New Bone Growth into Surgical Bone Defects Grafted with a Novel Cultivated Coral Graft: A Histomorphometric Study in Rabbit Calvarias.

Natural Coral Particles (NCPs) are a suitable scaffold material for Guided Bone Regeneration (GBR) procedures; it combines the placement of a bone substitute supporting a barrier membrane. Due to increasing sea pollution and the declarations of endangered coral species (KYOTO 1997), they are no longer suitable for the medical industry. Novel domestic corals have been grown under controlled conditions to produce cultivated coral graft (CCG) material. This study aimed to evaluate a new CCG in an in vivo experimental GBR procedure. The calvarias of 8 rabbits were surgically exposed, and circular defects 8 mm in diameter were prepared. One defect was filled with CCG particles (experimental group); the contralateral defect (control group) was spontaneously filled by blood clot. The defects were covered with a collagen membrane. Animals were euthanized after 8 weeks. Histological observations of the defects showed similar bone growth patterns in both experimental and control osteotomies. In the experimental defects, no traces of coral particles were observed. Histometric analysis showed denser bone in the pristine zone (65-66%) than in the peripheral zone for both the control (50%) and experimental defects (31%) (P= NS). The new bone percentage was reduced from the peripheral zone toward the middle and the center of the defect (31%, 32% and 27%, respectively) as the distance from the peripheral pristine bone borders increased. The existing data support the complete degradation of CCG as space-maintaining scaffold for GBR procedures.

Thermal Changes of One-Piece Versus Two-Piece Implants During Setting of an Autopolymerized Acrylic Resin.

Purpose: To evaluate differences in the temperature rise at the cervical area of one-piece vs two-piece implants during the setting of relined provisional crowns. Materials and Methods: A K-type thermocouple was fixed to the coronal thread of 15 one-piece implants and 15 two-piece implants that were mounted on a plexiglass apparatus. Baseline temperature (Bl Temp) was recorded before starting the curing process. The maximum temperature (Max Temp) reached during the process in both implant groups was also recorded. Total heat flux (THF) was calculated as well as the thermal amplitude (Temp-Amp) at the implant surface. Finally, the differences between the implant types were compared using unpaired t test. Results: The increase in temperature from baseline was statistically significantly greater in the one-piece implants than in the two-piece implants (P < .01). Similarly, the THF and Temp-Amp were significantly greater in the one-piece implants compared to two-piece implants (P < .01). Conclusions: The polymerization of PMMA-based resin temporary crowns produces a significant temperature rise in both one-piece and two-piece implants. It is advisable to use two-piece implants to restore immediately loaded implants to reduce the risk to implant surroundings that may occur due to the temperature rise at the implant neck.

Electrically Driven Plasmons in Metal-Insulator-Semiconductor Tunnel Junctions: The Role of Silicon Amorphization.

We investigate electrically driven plasmon (EDP) emission in metal-insulator-semiconductor tunnel junctions. We find that amorphization of the silicon crystal at a narrow region near the junction due to the applied voltage plays a critical role in determining the nature of the emission. Furthermore, we suggest that the change in the properties of the insulating layer above a threshold voltage determines the EDP spatial properties, from being spatially uniform when the device is subjected to low voltages, to a spotty pattern peaking at high voltages. We emphasize the role of the high-energy emission as an unambiguous tool for distinguishing between EDP and radiative recombination of electrons and holes in the semiconductor.

Immediate Maxillary Full-Arch Rehabilitation of Periodontal Patients with Terminal Dentition Using Tilted Implants and Bone Augmentation: A 5-Year Retrospective Cohort Study.

BACKGROUND: All-on-four protocols with tilted implants in the maxilla are used to rehabilitate the terminal dentition of the severe generalized periodontitis patients. Data on long-term biological complications are scarce. METHODS: Eighty-four axial and forty-six tilted immediate implants have been placed in the extraction sockets of 23 patients according to a four-six implants protocol combined with ridge augmentation. Within 72 h, a provisional prosthesis was cemented to the implants; after 6 months, a cemented ceramic-metallic prosthesis was delivered. The patients were followed for up to 5 years. RESULTS: The 5-year survival rate of the straight and tilted implants was 100% and 97.8, and the prosthetic one was 100%. Marginal bone loss (MBL) of the straight implants was 0.42 ± 0.67 and 0.59 ±1.01 mm on the mesial and distal sides; for the tilted, it was 0.37 ± 0.68 and 0.34 ±0.62 mm, and the differences were not statistically significant. Implant position, smoking, keratinized mucosal width, and cantilever did not affect MBL. Peri-implant mucositis involved 29.4% and 22.2% of the straight and tilted implants, respectively; peri-implantitis involved 5.8% and 4.4% of the straight and tilted implants, respectively, without statistical significance. CONCLUSIONS: This immediate loading protocol's 5-year survival and success rates were high. No difference between the straight and tilted implants was found regarding survival, success rates, and MBL.

