Effect of print orientation, storage conditions, and storage time on intaglio surface accuracy of implant surgical guides fabricated by using a stereolithography technology.

STATEMENT OF PROBLEM: The accuracy of printed implant surgical guides can be affected by different factors that negatively impact the planned implant position. How print orientation, storage time, and conditions influence manufacturing accuracy remains uncertain. PURPOSE: The purpose of this in vitro study was to evaluate the influence of print orientation, storage conditions, and storage time on the intaglio surface accuracy of implant surgical guides manufactured by using a stereolithography (SLA) printer. MATERIAL AND METHODS: A tooth-supported maxillary implant surgical guide design (control file) was used to fabricate the specimens (N=40, n=10). Four groups were created based on the print orientation used: 0 (Group 0), 45 (Group 45), 70 (Group 70), and 90 degrees (Group 90). The specimens were fabricated using an SLA printer (Form 3B+) and a biocompatible dental resin (Surgical Guide Resin V1) following the manufacturer's recommended protocol. Each group was divided into 2 subgroups based on the storage conditions: light (L subgroup) and dark (D subgroup) settings. Each specimen was digitized by using a desktop scanner (Medit T710) at days 0, 1, 7, and 14. The control file and each digitized specimen were superimposed by using the best-fit technique with a metrology program (Geomagic Control X). The root mean square (RMS) error was used to calculate the discrepancies between the control files and specimen files. Three-way ANOVA and pairwise comparison Tukey tests were used to analyze trueness. The Levene test was used to assess precision (α=.05). RESULTS: Significant trueness discrepancies were found among the groups tested (P<.001), but no significant differences were found among the subgroups (P=.100) and the storage times analyzed (P=.609). Additionally, the Tukey test showed significant RMS error mean value discrepancies between Group 0 and Group 45 (P<.001), Group 0 and Group 90 (P<.001), Group 45 and Group 70 (P<.001), and Group 70 and Group 90 (P<.001). The Levene test revealed significant SD discrepancies among the groups tested (P<.05). CONCLUSIONS: The trueness and precision of the intaglio surface of the implant surgical guides manufactured by using the printer and material tested were affected by the print orientation. However, storage conditions over a 14-day period did not impact the intaglio accuracy of the specimens.

Effect of different storage conditions on the fit of 3D-printed occlusal devices used to treat temporomandibular disorders.

STATEMENT OF PROBLEM: Research-based storage guidelines for 3-dimensional (3D)-printed occlusal devices are lacking. PURPOSE: The purpose of this in vitro study was to investigate the dimensional stability of the internal surface of 3D-printed occlusal devices under different storage conditions. MATERIAL AND METHODS: Maxillary and mandibular dental casts were scanned and exported to a 3D printer to fabricate 30 occlusal devices. The specimens were stored under 3 different conditions (n=10): air dried and stored under natural light (group DL), stored in a dark container with water (group W), and air dried and stored in a dark container (group D). The intaglio surfaces of the occlusal devices were scanned by a laboratory scanner at 4 time points: immediately after polymerization (t0, control), after 1 day (t1), after 7 days (t2), and after 27 days (t3). The dimensional changes of the fitting surfaces between t0 and t1 (Δt1), t0 and t2 (Δt2), and t0 and t3 (Δt3) were measured by using best fit alignment in a surface analysis software program. In addition, comparisons were made between the posterior and anterior sections. Statistical analysis was completed with Kolmogorov-Smirnov, 1-way ANOVA, Friedman, Kruskal-Wallis, Mann-Whitney, and unpaired t tests. RESULTS: The root mean square (RMS) of group DL between Δt1 and Δt2 (P=.002) and between Δt1 and Δt3 (P=.002) showed a statistically significant difference. The RMS of group W between Δt1 and Δt3 (P=.008) showed a statistically significant difference. When the groups were compared with each other at the different time points, the DL group showed a statistically significant difference compared with groups W and D at Δt1. The examination of different areas of the occlusal device (right molar, incisor, and left molar sites) indicated no statistically significant differences in RMS among all groups (P>.05). CONCLUSIONS: The occlusal devices of group DL showed the least dimensional change of the fitting surface for Δt1 in comparison with group W and D, while no statistically significant differences were found among the groups for Δt2 and Δt3. In terms of the different locations, no statistically significant differences were found among the 3 locations for any given group after 27 days.

