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Statement of problem Clinical studies comparing compatible computer-aided design and computer-aided manufacturing (CAD-CAM) titanium abutments (CAs) and original prefabricated 1-piece titanium abutments (PAs) for posterior fixed dental prostheses (FDPs) on Straumann Tissue Level (STL) implants are sparse. Purpose The purpose of this retrospective clinical study was to compare the performance of posterior FDPs supported by CAs and PAs on STL implants after a mean observation period of 7.2 years. Material and methods Patients who received STL implants and posterior FDPs by using CAs or PAs between January 2002 and December 2012 and returned for follow-up between January 2017 and September 2018 were included in this study. Technical and biological complications of FDPs were examined and recorded. Radiographs were used for the measurement of marginal bone loss (MBL) of each implant. Variables, complication rates, and MBL of the 2 groups were analyzed by using a generalized estimating equation and multivariable linear mixed model. Results Ninety-nine patients with 195 implants in the CA group and 75 patients with 143 implants in the PA group were included. The mean functional time of FDPs was 6.5 ±1.1 years for the CA group and 8.1 ±2.6 years for the PA group. No implant failure was noted in either group. The technical complication rate was 20.8% in the CA group and 26.3% in the PA group. Abutment screw loosening (ASL) was noted in the CA group (8.5%). The decementation rate was significantly higher in the PA group (14.1%) than that in the CA group (3.1%) (adjusted odds ratio=4.40, confidence interval=1.41 to 13.69, P=.011). No significant differences were found between the 2 groups in terms of the rates of ceramic chipping, peri-implantitis, peri-implant mucositis, or mean MBL. Conclusions Using CAs or PAs to support posterior FDPs on STL implants has no significant effect on the incidence rate of biological complications. However, a higher ASL rate and a lower decementation rate were noted with CAs than with PAs.

Purpose The aim of this study was to investigate how the physical variables of fibular reconstructed mandibles with dental implants affects the relative bite force in oral cancer patients. Materials and methods Over 7 years of follow-up, 13 oral cancer patients were enrolled who included 51 successful implants in the fibular flap. The tactile sensor analyzer evaluated the bite force. The crown-implant ratio, fibular, and rehabilitated dental length were measured using radiographic images. Linear regression was used to analyze the bite force related to the variables of the implants in the fibular reconstructed mandible. Results Even when the results showed no statistical significance (P > 0.05), increasing the crown-implant ratio, length of the fibular flap, and implant prosthetic reconstructed dentition had a tendency to decrease the bite force (estimate from −0.08% to −4.27%); there was a positive trend of occlusal force and the length of rehabilitative dentition compared with the dental antagonist (estimate = 6.95). Conclusion In this study, the crown-implant ratio, implant dentition, and fibular flap length revealed no significant impact on the bite force or implant success in oral cancer patients; however, a trend to weaken the bite force was suggested once the numerical values of these variables increased.

The human external auditory canal can become deformed when the mandible moves, and this changes the sound field in the external auditory canal. This study measured the sound field gain in the external auditory canal while varying mouth-opening in three levels. The mandible was fixed at the 1/3, the 2/3, and the maximal mouth-opening levels. Seven 65-dB tones of 200, 500, 1000, 2000, 4000, 6000, and 8000 Hz, which are the sound pressure level and frequency range when people are talking at a normal level, were adopted as the sound stimulus to measure sound field gains at 5, 10, 15, and 20 mm to the interior of the external auditory canal. The results show that, with the exception of the 1.25 dB decrease from 12.96 to 11.71 dB at a depth of 5 mm with a stimulus at 8000 Hz, the differences in the sound field gain at the other depths and stimulus frequencies were within 1 dB and were not statistically significant. These results suggest that mouth-opening level has no effect on the measurement of the sound field in the external auditory canal.