Histologic and Histomorphometric Evaluation of a Connective Tissue Graft Retrieved with a Novel Deepithelialization Procedure: A Case Series.

Various free connective tissue graft (CTG) harvesting techniques have been reported. The lining epithelium of the palatal graft may be retrieved either intra- or extraorally. This report presents a series of root coverage cases where deepithelialization was intraorally performed before harvesting the graft with a round diamond bur mounted on a low-speed handpiece. Ten single-tooth gingival recession defects in five patients were treated, applying a surgical procedure based on a coronally advanced flap combined with a free CTG that was deepithelialized in situ by the same method. Recession and probing depths and keratinized tissue and recession widths were recorded at baseline and the follow-up evaluations. Follow-up was between 7 and 21 months (mean: 12.1 ± 5.04 months). Clinical, esthetic, and histologic evaluations were performed. Mean root coverage was 89% ± 24.86% (range: 25% to 100%), and complete root coverage was observed in 80% of cases; the esthetic score range was 6 to 9 (mean: 7.44 ± 1.01). Epithelial remnants, although different in proportions, were evident in all samples (range of prevalence: 4.57% to 29.12%). Within the limitations of the small number of clinical cases, the presented in situ deepithelialization technique for CTG seems to be valuable and may accordingly be routinely applied.

Coronally Advanced Flap with Connective Tissue Graft for Treating Orthodontic-Associated Miller Class III Gingival Recession of the Lower Incisors: A One-Year Retrospective Study.

(1) Background: To assess the clinical outcome of coronally advanced flap combined with connective tissue graft for the treatment of orthodontic-associated Miller Class III gingival recession of the lower incisors. (2) Methods: This study included 15 patients who had undergone orthodontic treatment prior to development of recession. Measurements of recession depth, recession width, probing depth, and width of keratinized tissue were performed clinically immediately before surgery and after one year. In addition, digital measurements of recession depth, recession width, and root coverage esthetic score were performed on intraoral photographs. (3) Results: Significant reduction was observed for probing depth, recession depth, and recession width at one year, with significant increase in width of keratinized tissue. Mean root coverage was 83 ± 24% for recession depth, while complete root coverage was achieved in 10 out of 21 recessions (48%). The average root coverage esthetic score at 12 months was 7.1 ± 2.6. An interaction was found between initial recession depth and mean root coverage. (4) Conclusions: Within the limitations of this study, our results confirm that combination of coronally advanced flap and connective tissue graft is effective in reducing post-orthodontic Miller Class III recessions of the mandibular incisors, even when the correction of the tooth malposition, is unattainable.

The Effect of Coronal Implant Design and Drilling Protocol on Bone-to-Implant Contact: A 3-Month Study in the Minipig Calvarium.

Background: Stress concentrated at an implant's neck may affect bone-to-implant contact (BIC). The objective of this study was to evaluate four different implant neck designs using two different drilling protocols on the BIC. Methods: Ninety-six implants were inserted in 12 minipigs calvarium. Implants neck designs evaluated were: type 1-6 coronal flutes (CFs), 8 shallow microthreads (SMs); type 2-6 CFs,4 deep microthreads (DMs); type 3-4 DMs; type 4-2 CFs, 8 SMs. Two groups of forty-eight implants were inserted with a final drill diameter of 2.8 mm (DP1) or 3.2 mm (DP2). Animals were sacrificed after 1 and 3 months, total-BIC (t-BIC) and coronal-BIC (c-BIC) were evaluated by nondecalcified histomorphometry analysis. Results: At 1 month, t-BIC ranged from 85-91% without significant differences between implant types or drilling protocol. Flutes on the coronal aspect impaired the BIC at 3 m. c-BIC of implant types with 6 CFs was similar and significantly lower than that of implant types 3 and 4. c-BIC of implant type 4 with SMs was highest of all implant types after both healing periods. Conclusions: BIC was not affected by the drilling protocol. CFs significantly impaired the -BIC. Multiple SMs were associated with greater c-BIC.