Effect of firing and fabrication technique on the marginal fit of heat-pressed lithium disilicate veneers.

STATEMENT OF PROBLEM: Studies on the fit of heat-pressed anterior lithium disilicate veneers are sparse, and whether fit is affected by glaze firing or ceramic addition is unclear. PURPOSE: The purpose of this in vitro study was to evaluate and compare the marginal fit of heat-pressed anterior lithium disilicate veneers (IPS e.max Press) fabricated with the staining or cutback technique by using 3-dimensional analysis. MATERIAL AND METHODS: Two groups of heat-pressed maxillary left central incisor lithium disilicate veneers were fabricated (n=10) differing only in core thickness and the fabrication process. The tooth preparation was standardized at 0.6 mm cervical and middle third and 0.7 mm incisal third, with 1.5 mm of incisal reduction. Group S (staining) was an anatomic contour veneer with 1 glaze firing. Group CB (cutback) had a cutback core of 0.6 mm on the cervical and middle third and 0.5 mm on the incisal areas for ceramic application with 3 firings (wash, incisal, and glaze firing). The amount of ceramic application was standardized, and all veneers had identical final dimensions. Marginal fit was evaluated at 2 stages: after pressing the copings (control) and after glaze firing or ceramic addition using the virtual replica technique and 3-dimensional analysis. The wax copings were invested, eliminated, and pressed with IPS e.max lithium disilicate high translucency ingots, and the overall marginal fit and change in marginal fit after firing were measured in the cervical, mesial, distal, and incisal areas. The Shapiro-Wilk test was used to evaluate normality. Repeated-measures ANOVAs were used to explore differences between the 2 groups (S and CB) as per time (before and after firing) for each location (cervical, mesial, distal, and incisal) (α=.05). RESULTS: A statistically significant change in marginal fit after firing was found for the mesial and distal areas of the CB group (P<.05). In all other areas of measurements, no statistically significant differences were found (P>.05). The mean ±standard deviation marginal fit of group S was 63 ±13 µm and 62 ±9 µm for group CB. CONCLUSIONS: The results suggest that firing affects the marginal fit of heat-pressed anterior lithium disilicate veneers fabricated with the cutback technique but not for the staining technique.

Flexural strength of denture base acrylic resins processed by conventional and CAD-CAM methods.

STATEMENT OF PROBLEM: High flexural strength is one of the desirable properties for denture base resins, yet only few studies have evaluated the physical properties of newer denture bases such as computer-aided design and computer aided manufacturing (CAD-CAM) milled products. PURPOSE: The purpose of this in vitro study was to compare the flexural strength of 3 different types of denture base resins: compression molded, injection molded, and CAD-CAM milled. MATERIAL AND METHODS: Three groups (n=10) of acrylic denture base resins were tested: injection molded, compression molded, and CAD-CAM milled resin. ISO-compliant, rectangular specimens were fabricated (64×10×3.3 mm) (n=30). Specimens were stored in water for 1 week, and flexural strength was measured by using a 3-point bend test until failure. The Student t test was used to evaluate differences in the flexural strength and modulus of elasticity among specimen groups. The Bonferroni formula was used to set significance at α=.017 to account for multiple comparisons among the 3 groups. RESULTS: The flexural strength of the CAD-CAM milled group was significantly higher than that of the other 2 groups (P<.001), while the strength of the compression molded group was significantly greater than that of the injection molded group (P<.001). The flexural modulus of the CAD-CAM group was significantly higher than that of the other 2 groups (P<.001). CONCLUSIONS: CAD-CAM milled denture bases may be a useful alternative to conventionally processed denture bases in situations where increased resistance to flexural strength is needed.

The Association Between Occlusal Status and the Soft and Hard Tissue Conditions Around Single-Unit Dental Implants.

