Effect of Split-File Digital Workflow on Crown Margin Adaptation.

PURPOSE: Computer-aided design/computer-aided manufacturing (CAD/CAM) is becoming increasingly integrated into dental practice workflow at a pace that exceeds scientific validation. The aim of this study is to evaluate a complete digital split-file protocol relative to segmental digital and analog techniques for restoring a single maxillary anterior edentulous space with custom abutment and crown. MATERIALS AND METHODS: Four treatment workflows were assessed: complete digital (CD), segmental digital (SD), milled wax (AM), and heat pressed and hand waxed (AH) and heat pressed. The CD workflow "split" an abutment and crown into separate files to fabricate a zirconia abutment and both zirconia/lithium disilicate crown restorations. The SD workflow scanned the existing abutment for design of segmental restorations in zirconia, lithium disilicate, and milled wax (AM). The AH specimens were conventionally hand waxed. Both the AM and AH specimens were heat pressed with lithium disilicate. All restorations were evaluated with standardized measurements using scanning electron microscopy (SEM) as manufactured without internal adjustments and after manual adjustment. The number of adjustments, adjustment time, and location of adjustments were recorded. One-way ANOVA with repeated measures was used to report geometric means with 95% confidence intervals. RESULTS: The mean marginal gap after adjustment of the CD group was 69 µm, with an upper bound (UB) of 79 µm and a lower bound (LB) of 60 µm. SD group mean was 26 µm with an UB of 31 µm and LB of 22 µm. The AM group mean was 32 µm, with an UB of 49 µm and a LB of 20 µm; AH group mean of 26 µm with an UB of 34 µm and a LB of 20 µm. The SD, AM, and AH workflows were statistically similar (p = 1.000), and the CD workflow was statistically greater than the other three (p < 0.001). CONCLUSIONS: The split-file (CD) protocol results in marginal gap size within clinical standards after adjustment; however, 52 of the 60 digitally produced restorations showed a horizontal marginal offset that required adjustment for proper contours.

A lateral ridge augmentation study to evaluate a synthetic membrane for guided bone regeneration: an experiment in the canine mandible.

OBJECTIVES: To evaluate guided bone regeneration outcomes in defects protected with an in situ formed polyethylene glycol (PEG) hydrogel membrane as compared to a non-cross-linked collagen membrane (CM). MATERIAL AND METHODS: Four mandibular alveolar ridge defects were created in eight hound dogs. Regenerative procedures were randomly allocated to one of four groups consisting of freeze-dried bone allograft, which is referred to in this study as freeze-dried bone xenograft (FDBX) + PEG, autogenous bone (AB) + PEG, AB + CM, and AB alone. After 8 weeks, titanium dental implants were placed into augmented sites. After 8 weeks of allowed time for osseointegration, the animals were sacrificed to harvest block specimens for bone-to-implant contact (BIC) and ridge width histomorphometric analysis. RESULTS: Polyethylene glycol membranes had an exposure rate of 50% as compared to 12.5% for sites grafted with CM. Regenerative outcomes with respect to implant placement were least favorable for FDBX + PEG which had implants placed in 37.5% of augmented sites compared to 100% implant placement for all other groups. No statistically significant differences were noted between groups for ridge width measurements in implant and non-implant histologic sections (P > 0.05). Buccal BIC (%) values between treatment groups also failed to reach statistical significant difference (FDBX + PEG [60.2 ± 9.4]; AB + PEG [58.8 ± 8.5]; AB + CM [57.9 ± 12.8]; AB [61.0 ± 10.2]). CONCLUSION: When used in conjunction with FDBX, PEG had unpredictable bone formation and in most cases negatively impacted future implant placement.

A cone beam computed tomography (CBCT) study of buccal plate thickness of the maxillary and mandibular posterior dentition.