Thermal Changes at the One-Piece Implant Surface During the Setting of Two Autopolymerized Acrylic Resins.

PURPOSE: To compare the temperature changes during the setting process of two provisional crown materials, polymethyl methacrylate (PMMA)-based acrylic resin (Ac) and bis-acryl composite resin (Co), at the first thread surface of one-piece implants. MATERIALS AND METHODS: Twenty-two 3.3-mm-diameter one-piece implants were divided into two groups according to the provisional restoration material. Implants were mounted on a Plexiglas apparatus. A K-type thermocouple was fixed at the most coronal thread. Baseline (Bl Temp) and maximal (Max Temp) temperatures of both groups were recorded during the curing process. Total heat flux (THF) at the implant surface and thermal amplitude (Temp-Amp) were calculated. Differences between groups were compared using a t test for unpaired observations. RESULTS: Upon curing, a statistically significant increase in the Max Temp from the Bl Temp was detected in both groups, with a greater increase in the Ac compared with the Co group. The Temp-Amp and the THF were two times greater in the Ac group than the Co group. CONCLUSION: Significant heat is produced during the polymerization of PMMA-based resin and bis-acryl composite resin provisional crowns in one-piece implants. To decrease the risk of thermal challenge at the implant cervical aspect associated with restoration of immediately loaded implants, bis-acryl composite resin should be used.

Light Emission in Metal-Semiconductor Tunnel Junctions: Direct Evidence for Electron Heating by Plasmon Decay.

We study metal-insulator-semiconductor tunnel junctions where the metal electrode is a patterned gold layer, the insulator is a thin layer of Al2O3, and the semiconductor is p-type silicon. We observe light emission due to plasmon-assisted inelastic tunneling from the metal to the silicon valence band. The emission cutoff shifts to higher energies with increasing voltage, a clear signature of electrically driven plasmons. The cutoff energy exceeds the applied voltage, and a large fraction of the emission is above the threshold, ℏω > eV. We find that the emission spectrum manifests the Fermi-Dirac distribution of the electrons in the gold electrode. This distribution can be used to determine the effective electron temperature, Te, which is shown to have a linear dependence on the applied voltage. The strong correlation of Te with the plasmon energy serves as evidence that the mechanism for heating the electrons is plasmon decay at the source metal electrode.

Supportive periodontal therapy affects dental implants probing pocket depth, bleeding on probing, and bone level: a 4- to 8-year follow-up study.

Objective: To evaluate implant and patient characteristics 4 to 8 years after implant installation in a study involving immediate fixed restoration of dental implants. Method and materials: The study was a follow-up of treated generalized chronic periodontitis patients who received immediate restorations on dental implants as part of a previous study. The patients were examined clinically and radiographically at implant placement, 6 months, 1 year, and 4 to 8 years later. Supportive periodontal therapy (SPT), teeth and implant probing pocket depth (TPPD and IPPD), bleeding on probing (BOP [teeth, TBOP; implant, IBOP]), and bone level (BL) measurements around implants were documented. Cases were divided into three groups according to annual SPT rate: 0.00 to 0.99/year (SPT0), 1.00 to 1.99/year (SPT1), 2.00 or more/year (SPT2). Results: Twelve patients, with 26 implants and 242 teeth, were included. The mean ±â€¯standard deviation follow-up period was 6.08 ±â€¯1.25 years (range 4.04 to 7.94 years). All implants in the follow-up group were osseointegrated and survived during the follow-up period. The mean number of SPT appointments was 6.17 ±â€¯5.65. A weak negative correlation was found between SPT rate and ΔTPPD (-0.24, P = .0005), whereas a strong negative correlation was found between SPT rate and ΔIPPD (-0.76, P = .0005). Negative correlations were found between SPT rate and ∆TBOP (-0.20, P = .003), and between SPT rate and ∆IBOP (-0.5, P = .009). A moderate correlation was found between SPT rate and ΔBL (0.46, P = .02). Conclusion: SPT has a significant positive effect on PPD, BOP, and on implant BLs in long-term follow-up and should be an essential part of implant therapy.

