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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

Background: Clinical studies regarding zirconia implant abutments reported good survival rates in the short-term observation period. The purpose of this study was to assess the six-year clinical performance of zirconia abutments supporting all-ceramic crowns in anterior and premolar regions. Methods: The patients received zirconia implant abutments to support all-ceramic crowns in Chang-Gung Medical Center during the period August 2010 to August 2011 were enrolled. In the following six years of observation period after the implant-crown had finished, the clinical parameters of all of the included patients were registered on a special form. The records regarding the following variables: age, gender, implant location, the condition of edentulous site before implant placement, esthetic performance at baseline, presence or absence of technical complications, and biological outcomes were registered and scrutinized for evaluation. Results: Out of the 32 zirconia implant abutments and 32 all-ceramic crowns that were followed for six years. Neither abutments nor crowns were lost, yielding 100% survival rates for both zirconia abutments and crowns. The esthetic outcomes were excellent except that a score of 2 was given to two restorations. With regard to technical complications, there was one instance of abutment screw loosening, two cases of veneering ceramic chipping, one restoration with occlusal roughness, and three instances of crowns loosening. Overall, the success rates were 96.8% and 81.2% for abutments and crowns respectively. In biological performance, only 1 implant was classified in group II (satisfactory survival) in the Misch classification, while all the others were classified in group I (excellent). Conclusions: Zirconia abutments supporting all-ceramic crowns demonstrated high survival rate, good biological and esthetic results. While some technical complications were frequently observed, the complication-free rates were 96.8% for abutments and 81.2% for crowns in the medium-term observation period. Keywords: Zirconia implant abutment, All-ceramic crown, Esthetic performance, Technical complication, Biological complication

Background/purpose: Interleukin 1 beta (IL-1β) is a pro-inflammatory cytokine involved in the acute and chronic inflammatory processes of dental pulp. Intercellular adhesion molecule-1 (ICAM-1) and IL-8 are two major inflammatory mediators. However, the role of interleukin-1 receptor-associated kinases (IRAKs) signaling pathways in responsible for the inflammatory effects of IL-1β on dental pulp cells is not clear. Methods: Cultured human dental pulp cells were exposed to IL-1β with/without pretreatment and co-incubation with IRAK1/4 inhibitor or SB203580 (p38 inhibitor). IRAK-1 phosphorylation was evaluated by immunno fluorescent staining. The protein expression of ICAM-1 and IL-8 were tested by western blotting. The secretion of soluble ICAM-1 (sICAM-1) and IL-8 was measured by enzyme-linked immunosorbant assay (ELISA). Results: IL-1β stimulated IRAK-1 phosphorylation of pulp cells within 120 min of exposure. IRAK1/4 inhibitor attenuated the IL-1β-induced ICAM-1, but not IL-8 protein expression. IRAK1/4 inhibitor also prevented the IL-1β-induced sICAM-1, but not IL-8 secretion. SB203580 showed little effect on IL-1β-induced sICAM-1 secretion, but effectively inhibited its induction of IL-8 secretion in pulp cells. Conclusion: The Results reveal the important role of IL-1β in pulpal inflammatory responses via stimulation of IL-8 and ICAM-1 expression and secretion. Moreover, IL-1β-induced effects on IL-8 and ICAM-1 are differentially regulated by IRAK1/4 and p38 signaling in dental pulp cells. Blocking of IRAKs and p38 signaling may have potential to control inflammation of dental pulp in the future. Keywords: Dental pulp, Inflammation, ICAM-1, Interleukin-1β, IL-8, Signal transduction, IRAKs