BACKGROUND: Buccal plate thickness is of clinical importance in treatment planning for implants. The purpose of this study was to evaluate the buccal plate thickness in posterior dentate areas of both the maxilla and mandible using cone beam computed tomography in order to estimate the approximate distributions of this anatomic variable. METHODS: Two hundred and sixty-five subjects were included for a total of nine hundred and thirty-four roots assessed by cone beam computed tomography. CBCT scans were taken and evaluated at the ideal buccolingual cross-sections of each root at 1 mm, 3 mm, and 5 mm apical to the alveolar crest to measure buccal plate thickness. Data are reported by geometric means and 95% confidence intervals. RESULTS: Both arches demonstrated increasing buccal plate thickness from anterior to posterior. Maxillary teeth had a significant decrease in thickness from coronal to apical along the tooth root (P < 0.001), except at second molars. The first premolar and mesial root of the first molar were significantly thinner than all other roots in the maxilla. Conversely, the mandible demonstrated a significant increase in buccal plate thickness from coronal to apical (P < 0.001). The premolars were significantly thinner than all other roots. Age and sex were found to have limited impact on buccal plate thickness in both arches. CONCLUSIONS: Buccal plate thickness is highly dependent upon the arch position, tooth location, and measurement point, but age and sex have limited impact.

Evaluation of 3 dental unit waterline contamination testing methods.

Previous studies have found inconsistent results from testing methods used to measure heterotrophic plate count (HPC) bacteria in dental unit waterline (DUWL) samples. This study used 63 samples to compare the results obtained from an in-office chairside method and 2 currently used commercial laboratory HPC methods (Standard Methods 9215C and 9215E). The results suggest that the Standard Method 9215E is not suitable for application to DUWL quality monitoring, due to the detection of limited numbers of heterotrophic organisms at the required 35°C incubation temperature. The results also confirm that while the in-office chairside method is useful for DUWL quality monitoring, the Standard Method 9215C provided the most accurate results.

Co-relationships between glandular salivary flow rates and dental caries.

OBJECTIVE: This study was designed to evaluate the relationship of age, gender, ethnicity and salivary flow rates on dental caries in an adult population using data collected from the Oral Health San Antonio Longitudinal Study of Aging (OH: SALSA). BACKGROUND: Saliva is essential to maintain a healthy oral environment and diminished output can result in dental caries. Although gender and age play a role in the quantity of saliva, little is known about the interaction of age, gender and ethnicity on dental caries and salivary flow rates. MATERIALS AND METHODS: Data from the 1147 participants in the OH: SALSA were analysed. The dependent variables were the number of teeth with untreated coronal caries, number of teeth with root caries and the number of coronal and root surfaces with untreated caries. The independent variables were stimulated and unstimulated glandular salivary flow rates along with the age, sex and ethnicity (e.g. European or Mexican ancestry) of the participants. RESULTS: Coronal caries experience was greater in younger participants while root surface caries experience was greater in the older participants. Coronal caries was lower in the older age groups while the root caries experience increased. Men had a statistically significant (p < 0.02) higher experience of root caries than women. Values for unstimulated and stimulated parotid salivary flow rates showed no age difference and remained constant with age, whereas the age differences in the unstimulated and stimulated submandibular/sublingual salivary flow rates were significant. The mean number of teeth with coronal and root caries was higher in Mexican-Americans than in European-Americans. CONCLUSIONS: Over one-fourth of the adults between the ages of 60 and 79 have untreated root caries over one-third having untreated coronal caries. Lower salivary flow rates play a significant role in both the number of teeth and the number of surfaces developing caries in these adults. Women and individuals of European-American ancestry experience less caries.

Conventional SLA and chemically modified SLA implants in patients with poorly controlled type 2 diabetes mellitus--a randomized controlled trial.

