Vertical Loss Research Articles

Full Mouth Reconstruction of a Patient with Severely Worn Dentition: A Clinical Report

If remained untreated, progressive dental wear can lead to pulpal pathology, occlusal disharmony, and impaired function and esthetics. This case report describes prosthetic rehabilitation of a 53 year-old man with the loss of anterior guidance, severe wear of dentition and vertical dimension loss. Oral rehabilitation was performed by reconstruction of vertical dimension, crown lengthening, conventional implants, and custom cast gold post and cores as well as porcelain fused to metal restorations. Full mouth reconstruction of the patient with severely worn dentition was found to be successful after 4 years of follow up. Keywords: mouth rehabilitation, tooth wear, vertical dimension

Stability of simultaneously placed dental implants with autologous bone grafts harvested from the iliac crest or intraoral jaw bone.

BackgroundJaw bone and iliac bone are the most frequently used autologous bone sources for dental implant placement in patients with atrophic alveolar ridges. However, the comparative long-term stability of these two autologous bone grafts have not yet been investigated. The aim of this study was to compare the stability of simultaneously placed dental implants with autologous bone grafts harvested from either the iliac crest or the intraoral jaw bone for severely atrophic alveolar ridges.MethodsIn total, 36 patients (21 men and 15 women) were selected and a retrospective medical record review was performed. We compared the residual increased bone height of the grafted bone, peri-implantitis incidence, radiological density in newly generated bones (HU values), and implant stability using resonance frequency analysis (ISQ values) between the two autologous bone graft groups.ResultsBoth autologous bone graft groups (iliac bone and jaw bone) showed favorable clinical results, with similar long-term implant stability and overall implant survival rates. However, the grafted iliac bone exhibited more prompt vertical loss than the jaw bone, in particular, the largest vertical bone reduction was observed within 6 months after the bone graft. In contrast, the jaw bone graft group exhibited a slower vertical bone resorption rate and a lower incidence of peri-implantitis during long-term follow-up than the iliac bone graft group.ConclusionsThese findings demonstrate that simultaneous dental implantation with the autologous intraoral jaw bone graft method may be reliable for the reconstruction of edentulous atrophic alveolar ridges.

Wear properties of dental ceramics and porcelains compared with human enamel

Statement of problemContemporary pressable and computer-aided design/manufacturing (CAD/CAM) ceramics exhibit good mechanical and esthetic properties. Their wear resistance compared with human enamel and traditional gold based alloys needs to be better investigated. PurposeThe purpose of this in vitro study was to compare the 2-body wear resistance of human enamel, gold alloy, and 5 different dental ceramics, including a recently introduced zirconia-reinforced lithium silicate ceramic (Celtra Duo). Material and methodsCylindrical specimens were fabricated from a Type III gold alloy (Aurocast8), 2 hot pressed ceramics (Imagine PressX, IPS e.max Press), 2 CAD/CAM ceramics (IPS e.max CAD, Celtra Duo), and a CAD/CAM feldspathic porcelain (Vitablocs Mark II) (n=10). Celtra Duo was tested both soon after grinding and after a subsequent glaze firing cycle. Ten flat human enamel specimens were used as the control group. All specimens were subjected to a 2-body wear test in a dual axis mastication simulator for 120000 loading cycles against yttria stabilized tetragonal zirconia polycrystal cusps. The wear resistance was analyzed by measuring the vertical substance loss (mm) and the volume loss (mm3). Antagonist wear (mm) was also recorded. Data were statistically analyzed with 1-way ANOVA tests (α=.05). ResultsThe wear depth (0.223 mm) of gold alloy was the closest to that of human enamel (0.217 mm), with no significant difference (P>.05). The greatest wear was recorded on the milled Celtra Duo (wear depth=0.320 mm), which appeared significantly less wear resistant than gold alloy or human enamel (P<.05). ConclusionsThe milled and not glazed Celtra Duo showed a small but significantly increased wear depth compared with Aurocast8 and human enamel. Wear depth and volumetric loss for the glaze-fired Celtra Duo and for the other tested ceramics did not statistically differ in comparison with the human enamel.

