The influence of chronic stress imposed on pregnant rats on the induced bone loss in their adult offspring

Background and objectiveStress during pregnancy may alter offspring susceptibility to diseases during adulthood. In the present study, female Lewis rats were subjected to chronic stress during the gestational period, and the effect of this stress was evaluated histometrically on the progression of ligature-induced bone loss in their adult offspring.Material and methodsAfter confirming pregnancy, half of the pregnant rats were randomly designated as control animals (no stress regimen was imposed), and the other half was submitted to a chronic stress model (immobilization at cold temperature) between the 7th and the 18th gestational day. After birth, 12 male rats delivered by stressed mothers – Group 1 (G1) – and 12 male rats delivered by non-stressed mothers – Group 2 (G2) – were selected. When birthed rats reached 250 g of body weight, a silk ligature was placed around their maxillary right second molar in order to induce bone loss. The non-ligated left side served as a control. Sixty days later, these animals were sacrificed by anaesthetic overdose. After routine laboratorial processing, images of the histological sections were digitized and submitted for histometric measurement using two parameters: histological attachment loss and bone loss.ResultsOn the ligated side, G1 presented with greater histological attachment and bone loss than G2 (p < 0.05). On the non-ligated control side, neither of the groups presented with alterations in these parameters (p > 0.05).ConclusionThe chronic stress regimen imposed on pregnant rats produced a greater progression of ligature-induced bone loss in their adult offspring.     

Chronic stress may modulate periodontal disease: a study in rats

BACKGROUND: The present study aimed to evaluate whether chronic stress (CS) affects ligature-induced periodontal disease and to investigate the impact of CS on the mRNA levels of interleukin (IL)-1beta, -1 receptor antagonist, -6, and -10, interferon-gamma (IFN-gamma), receptor activator of nuclear factor-kappa B ligand (RANKL), and osteoprotegerin in the gingival tissues of rats. METHODS: Sixty male Wistar rats were assigned randomly to three groups: G1 (control; non-ligated sites), G2 (periodontal disease), and G3 (periodontal disease associated with restraint stress for 12 hours/day for the entire study). After 30 days, all animals were sacrificed by decapitation. Blood samples were taken, and the concentrations of corticosterone and catecholamines were measured as biomarkers of CS. Marginal tissues around ligated and non-ligated teeth were harvested, and gene expression was assessed by quantitative polymerase chain reaction. Moreover, the area of bone loss (ABL) was determined histometrically. RESULTS: Data analysis showed that CS increased serum levels of stress biomarkers (P <0.05), ligature placement resulted in a significant ABL compared to non-ligated sites, CS significantly increased the amount of ABL in inflamed sites (P <0.001), and CS significantly increased mRNA levels of proinflammatory (IL-1beta and -6 and IFN-gamma) and anti-inflammatory (IL-10) cytokines and proresorptive factor (RANKL) in ligated sites (P <0.05). CONCLUSION: CS significantly increased bone loss resulting from ligature-induced periodontitis by a local increase in proinflammatory and proresorptive factors.     

Long-term effects of selective desalivation on taste acuity in rats

To ascertain the relative contributions of individual salivary gland secretions in the maintenance of taste acuity, we arbitrarily divided 28 rats into four groups of seven each. Group A: sham-operated controls; Group B: surgical removal of parotid glands only; Group C: removal of all major salivary glands; and Group D: removal of submandibular-sublingual gland complexes. Taste acuity was measured with a 2-bottle technique and a wide concentration range of NaCl, sucrose (S), hydrochloric acid (HCl) and quinine sulphate (QS) solutions. Daily fluid consumption was used to calculate percentage preference. Groups A and B showed marked rejection of most QS solutions (range 1–53 per cent) while Groups C and D exhibited significantly (p < 0.01) less rejection (32–52 per cent). Groups A and B showed a similar rejection of most HCl solutions (range 2–57 per cent) while Group C showed significantly (p < 0.01) greater acceptance of four of the solutions and Group D showed a variable response. Groups A and B exhibited a marked preference for the more concentrated S solutions (range 40–98 per cent) while Groups C and D did not increase their S solution intake until very high concentrations and never showed as great a preference as controls (range 48–80 per cent) the differences generally being significant at p < 0.01. Groups A and B exhibited an essentially normal preference-aversion curve for the NaCl solutions. Groups C and D showed less rejection of the more concentrated solutions, the differences generally being significant. Thus it seems that removal of the major glands produces a severe taste defect that is closely mimicked by removal of the submandibular-sublingual glands alone.     