Oral and dental considerations of combat-induced PTSD: a descriptive study.

OBJECTIVE: Stress experienced as an intense and traumatic event can increase the odds of orofacial morbidities that may affect oral, periodontal, or masticatory system health. The aim of this study was to evaluate the dental, periodontal, oral, and bruxism situation among Israeli posttraumatic stress disorder (PTSD) war veterans. METHOD AND MATERIALS: This retrospective cohort pilot study aimed to examine the oral and facial manifestations in 71 Israeli veterans with combat PTSD. All patients underwent full dental, oral, and periodontal examination. Signs of parafunctional activity were also evaluated, accompanied by a full set of periapical and/or panoramic radiographs. RESULTS: The patients were 37 to 77 (mean 60.7 ± 10.15) years of age and presented a poor overall oral hygiene status (Plaque Index 0.75 ± 0.26). All patients (100.0%) suffered from periodontal disease, and most of them (66.0%) were severely affected. A significant correlation was found between signs of parafunctional activity and severe periodontal disease (P = .035). The patients had a high decayed, missing, and filled teeth (DMFT) score (20.06 ± 8.86), which was mainly attributed to the large number of "filled" (F) teeth (11.95 out of 20.06). The DMFT score was significantly lower among light smokers than among heavy, former, or nonsmokers (P = .012). Most patients (90%) had signs and symptoms of parafunctional activities. A significant positive and dose-dependent correlation was found between smoking and periodontal disease (P = .012). CONCLUSIONS: An association was found between combat PTSD and oral, dental, and periodontal morbidity.

Does cognitive flexibility affect the course of labor? A prospective study.

OBJECTIVE: To evaluate cognitive flexibility and labor and delivery outcomes. METHODS: A prospective study was conducted of nulliparas with singleton term pregnancy, admitted for labor to a tertiary referral center from 1 January to 31 July, 2017. After epidural anesthesia, parturients completed the validated Psychological Flexibility Questionnaire (20 questions that evaluate a person's level of cognitive flexibility) before delivery. They were asked to grade (from 1 to 10) their hope for vaginal delivery (Hope score). Within 2 hours after delivery, they graded (1-10) the similarity between their delivery and their expectations (Expectation score). Outcomes of the flexible versus less flexible group were compared. RESULTS: Among the flexible (n=120) versus less flexible (n=40) group, vaginal delivery was more common (74.2% vs 20.8%) than vacuum extraction (20.8% vs 35%) or cesarean delivery (5% vs 12.5%) (P=0.031). High Expectation score and delivery without grade III-IV perineal tear (P=0.032) were correlated. Groups were similar regarding Expectation (P=0.163) and Hope scores (P=0.591). The mode of delivery of parturients was not correlated with their mothers' (P=0.836) or sisters' (P=0.758). CONCLUSION: High cognitive flexibility increases the likelihood of vaginal delivery. These findings support the mind-body correlation. Maternal cognitive perceptions can influence labor and delivery and should be considered when counseling patients during labor.

Can we predict the need for antihypertensive treatment during the early postpartum period for women with preeclampsia or gestational hypertension?

OBJECTIVES: To determine factors that predict the need for antihypertensive treatment during early postpartum period among women with preeclampsia or gestational hypertension. STUDY DESIGN: Retrospective cohort of 358 women. MAIN OUTCOME MEASURES: Demographic, clinical and laboratory data of 63 women diagnosed with preeclampsia or gestational hypertension during a singleton pregnancy and who needed antihypertensive agents during early postpartum period were compared to 295 who did not. RESULTS: No difference was found between groups regarding age, parity, body mass index, or weight gain (p = 0.95, 0.19, 0.56, and 0.078, respectively). Early onset preeclampsia or gestational hypertension was diagnosed among 28.6% of the women who subsequently needed antihypertensive treatment, as compared to 4.1% who did not (p < 0.001). Antepartum, mean maximum blood pressure in the treated vs. untreated group was 165/109 mmHg vs. 150/100 mmHg, respectively (p = 0.001). Groups did not differ regarding symptoms of preeclampsia (38.7% vs. 31.5%, p = 0.273) or laboratory abnormalities. The group that received antihypertensive treatment during early postpartum period, had more preterm deliveries (p < 0.001) and Cesarean deliveries (p < 0.001), and more received magnesium sulfate during labor (p < 0.001). During the early postpartum period, mean maximum blood pressure was higher among the treated group (167/106 vs. 143/92, p = 0.001), as were symptoms of preeclampsia (p = 0.001). The groups were similar regarding laboratory abnormalities that define preeclampsia. CONCLUSIONS: Early onset preeclampsia or gestational hypertension, severe antepartum hypertension, magnesium sulfate during labor, preterm, and Cesarean delivery might be good predictors of the need for antihypertensive treatment during early postpartum period.