Background/purpose: Interleukin 1 beta (IL-1β) is a pro-inflammatory cytokine involved in the inflammatory processes of dental pulp. IL-8 and urokinase plasminogen activator (uPA) are two inflammatory mediators. However, the role of transforming growth factor beta-activated kinase-1 (TAK1) and mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathways in responsible for the effects of IL-1β on IL-8 and uPA expression/secretion of dental pulp cells are not clear. Methods: Human dental pulp cells were exposed to IL-1β with/without pretreatment with 5z-7-oxozeaneaeol (a TAK1 inhibitor) or U0126 (a MEK/ERK inhibitor). TAK1 activation was determined by immunofluorescent staining. The protein expression of IL-8 was tested by western blot. The expression of IL-8 and uPA mRNA was studied by reverse transcriptase-polymerase chain reaction (RT-PCR). The secretion of IL-8 and uPA was measured by enzyme-linked immunosorbent assay. Results: Exposure of dental pulp cells to IL-1β (0.1–10 ng/ml) stimulated IL-8 and uPA expression. IL-1β also induced IL-8 and uPA secretion of dental pulp cells. IL-1β stimulated p-TAK1 activation of pulp cells. Pretreatment and co-incubation of pulp cells by 5z-7oxozeaenol (1 and 2.5 μM) and U0126 (10 and 20 μM) prevented the IL-1β-induced IL-8 and uPA expression. 5z-7oxozeaenol and U0126 also attenuated the IL-1β-induced IL-8 and uPA secretion. Conclusion: IL-1β is important in the pathogenesis of pulpal inflammatory diseases and repair via stimulation of IL-8 and uPA expression and secretion. These events are associated with TAK1 and MEK/ERK signaling. Blocking of TAK1 and MEK/ERK signaling has potential to control inflammation of dental pulp. Keywords: Dental pulp, Healing, Inflammation, Interleukin-1β, MEK/ERK, Signal transduction, TAK1, Urokinase plasminogen activator

Background: The objective of this study was to evaluate the effects of opposite tooth conditions on change in marginal bone level (MBL) around submerged dental implants. Materials and methods: The study included healthy patients with one or two implants. Structures opposite implants were either natural teeth (NT) or fixed restorations (FRs). MBLs were measured on digital periapical radiographs at the mesial and distal aspects of each implant. Results: Sixty implants were inserted by the 3-year follow-up. Mean MBLs for NT were 0.21 ± 0.33 mm before prosthetic loading and 0.30 ± 0.41 mm 3 years later (p = 0.001). Mean MBLs with FRs were 0.36 ± 0.45 mm before loading and 0.53 ± 0.50 mm 3 years later (p &lt, 0.001). Changes in mean MBL from the 6-month follow-up to the 1- and 3-year follow-ups were statistically significant (p &lt, 0.01) for implants opposite NT. However, changes in mean MBL from the 6-month follow-up to the 1-year (p = 0.161) and 3-year follow-ups (p = 1.000) were not significant for implants opposite FRs. Between baseline and the 3-year follow-up, MBL change was relatively small and did not differ regarding NT and FRs. Conclusion: Bone loss was greater if submerged dental implants were opposed by FRs. MBLs around submerged implants continued to change after 3 years if NT opposed implants.

Absorbable porcine collagen membrane with a bovine bone graft can be considered for regenerative treatment in periodontal class II furcation defects. We evaluated the clinical efficacy of guided tissue regeneration (GTR) treatment with bovine bone xenograft and a porcine collagen membrane in molars with class II furcations. Probing depth (PD), clinical attachment level (CAL), and bone level (BL) were recorded at baseline and at 3, 6, and 9 months postoperatively. Thirty class II furcation defects from the lower and upper molars were assessed. Significant improvements in PD and CAL were observed from baseline to 9 months in all groups (p &lt, 0.01). BL improved in all groups except group A in the upper molars in radiographic assessment (p &lt, 0.05). The lower and upper molars showed PD reduction of 50.5% ± 7.44% and 46.2% ± 11.2%, respectively, at 9 months (p = 0.044). In furcations of 1–3 mm, the lower and upper molars showed PD reductions of 51.2% ± 4.49% and 36.5% ± 16.14%, respectively (p = 0.035). The lower and upper molars showed a CAL gain of 51.1% ± 4.64% and 33.6% ± 18.8%, respectively (p = 0.037). Thus, GTR with bovine bone graft and porcine collagen membrane yielded good results in class II furcations, with better results in the lower than in the upper molars.