Reflection loss estimation using shallow water ambient noise in the Arabian Sea off the west coast of India

This study focuses on the application of a recently developed array processing technique, for estimating the seabed reflection loss, using ambient noise in extremely shallow water (Siderius et al, 2013). According to synthetic array processing technique, the angular resolution of directionality and reflection loss derived from ambient noise can be improved. In this method, Toeplitz property of noise coherence function is used to improve the angular resolution in beamforming. The simulated result of the developed technique provides higher angular resolution for vertical directionality and reflection loss. Ambient noise data recorded in wind prevailing conditions, using a 12 element vertical array from the shallow waters off the west coast of India was used for the analysis. The results from the experimental data conclude that, the reflection loss derived from a 12 element physical array can achieve angular resolution, comparable to a synthetically expanded 6 element physical array.

Two-Body Wear of CoCr Fabricated by Selective Laser Melting Compared with Different Dental Alloys

The purpose of this study was to assess the two-body wear of cobalt–chromium (CoCr) samples fabricated by selective laser melting (SLM) in contrast to cast samples and enamel. The following materials were chosen for comparison with SLM-CoCr: a CoCr alloy for use in the lost-wax technique, four gold alloys with different hardness, titanium (grade 1), and human enamel. Seven specimens of diameter 12 mm and thickness 1 mm were produced from each material and polished with emery paper. Al2O3 ceramic balls served as antagonists in the biaxial chewing simulator. Multiple chewing cycles were applied with a static load of 50 N. Wear was analysed laser-optically by the use of cast replicas. Statistical analyses were performed with Kruskal–Wallis test and subsequent post hoc Mann–Whitney U tests at a significance level of 0.05. SLM-CoCr showed less wear than any of the other materials. The difference was statistically significant between SLM-CoCr (vertical loss −54.4 ± 6.9 µm after 300,000 cycles) and cast CoCr (vertical loss −117.2 ± 18.6 µm after 300,000 cycles). Greatest vertical wear was observed for titanium. SLM-CoCr exhibits a great resistance to wear and might represent an alternative for the manufacture of prosthetic restorations even in occlusal loading areas. Clinical relevance Clinical investigations on wear of SLM-CoCr are needed to assess its in vivo behaviour.

Comparative in vitro wear resistance of CAD/CAM composite resin and ceramic materials

Statement of problemComposite resin is a promising option in computer-aided design and computer-aided manufacturing (CAD/CAM) dentistry; however, the wear resistance of composite resin remains a primary concern. PurposeThe purpose of this in vitro study was to evaluate the wear resistance of 5 CAD/CAM materials (n=10), consisting of 4 composite resins (3M Lava Ultimate, Kerr experimental composite resin material, Vita Enamic, 3M Paradigm MZ100) and 1 ceramic (Vita Mark II) in contact with natural human enamel cusps. Material and methodsSpecimens were loaded into a computer-controlled mastication simulator and subjected to 200000 mechanical cycles (49 N) against natural human enamel simultaneously with 500 thermal cycles (5°C to 50°C to 5°C). The wear resistance was analyzed by measuring the vertical substance loss (the maximum depth of the worn area) in the contact point area of the specimen. The worn surfaces were observed by scanning electron microscopy to determine the wear patterns. ResultsVita Mark II exhibited the best wear resistance among the tested materials, followed by 3M Lava Ultimate, Vita Enamic, and 3M Paradigm MZ100. The Kerr experimental material exhibited the lowest wear resistance, yet its results were not significantly different from those of the 3 other composite resin blocks (P>.05). ConclusionsWithin the limitations of this in vitro study, the wear resistance of composite resin blocks in contact with enamel cusps was significantly lower than that of a ceramic block.

Impact of continuing scaling on the device performance of 3D cylindrical junction-less charge trapping memory**Project supported by the National Natural Science Foundation of China (Nos. 61474137, 61176073, 61306107).

This work presents a comprehensive analysis of 3D cylindrical junction-less charge trapping memory device performance regarding continuous scaling of the structure dimensions. The key device performance, such as program/erase speed, vertical charge loss, and lateral charge migration under high temperature are intensively studied using the Sentaurus 3D device simulator. Although scaling of channel radius is beneficial for operation speed improvement, it leads to a retention challenge due to vertical leakage, especially enhanced charge loss through TPO. Scaling of gate length not only decreases the program/erase speed but also leads to worse lateral charge migration. Scaling of spacer length is critical for the interference of adjacent cells and should be carefully optimized according to specific cell operation conditions. The gate stack shape is also found to be an important factor affecting the lateral charge migration. Our results provide guidance for high density and high reliability 3D CTM integration.