The occlusal status of single-unit dental implants were evaluated using traditional and computerized methods. The type of occlusal contact in maximum intercuspation and the presence of occlusal contacts on the implant during eccentric movements were recorded. A digital sensor was used for computerized analysis of occlusion. Forty-four patients with 74 implants were included. Twenty-nine implants (39%) presented with "heavy" occlusal contacts, 40 implants (54.1%) presented with "light" contacts, and 5 implants (6.8%) presented with "no contact." No statistically significant association was found between the occlusal status and any of the soft and hard tissue condition variables (P > .05).

Effect of cement type on the clinical performance and complications of zirconia and lithium disilicate tooth-supported crowns: A systematic review. Report of the Committee on Research in Fixed Prosthodontics of the American Academy of Fixed Prosthodontics.

STATEMENT OF PROBLEM: Zirconia and lithium disilicate have been commonly used as materials for tooth-supported complete-coverage restorations. Adhesive and conventional cements have been suggested for cementation of these restorations. However, evidence on the effect of cement type on the clinical outcomes of teeth restored with zirconia or lithium disilicate restorations is unclear. PURPOSE: The purpose of this systematic review was to evaluate the clinical outcomes of teeth restored with zirconia or lithium disilicate restorations when adhesive or conventional cements are used. MATERIAL AND METHODS: This systematic review adopted the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and was registered at the international prospective register of systematic reviews (PROSPERO) (CRD42018096493). An electronic search was performed in 2 databases (MEDLINE-PubMed and Cochrane Central), and a manual search, from January 2008 through January 2018. The primary clinical question was framed according to the Problem/Patient/Population, Intervention/Indicator, Comparison, Outcome (PICO) approach. The following question was the primary clinical question: "For patients requiring a single tooth-supported complete-coverage ceramic restoration, does adhesive cementation, as compared with conventional cementation, improve the clinical performance and limit the complications of this restoration?" The search included articles published in peer-reviewed journals in English and was limited to randomized clinical trials and prospective and retrospective clinical studies. RESULTS: Seventeen clinical studies met the eligibility criteria and were included for qualitative analysis. Included studies had 1280 participants who received 2436 zirconia and lithium disilicate crowns. The survival rates for adhesively cemented zirconia crowns ranged from 83.3% to 100%, whereas those reported for conventionally cemented zirconia crowns ranged from 82.0% to 100%. Survival rates for adhesively cemented lithium disilicate crowns ranged from 83.5% to 100%, whereas the survival rate reported for conventionally cemented lithium disilicate crowns was 98.5%. Commonly reported clinical complications included fracture of the veneering ceramic, crown fracture, and loss of crown retention. The mean follow-up time ranged from 25.5 months to 121.2 months. The studies that were assessed for risk of bias showed poor quality of evidence. CONCLUSIONS: Based on the available evidence and within the limitations of this systematic review, zirconia and lithium disilicate tooth-supported crowns exhibited comparable survival rates and complication patterns after adhesive or conventional cementation.

Accuracy of three digital workflows for implant abutment and crown fabrication using a digital measuring technique.

STATEMENT OF PROBLEM: The accuracy of a full digital workflow using an Atlantis abutment and a milled zirconia crown; a full digital workflow with a 3Shape split-file workflow using a zirconia abutment and crown; and an interrupted digital workflow using an Atlantis abutment and a milled zirconia crown is unclear. PURPOSE: The purpose of this in vitro study was to compare 2 full digital workflows relative to an interrupted workflow for restoring an implant with a custom abutment and crown. The secondary purpose of this study was to validate a digital means of measuring internal fit and marginal discrepancy using engineering software programs. MATERIAL AND METHODS: Three workflows were evaluated. The first group, interrupted digital Atlantis (IDA) workflow, included a customized Atlantis abutment that was designed, received, and then rescanned for the definitive crown design. The second group, full digital Atlantis (FDA) workflow, included a customized Atlantis abutment and its corresponding standard tessellation language (STL) file, the Atlantis Core File, which was immediately imported into design software and used for crown design and milling. The third group, full digital split-file (FDSF) workflow, used 3Shape's full digital workflow for abutment and crown design called the split-file workflow, in which the crown and abutment were designed and milled simultaneously. All restorations were evaluated with standardized measurements using a scanning electron microscope (SEM) for 2D measurements, followed by standardized measurements using Geomagic Control, an engineering software program, which facilitated 3D evaluations of the specimens. RESULTS: The 2 Atlantis workflows, IDA and FDA, had statistically smaller marginal openings (P=.002) than the FDSF when measured using 2D SEM. The FDA had a statistically smaller 2D SEM marginal gap than the other 2 groups, IDA (P=.002) and FDSF (P=.002). The FDA had a statistically smaller 3D Geomagic marginal gap than the other 2 groups, IDA (P=.004) and FDSF (P=.006). The FDSF had a statistically smaller 3D Geomagic internal fit than the other 2 groups, FDA and IDA (both P=.006). CONCLUSIONS: All 3 workflows evaluated in this study showed clinically acceptable results in terms of mean marginal gap below 120 µm. The SEM evaluation of mean marginal opening revealed that IDA and FDA mean marginal openings were statistically smaller than the FDSF mean marginal opening. SEM and Geomagic measurements revealed that the FDA mean marginal gap was significantly smaller than IDA and FDSF mean marginal gaps. Geomagic evaluation of mean internal fit revealed that the FDSF was significantly smaller than IDA and FDA. The use of Geomagic to measure and evaluate mean marginal gap and mean internal fit as defined in this study proved to be an acceptable form of measurement with statistical validation.