A charged black hole was predicted by the Einstein--Horndeski--Maxwell theory. In order to provide its observational signatures, we investigate its weak and strong deflection gravitational lensings. We find its weak deflection lensing observables, including the positions, magnifications and differential time delay of the lensed images. We also obtain its strong deflection lensing observables, including the apparent radius of the photon sphere as well as the angular separation, brightness difference and differential time delay between the relativistic images. Taking the supermassive black hole in the Galactic Center as the lens, we evaluate these observables and compare these signatures with those of the Schwarzschild, Reissner-Nordstr\"{o}m, tidal Reissner-Nordstr\"{o}m and charged Galileon black holes. After a detailed analysis of the feasibility of measuring these lensing observables, we conclude that although it is possible to detect some leading effects of the weak and strong deflection lensings by the charged Horndeski and other black holes with current technology, it would be unlikely to distinguish one kind of these black holes from the others based on these detections in the near future due to lack of enough highly angular resolution in astronomical observations to tell their differences., Comment: 32 pages, 2 figures

Statement of problem Information about the long-term evaluation of 2-piece zirconia abutments (TPZAs) with bonded titanium inserts for implant-supported restorations is sparse. Purpose The purpose of this clinical study was to evaluate the clinical outcome of TPZAs with bonded titanium inserts for implant-supported restorations. Material and methods This study retrospectively evaluated the records of patients who received implant restorations supported by TPZAs with bonded titanium inserts. The patients were recalled between January 2017 and December 2017 so that the restorations could be examined clinically and radiographically for technical and biological complications. Results A total of 27 patients with 30 restorations and 42 zirconia abutments (ZAs) were included in the study. The patient records revealed that all implants remained integrated. However, 5 restorations supported by seven ZAs in 4 patients had to be refabricated because of abutment failure before the recall. Six of the failed abutments were in the molar area, with a combination of zirconia and titanium as the connection platform. Additional complications included screw loosening (1 patient), ceramic chipping (1 patient), and peri-implantitis (1 patient). The mean observation period was 6.6 ±1.5 years (range: 3.6 to 9.2 years). Conclusions After a mean observation period of 6 years after insertion, TPZAs with bonded titanium inserts appear to be a suitable treatment option in the anterior and premolar regions. However, in the molar area, the use of the same type of ZA without a complete metal-to-metal connection platform to support the restoration led to a high incidence of fracture.

The mean white dwarf (WD) mass in the Galactic bulge cataclysmic variables (CVs) was measured by applying the the shock temperature-WD mass correlation of magnetic cataclysmic variables (mCVs) to the Galactic Bulge X-ray Emission (GBXE) spectra. However, the resulting mean WD mass is lower than that of the local CVs. This discrepancy could be explained by the dominating sources in the GBXE are non-mCVs instead of mCVs. In this work, we conduct an thorough investigation on the X-ray spectra of local DNe from \suzaku\ archives, and derive semi-empirical correlations between the shock temperature $T_{\rm max}$, the flux ratio of \fec\ to \feb\ lines, and WD mass for quiescent, non-magnetic CVs. By applying these correlations to the GBXE, we derive the average WD mass of CVs in the Galactic bulge to be $0.81\pm 0.07M_\odot$. This value is consistent with previous optical measurements of WD mass in local CVs., Comment: 11 pages, 4 figures, accepted for publication in The Astrophysical Journal

Osseointegrated dental implants in double-barrel, or single-barrel and then vertically distracted, fibula osteoseptocutaneous free flaps can achieve segmental mandibular reconstruction, dental rehabilitation, and premorbid facial height. However, it remains unknown which configuration provides better osseointegration outcomes.Between 2003 and 2009, all patients who underwent segmental mandibular defect reconstruction using vertical distraction osteogenesis of single-barrel fibula with secondary osseointegration (group A, 10 patients and 35 osseointegrated dental implants) or double-barrel fibula with primary osseointegration (group B, 13 patients and 36 osseointegrated dental implants) were evaluated prospectively for crown-implant ratios, mesial/distal marginal bone losses, and complications. In group B, 18 osseointegrated dental implants were surrounded by palatal mucosal grafts; the other retained fibula skin paddles.Palatal mucosal grafts in group B improved mesial (p0.001) and distal (p0.001) marginal bone losses. Mesial marginal bone loss of group B with palatal mucosal grafts was better than that of group A (p0.05), despite higher crown-implant ratios in group A (p0.01). Mesial (p0.01) and distal (p0.05) marginal bone losses of group A were better than that of group B osseointegrated dental implants without palatal mucosal grafts. Complications in group A were common and complex, unlike group B. All patients completed dental rehabilitation.Osseointegration was adequate to complete dental rehabilitation in group B without palatal mucosal grafts, but was significantly better in group A, and significantly best in group B with palatal mucosal grafts. Given the complexity and frequency of complications in group A, the authors recommend the double-barrel configuration with osseointegrated dental implants for segmental mandibular defect reconstruction. Palatal mucosal grafts have a definite advantage.Therapeutic, III.