An analytical model of a deformable cantilever structure rocking on a rigid surface: development and verification

SummaryThis paper extends previously developed models to account for the influence of the column and the foundation masses on the behavior of top‐heavy deformable elastic cantilever columns rocking on a rigid support surface. Several models for energy dissipation at impact are examined and compared. A novel Vertical Velocity Energy Loss model is introduced. Rocking uplift and overturning spectra for the deformable elastic cantilever model excited by sinusoidal ground motions are constructed. The effects of non‐dimensional model parameter variations on the rocking spectra and the overturning stability of the model are presented. It is shown that the remarkable overturning stability of dynamically excited large cantilever columns is not jeopardized by their deformability. Copyright © 2015 John Wiley &amp; Sons, Ltd.

Soft Tissue Alterations in Esthetic Postextraction Sites

Dimensional alterations of the facial soft and bone tissues following tooth extraction in the esthetic zone play an essential role to achieve successful outcomes in implant therapy. This prospective study is the first to investigate the interplay between the soft tissue dimensions and the underlying bone anatomy during an 8-wk healing period. The analysis is based on sequential 3-dimensional digital surface model superimpositions of the soft and bone tissues using digital impressions and cone beam computed tomography during an 8-wk healing period. Soft tissue thickness in thin and thick bone phenotypes at extraction was similar, averaging 0.7 mm and 0.8 mm, respectively. Interestingly, thin bone phenotypes revealed a 7-fold increase in soft tissue thickness after an 8-wk healing period, whereas in thick bone phenotypes, the soft tissue dimensions remained unchanged. The observed spontaneous soft tissue thickening in thin bone phenotypes resulted in a vertical soft tissue loss of only 1.6 mm, which concealed the underlying vertical bone resorption of 7.5 mm. Because of spontaneous soft tissue thickening, no significant differences were detected in the total tissue loss between thin and thick bone phenotypes at 2, 4, 6, and 8 wk. More than 51% of these dimensional alterations occurred within 2 wk of healing. Even though the observed spontaneous soft tissue thickening in thin bone phenotypes following tooth extraction conceals the pronounced underlying bone resorption pattern by masking the true bone deficiency, spontaneous soft tissue thickening offers advantages for subsequent bone regeneration and implant therapies in sites with high esthetic demand (Clinicaltrials.gov NCT02403700).

Clinical and laboratory surface finishing procedures for zirconia on opposing human enamel wear: A laboratory study

AimTo investigate the effect of laboratory and clinical finishing procedures for zirconia on antagonistic enamel wear. Materials and methodsForty-eight yttria-tetragonal partially stabilised zirconia (Y-TZP) specimens were prepared and divided into four groups according to their surface preparation: laboratory polished (LP); laboratory polished and glazed (G); clinically adjusted (CA); and clinically adjusted and repolished (CAR). Enamel opposing enamel was used as a control.Pre-testing surface roughness for each group was determined using contact profilometry.Two-body wear resistance tests were conducted using a masticatory simulator. Enamel specimens were subjected to 120,000 cycles in distilled water (frequency 1.6Hz, loading force of 49N). Volumetric and vertical enamel losses were measured by superimposition of pre- and post-testing images using a three-dimensional laser scanner and software analysis.Scanning electron microscopy was used for qualitative surface analysis of pre- and post-testing zirconia and enamel surfaces.One-way ANOVA and multiple comparisons with Bonferroni corrections were used for statistical analysis at a significance level of α=0.05. ResultsThere was no statistical difference in volumetric and vertical enamel loss between CAR, G and LP.CAR produced statistically significantly less volumetric enamel loss compared with CA and control, and statistically significantly less vertical enamel loss compared with CA. Volumetric and vertical enamel loss were highly correlated in all groups. ConclusionsEnamel wear by clinically ground zirconia is comparable to that of opposing enamel surfaces and greater than clinically repolished zirconia. Repolishing of zirconia restorations following clinical adjustment with diamond burs is effective in reducing antagonistic enamel wear.