Influence on dimensional accuracy of volume of wash material introduced into pre-spaced putty/wash impressions

This study compared the accuracy of stone models obtained from two-stage, pre-spaced putty/wash impressions under conditions in which known volumes of wash material were introduced during the second stage of the impression: Group I, a quantity of wash material corresponding to the space provided; Group II, double the quantity of wash material as the space provided; Group III, double the quantity of wash material, but with V-shaped vents in the putty for escape of excess material. Percentage deviations of the vertical dimensions of stone dies with respect to the master model were significantly different between Groups I and II (the latter being shorter) (p < 0.05). For horizontal dimensions, differences were less consistent, although the deviations for Groups I and II and Groups II and III, with respect to the master model, were significantly different from each other for two of the three dimensions measured (Group II inter-abutment distances were generally larger) (p < 0001 and p < 0.05, respectively). It is concluded that putty recoil, resulting from compression by excess wash material, plays a significant role in the undersizing of working dies, although the level of clinical relevance is less clear.     

Enameloplasty effects on microleakage of pit and fissure sealants under load: an in vitro study

Enameloplasty has been implicated in the successful application of pit and fissure sealants. The present study aimed to evaluate the effect of enameloplasty technique on microleakage of sealants when occlusal force was applied on the teeth. The study also allowed a direct comparison of the effectiveness of enameloplasty, when two different burs were used. Six groups of ten human extracted wisdom teeth were tested. Group A: no load, conventional (no enameloplasty--control); Group B: no load, enameloplasty 1/2 round bur (Brasseler USA); Group C: no load, enameloplasty diamond fissure bur REF/UP 791 (Ultradent); Group D: load 500 N, conventional, Group E: load 500 N, 1/2 round bur; Group F: load 500 N, diamond fissure bur. Specimens were thermocycled for 500 cycles at 5 degrees C and 55 degrees C with a dwell time of 30 seconds after load application. Microleakage was scored as distance of dye penetration with 0 = no microleakage and 3 = microleakage to underling fissure. The Kruskal-Wallis One Way Anova and Mann-Whitney U test showed group D having the greatest degree of microleakage statistically significant (p < 0.05) comparing with other groups. Sealants prepared with the conventional technique (A, D) had statistically significant differences in microleakage with those prepared with enameloplasty (B, C, E, F) (p = 0.01). Enameloplasty in groups with no load (B, C) did reduce microleakage, but not significantly (p = 0.3). However, loaded teeth with enameloplasty appeared to perform superior, as compared to those without (p = 0.005). Regarding the effect of load, teeth without load (Groups A, B, C) were found to have significantly less microleakage than teeth where mechanical force had been applied (Groups D, E, F), (p = 0.01). Microleakage in Group A (conventional technique without load) was significantly less than microleakage in Group D (conventional technique with load), (p = 0.04). However, load did not seem to influence microleakage when enameloplasty had been performed. This finding was true for both round bur enameloplasty (p = 0.29), and fissure bur enameloplasty (p = 0.26). There was no statistically significant difference between Groups B, E (round bur) and C, F (fissure bur) (p > 0.05), or between Groups B and C (p > 0.05) and between Groups E and F (p > 0.05). The results of the study indicated that enameloplasty reduced microleakage of pit and fissure sealants, especially when load was applied to teeth, irrespective of what bur was used to enlarge the fissure, as there was no statistical significant differences between the round and fissured diamond burs. The application of occlusal force to the tooth produces significantly more microleakage, unless enameloplasty is performed.     