Preclinical Evaluation of a Crown-Splinted Custom Root-Shaped Implant.

OBJECTIVE: To test whether a Maryland bridge-type splint provides adequate stability for a custom root-shaped implant to osseointegrate in a manner substantially equivalent to that of a threaded implant. METHODS: Six beagle dogs were subjected to intraoral impressions and cone beam scans that were used to fabricate custom root-shaped implants (RTIs) and crowns. Premolars in the mandible (P4) and in the maxilla (P3) were extracted, and 24 RTIs were immediately placed in extraction sockets. Splint extensions of the crowns were bonded to mesial and distal teeth. Twelve mandibular molars (M2) were extracted, and threaded implants (DXI), serving as controls, were placed immediately. Animals were placed on a soft diet after surgery. Weekly intraoral photographs and radiographs were taken, and animals were sacrificed at 4 months. Fluorescent labels were injected 35, 21, and 7 days before sacrifice. Clinical implant stability and vertical pullout forces were tested, and loss of vertical bone height was measured on radiographs. Histomorphometric measurements of percent bone-to-implant contact (BIC) and mineral apposition rates were made from undecalcified sections. RESULTS: Three RTI splints broke or debonded, and the implants were removed. No loss of DXI implants was noted. All remaining implants were clinically stable. Mean pullout forces were 366.7 ± 182.8 N for RTI (no pullout data for the threaded DXI). Mean vertical bone loss was 0.4 ± 0.6 mm mesially and 0.2 ± 0.7 mm distally for RTI and 0.8 ± 1.1 mm mesially and 0.8 ± 1.0 mm distally for DXI, with no significant differences between groups. BIC values were 70.8% ± 12.7% for mandibular RTI, 68.3% ± 11.6% for maxillary RTI, and 78.8% ± 5.5% for DXI. Mineral apposition rates within local osteons were 1.9 ± 0.5 µm for RTI and 1.7 ± 0.3 µm for DXI; at the implant surface, they were 2.5 ± 1.2 µm for RTI and 3.3 ± 1.8 µm for DXI, with no significant differences between groups. CONCLUSION: All RTIs with intact splints exhibited clinically successful integration, similar to that of control threaded implants. The RTI may be a viable option for single-tooth replacement.

The Role of Occlusion in the Dental Implant and Peri-implant Condition: A Review.

Dental implants have become a widely used dental treatment approach. It is important to identify factors that can be detrimental to dental implants and the peri-implant complex. There is controversy regarding whether occlusion plays a role in the implant and peri-implant condition. The present study aims to review the scientific literature regarding this topic. Animal and human studies, and previous reviews on the topic are included and presented. There is a wide heterogeneity among study designs. Several articles demonstrated that occlusion and occlusion overload could detrimentally affect the peri-implant condition, while other articles did not support these results. More studies are needed to help understand the mechanisms by which occlusion might play a role in the peri-implant condition.

Effect of longitudinal flutes on miniscrew implant stability and 3-dimensional bone formation.