Statement of problem In addition to the original abutments provided by implant companies, compatible computer-aided design and computer-aided manufacturing (CAD-CAM) abutments are also available from different manufacturers. However, the combination of abutments and implant systems from different manufacturers may lead to mechanical problems between components. Little has been reported on the clinical performance of this treatment option. Purpose The purpose of this retrospective case series was to evaluate the outcome of compatible CAD-CAM titanium abutments (TiAs) for posterior single-implant tooth replacement (PSITR) up to 6 years after insertion. Material and methods Eighty-one patients (34 men, 47 women) who received PSITR restored with compatible CAD-CAM TiAs and had a final recall examination between May 2014 and April 2015 were included in this study. Clinical and radiographic examinations were documented. Retrospective evaluation of the patient records was also performed. Correlations between bone-level changes and variables were calculated using the Spearman correlation. Results Implant and prosthesis survival rates were 100%. Twenty technical complications were observed, including 9 decementations of the crown, 6 screw loosenings, and 5 ceramic fractures. Periimplant mucositis was diagnosed in 36 patients (44.4%) and periimplantitis in 6 patients (7.4%). Correlation analysis showed a significant effect of the extent of periodontal bone loss of the remaining teeth on the marginal bone-level changes around implants ( r =0.548, P Conclusions Compatible CAD-CAM TiAs provide a viable treatment option for PSITR. However, in light of relatively high screw-loosening and decementation rates, choosing appropriate cements and abutment manufacturers is essential to improve the clinical performance of this treatment option.

Background Aesthetic and functional mandibular reconstruction can be achieved in 1-stage. It involves simultaneous dental implant placement in a free vascularized fibula transfer with a low-profile reconstruction plate. The aim of this study was to assess the postoperative aesthetic profile and oral functional result. Material and methods Ten patients with a mean age of 31.6 years and an average follow-up time of 83.7 months underwent 1-staged mandibular reconstructions after segmental mandibulectomies. Simultaneous dental implantation was placed at the fibular segment according to the maxillary dentition. The fibula-implant construct was stabilized superiorly with miniplates and an additional low-profile reconstruction plate recreated the inferior mandibular contour. Any remaining vascularized soft tissue was used for augmentation. Palatal mucosa grafts were placed around the dental implant healing abutment at the uncovering stage surface. Aesthetic profile and oral function were evaluated postoperatively for 5 years. Results All microsurgical transplantations were successful. None of the patients required subsequent revisions. All patients completed prosthodontic rehabilitation. All patients had palatal mucosal grafts placed around the dental implants. The mean probing pocket depths were shallower around the implants, 3.09 ± 0.82 mm at mesial, 3.33 ± 1.05 mm at distal, 3.02 ± 1.13 mm at buccal, and 3.23 ± 1.17 mm at lingual surfaces. Radiographs revealed no statistical differences in mean of the mesial [0.27 ± 0.26 mm] and distal [0.33 ± 0.25 mm] of peri-implant bone loss. The prosthetic load mean follow-up time was 71.7 months with a satisfactory implant-supported prosthesis. Two slender female patients palpated the reconstruction plate beneath the soft tissue envelope. Conclusions This approach is selectively fashioned for patients with benign disease when the overlying soft tissue drape is adequate. The technique described results in improved appearance and function through definition of the lower third of the face and simultaneous dental implant replacement.

