Sandblasted/acid-etched vs smooth-surface implants: implant clinical reaction to experimentally induced peri-implantitis in Beagle dogs

This study uses a sandblasted/acid-etched implant vs a smooth-surface implant to compare implant mobility and clinical reactions of peri-implant tissues to experimentally induced peri-implantitis in Beagle dogs. The right and left mandibular premolars were extracted from 5 Beagle dogs, and 2 smooth-surface (SS) implants and 2 sandblasted/acid-etched (SLA) implants were placed in each animal. After 120 days, healing abutments were connected. Fifteen days later, the prosthetic abutments were connected, the hygiene regimen was suspended, and peri-implantitis was induced by the insertion of cotton ligatures into the soft tissue around the implants. At baseline and 30, 60, and 90 days later, clinical attachment level (CAL), probing depth (PD), and mobility (MO) were measured. Probing depth increased significantly in the SLA group alone when baseline PD was compared with 30-, 60-, and 90-day evaluations (P < .05). No significant differences were noted between the 2 implant groups (P > .05). The loss in CAL was significant in both groups when the baseline value was compared with 30-, 60-, and 90-day evaluations (P < .02). Comparison between the 2 implant groups revealed a greater loss in CAL in the SLA group at the 90-day evaluation period (P = .04). A significant increase in mobility was seen in both groups when baseline values and 90-day evaluations were compared (P < .04). However, no statistically significant differences were noted between the 2 implant groups (P > .05). Experimentally induced peri-implantitis results in a greater loss of CAL in SLA implants than in SS implants in dogs; however, no differences in mobility or in PD have been noted between the 2 implant groups.     

Furcation perforation repair comparing gray and white MTA: a dye extraction study

The purpose of this study was to evaluate the ability of gray and white ProRoot MTA to seal furcation perforations in mandibular molars using a dye extraction leakage model. Sixty-four mandibular molars were randomly divided into four experimental groups. Six teeth with perforations were used as positive controls and six teeth without perforations were used as negative controls. Perforations in groups 1 and 2 were repaired with white MTA. Groups 3 and 4 were repaired with gray MTA. Dye leakage was tested from an orthograde direction (groups 1 and 3) and a retrograde direction (groups 2 and 4). After dye extraction, absorbance was measured on a spectrophotometer at 550 nm. No statistically significant difference in leakage was found between gray and white MTA when used as a furcation perforation repair material. However, there was significantly more leakage when the perforations were challenged from the orthograde than the retrograde direction (p < 0.001).     

Solubility study of phytochemical cross-linking agents on dentin stiffness

Objectives

The effects of interactions between cross-linking proanthocyanidins (PA) in polar solvents and type-I collagen of demineralized dentin were investigated.

Methods

Three PA-rich extracts, two from grape seed (GSEP and GSES) and one from cocoa (COE), were dissolved (water, ethanol:water and acetone:water) and analyzed for their ability to increase the modulus of elasticity of demineralized dentin. Sound dentin beams (0.5 mm × 1.7 mm × 7 mm) were fully demineralized and divided into 12 groups according to the type of cross-linking agent and solvents used. Specimens were immersed in the respective solutions and tested at baseline, 10, 30, 60, 120 and 240 min.

Results

The elastic modulus (EM) of dentin was significantly increased by the PA treatment regardless of time (p < 0.05 for all times). The extracts showed different solubility in different solvents. GSEP showed the highest increase in EM when diluted in distilled water and acetone at all exposure times. Both GSEs showed superior results when diluted in distilled water and after 4 h of treatment, while COE produced strongest enhancement when dissolved in ethanol:water.

Conclusions

The results indicates that herbal extraction process and other pharmacognostic parameters have an important influence on extract solubility as well as constitution and, consequently, on the PA–dentin matrix interaction.     

Horizontal root fracture with displacement in the primary dentition

Root fractures in the primary dentition are uncommon and little information is available concerning adequate treatment and prognosis. The most recently published guidelines recommend more invasive approaches but also discuss the need for further studies. This article examines how a horizontal root fracture in the primary dentition of a 3-year-old girl was treated by reducing the coronal fragment, followed by semi-rigid containment for 21 days. Radiographs taken one year after the initial trauma confirmed the success of this alternative approach.     

Effect of bur type on microtensile bond strengths of self-etching systems to human dentin

PURPOSE: To compare the microtensile bond strength (microTBS) of five adhesives to human dentin prepared with 600-grit SiC abrasive paper (SiC), a diamond rotary instrument, or a carbide bur. The null hypothesis was that different cavity preparation instruments do not affect adhesion of resin adhesives. MATERIALS AND METHODS: Human molars (n = 45) were randomly divided into three groups according to surface treatment. Each group was bonded using a total-etch adhesive (Single Bond, 3M ESPE), one of three self-etching primer systems (Clearfil SE Bond or ABF, Kuraray; Imperva Fluorobond, Shofu), or a self-etching adhesive (One-Up Bond F, Tokuyama). A 4-mm composite crown was built over the bonded surface. Specimens were stored in water for 24 h at 37 degrees C. They were sectioned into 0.7-mm-thick slabs, trimmed to a cross-sectional area of 1 mm2, and loaded to failure at a crosshead speed of 1 mm/min using a tabletop tester (EZ-Test, Shimadzu). Microtensile bond strength data were analyzed using analysis of variance and Fisher's PLSD test. RESULTS: Surface preparation using a carbide bur generally yielded higher bond strengths than preparation using either a diamond rotary instrument or SiC abrasive paper. SE Bond had the highest mean microTBS of the five adhesives tested. CONCLUSION: Resin-dentin bond strengths can be affected by the type of instrument used to prepare the tooth. Specifically, higher bond strengths might be achieved by using carbide burs rather than diamond cutting instruments.     

Effects of diagnostic threshold and overlapped approximal surfaces on reported caries status

The aims of this study were to examine the influence upon reported caries status of: 1) employing different diagnostic thresholds and 2) using differing conventions for treating approximal surfaces which appeared overlapped on posterior bitewing radiographs. Caries prevalence data from a group of 211 Scottish schoolchildren aged 5-15 yr studied during a trial of elective temporary tooth separation in general dental practice in Scotland were used. In this "moderate" caries group, values for dmft/DMFT rose significantly (P less than 0.001) when the D1 diagnostic threshold (all grades of lesion accepted) was applied in comparison with the D3 threshold (only caries into dentine recognised); dmft increasing from 3.9 to 5.4 and DMFT increasing from 1.7 to 4.7. This demonstrated that an over-optimistic impression of overall caries levels may be given when only the D3 threshold is used uncritically. In this study the status of approximal surfaces which were overlapped on bitewing radiographs was assessed by direct clinical examination using the temporary elective tooth separation technique. The investigation showed that, for this juvenile population, most (81.8% mesial, 93.1% distal) overlapped approximal surfaces were sound. Significantly more mesial than distal surfaces were found to be overlapped.