OBJECTIVE: The objective of this study was to evaluate the potential for a chemically modified Sand blasted, Large grit, Acid etched (SLA) surface, compared with a conventional SLA surface, to enhance implant healing and integration in poorly controlled diabetic patients, a group previously demonstrated to have compromises and delays in implant stabilization during the metabolically active healing period following implant placement. MATERIALS AND METHODS: The study enrolled 24 patients with type 2 diabetes, baseline HbA1c levels between 7.5-11.4%, and a minimum of two posterior mandibular tooth sites at least 4 months following extraction and appropriate for implant placement. Each patient, at a randomly selected site, received an implant with the conventional SLA surface; at the second site, the patient received an implant with the chemically modified SLA (modSLA) surface. Thus, 48 study implants were placed. Implant stability was assessed using Resonance Frequency Analysis (RFA). Readings were taken from the buccal and proximal directions for each implant. Implant stability (ISQ) was assessed at the time of surgical placement (baseline) and 2, 3, 4, 6, 8, 10, 12, and 16 weeks following implant placement. RESULTS: No significant differences in implant stability were observed between conventional SLA implants and modSLA implants, and the time courses of implant stabilization following implant placement were similar for the two implant types. Baseline ISQ and minimum ISQ was slightly higher in subjects with higher HbA1c levels, but were similar during 12-16 weeks following implant placement. Forty-seven (98%) of the 48 implants were determined to be successfully osseointegrated and continued to restoration. CONCLUSION: Implant stabilization was similar for the conventional SLA and chemically modified SLA implants in type 2 diabetic patients with relatively poor glycemic control. Furthermore, this study demonstrated clinically successful implant placement even in poorly controlled diabetic patients.

The biofilm-controlling functions of rechargeable antimicrobial N-halamine dental unit waterline tubing.

OBJECTIVE: A study was conducted to test the biofilm-controlling functions of N-halamine tubing over an eight-month period. METHODS: A laboratory system, simulating a teaching dental clinic, was used to test rechargeable N-halamine tubing (T) compared to an untreated control (C) using the unit manufacturer's tubing. For the long-term study, a recharged tubing (RC) treated with bleach was used to compare with the test (T) and the control (C) tubing. Source tap water was cycled through the lines at 1.4 mL/minute, five minutes on and 25 minutes off, eight hours/day, five days/week. Every three weeks, samples of effluent, recovered adherent bacteria from inside tubing surfaces, and SEM images were examined for bacterial and biofilm growth. After sampling, a recharging solution of chlorine bleach (1 : 10 dilution) was run through T and RC lines, left overnight, and rinsed out the next morning. One-way ANOVAs and Spearman correlations were performed to detect significant differences for T, RC, and C, and determine significance with time period and source water, respectively. RESULTS: Mean log CFU/mL for C effluent > T (p = 0.028), and C tubing > T (p = 0.035). Spearman correlations were significant between effluent and source water level for T (rho = 0.817), and T tubing (0.750); between RC tubing and source water level (rho = 0.836), and time (rho = 0.745); and between C and time (rho = 0.873). SEM imaging confirmed the presence of biofilm inside RC and C, but not inside T. CONCLUSION: N-halamine tubing completely inhibited biofilm formation without negatively affecting the physical properties of the effluent water. Further research on N-halamine tubing using a pure water source is recommended, as T effluent bacterial levels reflected the source tap water quality and proliferation of planktonic bacteria with no biofilm activity.

A prospective randomized clinical study of changes in soft tissue position following immediate and delayed implant placement.