Postcoital bleeding is a predictor for cervical dysplasia.

BACKGROUND: Postcoital bleeding (PCB) is a common gynecological symptom that may cause concern among both patients and physicians. Current literature is inconclusive regarding management recommendations. OBJECTIVE: To identify risk-factors for dysplasia/cancer among patients presenting post-coital bleeding (PCB). METHODS: Using large health maintenance organization (HMO) database, all women reporting PCB in 2012-2015 were identified. PCB patient records in a single colposcopy center were reviewed. Age, marital status, ethnicity, gravidity, parity, BMI, smoking, PAP smear result (within 1 year of PCB presentation), colposcopy and biopsy results were recorded. Cases were matched by age and socio-economic enumeration area to controls accessing primary care clinics for routine care. RESULTS: Yearly incidence of PCB ranged from 400 to 900 per 100,000 women; highest among patients aged 26-30 years. Among the sample of 411 PCB cases with colposcopy, 201 (48.9%) had directed biopsy. Biopsy results included 68 cervicitis (33.8%), 61 koilocytosis/CIN 1/condyloma (30.3%), 44 normal tissue (21.9%), 25 cervical polyp (12.4%), 2 CIN 2/3 (1%) and 1 carcinoma (0.5%). Positive predictive value for koilocytosis/CIN 1 or higher pathology was 15.6% (64/411) and 0.7% for CIN 2 or higher grade pathology (3/411). In conditional logistic regression, multiparty was a protective factor: OR 0.39 (95% CI 0.22-0.88, P = 0.02), while pathological PAP smear was a related risk-factor: OR 3.3 (95% CI 1.31-8.35, P = 0.01). When compared to controls, PCB patients were significantly (P = 0.04) more likely to present CIN 1 or higher grade pathology (OR 1.82, 95% CI 1.02-3.33). CONCLUSIONS: Study results indicate that PCB may require colposcopy, especially for nulliparous women with an abnormal PAP smear.

Clinical and Patient-Related Outcomes of a Tapered Implant System With Switched Platform Conical Abutments: A Private Practice Field Trial.

The aim of this prospective cohort observational field trial was to examine 1-year survival and success rates of a recently introduced tapered implant system with switched platform conical abutments and to evaluate patient related outcomes of therapy. Partially edentulous patients aged between 18 and 75 years, with available bone height for dental implants ≥10 mm desiring to restore the missing tooth/teeth with implant supported restoration, were recruited by 7 periodontists in their respective private practices. Dental implants were installed according to standard implant therapy protocol. Three to 6 months postoperatively, after evaluating interim implant success, implants were restored by the referring dentists. Patient, Ramfjord teeth, and implant data, including baseline and 1-year postoperative, were collected. A total of 60 patients were recruited and received 117 implants. Complete 1-year clinical and radiographic data were available for 83 and 65 implants, respectively. Two implants failed during the first year, resulting in a 1-year survival rate of 98.3%. Mean implant probing pocket depth was 2.29 ± 0.84 mm. Mean radiographic bone distance from implant's shoulder at the mesial and distal sites at 1 year was 0.66 ± 0.5 and 0.79 ± 0.64mm, respectively, resulting in a success rate of 95.4%. Patient subjective evaluation of therapy exhibited a median pain experience of 1 and median esthetics, function, and general satisfaction evaluation of 10 on a scale of 1 to 10. The tapered conical connection dental implant system, used in private dental practices, shows good 1-year survival and success rates that are similar to other implant systems on the market.

Comparison between mineralized cancellous bone allograft and an alloplast material for sinus augmentation: A split mouth histomorphometric study.