Both periodontitis and osteoporosis have similar sign of bone resorption in nature. However, the relationship of the severity between these 2 bone-loss diseases is still uncertain. The aim of this study was to investigate the association between the severity of osteoporosis and periodontitis regarding the impact of oral hygiene maintenance. In total, 35,127 osteoporosis patients and 50,498 comparisons were derived from the Longitudinal Health Insurance Database of Taiwan between 2000 and 2010. The population was subdivided into groups according to the different level oral hygiene maintenance and the severity of periodontitis and osteoporosis. The association between osteoporosis and periodontitis was estimated by multinomial logistic regression and rank correlation by Kendall rank correlation test, presented by odds ratio (OR), and 5% confidence intervals (CIs). After controlling the age, sex, and comorbidities, variables in the good oral hygiene maintenance population, we found that periodontitis raised 1.29-fold risk of osteoporosis (95% CI = 1.12–1.49); the risk of osteoporosis was increased with the elevated severity of periodontitis from 1.27 (95% CI = 1.08–1.48) to 1.38 (95% CI = 1.01–1.89). There is a positive correlation between the severity of periodontitis and osteoporosis occurrence in this population (OR = 1.27–1.46; Kendall rank correlation test P = 0.0003). In the poor oral hygiene maintenance population, periodontitis patients had 6.02-fold risk of osteoporosis than those who without periodontitis (95% CI = 4.65–7.81); the risk of osteoporosis was increased with periodontitis severity from 5.96 (95% CI = 4.48–7.92) to 6.37 (95% CI = 3.36–12.1). This result indicated the periodontitis and osteoporosis are conjunctive. The sudden periodontal breakdown of those who with good oral hygiene maintenance might be an indicator for the risk of osteoporosis; if those who were diagnosed as osteoporosis must pay more attention to their periodontal health. Good oral hygiene maintenance might be a crucial factor for preventing the deterioration of osteoporosis progressing; the oral hygiene maintenance plays a significant influence on the association between periodontitis and osteoporosis.

BACKGROUND Functional and aesthetic mandibular reconstruction can be achieved in a single operation by means of a double-barreled fibula osteoseptocutaneous free flap with dental implants loaded simultaneously into the upper barrel. The aim of this study was to evaluate the quality and result of such reconstruction. METHODS From 2005 to 2007, 10 patients underwent segmental mandibular defect reconstructions with double-barreled fibula osteoseptocutaneous flaps and simultaneous dental implantations. Implant marginal bone loss, clinical mucosal changes, marginal plaque indices, bleeding on probing, and pocket probe depth were evaluated at an average of 22.2 months after implant functional loading. RESULTS Ten patients with a total of 25 osseointegrated implants were evaluated. The mean implant marginal bone loss was 0.18 ± 0.18 mm (range, 0 to 0.6 mm) at the mesial surfaces and 0.25 ± 0.2 mm (range, 0 to 0.6 mm) at the distal surfaces. Probing pocket depth was shallower for implants protected by palatal mucosal grafts (2.56 ± 0.54 mm) than by skin flaps (3.50 ± 0.90 mm) (p < 0.05). There was a significant difference in marginal bone loss between palatal mucosal grafts (0.11 ± 0.09 mm) and skin flaps (0.29 ± 0.23 mm) (p < 0.05). Bleeding on probing was more prominent when pocket depth exceeded 5 mm and occurred more frequently in skin flap-protected than in keratinized mucosa graft-protected implants. CONCLUSIONS The one-stage combined surgical method is safe and reliable. Both oral function and mandible contour were good. Firmly attached gingiva-like palatal mucosal grafts prevent periimplant soft-tissue inflammation and facilitate maintenance of oral hygiene. CLINICAL QUESTION/LEVEL OF EVIDENCE Therapeutic, V.

Excessive thickness and mobility of the skin flap and lack of a vestibular sulcus in composite vascularized bone grafts for mandibular reconstruction limit the usefulness of endosteal implants to support a prosthetic device. Palatal mucosal grafts and a simple acrylic stent are an excellent means to overcome these problems. The technique is presented in this paper.

Background and Aims Little is currently known about the risk of developing bisphosphonate-related osteonecrosis of the jaw (BRONJ). This study sought to determine the incidence of BRONJ in osteoporotic patients. We also sought to identify the nature and types of risk factors of osteonecrosis of jaw (ONJ) related to the use of oral bisphosphonates (BPs). Materials and Methods Data from the National Health Insurance system of Taiwan. This cohort study included 19,399 adult osteoporosis patients received dental extraction in 2000-2010 (osteoporosis cohort) and 38,669 age and gender matched comparisons selected from dental extraction people without osteoporosis and osteonecrosis history (comparison cohort). All study subjects were followed from the date of their dental extraction (index date) to the development of ONJ and were included in the study up to 2011 or were lost to the study, whichever occurred first. Cox proportional hazard regression was used to estimate the hazard ratio and 95% confidence intervals for the two cohorts. Results Patients with osteoporosis had a significantly higher risk to develop ONJ than healthy persons (adjusted HR, 2.05; 95% confidence interval, 1.58–2.65). The risk of ONJ increased with the severity of osteoporosis, no matter whether patient with cancer or not. A cumulative effect of dental extraction frequency may increase the risk of ONJ. Conclusions We concluded that ONJ is caused by a number of factors. Osteoporosis and past dental history play the very important roles, while BPs play the synergistic effect.