After tooth extraction, alveolar ridge loss due to resorption is almost inevitable. Most of this bone loss occurs during the first six months after the extraction procedure. Many studies have indicated that applying socket-filling biomaterials after extraction can effectively reduce the resorption rate of the alveolar ridge. The purpose of this study was to investigate the clinical efficacy of the application of a hydroxyapatite/&beta, tricalcium plus collagen (HA/&beta, TCP + collagen) dental bone graft in dental sockets immediately after tooth extraction, so as to prevent socket resorption. The study was conducted on 57 extraction sockets located in the mandible and maxilla posterior regions in 51 patients. HA/&beta, TCP + collagen was inserted into all of the dental sockets immediately after extraction, and was covered with a flap. Follow-up was performed for three months after extraction, using radiographs and stents for the vertical and horizontal alveolar ridge measurements. A minimal alveolar bone width reduction of 1.03 &plusmn, 2.43 mm (p &lt, 0.05) was observed. The height reduction showed a slight decrease to 0.62 &plusmn, 1.46 mm (p &lt, 0.05). Radiographically, the bone height was maintained after three months, indicating a good HA/&beta, TCP + collagen graft performance in preserving alveolar bone. In conclusion, the HA/&beta, TCP + collagen graft demonstrated adequate safety and efficacy in dental socket preservation following tooth extraction.

Objective: To describe remodeling of the mesial and distal marginal bone level around platform-switched (PS) and platform-matched (PM) dental implants that were sandblasted with large grit and etched with acid over a three-year period. Materials and Methods: Digital periapical radiographs were obtained at the following time-points: during Stage I of the surgical placement of dental implants, before loading, immediately after loading (baseline), and one, three, six, 12, and 36 months after loading for measuring the horizontal and vertical marginal bone levels. Results: Sixty implants were successfully osseointegrated during the overall observation period. Vertical marginal bone levels for the PS and PM dental implants were 0.78 &plusmn, 0.77 and 0.98 &plusmn, 0.81 mm, respectively, whereas the horizontal marginal bone levels for the PS and PM implants were 0.84 &plusmn, 0.45 and 0.98 &plusmn, 0.68 mm, respectively. During the time leading up to the procedure until 36 months after the procedure, the average vertical marginal bone level resulted in less bone loss for the PS and PM groups&mdash, 0.96 &plusmn, 1.28 and 0.30 &plusmn, 1.15 mm, respectively (p &lt, 0.05). The mean levels of the horizontal marginal bone also showed increases of 0.48 &plusmn, 1.01 mm in the PS and 0.37 &plusmn, 0.77 mm in the PM groups from the time before loading until 36 months after the procedure. However, these increases were not statistically significant (p &gt, 0.05). Conclusion: PS dental implants appeared to be more effective than PM implants for minimizing the mean marginal vertical and horizontal marginal bone loss during the three-year period. Regardless of which abutment connection was used, the dental implant in the present retrospective investigation exhibited minimal marginal bone remodeling, thus indicating long-term stability.

Background/purpose: Implant-abutment connection is the component responsible for the transmitting of occlusal force from the crown down to the implant fixture. Different connection geometric structure will lead to different mechanical performance. The purpose of this study was to compare the stability of internal hex Implant -abutment connection with internal hex with Morse taper implant-abutment connection by testing their compressive strength. Materials and methods: This was an in vitro study. The test group and the control group had 8 specimens separately. The test group was internal hex combined with Morse taper implant connection design, and the control group was internal hex connection design. Static force was applied to the specimens at a 30° angle until failure. The testing protocol was designed according to ISO14801 regulations. We compared the compressive strength of both groups. Results: The control group showed significantly higher compressive strength than the test group (p