Oroantral communication repair using bone substitute and platelets rich fibrin

PurposeThe aim of this study is to evaluate oroantral communication (OAC) repair using one bone substitute (Fisiograft) and platelets rich fibrin (PRF). Patients and methodsIn the present study, eight patients complaining from OAC following extraction of maxillary posterior tooth were selected. The bony defect of the OAC was grafted with Fisiograft sandwiched between two PRF membranes. Then the graft was covered by buccal advancement flap. The patients were followed up clinically after 1, 2, 4 and 12 weeks postoperatively. Radiographic evaluation was performed immediately and after twelve weeks postoperatively. ResultsSuccessful closure of the OAC was achieved in all cases. None of the cases reported recurrence of the OAC or regurgitation of fluids from the nose. There were no signs of dehiscence, infection, allergic reaction, ulceration, or exposure of the material. The covering mucosa returned to the normal color and texture by the end of the first month. Radiographically, the bony defect appeared radiolucent immediate postoperatively. After three months, there was almost complete healing of the bony defect of the OAC. Densitometric measurements showed statistically significant increase in the bone density at the defect area after three months postoperatively. Linear measurements showed no statistically significant vertical loss of alveolar bone after three months postoperatively.

Mandibular Ridge Augmentation Using a Mineralized Ilium Block: A Case Letter

Mandibular Ridge Augmentation Using a Mineralized Ilium Block: A Case Letter

Mode characteristics and vertical radiation loss for AlGaInAs/InP microcylinder lasers

Mode characteristics are experimentally and numerically investigated for the AlGaInAs/InP microcylinder lasers with radii R ranging from 3.25 to 5.5&#xA0;&#x3BC;m. The measured lasing spectra suggest wavelength crossing between different radial-order modes at R=3.5&#x2009;&#x2009;&#x3BC;m, and the threshold current dramatically increases as R&lt;3.5&#x2009;&#x2009;&#x3BC;m, which can be well explained by three-dimensional finite-difference time-domain simulation. The simulated mode Q factors greatly degrade in the microcylinder resonators as R&lt;3.5&#x2009;&#x2009;&#x3BC;m and strongly depend on the mode wavelength because of vertical radiation loss, which results in a limitation for low threshold lasing. In addition, the near coincidence of mode wavelengths for different radial modes indicates the possible mode coupling at R=3.5&#x2009;&#x2009;&#x3BC;m.

A NUMERICAL MODELING STUDY ON UPWELLING MECHANISM IN SOUTHERN MAKASSAR STRAIT

&lt;p&gt;&lt;strong&gt;&lt;em&gt;ABSTRACT&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt; &lt;p&gt;&lt;em&gt;While it has been well documented in the previous studies that upwelling events in the southern Makassar Strait (MAK) during the Southeast Monsoon (SEM) period are associated with low sea surface temperature (SST) and high chlorophyll-a (Chl-a) concentrations in the seawater, the dynamic and physical processes that trigger these upwelling events are still less well understood. In the present study we proposed a mechanism of the upwelling event using a numerical model of the Regional Ocean Modeling System (ROMS). Model validations showed a high correlation of SST climatology between the model and the NOAA-AVHRR satellite data. Moreover, &lt;/em&gt;&lt;em&gt;velocity fields of the Indonesian Throughflow (ITF) Makassar in Libani Channel was well reproduced by proposed model, revealing an intensification of the flow centered near 120 m depth, which is in good agreement with the observation data. &lt;/em&gt;&lt;em&gt;The model demonstrated that during the SEM period strong southeasterly winds that blow over southern Sulawesi Island can increase high vertical diffusivity and heat loss through heat flux. Hence, these physical processes lead to increased vertical mixing that, in turn, generates low SST, as a proxy of upwelling event. Furthermore, the upwelling process is enhanced by the ITF Makassar jet that creates large circular eddies flow due to complex topographic within the triangle area of southern Makassar - eastern Java Sea - western Flores Sea. The eddies generate the area of convergence offshore along the ITF pathways and divergence area in the coastal waters close to southern Sulawesi Island. Model experiment with closing/opening Selayar Strait revealed a change of intensity and area of upwelling, suggesting that the Selayar Island forms a barrier for the outflow from MAK to northern part of Flores Sea.&lt;/em&gt;&lt;em&gt; &lt;/em&gt;&lt;/p&gt; &lt;p&gt;&lt;em&gt; &lt;/em&gt;&lt;/p&gt; &lt;strong&gt;&lt;em&gt;Keywords: &lt;/em&gt;&lt;/strong&gt;&lt;em&gt;Upwelling, ITF Makassar, SE monsoon winds, ROMS-AGRIF, Makassar Strait.&lt;/em&gt;