The prevalence of hypodontia is reported to be between 1.5% to 10% in the permanent dentition. In the anterior teeth, maxillary lateral incisors and mandibular central incisors are the most frequently involved teeth. This causes esthetic problems for the patient. Several reports have focused on restoration of retained maxillary primary anterior teeth, but none have described restoration of retained mandibular primary incisors. This clinical report describes the restoration of infra-occluded retained primary mandibular central incisors of a 17 year-old girl diagnosed with hypodontia. All-ceramic crowns made with computer-aided design/ computer-aided manufacturing technology were used to restore the teeth incisally and interproximally. Due to a relatively short root length and inadequate crown-root ratio, the primary mandibular central incisors were splinted and adjusted to distribute the protrusive force evenly across the maxillary and mandibular incisors. Functional and esthetic results were achieved.

PROCEDURE 1. Cover the implant shoulder margin with peri-implant mucosa (Fig. 1, A). 2. Remove the closing screw and use the ITI torque wrench to place the selected solid abutment at 35 Ncm. 3. Snap the impression cap over the abutment to retract peri-implant mucosa for 5 minutes (Fig. 1, B). 4. Remove the impression cap with needle holder or mosquito forceps. 5. Expose the implant shoulder margin without bleeding (Fig. 1, C). 6. Fabricate provisional restoration. Repeat steps 3 and 4 if the peri-implant mucosa collapses again before provisional restoration cementation. If the overgrown peri-implant mucosa impedes the impression cap from being seated, mucogingival surgery may be needed to expose the implant shoulder margin.

There appears to be no convenient method for fabricating an optimal emergence profile for the definitive restoration of an ITI solid abutment when the implant is installed subgingivally. This article describes an efficient technique to solve this problem and reviews its advantages and disadvantages.

For patients treated with implant prostheses, an implant overdenture may be the restoration of choice.1-3 However, occlusal contact of the implant superstructure with the opposing dentition may occur on removal of the overdentures. Contact of the opposing occlusion or prosthesis with the superstructure may cause patient discomfort and possible implant abutment wear in patients with a single overdenture and a history of parafunction.4 Wear of an ERA metal matrix (APM Sterngold, Attleboro, Mass.) on implant abutments or the opposing dentition, for example, may occur if not properly prevented.5 The manufacturer of ERA attachments offers a rubber cap to reduce irritation caused by the abutment. Putting such caps on ERA overdenture abutments could be inconvenient for a patient with bruxism and multiple implants, and the task could be difficult for some elderly patients. Moreover, these small components could be dropped and/or accidentally swallowed. For these reasons, implant night guards5,6 for implant overdenture abutments may be indicated. A simple method of fabricating such a night guard is presented.

1. Punch small holes in a piece of rubber dam (Dental Dam; Hygenic, Coltene/Whaledent Inc, Mahwah, N.J.) 2. Cut out small rings of the rubber dam with 2to 3-mm borders around each hole (Fig. 1, A). 3. Apply the rubber dam rings over the ERA abutments before the pick-up procedure. The rings will cover and hold the block-out material in place during the pick-up procedure (Fig. 1, B). This simple technique will produce a clean acrylic resin surface uncontaminated by the block-out material. If the undercuts around the ERA abutment are minimal, the rubber dam ring itself will provide adequate block-out. Multiple rubber dam rings can be used to reduce the amount of block-out material required.