Background/purpose This study investigated the cumulative survival rate of the mandibular implant-supported overdentures in patients treated from 2005 to 2014 at the Chang Gung Memorial Hospital Implant Center. Materials and methods Mandibular implant-supported overdentures were placed in 61 patients (32 males and 29 females) during the period from 2005 to 2014. These patients were categorized into two groups according to the type of attachment system used, namely, Group A and Group B. Group A included 31 patients (17 males and 14 females who received a total of 124 implants) whose denture was retained by a Hader bar and cast ERA attachments, whereas Group B included 30 patients (15 males and 15 females who received a total of 120 implants) whose denture was retained by a Hader bar and bilateral, extension cantilevers with clips. Results At the end of the follow-up period, 238 implants remained. Among the failed implants, two implants were in Group A (failure rate 2/124 = 1.6%), whereas four implants were in Group B (failure rate 4/120 = 3.3%). Fifty percent (3/6) of the failed implants were placed in the distal anterior mandible and 50% (3/6) were placed in the middle anterior mandible. The condition of the opposing arch was also analyzed in relation to the survival rate. The failure rate among patients with maxillary complete dentures was only 1.6%, whereas those wearing maxillary removable partial dentures had the highest implant failure rate (3/61 = 4.9%). Conclusion Our results indicate that implant-supported overdentures provide a reliable and effective alternative to conventional complete mandibular dentures. Overdentures with Hader bars and bilateral, cast ERA attachments resulted in fewer prosthetic complications.

Background/purpose The purpose of this study was to determine fracture loads of human maxillary first premolars restored with condensable composite resin (Surefil, Dentsply) or leucite-reinforced ceramic inlays (ProCAD, Ivoclar Vivadent) in mesial occlusal distal cavity preparations of differing pulpal depths and isthmus widths. Materials and methods Ninety freshly extracted intact maxillary first premolars were divided into nine groups of 10. One group was an unprepared control. Eight groups of teeth were prepared to create different widths and depths of mesial occlusal distal cavities. Subsequently, teeth were restored with either condensable composite resin or ceramic inlay. Specimens were then subjected to axial loading with a 4.82-mm diameter steel ball in a universal testing machine at a crosshead speed of 0.5 mm/minute. Loads were applied against tooth structure, and the steel ball did not contact restorative material. Data were analyzed with multiple analysis of variance and Tukey post hoc testing. Results Mean fracture load of teeth restored with Surefil and a 3-mm cavity width was greater than in groups with a 2-mm cavity width (P = 0.0315). Teeth restored with ProCAD were observed to have significantly higher mean cusp fracture load compared to teeth restored with composite resin (P = 0.0003). Conclusion A bonded ceramic restoration restores the fracture load of a tooth comparable to an intact tooth independent of the examined design parameters, whereas the fracture loads of composite-resin-restored teeth were dependent on cavity widths. Cavity pulpal floor depth is not a significant factor of cusp fracture resistance in a tooth restored with either a ceramic inlay or composite resin.

Background: The purpose of this study was to compare patients' subjective experiences with respect to long-term satisfaction with mandibular implant-retained overdentures versus conventional complete dentures. Methods: Among 85 completely edentulous patients, 60 were treated with four one-stage titanium implants and overdentures retained by a cast bar with extracoronal attachments. These patients constituted the experimental group, and were subsequently evaluated clinically over a period of up to 6 years. The other 25 patients constituted the control group and were treated with conventional complete dentures without implant retained. All the patients ( n = 60) in the experimental group responded to questions on their experiences before and after treatment with the implant-retained overdentures. Sixty percent ( n = 15) of the 25 patients in the control group responded to the questionnaire. Results: No implants or restorations failed during the observation period. The experimental group, however, showed significant differences with the control group in terms of their responses to the questionnaire. Conclusion: The use of implants to retain and support the overdenture improved comfort and gave the experimental patients greater self-confidence in social interactions, in addition to more effective oral rehabilitation. The results demonstrate that the effects of rehabilitation of the mandibular arch with an implant-retained overdenture are predictable.