A NUMERICAL MODELING STUDY ON UPWELLING MECHANISM IN SOUTHERN MAKASSAR STRAIT

ABSTRACT While it has been well documented in the previous studies that upwelling events in the southern Makassar Strait (MAK) during the Southeast Monsoon (SEM) period are associated with low sea surface temperature (SST) and high chlorophyll-a (Chl-a) concentrations in the seawater, the dynamic and physical processes that trigger these upwelling events are still less well understood. In the present study we proposed a mechanism of the upwelling event using a numerical model of the Regional Ocean Modeling System (ROMS). Model validations showed a high correlation of SST climatology between the model and the NOAA-AVHRR satellite data. Moreover, velocity fields of the Indonesian Throughflow (ITF) Makassar in Libani Channel was well reproduced by proposed model, revealing an intensification of the flow centered near 120 m depth, which is in good agreement with the observation data. The model demonstrated that during the SEM period strong southeasterly winds that blow over southern Sulawesi Island can increase high vertical diffusivity and heat loss through heat flux. Hence, these physical processes lead to increased vertical mixing that, in turn, generates low SST, as a proxy of upwelling event. Furthermore, the upwelling process is enhanced by the ITF Makassar jet that creates large circular eddies flow due to complex topographic within the triangle area of southern Makassar - eastern Java Sea - western Flores Sea. The eddies generate the area of convergence offshore along the ITF pathways and divergence area in the coastal waters close to southern Sulawesi Island. Model experiment with closing/opening Selayar Strait revealed a change of intensity and area of upwelling, suggesting that the Selayar Island forms a barrier for the outflow from MAK to northern part of Flores Sea. Keywords: Upwelling, ITF Makassar, SE monsoon winds, ROMS-AGRIF, Makassar Strait.

Bruxism – Literature review

Introduction: Bruxism is an oral parafunction prevalent in all age groups which is characterized by the involuntary teeth grinding and/or clenching that may occur at any time of the day. It has a multifactorial etiology associated with occlusal and psychological factors and / or habits that can compromise the orthognatic system that may bring negative consequences. Objective: To make a revision article from the existing literature on the etiological factors, clinical manifestations and treatment of bruxism. Materials and methods: Data search was accomplished using Pubmed and ScienceDirect databases applying the keywords “bruxism”, “etiology and symptoms”, “attrition injuries”, “teeth grinding”, “muscular-articular disorders”, “TMJ dysfunction”. From the 102 articles, after analysis of all the abstracts, 34 articles and 4 textbooks were included. Results: The main consequences of bruxism are muscle fatigue, pain, use of incisal edges and occlusal surfaces of the teeth, and in more severe cases teeth loss, headache, periodontal lesions and temporomandibular joint disorders (TMJ disorders). These clinical manifestations may increase the difficulty of oral rehabilitation of edentulous areas and teeth restoration. They may also cause vertical dimension loss and the decrease of patients’ quality of life. Early diagnosis and identification of the etiologic factors are important to prevent the progression of lesions in the orofacial structures such as pain relief of the craniofacial muscles, restoration of the lost structures and reestablishment of vertical dimension. Conclusion: Bruxism presents a high frequency in all age groups and has become an important oral health issue. This parafunctional habit consists in an important change in the oral sensory-motor system, requiring a multidisciplinary approach, in order to reduce injuries in osteodental structures. Lately, its prevalence has increased and is associated with several factors such as stress, drugs, anxiety and sleep disorders, among others. The dentist should be aware of the signs and symptoms in order to prescribe the best treatment, providing the patients a better quality of life.

Cone-Beam Computed Tomography Evaluation of Horizontal and Vertical Dimensional Changes in Buccal Peri-Implant Alveolar Bone and Soft Tissue: A 1-Year Prospective Clinical Study.

