Retrospective comparison of posterior fixed dental prostheses supported by two different titanium abutments on tissue level implants.

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.

Clinical evaluation of two-piece zirconia abutments with bonded titanium inserts for implant-supported restorations.

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.

Effect of mouth-opening levels on sound field gain in the ear canal.

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.

Compatible CAD-CAM titanium abutments for posterior single-implant tooth replacement: A retrospective case series.

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<.001). 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.

Aesthetic and functional mandibular reconstruction with immediate dental implants in a free fibular flap and a low-profile reconstruction plate: five-year follow-up.

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.

S-index periodicity detection based on multiple random spectral observations.

The solar magnetic activity cycle has a profound impact on our lives, yet its underlying causes remain elusive. While similar cycles have been observed in other stars, these results are scarce due to the significant challenge posed by the length of time required for observation. Continuous observation over an extended period is a luxury, making it difficult to gather large samples. However, multiple random observations can be made at a lower cost, and flexible time management enables non-professionals to become competent. In this study, we analyzed multiple random observations of the S-indices of several stars captured incidentally by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope. Our findings reveal potential periodicity that could be associated with magnetic activity cycles. Notably, obtaining S-index is relatively less challenging, indicating the feasibility of developing dedicated commercial or charitable equipment for non-astronomers. A more extensive data is essential to establish a definitive correlation between S-index periodicity and magnetic activity cycles in stars, as well as to uncover additional magnetic activity cycles.

Vertical dimension of occlusion related to mandibular movement during swallowing.

BACKGROUND: Increasing the vertical dimension of occlusion (VDO) is a common procedure in complicated prosthodontic treatment. The swallowing technique had been verified as a functional method to determine the VDO. The purpose of this study was to investigate the association between increasing VDO and mandibular movement during swallowing. METHODS: 26 females and 14 males were enrolled (age range: 21 to 30 year-old). Under different increased VDO (3, 5, and 8 mm), the mandibular trajectory during swallowing was measured by K7 Evaluation System (Myotronics®). When the subjects were instructed to salivary swallowing, the range of mandibular movement in vertical, anteroposterior and lateral directions were recorded. RESULTS: Increasing VDO significantly impacted the range of mandibular movement in lateral direction during swallowing (p < 0.0001, F value = 40.09). The average variance of the mandibular movement distance in lateral direction during swallowing raise 1.58 (p = 0.001); 3.59 (p = 0.0001) and 2.01 (p = 0.001) when th VDO was raised from 3 mm to 5 mm; from 3 mm to 8 mm and from 5 to 8 mm respectively. The range of mandibular movement was significantly correlated to the increasing VDO (p ≤ 0.05) under the analysis of the Post Hoc test. CONCLUSIONS: VDO was closely correlated to the trajectory of mandibular motion during swallowing. The increase in VDO could change the extent of mandibular trajectory during swallowing if the increase was more than 3 mm. The range of mandibular motion when swallowing had positive correlative tendency as the VDO was increased.

The association of variables of fibular reconstructed mandible and bite force in oral cancer patients with dental implant rehabilitation.

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 Impact of Oral Hygiene Maintenance on the Association Between Periodontitis and Osteoporosis: A Nationwide Population-Based Cross Sectional Study.

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.

Using the T-scan III system to analyze occlusal function in mandibular reconstruction patients: a pilot study.

BACKGROUND: This study was designed to analyze the post-rehabilitation occlusal function of subjects treated with complex mandibular resection and subsequently rehabilitated with fibula osteoseptocutaneous flaps, dental implants, and fixed prostheses utilizing the T-scan system. METHODS: Ten mandibular complex resection cases that adopted fibula osteoseptocutaneous flaps, dental implants, and fixed prostheses to reconstruct occlusal function were analyzed. The mandibular reconstructions were divided into three groups based on size: full mandibular reconstructions, mandibular reconstructions larger than half of the arch, and mandibular reconstructions smaller than half of the arch. The T-scan III system was used to measure maximum occlusal force, occlusal time, anterior-posterior as well as left-right occlusal force asymmetries, and anterior-posterior as well as left-right asymmetrical locations of occlusal centers. RESULTS: Subjects with larger mandibular reconstructions and dental implants with fixed partial dentures demonstrated decreased average occlusal force; however, the difference did not reach the statistically significant level (p > 0.05). The most significant asymmetry of occlusal center location occurred among subjects with mandibular reconstructed areas larger than half of the mandibular arch. CONCLUSIONS: Comparison of the parameters of T-scan system used to analyze the occlusal function showed that the occlusal force was not an objective reference. Measurements of the location of the occlusal center appeared more repeatable, and were less affected by additional factors. The research results of this study showed that the size of a reconstruction did not affect the occlusal force after reconstruction and larger reconstructed areas did not decrease the average occlusal force. The most significant parameter was left and right asymmetry of the occlusion center (LROC) and was measured in subjects with reconstruction areas larger than half of the arch.

Impact of bisphosphonate-related osteonecrosis of the jaw on osteoporotic patients after dental extraction: a population-based cohort study.

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.

Outcome of osseointegrated dental implants in double-barrel and vertically distracted fibula osteoseptocutaneous free flaps for segmental mandibular defect reconstruction.

BACKGROUND: 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. METHODS: 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. RESULTS: Palatal mucosal grafts in group B improved mesial (p<0.001) and distal (p<0.001) marginal bone losses. Mesial marginal bone loss of group B with palatal mucosal grafts was better than that of group A (p<0.05), despite higher crown-implant ratios in group A (p<0.01). Mesial (p<0.01) and distal (p<0.05) 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. CONCLUSIONS: 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. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Dental implant outcome after primary implantation into double-barreled fibula osteoseptocutaneous free flap-reconstructed mandible.

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.

Esthetic restoration of infra-occluded retained primary mandibular incisors with all-ceramic crowns in adult dentition.

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.

Developing an optimal emergence profile of the definitive restoration with a modified impression cap technique for ITI solid abutment.

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.