Effect of Denture Cleansers on the Surface Roughness and Hardness of a Microwave-Cured Acrylic Resin and Dental Alloys

PURPOSE: This study evaluated the effect of denture cleansers on the surface hardness of a denture base resin, and on the surface roughness of the resin and Co-Cr and Ti-6Al-4V alloys. MATERIALS AND METHODS: Forty-eight disc-shaped specimens were fabricated of a microwave-cured acrylic resin, each having one of the alloys attached to its surface. The specimens were randomly divided into 6 groups, each consisting of 8 samples. Specimens were exposed to one of the three cleansing treatments (polident, manipulation pharmacy cleanser, and water) as follows. Group I: Co-Cr + polident; Group II: Co-Cr + manipulation; Group III: Co-Cr + water; Group IV: Ti-6Al-4V + polident; Group V: Ti-6Al-4V + manipulation; and Group VI: Ti-6Al-4V + water. Three exposures lasting 5 minutes each were conducted daily, and repeated after storage periods of 1, 14, and 29 days in artificial saliva at 37 degrees C. Hardness and roughness measurements were undertaken immediately after specimen preparation (T0) and on the 1st (T1), 15th (T15), and 30th (T30) day following the beginning of storage. Three roughness and hardness evaluations were carried out for each sample and testing time, and mean values were calculated. Results were analyzed using ANOVA and linear regression. RESULTS: The Knoop hardness test demonstrated differences (p < 0.05) between Groups I and IV at T1 and T30 (14.30 +/- 2.78; 14.06 +/- 1.76) and between Groups II and V at T15 (16.99 +/- 2.24). Significant differences (p < 0.05) in resin roughness (in microm) were observed between Groups I and IV at T15 and T30 (0.14 +/- 0.06; 0.21 +/- 0.38). With regard to Co-Cr, roughness data showed differences (p < 0.05) for all groups at T30 (Group I: 0.15 +/- 0.07; Group II: 2.43 +/- 0.66; Group III: 4.05 +/- 1.03), for Group II at T1 (0.10 +/- 0.03), and for Group I at T15 (0.15 +/- 0.02). There were significant differences (p < 0.05) in titanium roughness for Group IV at T15 (0.12 +/- 0.01) and T30 (0.11 +/- 0.04). CONCLUSIONS: Manipulated cleanser containing sodium perborate increased surface roughness and hardness, probably due to its incapacity to remove the pellicle formed on the acrylic resin and dental alloys.     

Effects of extended systemic and topical folate supplementation on gingivitis of pregnancy

Abstract A former double-blind study evaluated the effect of a 14–day period of systemic and topical folate supplementation on gingival inflammation during pregnancy (Pack & Thomson 1980). The current experiment was similar to the earlier one except that supplementation was for 28 days during the eighth month only. Thirty women during their 32nd week of pregnancy were randomly divided into three equal groups. Control Group A received placebo mouthwash (MW) and placebo tablets; Group B received placebo MW and one 5 mg folate tablet daily; Group C received placebo tablets and rinsed with folate MW twice daily for 1 min. At the beginning and end of the experimental period, oral status was determined using a plaque index (PII) and a gingival index (GI). Each subject furnished a 1–week diet record which was analysed for dietary folate. No differences in parameters existed between groups at the commencement of the study except for folate levels which were lower in Group B. Results confirmed the findings of the former experiment. Group C showed highly significant improvement in Gl despite no significant changes in PII (0.00 < p < 0.01), whilst in Group B, changes in gingival health were not statistically significant (0.05 < p < 0.10). No significant changes were demonstrated in Group A. Folate levels increased significantly in Groups B and C. Dietary folate was similar in all groups.     

Resin-based sealing of root canals in endodontic therapy

This study evaluated the effect of the obturation technique on leakage, which may be the primary cause of failure in endodontic treatment. The apical seal and leakage behavior of teeth obturated with a resin-based sealer and gutta-percha alternative were compared to conventionally obturated teeth. Sound premolars (N = 10) were instrumented and treated by conventional root canal obturation. A second group (N = 10) was treated with the Resilon-Epiphany system and the remaining 10 roots were divided into two groups (N = 5) and obturated without sealer. A detector electrode was placed coronally in each root in contact with the obturation system and sealed in place and the apices were left patent. The teeth were immersed in 0.9% sodium chloride with a stainless steel counter electrode. A 20V potential was connected between the stainless steel and each tooth in turn with current flow determined by voltage drop across a standard resistor. Leakage was followed for 30 days and statistically analyzed for differences between groups. All teeth in Groups 1, 3A, and 38 (p > 0.05) leaked at 30 days. In Group 2, four roots showed no leakage, five roots showed minimal leakage, and one root exhibited a leakage current at a greater magnitude than the others in the group. A significant difference (p < 0.005) was found between Groups 1 and 2 but not between Group 1 and Groups 3A and 3B (p > 0.05) or between Group 2 and Groups 3A and 3B.     