INTRODUCTION: The purpose of this study was to evaluate the effects of longitudinal flutes on miniscrew implant (MSI) stability and bone healing. METHODS: Using 11 skeletally mature New Zealand white rabbits, we placed 31 longitudinally fluted and 31 nonfluted, 3-mm-long MSIs in standardized positions in their calvaria and immediately loaded them with 100 g using nickel-titanium coil springs. Insertion torque values were obtained for each MSI placed; removal torque values were obtained for 28 MSIs that had been in place for 6 weeks and 20 MSIs that had been in place for 2 weeks. The bone volume fractions at 6 to 24, 24 to 42, and 42 to 60 µm from the MSI surfaces were evaluated using microcomputed tomography with an isotropic resolution of 6 µm. RESULTS: The success rate was 97% for both the fluted and nonfluted MSIs. The difference in insertion torque between the fluted and nonfluted MSIs was not statistically significant (P = 0.930). After 2 weeks, there was no statistically significant (P = 0.702) difference in removal torque between the fluted and nonfluted MSIs. After 6 weeks, removal torque values were significantly (P = 0.008) higher for the fluted (3.42 ± 0.26 N.cm) than the nonfluted (2.49 ± 0.20 N.cm) MSIs. Bone volume fractions of the 6-to-24-, 24-to-42-, and 42-to-60-µm layers were significantly (P <0.05) greater for the nonfluted than the fluted MSIs. CONCLUSIONS: Loaded 3-mm-long MSIs with and without flutes have high success rates. Longitudinal flutes placed in 3-mm MSIs increased their removal torque by 37% and decreased the amount of bone immediately surrounding them.

Elastic Properties of Chimpanzee Craniofacial Cortical Bone.

Relatively few assessments of cranial biomechanics formally take into account variation in the material properties of cranial cortical bone. Our aim was to characterize the elastic properties of chimpanzee craniofacial cortical bone and compare these to the elastic properties of dentate human craniofacial cortical bone. From seven cranial regions, 27 cylindrical samples were harvested from each of five chimpanzee crania. Assuming orthotropy, axes of maximum stiffness in the plane of the cortical plate were derived using modified equations of Hooke's law in a Mathcad program. Consistent orientations among individuals were observed in the zygomatic arch and alveolus. The density of cortical bone showed significant regional variation (P < 0.001). The elastic moduli demonstrated significant differences between sites, and a distinct pattern where E3 > E2 > E1 . Shear moduli were significantly different among regions (P < 0.001). The pattern by which chimpanzee cranial cortical bone varies in elastic properties resembled that seen in humans, perhaps suggesting that the elastic properties of craniofacial bone in fossil hominins can be estimated with at least some degree of confidence. Anat Rec, 299:1718-1733, 2016. © 2016 Wiley Periodicals, Inc.

The Effect of an Er,Cr:YSGG Laser in the Management of Intrabony Defects Associated with Chronic Periodontitis Using Minimally Invasive Closed Flap Surgery. A Case Series.

Aims: This is an extended case series of patients treated with an Erbium, Chromium: Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) laser as an adjunct to scaling for the management of intrabony defects. Materials & methods: 46 patients with 79 angular intrabony defects associated with pocket depths of >5mm, and a mean age of 53 ± 9 years presenting with chronic periodontitis were included in the analysis. All patients underwent a localized minimally invasive closed flap surgery utilizing Er,Cr:YSGG laser therapy. Final radiographs and pocket depths were compared to pretreatment measurements with a time period of 8 ± 3 months. Results: Treatment resulted in significant overall pocket depth reduction. The mean pre-op probing depth was 8.1 ± 1.9mm, reducing to 2.4 ± 0.9mm post-treatment. Bony infill of the defects was visible radiographically and there was an increase in overall radiographic coronal osseous height compared to a pre-treatment baseline. Radiographs of 15 of the defects were available for further measurements after >12 months, and showed in these sites there was a significant reduction in intrabony defect depth, but no change in suprabony bone height. 9 of the 15 sites showed 50% or more, bony infill of the intrabony defect. Conclusions: The results demonstrate that the utilization of an Er,Cr:YSGG laser in a closed flap approach with chronic periodontitis may be of significant clinical benefit. Further studies using this laser surgical protocol are required to test these observations in well-designed randomized controlled trials.