BACKGROUND: Several grafting materials have been used in sinus augmentation procedures including autogenous bone, demineralized freeze-dried bone, hydroxyapatite, ß-tricalcium phosphate, anorganic deproteinized bovine bone, and combination of these and others. Yet, the issue of the optimal graft material for sinus floor augmentation is controversial. PURPOSE: This prospective, randomized split-mouth study was undertaken to histomorphometrically compare a biphasic calcium phosphate (BCP) alloplastic bone substitute and a human bone mineral allograft (freeze-dried bone allograft, FDBA) in patients undergoing bilateral maxillary lateral sinus floor augmentation. MATERIAL AND METHODS: Apico-coronal core biopsies were harvested at 9 months from 26 bilateral sites in 13 treated patients. Specimens were processed for histological and histomorphometrical analyses. RESULTS: Newly formed bone (NB) was evident in all specimens with values of 27.5% and 24.0% at the FDBA and BCP sites, respectively (P = .331). The residual graft particle values were 12.5% and 25.4% (P = .001), and the connective tissue values were 60.0% and 50.6%, respectively. The osteoconductive value was 52.6% for the FDBA and 26.7% for the alloplast (P = .001). The values for the measured residual graft particles, connective tissue, and osteoconductivity, but not for NB, showed highly significant differences between the two groups. All sections in the alloplast material showed evidence of a light chronic inflammatory infiltrate, mainly comprising lymphocytes and multinucleated giant cells. CONCLUSIONS: Both graft materials are suitable for sinus floor augmentation, with the allograft material being more osteoconductive.

Differences in crestal bone-to-implant contact following an under-drilling compared to an over-drilling protocol. A study in the rabbit tibia.

OBJECTIVES: The objective of this study is to compare bone-to-implant contact (BIC) between implants inserted at high torque due to under-drilling of the crestal bone to those inserted at low torque due to over-drilling of the crestal bone. MATERIALS AND METHODS: Forty implants with diameters of 3.75 mm (group A) or 3.55 mm (group B) were inserted in the proximal tibiae of NZW rabbits in two separate surgeries on day 0 or 21. Osteotomy of the crestal bone was finalized with a 3.65-mm drill. In group A, implants were inserted at torque ≥35 Ncm (under-drilling) and in group B with torque <10 Ncm (over-drilling). Implants and their surrounding bone were retrieved on day 42, thus creating 3- and 6-week observation periods, processed for non-decalcified histology and stained with toluidine blue. Crestal BIC (c-BIC) and total BIC (t-BIC) were measured. Wilcoxon test was used to evaluate differences between groups. RESULTS: Three weeks post-surgery, the mean c-BIC in group A was 16.3 ± 3.3 vs 31.5 ± 3.4 % in group B (P < 0.05). At 6 weeks, a similar trend was observed (group A: 28.7 ± 3.6 %; group B: 38.4 ± 4.9 %) (P > 0.05). No differences in t-BIC were noted at 3 weeks and at 6 weeks between the groups. CONCLUSIONS: Insertion of implants with an over-drilling protocol of the crestal aspect of the osteotomy resulted in increased short-term crestal bone-to-implant contact. CLINICAL RELEVANCE: Insertion of implants with a high torque following an under-drilling protocol, commonly used for immediate loading, may reduce crestal bone-to-implant contact at early healing stages.

Primary stability following abutment preparation of one-piece dental implants.

PURPOSE: One-piece dental implants are commonly used for the immediate restoration of missing teeth. In most cases, the clinician has to prepare the abutment intraorally to ensure a proper emergence profile and abutment angulation. However, this procedure might impair primary stability and thus potentially compromise osseointegration. The aim of this study was to determine the effect of abutment preparation on the primary stability of a one-piece implant system (UNO MIS). MATERIALS AND METHODS: Implant stability was assessed by resonance frequency analysis with a novel custom-made external fixation device, validated previously, developed specifically for resonance frequency measurements of this implant. Thirty 3 × 13-mm implants were inserted in porcine jawbone with insertion torque of 15 Ncm (group A, 15 implants) or 30 Ncm (group B, 15 implants). Abutments were prepared by reducing the facial aspect of the implant abutment with a high-speed dental turbine (400,000 rpm) equipped with a medium-roughness diamond bur. Implant stability quotients (ISQs) were measured before and after abutment preparation. RESULTS: Mean ISQs measured in group A and group B before abutment preparation were very similar (58.2 ± 1.4 and 57.4 ± 0.9, respectively; P > .05). Following abutment preparation, three implants in group A lost primary stability. The mean ISQ value in group A was reduced from 58.2 ± 1.4 to 54.9 ± 7.9 following abutment preparation (P < .05). The mean ISQ in group B was not affected by abutment preparation (57.4 ± 0.9 versus 57.3 ± 1.0; P > .05). CONCLUSIONS: Abutment preparation of a one-piece dental implant inserted with low insertion torque might impair implant primary stability.