The sealing ability of a new silicone-based root canal filling material (GuttaFlow): an in vitro study using the percentage of gutta-percha-filled area

Percentage of gutta-percha-filled area (PGFA) was used to investigate the sealing ability of GuttaFlow. A total of 80 mandibular first premolars with single canal were randomly divided into 4 Groups (n=20) according to root canal filling technique and/or material - Group1: cold lateral condensation technique; Group 2: continuous wave condensation technique; Group 3: GuttaFlow; Group 4: GuttaFlow and accessory gutta-percha cones without lateral condensation. The PGFA values of Groups 3 and 4 were significantly higher than those of Groups 1 and 2 (p<0.05), but there were no significant differences between Group 3 and Group 4 (p>0.05). It was concluded that GuttaFlow provided superior sealing ability, such that accessory gutta-percha cones became unnecessary when filling root canals with GuttaFlow.     

Histologic evaluation of the effect of nicotine administration on bone regeneration. A study in dogs

The objective of this study was to investigate the histometric impact of nicotine on bone regeneration of surgically created alveolar ridge defects in dogs. Sixteen mongrel dogs were used. One defect was surgically created unilaterally in the mandible, and left to heal spontaneously. The animals were randomly assigned to one of the following groups: Group 1--control (n = 8) and Group 2--subcutaneous nicotine administration (2 mg/kg) twice a day (n = 8). After 4 months, the animals were sacrificed and the specimens routinely processed for semi-serial decalcified sections. Bone height (BH), bone width (BW), bone density (BD), and bone area (BA) of the newly-formed bone were evaluated. Intergroup analysis (Mann-Whitney rank sum test) showed that regardless of the presence of nicotine, no significant differences were observed regarding bone width (BW), bone area (BA) and bone height (BH) (p > 0.05). On the other hand, it was demonstrated that nicotine administration significantly influenced the proportion of mineralized tissue within the limits of the newly-formed bone (BD) (p < 0.001). Within the limits of the present study, it can be concluded that nicotine might affect but not prevent bone healing in defects left to heal spontaneously.     

Removal of intracanal smear layer by doxycycline: SEM analysis

The aim of this study was to verify the efficacy of doxycycline used alone or in association with sodium hypochlorite on smear layer removal. The canals of extracted human teeth were instrumented using a stepback technique. At the end of preparation, they were irrigated with doxycycline (Group 1), ethylenediaminetetraacetic acid + sodium hypochlorite (Group 2), doxycycline + sodium hypochlorite (Group 3) and water (Group 4). The dentinal wall of the cervical, middle and apical thirds was graded according to the amount of remaining debris and smear layer. The results were analysed using the Kruskal–Wallis test (P < 0.05). In Groups 2 and 4, the dentine was completely free and covered with smear layer, respectively. The results from the cervical and middle thirds of Group 3 were worse than those in Groups 1 and 2 (P < 0.05). In relation to apical third, there were differences (P < 0.05) between all groups with best results for Group 2. Doxycycline was effective in removing smear layer from cervical and middle thirds. The use of doxycycline + sodium hypochlorite was partially effective in the cervical and middle thirds, but ineffective in the apical third.     

Effects of different types of adhesive systems on the microleakage of compomer restorations in Class V cavities prepared by Er,Cr:YSGG laser in primary teeth

The aim of this in vitro study was to evaluate the effects of different types of adhesive systems on the microleakage of compomer restorations in Class V cavities prepared by erbium, chromium: yttrium scandium gallium garnet (Er,Cr:YSGG) laser. There were five test groups according to the type of adhesive applied to the cavities: Adper Single Bond 2 (Group 1), Scotchbond Multi-Purpose Plus (Group 2), Xeno III (Group 3), Clearfil Protect Bond (Group 4), Prime&Bond NT (Group 5). Dye penetration was evaluated under a stereomicroscope, and data were statistically analyzed by Kruskal-Wallis and Wilcoxon Signed Ranks tests. Gingival margins showed significantly higher microleakage than occlusal margins in all the test groups (p<0.05). Groups 1 and 2 showed significantly less microleakage than Group 5 (p<0.05), and there were no statistically significant differences among Groups 3, 4, and 5 (p>0.05). None of the dentin bonding agents eliminated microleakage completely, and higher microleakage scores were observed along the gingival margin than the occlusal margin.     

