/cm2 fluence showed the lowest stimulatory effect on cell viability/proliferation, it was the most effective in inducing SHED migration, upregulation of odontogenesis-related genes (DSPP, ALP, BMP-2) at specific time-points, and the in vitro biomineralization potential of SHED compared to the other two energy fluences. CONCLUSIONS: LLLI proved beneficial in promoting SHED biological processes critical for pulp repair in deciduous teeth. Overall, the 8 J/cm2 energy fluence showed the most beneficiary effects. CLINICAL RELEVANCE: These results provide insights on a narrow "therapeutic window" of LLLI application in vital pulp therapies of deciduous teeth, paving the way for the establishment of effective clinical protocols.

The effect of prosthetic margin location on caries susceptibility. A systematic review and meta-analysis.

BACKGROUND: The prosthetic margin location relevant to the free gingival margin may influence the incidence of secondary caries due to the differences that exist between the micro-environment within the gingival crevice compared to the rest of the oral environment. OBJECTIVE: The purpose of this study was to systematically review the effect of prosthetic margin placement on caries susceptibility of abutment teeth. METHOD: Two independent authors identified cohort studies using MEDLINE, EMBASE, CDSR, CENTRAL, Google Scholar and Scopus through March 2012. Reference lists were also scanned. Included studies had to report on caries incidence with regard to location of prosthetic margins, with a minimum follow-up period of two years. RESULTS: A total of 5,541 references were identified and, after application of the inclusion criteria, 22 studies were included in the systematic review. Random-effects meta-analysis could be made in two studies, in which secondary caries incidence did not differ between margins placed subgingivally compared to equi- or supragingivally placed margins for a follow-up period up to ten years. Indications were found of a possible lower secondary caries rate at 15 years of follow up, based on one study. CONCLUSION: This systematic review and meta-analysis failed to detect a significantly different secondary caries rate of subgingivally located prosthetic margins in the short to mid-term (≤10 years). Due to the small number and the limitations of the included studies the results do not provide conclusive evidence as to the effect of prosthetic margin placement on the incidence of secondary caries.

A systematic review of single crowns on endodontically treated teeth.

OBJECTIVES: To test the hypothesis that the placement of a crown is associated with improved (long term) survival of root canal treated teeth, using a systematic review process of clinical studies. DATA SOURCES: Papers referring to single crowns on endodontically treated teeth were located by a MEDLINE search and hand searching. One thousand six hundred and nine references were found, and they were subjected to a systematic review procedure. STUDY SELECTION: A three-step inclusion-exclusion procedure was applied to identify papers that represented; good scientific practice (GSP), reported results of all patients, restorations on root canal treated teeth (RCT) for more than 2 years and had sufficient data to generate life table analyses. The outcomes were 'survival of RCT restored with crowns' and 'survival of RCT with direct restorations'. Ten studies survived. These data showed an overall mean GSP of 0.605 with a 10-year survival of 81% for crowned RCT and a 10-year survival of 63% for RCT with direct restorations (resin composites, amalgam, cements). CONCLUSION: RCTs restored with crowns show an acceptable long-term survival of 10 years, while direct restorations have a satisfactory survival only for a short period.

Palatal lift prosthesis for palatopharyngeal closure in Wilson's disease.

This is a report of our work on a female patient with Wilson's disease who was treated for speech improvement. A palatal lift prosthesis was constructed to displace the soft palate superiorly and posteriorly and partially restore the functional deficiencies of palatopharyngeal insufficiency. Cephalometric radiographs confirm the association between the displacement of the soft palate and speech improvement.

Gingival recession: a cross-sectional clinical investigation.

In this cross-sectional study, risk and potentially causative factors of gingival recession were examined and their relationship to apical migration of the gingival margin evaluated. Thirty eight patients (18-60 years), displaying one or more sites with gingival recession but without any significant periodontal disease participated. A total of 28 parameters were evaluated in both 'test' teeth (50 teeth with gingival recession) and 'control' teeth (50 contralateral teeth). The results revealed that gingival margin recession was associated with both high inflammatory and plaque scores, with decreased widths of keratinized and attached gingiva and with the subjects' toothbrush bristle hardness.

Facial approach to stabilization of mobile maxillary anterior teeth with steep vertical overlap and occlusal trauma.