This study evaluated changes in the horizontal and vertical dimensions of the buccal alveolar bone and soft tissue over a 1-year period following implant prosthesis. Thirty-three participants with no history of guided bone regeneration or soft tissue augmentation underwent dental implant placement with different types of connections. The dimensions of the buccal alveolar bone and soft tissue were evaluated immediately and at 1 year after prosthesis from reconstructions of cross-sectional cone-beam computed tomography images. The vertical and horizontal loss of buccal bone and soft tissue around implants with conical connections were lower than around those with external or internal connections. Statistically significant negative correlations were observed between initial horizontal bone thickness and changes in vertical bone and soft tissue height (p < .05), and between initial horizontal soft tissue thickness and the change in vertical soft tissue height (p < .05). Implants with a conical connection preserve peri-implant alveolar bone and soft tissue more effectively than other connection types. Furthermore, the initial buccal alveolar bone and soft tissue thickness around the implant platform may influence their vertical dimensional changes at 1 year after implant prosthesis.

Prevalence of Temporomandibular Joint Disorder and Stress Related Dental Attritions Among Army Personnel

Background: Dental attrition is capable of causing toothache, temporomandibular disorders (TMDs), and vertical facial dimension loss. It may also harden prosthesis fabrication. The most frequent causes of this problem are stress and mental tensions. Objectives: However, there is no documented or published data on the prevalence of dental attrition and TMDs among army personnel. Nevertheless, by timely recognition of the susceptible cases, it is possible to prevent or stop the development of this condition. Patients and Methods: The participants were patients seeking general dentistry treatments in two military based centers in Tehran. Sample consisted of 200 army personnel and 200 civilian patients. All the participants were divided into three age groups: under 30, between 30 and 50, and above 50 years old. The examinations included dental attrition, temporomandibular joint (TMJ) click on opening or closing, limitation on mouth opening, pain on TMJ or chewing muscle or tenderness in palpation. The participants were also asked to declare whether they have contributed in the imposed war. Results: Dental attrition was significantly more frequent in army personnel than civilian population. Also the prevalence of such a problem was significantly more frequent in those participated at war. Considering other examinations, no statistically significant differences were seen between army personnel and lay persons. Conclusions: In order to prevent or treat dental attrition in susceptible army personnel, part-time wear of night guard may be prescribed. Keywords: Tooth Attrition; Military Personnel; Temporomandibular Joint Disorders

Wear properties of a novel resin composite compared to human enamel and other restorative materials.

The purpose of this in vitro study was to compare the two-body wear resistance of human enamel, a pressable glass-ceramic (Imagine PressX), a type 3 gold alloy (Aurocast8), three resins composites currently available on the market (Enamel plus HRi, Filtek Supreme XTE, Ceram.X duo), and one recently introduced resin composite (Enamel plus HRi-Function). Resin composites were tested after simple light curing and after a further heat polymerization cycle. Ten cylindrical specimens (7 mm in diameter) were manufactured with each dental material according to standard laboratory procedures. Ten flat enamel specimens were obtained from freshly extracted human molars and included in the control group. All samples were subjected to a two-body wear test in a dual-axis chewing simulator over up to 120,000 loading cycles, against yttria stabilized tetragonal zirconia polycrystal cusps. Wear resistance was analyzed by measuring the vertical substance loss (mm) and the volume loss (mm(3)). Antagonist wear (mm) was also recorded. Data were statistically analyzed using one-way analysis of variance (ANOVA) (wear depth and volume loss) and Kruskal-Wallis one-way ANOVA on ranks (antagonist wear). Heat-cured HRi function and Aurocast8 showed similar mean values for wear depth and volumetric loss, and their results did not statistically differ in comparison with the human enamel.

Broadband investment and welfare under functional and ownership separation

We study how the vertical industry structure affects investment in network quality and social welfare, with a focus on the prospective deployment of high-speed broadband access networks (the so-called NGA). We model pros and cons of vertical separation, namely, pro-competitive effects and loss of some efficiencies of vertical integration, and distinguish functional separation from ownership separation. Our findings challenge the presumption that (compared with vertical integration) vertical separation reduces investment incentives and involves a trade-off between promoting consumer surplus and ensuring investment. While investment is higher under ownership rather than functional separation, the latter may yield the highest social welfare among vertical industry structures. Furthermore, the incumbent may voluntarily opt for functional separation, but in some of these cases, prohibiting separation improves welfare.