PURPOSE: The purpose of this investigation was to compare the efficacy of two therapeutic options-immediate implant placement and ridge preservation with delayed implant placement-in maintaining the position of the soft tissue margins following tooth extraction. MATERIALS AND METHODS: This randomized controlled study evaluated apicocoronal changes in the midbuccal and proximal mucosal positions at implant placement sites from tooth extraction to 3 and 6 months following extraction. Twenty-four patients (26 sites) randomly received either immediate implant placement or ridge preservation (grafting with freeze-dried bone allograft and a collagen membrane) followed by implant placement 3 months later. Immediate placement sites received bone grafting for horizontal defects > 2 mm (from implant to cortical wall). Soft tissue measurements, vertical measurements, and ridge width measurements were performed and compared for immediate versus delayed implants and thin versus thick biotype. RESULTS: The midbuccal soft tissue margins showed minimal recession over 6 months from the time of extraction (mean 0.17 +/- 0.47 mm), with no differences between treatment groups. Interproximal tissue height decreased significantly from extraction to 6 months (mesial, 1.73 +/- 0.71 mm; distal, 1.48 +/- 0.80 mm), with no significant differences between immediate and delayed placement. Immediate implant sites had greater reductions in ridge width 6 months after extraction than delayed placement sites. Tissue biotype failed to show any significant relationship with the changes identified. CONCLUSIONS: This randomized controlled study comparing soft tissue changes following extraction failed to identify differences between patients treated with immediate or delayed approaches for midbuccal or interproximal soft tissue margins, although greater decreases in ridge width were observed in sites lacking bone grafting. Both immediate and delayed treatment approaches appear to be appropriate following tooth extraction, with the preferred treatment based on factors other than resultant soft tissue changes.

Bone changes around early loaded chemically modified sandblasted and acid-etched surfaced implants with and without a machined collar: a radiographic and resonance frequency analysis in the canine mandible.

PURPOSE: The purpose of this study was to evaluate the radiographic bone level and stability changes around early loaded chemically modified sandblasted and acid-etched implants with and without a machined collar. MATERIALS AND METHODS: Seventy-two chemically modified sandblasted and acid-etched implants 4.1 mm in diameter and 8 mm in length were placed in six dogs. Thirty-six implants had no machined collar (NMC) and 36 had a 2.8-mm machined collar (MC). Resonance frequency measurements were obtained at placement and weekly for 3 weeks. All implants were loaded 21 days after surgery. Standardized periapical radiographs were obtained at baseline, at 3 weeks, and at 3, 6, 9, and 12 months. The radiographs were randomized and digitized, and linear measurements of the distance from the first bone-to-implant contact to the shoulder of the implant were performed at the mesial and distal aspects of each implant. For statistical analysis, mixed-model repeated-measures analysis of variance was used. RESULTS: All implants achieved hard and soft tissue integration clinically and radiographically and were clinically immobile. From placement to week 3, the mean implant stability increased for MC implants by more than 5 ISQs and for NMC implants by more than 7 ISQs. Radiographically, there were significant differences between treatment groups beginning at 3 months. After 12 months of loading, the MC implants presented a mean bone loss of 1.00 mm and the NMC implants presented a mean bone gain of 0.11 mm. CONCLUSIONS: Chemically modified sandblasted and acid-etched implants without a machined collar presented bone gain, and implants with a machined collar showed bone loss after a 1 year following early (21-day) loading. The tendency toward a coronal apposition of bone observed under these conditions may be attributed to the osteoconductive properties of the chemically modified surfaces of these implants and to the absence of the machined collar.

A pilot experimental lateral ridge augmentation study using bone morphogenetic protein 2 in dogs.

The loss of multiple teeth in the posterior mandible often results in deficient ridge width for prosthetic tooth rehabilitation. Multiple approaches have been used to regenerate lost bone; however, the outcomes are highly variable. Several approaches use combination therapy to make the procedure more predictable. In this experimental study in dogs, a chronic defect was created and then treated with one of four therapies: (1) autograft, (2) recombinant human bone morphogenetic protein 2 (rhBMP-2) in absorbable collagen sponge (ACS), (3) ACS wrapped around a collagen-ceramic matrix, and (4) rhBMP-2 in ACS around the collagen-ceramic matrix. Two metal screws were used for space maintenance. After 2 months, the metal pins were removed and an endosseous dental implant was placed in the regenerated bone. Two months later, the animals were sacrificed and specimens prepared for histologic evaluation. Only five animals were used, with each condition evaluated in each animal. With this low number of animals and with the observed variability, no quantitative differences were found between each of the four conditions evaluated. All conditions resulted in new bone growth. Dense native bone was found in the autograft sites and the sites treated with rhBMP-2 and ACS. Sites treated with the collagen-ceramic matrix with and without rhBMP-2 in the ACS had residual ceramic and large porous areas. Bone was found in varying degrees along the implant surfaces. These results suggest that multiple approaches can be used to augment bone horizontally in the posterior mandible of dogs. Interestingly, rhBMP-2 combined with a non-space maintaining collagen carrier yielded new bone densities similar to the autograft in this model.