Marginal adaptation of three Class II composite restorative techniques in vitro

The purpose of this study was to evaluate the marginal integrity of three different Class II restorative techniques in vitro. Mesioocclusal (MO) preparations (no bevels) 4 mm x 3 mm x 2 mm were made on 15 freshly extracted human premolars mounted in cold cure acrylic. The preparations were randomly divided into three groups of five: Group I: Direct technique Group II: Indirect single-visit technique Group III: Indirect laboratory technique Group II cavity preparations were duplicated using alginate impression material (Jeltrate Plus, DENTSPLY Caulk) and a polyvinylsiloxane die material (Mach II, Parkell). Group III preparations were duplicated using polyether impression material (Impregum, ESPE) and type IV die stone (G.C. America Inc., Fujirock). All restorations were fabricated with Tetric Ceram (Vivadent-Ivoclar) microhybrid composite according to manufacturers' recommendations. The inlays were cemented using a dual-cure bonding system (All Bond II, Bisco) and a resin-based cement (Variolink, Vivadent-Ivoclar) and polished according to manufacturers' recommendations. The specimens were examined under an environmental scanning electron microscope (Electroscan). None of the samples was sectioned before examination. The width of the largest gap at the gingival margin, between the restorations and preparations, was recorded in microns. The average gap width for each group was the following: Group I: 63.4 +/- 9.06 microns Group II: 73.54 +/- 13.9 microns Group III: 89.58 +/- 18.5 microns Statistical analysis (one-way ANOVA) revealed that a significant difference exists among the three groups (p = 0.03). Students t-tests revealed a statistical significant difference between Groups I and III (p < 0.02), but did not prove significant between Groups I and II (p > 0.10) and Groups II and III (p > 0.05).     

Effect of diphosphonate on the prevention of X-radiation-induced inhibition of bone formation in rats

A histologic and histometric study of the effect of EHDP (ethane- 1–hydroxy-1,1–diphosphonate) on the alveolar wound healing of irradiated animals is presented. This drug was selected based on its osteosclerotic effect when applied at low doses. The three left mandibular molars of 80 male Wistar rats were extracted. The rats were grouped into 4 sets of 20 rats each. Group I received no further treatment; Group II received daily intraperitoneal injections of EHDP (7.5 mg/Kg of body weight during 10 days); Group III: 15 Gy of X-radiation were applied to the head; and Group IV were irradiated and injected with EHDP as were animals of Groups III and II. Half of the animals were killed after 14 days and the other half 30 days post-extraction. Sections were made at the level of the mesial socket of the first molar in a buccolingual orientation, on which histometric determinations of bone activity were made. The results showed the attenuation of the inhibitory effect of radiation on bone formation when the animals were treated with EHDP.     

Effect of platelet-rich plasma on bone healing of autogenous bone grafts in critical-size defects

Aim: This study histologically analysed the effect of autogenous platelet-rich plasma (PRP), prepared according to a new semiautomatic system, on healing of autogenous bone (AB) grafts placed in surgically created critical-size defects (CSD) in rabbit calvaria.
Material and Methods: Sixty rabbits were divided into three groups: C, AB and AB/PRP. A CSD was created in the calvarium of each animal. In Group C (control), the defect was filled by blood clot only. In Group AB (autogenous bone graft), the defect was filled with particulate autogenous bone. In Group AB/PRP (autogenous bone graft with platelet-rich plasma), it was filled with particulate autogenous bone combined with PRP. All groups were divided into subgroups ( n =10) and euthanized at 4 or 12 weeks post-operatively. Histometric and histologic analyses were performed. Data were statistically analysed ( anova , t -test, p <0.05).
Results: Group C presented significantly less bone formation compared with Group AB and AB/PRP in both periods of analysis ( p <0.001). At 4 weeks, Group AB/PRP showed a statistically greater amount of bone formation than Group AB (64.44 ± 15.0% versus 46.88 ± 14.15%; p =0.0181). At 12 weeks, no statistically significant differences were observed between Groups AB and AB/PRP (75.0 ± 8.11% versus 77.90 ± 8.13%; p >0.05). It is notable that the amount of new bone formation in Group AB/PRP at 4 weeks was similar to that of Group AB at 12 weeks ( p >0.05).
Conclusion: Within its limitation, the present study has indicated that (i) AB and AB/PRP significantly improved bone formation and (ii) a beneficial effect of PRP was limited to an initial healing period of 4 weeks.     