The necessity for splinting and the advantages of some types of permanent, semipermanent, and temporary splinting are given. Specific step-by-step instructions are given for a special purpose splint that can be used for stabilizing mobile maxillary teeth when the patient has thin teeth faciolingually and a steep vertical overlap. This can be the treatment of choice for such patients.

Effectiveness of conservative treatment for craniomandibular disorders: a 2-year longitudinal study.

The severity of symptoms of craniomandibular disorders was studied during a 2-year period in 195 patients treated with conservative therapeutic schemes. Results revealed a continuing improvement and a statistically significant tendency for the great majority of patients to become asymptomatic or show a decrease in the severity of symptoms. By the end of the 2 years, 66.7% of the patients were symptom free, 25.6% presented with slight symptomatology, and 3.1% were recorded with a fluctuating recurrence of symptoms. This investigation provided the data to develop an exponential model for the hypothesis that stabilization of effectiveness of conservative treatment is achieved between 6 months and 1 year after the initiation of treatment.

Effect of age and sex on craniomandibular disorders.

The purpose of this study was to investigate the effect of age and sex on craniomandibular disorders. A total of 195 subjects were examined, 148 women and 47 men. The range of age was 16 to 70 years. Clinical and anamnestic examination data established the ratio of women to men as 4:1. The prevalence of clicking, headache, teeth-clenching, hypomobility, difficulty in mastication, and neuromuscular symptoms was greater among young women than in other age and sex groups. There was a statistically significant correlation between severity of symptoms and age among women, and a relative decline by age in the prevalence of symptoms for both sexes. Finally, younger patients showed a greater prevalence of neuromuscular symptoms, whereas older patients had more peripheral symptoms.

Color consistency, plaque accumulation, and external marginal surface characteristics of the collarless metal-ceramic restoration.

Four techniques for making collarless metal-ceramic restorations were investigated in this study to examine the final color consistency, the bacterial plaque accumulation, and the surface characteristics of the porcelain margin. Twenty crowns were constructed and data revealed the superiority of the platinum foil technique in producing consistent color, whereas the shoulder porcelain technique resulted in the most significant color deviation. Metal surfaces exhibited the greatest in vitro bacterial plaque accumulation (42.43%), and the margins of the platinum foil technique accumulated the least plaque (7.23%). In addition, the wax binder and the platinum foil techniques produced the smoothest surfaces, whereas again the shoulder porcelain technique exhibited pronounced surface roughness. From the obtained results, and with the limitations of this in vitro study, one can speculate that surface roughness is not a predominant factor in the initial process of bacterial plaque accumulation.

A standardized system for evoking masseteric silent periods with decreased variance.

Masseteric silent periods have been evoked in a group of normal subjects under a standardized system and under nonstandardized conditions. In the designed system, head position, electrode placement, bite force, tap force, direction of tap, and surface zone of tap force delivery were controlled. Analysis of data confirmed the hypothesis that standardization of the procedure for eliciting the silent period results in measurements of duration with decreased standard deviations and variances. In the present study, under the standardized system the SPD range of standard deviations was between 1.37 and 3.68 (mean 2.97) and the range of variances was between 1.89 and 13.54 (mean 8.85). The recorded low variability suggests a high degree of reproducibility of the system. High reproducibility and low variability of measurements are necessary if an accurate measure of silent period duration is to be achieved and used in the interpretation of diagnostic findings for craniomandibular disorders.

Clinical crown contours: contemporary view.

Crown contours represent a group of characteristics critical for the longevity and success of dental restorations. This article presents the theories that have been developed about crown contours, describes each feature in detail, and clarifies potential interrelationships with all components of the mouth. When identified early, crown contours can be incorporated in treatment planning and restorative procedures.

Proximal tooth surface quality and periodontal probing depth.

The proximal tooth surface integrity of 826 patients was correlated with periodontal probing depths. Results show relatively increased probing depths adjacent to restored proximal tooth surfaces, with the greatest probing depths adjacent to overhanging restorations and restorations with recurrent caries. The data confirm the significant tendency of the periodontal condition to deteriorate as a function of decreasing surface quality. Probing depth appeared to increase with the patient's age. Surface condition, however, showed a significant relationship with probing depths in all age groups.