VOLUME 83 NUMBER 2 In the evaluation and surgical stage for implant therapy, stents are needed for a successful treatment result. Many methods have been reported for fabrication of radiographic stents and surgical stents,1-8 many of which require extensive laboratory time to fabricate. A vacuum-formed matrix, often used in the fabrication of fixed provisional prostheses,9-12 has been used in the fabrication of stents for radiographic examination and in the surgical stage of implant therapy.7,8 This article presents a simple method of fabricating a vacuum-formed matrix filled with clear acrylic resin and a gutta-percha marker. The matrix can be used not only as a radiopaque marker for evaluation but also as a surgical guide during the surgical stage for single implant therapy.

cation of a fixed provisional prosthesis,1-4 and stents for radiographic examination or the surgical stage in implant therapy.5,6 Carbide burs or hot instruments have been the instrument of choice to remove the plastic sheet after the matrix has been formed on the cast. However, burs may jeopardize the surface of the cast and a hot instrument needs to be heated repeatedly. This article presents a simple method to remove the plastic sheet from the cast by using a butane gaspowered soldering iron to cut along the border of the matrix without damaging the original cast (Figs. 1 and 2). The soldering iron provides a constant and continuous hot tip to cut the matrix from the vacuumformed shell. The cast surface is not damaged and remains intact after removing the matrix from the cast. REFERENCES

A daily medicine box with multiple partitions and individual covers can be purchased from any drugstore and is ideal for organizing the small components used in prosthetic treatment. Modify the box by drilling small holes in the bottom of it with a high-speed carbide round bur (Shofu carbide round bur No. 1, Kyoto, Japan) (Fig. 1). Sort and organize prosthetic components into the individual partitions of the medicine box, putting each in its own partition with a snap-on cover (Fig. 2). Because the box has holes drilled into the bottom, it can be rinsed under running tap water and put into an ultrasonic cleaner. The components will not be mixed or lost during cleaning procedures (Figs. 3 and 4). If chemical sterilization is appropriate, the box can be put into a sterilizing solution such as Cidex (Johnson

VOLUME 82 NUMBER 3 In the procedures of prosthetic restoration of Calcitek Spline (Sulzer Calcitek Inc, US Patent No. 5449291) implant-supported crowns and fixed partial dentures, transfer impression with a transfer coping on a shouldered abutment is necessary for the fabrication of the prosthesis. According to the manufacturer’s technical manual, before making an impression, the abutment should be tightened to the implant with an abutment driver and the transfer coping should be tightened to the abutment with a hex driver1 (Fig. 1). A periapical film must then be taken to confirm the complete seating of all parts. However, sometimes when the impression has been made and one tries to unscrew the transfer coping from the abutment, the transfer coping and abutment are both removed with a hex driver as a result of being too tightly screwed together during the previously described procedures (Fig. 2 ). The transfer coping and abutment have to be separate before proceeding further, but it can become more difficult, especially when tightly screwed together. A method to separate a tightly screwed abutment and transfer coping is not included in the manufacturer’s manual. Even though a hex driver can be used on the end of transfer coping, because the other end of the tightened abutment is the screw on the abutment itself, one must handle this assembly with care so the threads are not jeopardized. This makes it more difficult to unscrew the abutment and transfer coping. Forceps or pliers may not work when trying to unscrew the abutment. Unscrewing the 2 parts with a driver and bare hands also may not be possible when the abutment and transfer coping are tightly connected. This article presents a simple method of unscrewing a tightened abutment.

VOLUME 82 NUMBER 1 A claspless removable partial denture (RPD) with extracoronal resilient attachments (Stern ERA Attachment System, APM-Sterngold, Attleboro, Mass.) can fulfill the esthetic requirement of a partially edentulous patient. Clinically, the difficulties and discrepancies that occur during framework try-in and jaw registration increase because the claspless frameworks often lack of sufficient retention, support, and stability.1,2 This article describes a simple method of fabricating an ERA-included claspless RPD in accordance with conventional RPD design principles and clinical procedures and without complicated operatory and laboratory works.

The vacuum-formed matrix has been applied in the fabrication of provisional restorations for about three decades, ls but for long-span provisional restorations with multiple pontics, excessive shrinkage of cold-curing acrylic resin in the pontic area is still a problem. The following procedure uses denture teeth in the pontic area, and the provisional restorations are fabricated with an indirect technique. This procedure can reduce the bulk of the cold-curing acrylic resin and can improve the situation with the reduction of excessive shrinkage of the provisional restorations.