A novel device for resonance frequency assessment of one-piece implants.

PURPOSE: Immediate loading and/or restoration of dental implants requires the assessment of implant stability, which is best performed by resonance frequency analysis (RFA) prior to loading. One-piece dental implants are usually used for immediate loading, but there is currently no available reliable method to assess the primary stability of one-piece dental implants. Therefore, this study sought to validate a novel device designed for RFA measurements of one-piece implants. MATERIAL AND METHODS: Thirty (3.75 x 13 mm) internal-hex implants (Seven, MIS) were divided into two groups; 15 were placed in an acrylic glass block and 15 were placed in fresh porcine jawbone using 30 N/cm2 of insertion torque. Implant stability quotient (ISQ) values were measured using the Osstell Mentor device; then, a new external fixation device was attached to the implant abutment with a 10-mm arm extending from the implant to an internal-hex ring at its proximal end. ISQ values were measured at the implant's internal hex and at the internal hex of the device, and the damping ratio was calculated. The measurements were repeated with 15 (3 x 13 mm) one-piece implants (UNO, MIS) attached to the same device. RESULTS: The damping ratio between the implant and the proximal device was 23.6% ± 4% in acrylic glass (50.1 ± 1.7 ISQ and 38.2 ± 1.8 ISQ, respectively) and 23.1% ± 3% in porcine bone (74.9 ± 2.8 ISQ and 57.5 ± 0.5 ISQ, respectively). ISQ values determined by the device on one-piece and two-piece implants were similar (57.4 ± 0.9 and 57.5 ± 0.5, respectively). CONCLUSION: With the present validation of this external fixation device for the measurements of implant stability using RFA, it is now possible to measure primary stability of any one-piece implant system, obviating the need for custom-made Osstell adaptors.

Cooling profile following prosthetic preparation of 1-piece dental implants.

The aim of this study was to evaluate the effect of water irrigation on heat dissipation kinetics following abutment preparation of 1-piece dental implants. UNO 1-piece dental implants were mounted on Plexiglas apparatus clamping the implant at the collar. T-type thermocouple was attached to the first thread of the implant and recorded thermal changes at 100 millisecond intervals. Implants were prepared using highspeed dental turbine at 400,000 RPM with a coarse diamond bur. Once temperature reached 47 degrees C, abutment preparation was discontinued. Thirty implants were divided into 2 groups. Group A: Passive cooling without water irrigation. Group B: Cooling with turbine's water spray adjacent to the implant (30 mL/min). The following parameters were measured: T47 (time from peak temperature to 47 degrees C), T50%, T75% (time until the temperature amplitude decayed by 50% and 75%, respectively), dTemp50%/dt decay, and dTemp75%/dt decay (cooling rate measured at 50% and 75% of amplitude decay, respectively). Water spray irrigation significantly reduced T47 (1.37+/-0.29 seconds vs 19.97+/-3.06 seconds, P<0.0001), T50% (3.04+/-0.34 seconds vs 27.37+/-2.56 seconds, P<0.0001), and T75% (5.71+/-0.57 seconds vs 57.61+/-5.47 seconds, P<0.0001). Water spray irrigation also increased cooling capacity ninefold: dTemp50%/dt decay (4.14+/-0.61 degrees C/s vs 0.48+/-0.06 degrees C/s, P<0.0001), and dTemp50%/dt decay (1.70+/-0.29 degrees C/s vs 0.19+/-0.03 degrees C/s, P<0.0001). The continuous use of water spray adjacent to the abutment following the cessation of implant preparation might prove beneficial for rapid cooling of the implant.