Background/purpose The present study analyzed the subjective responses of patients to surgical placement of dental implants and the subsequent functioning of mandibular implant-retained overdentures as compared with the functioning of conventional dentures. This study sought to ascertain patient satisfaction and long-term effectiveness of tooth replacement with mandibular implant-retained overdentures. Materials and methods Patients (n = 86) unable to adapt to a conventional mandibular complete denture were treated with four one-stage titanium plasma sprayed or sandblasted, large-grit, and acid-etched threaded implants supporting an overdenture retained by a cast bar and extracoronal attachments. These patients were evaluated clinically during periods ranging from 6 months to 12 years. Eighty-three patients provided answers to queries regarding their impressions and feelings both prior to and after treatment for the implant-retained overdentures. Results During the study period, none of the implants or restorations failed. Ninety-eight percent of patients responding to the questionnaire were satisfied with their new overdentures. Retaining and supporting mandibular overdentures with implants yielded improvements in comfort, providing the patients with not only effective oral rehabilitation but also greater self-confidence in social situations. Conclusion The results indicate that mandibular arch rehabilitation by using implant-retained overdenture therapy serves as a predictable and effective treatment protocol.

Modification of the physiochemical properties of titanium surfaces using glow discharge plasma (GDP) and fibronectin coating has been shown to enhance the surface hydrophilicity, surface roughness, cell adhesion, migration, and proliferation. Thisin vivostudy aimed to evaluate the bone integration efficacy of a biologically modified implant surface. Two different surface-modified implants (Ar-GDP and GDP-fib) were placed in the mandibular premolar area of six beagle dogs for 2–8 weeks. Three techniques [histologic evaluation, resonance frequency analysis (RFA), and microcomputed tomography (micro-CT) evaluation] were used to detect the implant stability and bone-implant contact. The implant stability quotient values of GDP-fib implants were significantly greater than the Ar-GDP implants at 2 and 4 weeks (P<0.01). The bone volume/total volume ratio of GDP-fib implants was greater than the Ar-GDP implants in micro-CT evaluation. A high positive correlation was observed between RFA and micro-CT measurements. At 2 weeks, osteoblasts were seen to line the implant surface, and multinuclear osteoclasts could be seen on the surface of old parent bone. After 8 weeks, a majority of the space in the wound chamber appeared to be replaced by bone. Enhancement of the stability of biologically modified implants was proved by the results of RFA, micro-CT, and histological analysis. This enhanced stability may help fasten treatment and be clinically beneficial.

To evaluate the retentive strength of 7 different luting agents in cement-retained implant abutment/analog assemblies. Fifty-six externally hexed dental implant abutment/analog assemblies and cast superstructures were divided randomly into 7 groups for cementation with each of the 7 luting agents. Five definitive cements tested were zinc phosphate cement, All-Bond 2, Maxcem, RelyX Luting cement, HY-Bond, and two provisional cements, ImProv and Premier. Cast superstructures were cemented onto the implant abutments and exposed to 1000 thermal cycles (0°C–55°C) and 100 000 cycles on a chewing simulator (75 N load). A universal testing machine was used to measure cement failure load of the assembled specimens. Cement failure load was evaluated with 1-way ANOVA and Duncan's multiple range analysis. Significant differences in cement failure loads were measured (P < .0001). Post hoc testing with Duncan's multiple range indicated 4 separate groupings. Maxcem and All-Bond 2 were comparable, having the greatest load failure. RelyX and zinc phosphate cement were analogous, and higher than HY-Bond. Improv and Premier constituted a pair, which demonstrated the lowest retentive values. Within the limitations of this in vitro study, Maxcem and All-Bond 2 are good candidates for cement-retained implant prostheses while concerning retention.

Conventional complete denture therapy for patients with severe residual ridge resorption is challenging. The dental implant therapy may be a treatment option for improving the denture support, retention, and stability. However, the neutral zone technique is also considered to be an important alternative approach to patients complaining of unstable dentures, particularly when implant therapy is not feasible. This technique is by no means new, but is not widely practiced due to lack of experience of dentists. The aim of this article is to describe historical perspectives on the neutral zone concept. In addition, a modified modern neutral zone technique is presented to reconstruct a lower complete denture for a patient with severe ridge resorption. The new definitive complete denture successfully improves stability, comfort, and function for the patient with severe mandibular ridge resorption.