The linear shrinkage and microhardness of packable composites polymerized by QTH or PAC unit

This study evaluated the effectiveness of a plasma arc curing (PAC) unit for packable resin composite curing. The amount and speed of polymerization shrinkage and the microhardness of packable composites were evaluated in order to compare the PAC unit's effectiveness with a quartz tungsten halogen (QTH) unit. Sure Fil (Dentsply Caulk), Pyramid (BISCO Inc) and Synergy Compact (Colténe/Whaledent) were used as the packable composites. In the case of curing with the PAC unit, the composites were light cured with Apollo 95E (DMD System Inc) for 1 second (Group 1), 2 seconds (Group 2), 3 seconds (Group 3), 6 seconds (Group 4) and 12 seconds (Group 5). For light curing with the QTH unit, the composites were light cured for 60 seconds using XL3000 (Group 6). The linear polymerization shrinkage of each composite was measured using a custom made linometer, and the data was stored in a computer every 0.5 to 0.55 seconds for a total of 60 seconds. For each composite, the amount of polymerization was compared using one-way ANOVA with Tukey at the 95% confidence level. In order to compare the speed of polymerization, the peak time (PT), showing the highest speed of polymerization and maximum speed of polymerization (Smax), were determined from the data and compared using one-way ANOVA with Tukey at the 95% confidence level for each material. Based on the statistical analysis among the PAC-cure groups (Groups 1 through 5), the group that was not statistically different from the QTH-cure group (Group 6) in the amount of linear polymerization shrinkage was determined for each material, and the corresponding curing time of the group was defined as the tentative minimum PAC-curing time (TMPT). For microhardness measurements, the samples were placed in a 2-mm thick Teflon plate. Twenty specimens, randomly divided into the PAC-cure group (Group 1) or the QTH-cure group (Group 2), were prepared for each material. In Group 1, each composite was light cured for TMPT with the PAC unit. In Group 2, each composite was light cured for 60 seconds with the QTH unit. Microhardness was measured on the upper and lower surface. For each material, the microhardness of the upper and lower surface of Groups 1 and 2 was analyzed using two-way ANOVA with Tukey at the 95% confidence level. The amount of polymerization was Group 1相似文献   

The effect of salivary gland extracts on the histology of lymphoid organs and salivary glands in mice

Ligation of the excretory duct and artery of the submandibular gland (SMG) of male Swiss mice led to atrophy of the gland within 7 days. The effects of a crude extract of the SMG and sublingual gland (SLG) on the histology of spleen, thymus, lymph nodes, SMG and SLG were studied. Four groups of mice were used. Three groups were injected intraperitoneally for 7 consecutive days with SLG extract (Group I), SMG extract (Group II), saline (Group III) and Group IV was not treated. On day 7, the animals were killed and the spleen, thymus, salivary glands with the regional lymph nodes were weighed and fixed. Histological studies and histometric measurements were made of the thymus, the spleen and of the acinar and tubular areas of the SMG. The volumes of the SMG and SLG were also estimated. In the SMG and SLG, infiltration of mononuclear cells occurred in Groups I and II. At the same time there was a reduction of the tubular part of the SMG and a decrease in the volume of the SMG and SLG, compared with Groups III and IV. An immune response was detected in the spleen and regional lymph nodes and the number of lymphoblasts had increased in the cortex of the thymus. Injections of SMG and SLG extracts induced both an antibody and a cell-mediated immune response.     