Enamel-Caries Prevention Using Two Applications of Fluoride-Laser Sequence.

Studies demonstrated a significant synergism between fluoride and laser in reduction of enamel solubility. However, minimal research has focused on testing the sequence of their application and no other research investigated the preventive effect of repeated applications of a combined treatment. This study investigated the effect of two applications of fluoride-laser sequence on the resistance of sound enamel to cariogenic challenge compared to one-time application. Sixty enamel slabs were cut from 10 human incisors, ground flat, polished and coated with nail varnish except a 2 x 2 mm window. Specimens were randomly assigned into five groups of 12 specimens; (CON-) negative-control received no treatment, (CON+) positive-control received pH challenge, (FV) treated with M fluoride varnish, (F-L1) one-application fluoride-varnish followed by CO2 laser-treatment (short-pulsed 10.6 µm, 2.4J/ cm2, 10HZ, 10sec), and (F-L2) two-applications of fluoride varnish-laser treatment. Specimens were left in distilled water for one day between applications. Except CON-, all groups were submitted to pH cycling for 9-days (8 demin/ remin + 1 day remineralisation bath) at 37°C. Enamel demineralization was quantitatively evaluated by measurement of Knoop surface-microhardness (SM H) (50-grams/10 seconds). Data were analyzed using one-way ANOVA (p ≤ 0.05) followed by Duncan's Multiple Range Test. Within the limitations of this study, it was found that one or two applications of fluoride-laser sequence significantly improved resistance of the sound enamel surface to acid attack compared to FV-treated group. Although the two applications of fluoride-laser sequence (F-L1 and F-L2) showed higher SMH values, significant resistance to demineralization was only obtained with repeated applications.

Fracture resistance of lithium disilicate restorations after endodontic access preparation: An in vitro study.

STATEMENT OF PROBLEM: Endodontic access preparation through a lithium disilicate restoration is a frequently encountered clinical situation. The common practice of repairing the accessed crown with composite resin may result in a weakened restoration. PURPOSE: The purpose of this in vitro study was to determine the effect of endodontic access preparation on the fracture resistance and microstructural integrity of monolithic pressed and monolithic milled lithium disilicate complete coverage restorations. MATERIAL AND METHODS: Twenty monolithic pressed (IPS e.max Press) and 20 monolithic milled (IPS e.max CAD) lithium disilicate restorations were fabricated. Ten of the pressed and 10 of the milled crowns were accessed for a simulated endodontic treatment and subsequently repaired by using a porcelain repair system and composite resin. All specimens were submitted to cyclic loading and then loaded to failure. Force data were recorded and analyzed with 2-way ANOVA followed by a post hoc test (Sidak correction) to indicate significant differences among the groups (α=.05). A Weibull analysis was also performed for each group. Eight (4 pressed and 4 milled) additional restorations were fabricated to complete a scanning electron microscope (SEM) analysis and evaluate the surface damage created by the endodontic access preparation. RESULTS: A statistically significant difference (P=.019) was found between the pressed intact and pressed repaired restorations and between the pressed intact and milled repaired restorations (P=.002). Specimens that were examined with an SEM showed edge chipping involving primarily the glaze layer around the access openings. CONCLUSIONS: Endodontic access preparation of lithium disilicate restorations resulted in a significantly reduced load to failure in the pressed specimens, but not in the milled specimens.

Fracture resistance of compromised endodontically treated teeth restored with bonded post and cores: An in vitro study.

STATEMENT OF PROBLEM: It is unclear which post and core system performs best when bonded to severely compromised endodontically treated teeth. PURPOSE: The purpose of this study was to investigate the fracture resistance and mode of failure of severely compromised teeth restored with 3 different adhesively bonded post and core systems. MATERIAL AND METHODS: Thirty extracted endodontically treated maxillary anterior teeth were randomly divided into 3 groups, CPC, gold cast post and core; TPC, titanium prefabricated post/composite resin core; and FPC, quartz fiber reinforced post/composite resin core. All posts were adhesively cemented. All cores resembled a central incisor preparation with no remaining tooth structure above the finish line. Cast gold crowns were fabricated and cemented adhesively. The specimens were aged with thermocycling and cyclic loading. Two specimens per group were randomly selected for micro-computed tomographic imaging before and after aging. Failure was induced with a universal testing machine. The mode of failure was characterized by the interface separation. Data were analyzed with 1-way ANOVA (α=.05) followed by post hoc tests (Bonferroni). RESULTS: A statistically significant difference was found among the 3 groups (P=.002). CPC was significantly different than TPC (P=.008) or FPC (P=.003). The primary mode of failure for CPC and TPC was root fracture, and for FPC post debonding. CONCLUSIONS: Severely compromised endodontically treated teeth restored with bonded gold cast post and cores showed significantly higher fracture resistance.