A prospective multicenter 5-year radiographic evaluation of crestal bone levels over time in 596 dental implants placed in 192 patients.

BACKGROUND: Dental implants have been used to replace missing teeth to provide function and esthetics. One goal of such restorations is to maintain host tissue around the implants. The purpose of this prospective multicenter human clinical trial was to evaluate radiographic marginal bone levels around non-submerged hollow cylindrical and solid-screw implants for 5 years after loading. METHODS: Patients older than 18 years of age with sufficient native bone to surround a dental implant without imposing on a vital structure were recruited at five sites. Solid-screw or hollow-cylinder implants with a titanium plasma-sprayed implant surface were placed in the anterior maxilla or anterior mandible and restored with fixed restorations. Baseline radiographs were taken at the time of implant placement. Subsequent radiographs were taken at the time of final prosthesis placement, at 6 months after prosthesis placement, and annually from prosthesis placement for 5 years. RESULTS: The results of 596 implants in 192 patients at five international sites revealed that clinically significant remodeling of the marginal bone occurred during the first 6 months after implant placement, with a mean (+/- SD) marginal bone loss of 2.44 +/- 1.20 mm. After that, clinically insignificant mean changes in the bone were observed. Overall, 0.22 +/- 0.42 mm of bone loss occurred between the time of prosthesis placement and 1-year postloading. Between 1-year postloading and the last 5-year recall, 0.18 +/- 0.88 mm bone loss occurred. Because 2.84 +/- 1.63 mm of bone loss occurred between implant placement and the 5-year postloading follow-up, 86% of the total mean bone loss over the course of 5 years was accounted for at the time of prosthesis placement. These same trends occurred if the data were analyzed with regard to implant design (solid screw and hollow cylinder), type of restoration (single and multiple), and length of implant (8 to 10, 12, and 14 to 16 mm). CONCLUSIONS: These data demonstrate that, in general, clinically significant marginal bone remodeling occurred between the time of implant placement and final prosthesis placement around one-stage non-submerged titanium implants with a titanium plasma-sprayed surface. Subsequent to that, bone loss observed around implants up to 5 years postloading was minimal. These results suggest that the factors that influence early healing around implants are significantly different from those that affect later marginal bone remodeling.

The biologic width around titanium implants: histometric analysis of the implantogingival junction around immediately and early loaded implants.

This study compared the dimensions of the peri-implant soft tissues around immediately and early loaded one-piece implants as well as conventionally loaded one-piece implants. Comparisons of the peri-implant soft tissue dimensions were made among four different loading periods. Forty-eight titanium sandblasted/acid-etched implants were placed in four foxhounds. The implants were placed at four time periods in groups of three. The first group (A) had implants placed 3 months before the placement of restorations. Further groups of three implants each were placed at 21 days (group B), 10 days (group C), and 2 days (group D) before restoration. Three months after abutment connection, all dogs were sacrificed. Histometric analysis of the undecalcified histologic sections included dimensional measurements of the sulcus depth plus junctional epithelium, the connective tissue contact area, and recession measured from the interface to the gingival margin. No statistically significant differences were observed among the four groups. The data suggest that the dimensions of the peri-implant soft tissues around immediately and early loaded one-piece implants are similar to those around conventionally loaded one-piece implants and comparable to the dimensions of the biologic width around natural teeth.

Clinical evaluation of demineralized freeze-dried bone allograft with and without enamel matrix derivative for the treatment of periodontal osseous defects in humans.