Effect of diphosphonate on the prevention of X-radiation-induced inhibition of bone formation in rats

A histologic and histometric study of the effect of EHDP (ethane-1-hydroxy-1,1-diphosphonate) on the alveolar wound healing of irradiated animals is presented. This drug was selected based on its osteosclerotic effect when applied at low doses. The three left mandibular molars of 80 male Wistar rats were extracted. The rats were grouped into 4 sets of 20 rats each. Group I received no further treatment; Group II received daily intraperitoneal injections of EHDP (7.5 mg/Kg of body weight during 10 days); Group III: 15 Gy of X-radiation were applied to the head; and Group IV were irradiated and injected with EHDP as were animals of Groups III and II. Half of the animals were killed after 14 days and the other half 30 days post-extraction. Sections were made at the level of the mesial socket of the first molar in a bucco-lingual orientation, on which histometric determinations of bone activity were made. The results showed the attenuation of the inhibitory effect of radiation on bone formation when the animals were treated with EHDP.     

Evaluation of nano-technology-modified zirconia oral implants: a study in rabbits

Objective: The objective of this study was to screen candidate nano-technology-modified, micro-structured zirconia implant surfaces relative to local bone formation and osseointegration.
Materials and Methods: Proprietary nano-technology surface-modified (calcium phosphate: CaP) micro-structured zirconia implants (A and C), control micro-structured zirconia implants (ZiUnite™), and titanium porous oxide implants (TiUnite™) were implanted into the femoral condyle in 40 adult male New Zealand White rabbits. Each animal received one implant in each hind leg; thus, 20 animals received A and C implants and 20 animals received ZiUnite™ and TiUnite™ implants in contralateral hind legs. Ten animals/group were euthanized at weeks 3 and 6 when biopsies of the implant sites were processed for histometric analysis using digital photomicrographs produced using backscatter scanning electron microscopy.
Results: The TiUnite™ surface demonstrated significantly greater bone–implant contact (BIC) (77.6±2.6%) compared with the A (64.6±3.6%) and C (62.2±3.1%) surfaces at 3 weeks ( p <0.05). Numerical differences between ZiUnite™ (70.5±3.1%) and A and C surfaces did not reach statistical significance ( p >0.05). Similarly, there were non-significant differences between the TiUnite™ and the ZiUnite™ surfaces ( p >0.05). At 6 weeks, there were no significant differences in BIC between the TiUnite™ (67.1±4.2%), ZiUnite™ (69.7±5.7%), A (68.6±1.9%), and C (64.5±4.1%) surfaces ( p >0.05).
Conclusion: TiUnite™ and ZiUnite™ implant surfaces exhibit high levels of osseointegration that, in this model, confirm their advanced osteoconductive properties. Addition of CaP nano-technology to the ZiUnite™ surface does not enhance the already advanced osteoconductivity displayed by the TiUnite™ and ZiUnite™ implant surfaces.     

Surgical versus non surgical treatment and recurrent periodontal disease in beagle dogs

The present study was designed to compare clinical, microbiologic and histometric parameters of recurrent periodontal disease in areas which had been treated either surgically (SU) or nonsurgically (NS). Periodontal disease was induced for 6 months in 3 quadrants in each of 6 beagle dogs. 2 of the 3 diseased quadrants were treated by definitive surgical or nonsurgical therapy followed by plaque control for 4 months. 2 dogs were then sacrificed to provide histometric data. Periodontal disease was reinduced in the remaining 4 dogs by allowing plaque accumulation for 6 months after which the dogs were sacrificed for histometric analysis. Clinical parameters were recorded and darkfield microscopic analysis of subgingival plaque samples was performed at regular intervals. Following 6 months of plaque accumulation during disease reinduction, there were significant changes (p less than 0.05) in the pocket depths, bleeding scores and attachment levels in both the SU and NS areas. These changes were accompanied by significant increases (p less than 0.05) in the proportions of spirochetes and motile rods and decreases in the proportions of coccoid cells in both the SU and NS areas. There were, however, no significant differences between the SU and NS areas when clinical and microbiologic parameters were compared. At the end of disease reinduction phase, the length of inflammatory cell infiltrate and % inflamed connective tissue had increased significantly in both the SU and NS areas.(ABSTRACT TRUNCATED AT 250 WORDS)