Congenital adrenal hyperplasia: a case report with premature teeth exfoliation and bone resorption.

Congenital adrenal hyperplasia (CAH) is an inherited autosomal recessive disorder characterized by insufficient production of cortisol. The aim of this case report was to present a child with CAH, premature exfoliation of primary teeth and accelerated eruption of his permanent teeth related to bone resorption. A 4.5-year-old Caucasian boy with CAH and long-term administration of glucocorticoids was referred for dental restoration. Clinical examination revealed primary molars with worn stainless steel crowns, severe attrition of the upper canines, and absence of the upper incisors. Before the completion of treatment, abnormal mobility of the first upper primary molars and the lower incisors was detected, and a few days later the teeth exfoliated prematurely. Histologic examination revealed normal tooth structure. Alkaline phosphatase and blood cells values were normal. Eruption of the permanent dentition was also accelerated. Tooth mobility was noticed in the permanent teeth as soon as they erupted, along with bone destruction. Examination revealed an elevated level of receptor activator of nuclear factor-κB ligand and lower-than-normal osteoprotegerin and vitamin D levels. The patient was treated with vitamin D supplements, and his teeth have been stable ever since. CAH is a serious chronic disorder appearing in children with accelerated dental development and possibly premature loss of primary teeth.

Reduction in dental hypersensitivity with nano-hydroxyapatite, potassium nitrate, sodium monoflurophosphate and antioxidants.

OBJECTIVE: This clinical study aimed to evaluate effectiveness of a commercially available toothpaste containing potassium nitrate, sodium monoflurophosphate, and nano-hydroxyapatite as well as antioxidants phloretin, ferulic acid and silymarin in reducing dental hypersensitivity in adults. METHODS: The clinical trial enrolled patients with a history of dentin hypersensitivity. A test toothpaste was introduced into the daily routine, which included initial instruction on usage. Patients completed a five-question visual analog scale (VAS) at the inception/baseline, after two days and after two weeks of using the toothpaste to determine their level of tooth sensitivity at baseline with the use of the toothpaste over time. RESULTS: Patients that had significant sensitivity at baseline had a range of 52% to 76 % improvement after 48 hours and a range of 70% to 84% improvement after two weeks. CONCLUSION: A toothpaste containing potassium nitrate, sodium monoflurophosphate, and nano-hydroxyapatite plus antioxidants phloretin, ferulic acid and silymarin applied daily significantly decreased tooth pain of dentin hypersensitivity within a two-day and two-week time period. CLINICAL SIGNIFICANCE: Based on the clinical study results, a daily application of a toothpaste containing potassium nitrate, sodium monofluorophosphate, and nano-hydroxyapatite plus antioxidants phloretin, ferulic acid and silymarin can significantly and quickly reduce tooth pain of dentin hypersensitivity.

Dentate transport discs can be used to reconstruct large segmental mandibular defects.