BACKGROUND: Beneficial clinical effects have been demonstrated with the addition of enamel matrix derivative (EMD) to demineralized freeze-dried bone allograft (DFDBA) compared to EMD alone. The purpose of this study was to evaluate the effectiveness of DFDBA combined with EMD compared to DFDBA alone in the treatment of intraosseous defects of chronic periodontitis. METHODS: Thirty-two patients with 41 intrabony defects > or = 3 mm were randomly assigned to one of two treatment groups. Intrabony defects were treated with DFDBA alone or in combination with EMD. Soft tissue measurements included probing depth (PD), gingival recession, and clinical attachment level (CAL). Hard tissue measurements included height of the alveolar crest, defect depth, and defect morphology. Following 6 months of healing, all measurements were repeated with the use of a surgical reentry procedure on 29 patients. Data were analyzed to determine PD reduction, CAL gain, change in recession, crestal resorption, defect fill, defect resolution, percentage of defect fill, and percentage of defect resolution. RESULTS: Analysis of soft and hard tissue measurements demonstrated a statistically significant difference from baseline within each group (P <0.001); however, there was no statistically significant difference between the groups. CONCLUSION: Both treatments were shown to be safe and effective therapy for periodontal defects; however, the addition of EMD to DFDBA provided no statistically significant improvement to the soft and hard tissue parameters measured.

The influence of non-matching implant and abutment diameters on radiographic crestal bone levels in dogs.

BACKGROUND: It has been shown that different implant designs and different vertical implant positions have an influence on crestal bone levels. The aim of the present study was to evaluate radiographic crestal bone changes around experimental dental implants with non-matching implant-abutment diameters placed submucosally or transmucosally at three different levels relative to the alveolar crest. METHODS: Sixty two-piece dental implants with non-matching implant-abutment diameters were placed in edentulous spaces bilaterally in five foxhounds. The implants were placed submucosally or transmucosally in the left or the right side of the mandible. Within each side, six implants were randomly placed at three distinct levels relative to the alveolar crest. After 12 weeks, 60 crowns were cemented. Radiographs were obtained from all implant sites following implant placement, after crown insertion, and monthly for 6 months after loading. RESULTS: Radiographic analysis revealed very little bone loss and a slight increase in bone level for implants placed at the level of the crest or 1 mm above. The greatest bone loss occurred at implants placed 1 mm below the bone crest. No clinically significant differences regarding marginal bone loss and the level of the bone-to-implant contact were detected between implants with a submucosal or a transmucosal healing. CONCLUSIONS: Implants with non-matching implant-abutment diameters demonstrated some bone loss; however, it was a small amount. There was no clinically significant difference between submucosal and transmucosal approaches.

Prevalence of Dental Implants and Evaluation of Peri-implant Bone Levels in Patients Presenting to a Dental School: A Radiographic Cross-Sectional 2-Year Study.

PURPOSE: To evaluate the number of patients with dental implants who present to a dental school clinic for screening and to report the prevalence of peri-implant bone level change detected on digital panoramic radiographs of those subjects. MATERIALS AND METHODS: Patient screening files for 9,422 patients over a 2-year period were examined to see how many patients presented with dental implants. Those patients with at least one implant were further evaluated by measuring the bone level on the mesial and distal sides of the implant using the screening radiograph. RESULTS: A total of 187 patients (2%) had at least one implant. In regard to implants, 423 were examined and 146 (33%) had no detectable bone loss defined as bone level below the top of the implant. When thresholds of bone loss were evaluated, 109 implants (25%) had ≥ 2 mm of bone loss on either the mesial or distal sides or both. The median bone loss was 1.74 mm for the 277 implants with detectable bone loss and 2.97 mm for the 109 implants that had ≥ 2 mm bone loss. Interestingly, patients who were ≥ 70 years of age had significantly (P = .03) more bone loss in the mandible compared with the maxilla, while patients who were 60 to 69 years of age had significantly greater loss in the maxilla. CONCLUSION: These data reveal that for patients presenting to the dental school for a screening over a 2-year period, 1.98% had one or more dental implants. Furthermore, those patients with implants had a minimum amount of bone loss as measured from the top of the implant.