PURPOSE: This study tested the use of a dentate transport segment for the reconstruction of a large U-shaped defect in the anterior segment of the canine mandible using a novel curved reconstruction plate. The quality and quantity of bone regenerate formed by dentate versus edentulous transport segments were compared. MATERIALS AND METHODS: In 5 adult foxhound dogs, a defect of 70 to 75 mm was created in the canine mandible by excising the mandible anterior to the right and left fourth premolars. Reconstruction was performed by trifocal distraction osteogenesis using a bone transport reconstruction plate (BTRP-02), with 2 transport units being activated simultaneously, one on either side of the defect, 1 dentate and 1 edentulous. Bilateral distraction proceeded at a rate of 1 mm/day until the segments docked against each other in the midline. After 39 to 44 days of consolidation, the animals were euthanized. The quantity and quality of bone regeneration on the 2 sides were compared using micro-computed tomography. RESULTS: The defect reconstruction was successful. The amount and quality of bone formed by the transport segments were similar on the 2 sides. There were no major differences in the bone volume fraction and density of the regenerate bone formed by the 2 transport segments. The bone volume fraction and density of the regenerate bone were considerably lower than those of the host bone in the distal segments, likely owing to the short consolidation period. CONCLUSIONS: Bone transport remains a viable option in reconstructing anterior segmental defects in the mandible. The use of dentate or edentulous transport segments for reconstruction provides options for the surgeon in often highly compromised patients requiring these surgeries.

Local application of zoledronate enhances miniscrew implant stability in dogs.

INTRODUCTION: The primary purposes of this study were to evaluate how locally delivered zoledronate affects the longitudinal stability of miniscrew implants (MSIs) and the healing of bone around MSIs. METHODS: Using a randomized split-mouth design, 60 unloaded MSIs (5 × 1.6 mm) were placed in skeletally mature male foxhound-mixed breed dogs. The MSIs were randomly assigned to bilateral pairs of pilot holes (1.1 mm) that had been injected with either bisphosphonate zoledronate (n = 30, experimental group) or buffered saline solution (n = 30, control group). MSI stability was evaluated weekly for 8 weeks using resonance frequency analyses (Osstell Mentor; Integration Diagnostics, Göteborg, Sweden). Microcomputed tomography (6-µm voxel size) was used to determine the bone volume fractions of 3 layers of bone (6-24, 24-42, and 42-60 µm) surrounding the MSIs. RESULTS: Resonance frequency analysis showed that the control MSIs were significantly (P <0.05) less stable than the experimental MSIs. Although there was little or no change in stability over time for the MSIs treated with zoledronate, the stability of the control MSIs decreased during the first 4 weeks, increased through week 6, and then decreased again. The 6- to 24-µm layer closest to the MSIs, on both the experimental and the control sides, showed significantly (P <0.05) less bone than did the 24- to 42-µm and the 42- to 60-µm layers. After 8 weeks, there was significantly more cortical bone surrounding the control than the experimental MSIs. In contrast, there was significantly more trabecular bone surrounding the experimental than the control MSIs. CONCLUSIONS: One small locally delivered dose of zoledronate maintained the stability of MSIs over time, primarily because of greater amounts of trabecular bone surrounding the MSIs. Even though zoledronate enhanced the stability of MSIs in dogs, it should not be used clinically until further studies confirm its safe use in patients.

Evaluation of a topical gel containing a novel combination of essential oils and antioxidants for reducing oral malodor in dogs.

OBJECTIVE: To evaluate the effectiveness of a topically applied gel containing essential oils (menthol and thymol) and polyphenolic antioxidants (phloretin and ferulic acid) for reducing halitosis in dogs. ANIMALS: 20 dogs. PROCEDURES: A blinded crossover clinical trial was conducted. Dogs received a dental cleaning and examination (periodontal examination including periodontal probing and assessments of plaque, calculus, and gingivitis). Owners then applied a gel (active or placebo) to oral soft tissues twice daily for a 4-week period. Teeth of the dogs were cleaned again, and owners applied the other gel for a 4-week period. Clinicians scored halitosis immediately after the initial cleaning and at 4 and 8 weeks, and owners scored halitosis weekly. RESULTS: Halitosis assessment by clinicians revealed that both groups had improvement in halitosis scores. Two dogs were removed because of owner noncompliance. In the active-to-placebo group (n = 9), halitosis was significantly reduced during application of the active gel but increased during application of the placebo. Seven of 9 owners reported increased halitosis when treatment was changed from the active gel to the placebo. In the placebo-to-active group (n = 9), halitosis decreased during application of the placebo and continued to decrease during application of the active gel. Seven of 9 owners reported a decrease in halitosis with the active gel. CONCLUSIONS AND CLINICAL RELEVANCE: An oral topically applied gel with essential oils and polyphenolic antioxidants applied daily after an initial professional dental cleaning decreased oral malodor in dogs.