The efficacy of subgingival calculus removal with endoscopy-aided scaling and root planing: a study on multirooted teeth.

BACKGROUND: The dental endoscope was developed to facilitate visualization of the subgingival environment as an aid in diagnosis and non-surgical root debridement. The purpose of this study was to determine whether endoscopy-aided scaling and root planing (SRP) resulted in a greater reduction of residual calculus compared to SRP alone in multirooted teeth. METHODS: Twenty-four patients were enrolled and contributed 35 tooth pairs (70 teeth in total). Each tooth per pair was randomly assigned to receive endoscopy-aided SRP (test) or SRP alone (control). Both teeth were extracted immediately after treatment, washed with water, and stained with methylene blue. The percentage of residual calculus was determined via stereomicroscopy and digital image software by a single masked examiner. RESULTS: Overall, there was 1.16% (P = 0.097) less residual calculus at test versus control sites. At interproximal surfaces, test roots had 2.63% less residual calculus than control roots (P = 0.003), whereas test roots had slightly more residual calculus than controls at buccal/lingual surfaces (0.36%; P = 0.652). There were no statistically significant differences in residual calculus between groups at deeper probing depths or at sites with deep furcation invasions. Only at shallower interproximal sites with probing depths < or =6 mm was significantly less residual calculus seen in roots treated with endoscopy (P = 0.020). Treatment time decreased significantly as operator experience increased; however, no significant improvement in residual calculus levels was noted with greater experience. CONCLUSION: Within the confines of this study, the use of the endoscope as an adjunct to traditional SRP provided no significant improvement in calculus removal in multirooted molar teeth.

The effectiveness of subgingival scaling and root planing: an evaluation of therapy with and without the use of the periodontal endoscope.

BACKGROUND: A fiber-optic periodontal endoscope was developed to aid in the visualization of subgingival structures and to improve the diagnosis and management of periodontal diseases. The purpose of this study was to determine whether use of the periodontal endoscope with scaling and root planing (SRP) resulted in a decrease in residual calculus compared to SRP alone. METHODS: Fifteen subjects with 50 tooth pairs participated in this study. Each tooth per pair was randomized to receive SRP with or without the endoscope. Teeth were extracted, and a stereomicroscope and digital image analysis was used to determine percent residual calculus present in a masked fashion. RESULTS: There was 2.14% (P < 0.001) more residual calculus at control versus test sites. At buccal/lingual and interproximal surfaces, mean differences in residual calculus were 1.30% (P <0.015) and 2.93% (P < 0.001), respectively. Test treatment time decreased significantly as operator experience increased. There were no statistically significant differences between residual calculus for test and control teeth at shallower probing depths; however, at deeper probing depths, the use of the endoscope resulted in significantly less residual calculus. CONCLUSIONS: The use of the periodontal endoscope resulted in a statistically significant overall improvement in calculus removal during SRP, which was most evident in deeper probing depths. The clinical significance of this level of improvement is unknown.

Evaluation of two different resonance frequency devices to detect implant stability: a clinical trial.

BACKGROUND: Resonance frequency analysis (RFA) provides a non-invasive assessment of implant stability. The established RFA device uses electronic technology, whereas a recently developed device uses magnetic technology. The goal of this clinical trial was to evaluate the ability of the magnetic RFA device to detect changes in stability during early healing following implant placement and to determine whether the implant stability quotient (ISQ) values obtained correlated with those made with the electronic device. METHODS: RFA assessments were performed using electronic- and magnetic-based devices on 34 non-submerged titanium dental implants in 17 patients. Each patient received two implants in the posterior maxilla or mandible. Implant stability was measured at placement and weekly until week 6, when implants received provisional crowns, and at 12 weeks, when definitive crowns were cemented. During each visit, measurements were taken three times and averaged to obtain a single representative ISQ for each device. RESULTS: At placement, the mean ISQ obtained with the electronic device was 61.9 (95% confidence interval [CI], 59.4 to 64.3); it increased to 63.2 (95% CI, 61.2 to 65.2) at 12 weeks. With the magnetic device, the mean ISQs were 70.6 (95% CI, 68.4 to 72.8) and 75.9 (95% CI, 74.2 to 77.7), respectively. Both devices indicated a pattern of decreased mean stability from 1 to 3 weeks post-placement, small fluctuations in mean ISQ from 3 to 6 weeks, and significantly increased mean stability from 6 to 12 weeks. For the complete set of implant measures across all weeks, the paired electronic and magnetic ISQ values correlated significantly (r = 0.52; P <0.001). CONCLUSIONS: This study demonstrates that changes in implant stability measured with the newer magnetic device correlate well with those found with the electronic device. Both devices confirmed the initial decreases in implant stability that occur following placement and identified an increase in stability during the first 6 weeks of functional loading.

Thickness of the Buccal Plate in Posterior Teeth: A Prospective Cone Beam Computed Tomography Study.

Buccal plate thickness is an important clinical parameter for postextraction implant treatment planning. The purpose of this study was to assess buccal plate thickness of the posterior maxilla and mandible using cone beam computed tomography (CBCT). A total of 265 patients and 934 teeth met the inclusion criteria for this study. CBCT volumes were taken and aligned for measurement at the ideal midsagittal cross-section. Buccal plate thickness was measured at 1, 3, and 5 mm apical to the alveolar crest. The frequency of thick (≥ 1 mm), thin (< 1 mm), and radiographic absence of the buccal plate were determined. The frequency of thin buccal plate decreases from anterior to posterior, with first premolars and first molar mesial roots most affected. Radiographic absence of the buccal plate was more common in the mandible, at first premolars, and among women. Thin and absent buccal plate are not uncommon in the posterior jaws; consequently, ridge preservation may be indicated even at posterior teeth.

Application of periodontal tissue engineering using enamel matrix derivative and a human fibroblast-derived dermal substitute to stimulate periodontal wound healing in Class III furcation defects.

BACKGROUND: Enamel matrix derivative (EMD) has been shown to promote several aspects of periodontal regeneration in vitro and in vivo. Recently, a bioengineered tissue (DG) was developed to promote wound healing of chronic skin ulcers. This pilot study sought to assess the effects of EMD and DG, alone or in combination, on periodontal wound healing in surgically created Class III furcation defects. METHODS: Six female baboons received bilateral ostectomy of approximately 10 mm around the first and second mandibular molars to achieve Class III, subclass C furcation defects. Wire ligatures and cotton pellets were left in place for 2 months to maintain the depth of the defects and promote plaque accumulation. Each furcally involved molar was then assigned to one of four treatments: open flap debridement (OFD), OFD plus EMD, OFD plus DG, or OFD plus DG and EMD. This resulted in six total sites per treatment group. Seven months after defect creation and 5 months after treatment, and after no oral hygiene, tissue blocks of the mandible were taken for blinded histometric analysis to assess parameters of periodontal regeneration adjacent to furcal root surfaces and from the mid-furcal aspect (i.e., new bone, new connective tissue attachment, new epithelial attachment, and new cementum formation). RESULTS: Histometric analysis demonstrated differential regenerative responses with respect to treatment within each animal. However, statistically significant differences between treatments from all six animals were not observed (P >0.20, mixed-model analysis of variance). EMD-treated sites presented mildly positive regenerative results and no negative responses. Both DG only and combination therapy demonstrated similar or less than positive responses relative to OFD controls. CONCLUSION: The descriptive analysis may suggest a positive effect of enamel matrix proteins and a negative effect of DG used alone or in combination with enamel matrix proteins on the regeneration of Class III furcation defects in baboons.