Accuracy of Digital Impressions at Varying Implant Depths: An In Vitro Study.

PURPOSE: Implants placed at variable depths may vary the amount of visible scannable surface of a scan body. Intraoral scanner technology uses advanced optical principles to record the surface of the scan body to accurately capture the implant position. The purpose of this study is to investigate the effect implant placement depth has on the accuracy of digital implant impressions using an intraoral scanner. MATERIALS AND METHODS: A partially edentulous gypsum master model was fabricated to allow the positioning of a single implant analog at different depths. Four groups were created based on the planned implant depths of 7, 6, 3, and 0 mm and corresponding visibility of the scan body at 2, 3, 6, and 9 mm. The model was digitized with a laboratory scanner for the reference scan and with an intraoral scanner to generate 15 test scans per group, with a total of 60 scans. The test scans were superimposed onto the reference scan using the best fit algorithm to analyze and measure the positional (dXYZ) and angular deviation (d⍬) of the scan body using three-dimensional metrology software. Statistical analysis was performed using a one-way ANOVA and pairwise comparison was done with a Tukey-Kramer HSD test (α = 0.05). RESULTS: The one-way ANOVA of the groups for the dXYZ and dθ parameters was statistically significant (F3,56 = 11.45, p < 0.001, F3,56 = 24.04, p < 0.001). Group D (9 mm) showed the least positional deviation at 38.41 µm (95% CI 30.26; 46.56) and the least angular deviation of 0.17° (95% CI 0.12; 0.21). Group A (2 mm) showed the greatest positional deviation of 77.17 µm (95% CI 65.23; 89.11) and greatest angular deviation of 0.84° (95% CI 0.65; 1.03). The positional and angular deviation increased with increased implant depth. CONCLUSIONS: The accuracy of digital impressions is influenced by the implant depth and the amount of visibility of the scan body. The trueness and precision are highest when the implant is placed at 0 mm depth with complete visibility of the scan body and decreases with subgingival implant placement.

Immediate Loading of Four Guided Unsplinted Narrow Implants Supporting a Maxillary Overdenture: A Minimally Invasive Approach.

INTRODUCTION: Little evidence is available on the loading protocols for implant-supported overdentures in the treatment of the edentulous maxilla. There are only a few case-reports available to document the feasibility of immediate loading for maxillary overdenture, and the majority of the publications include the use of splinted implants. This paper presents a case report of immediately loaded narrow diameter implants supporting a maxillary overdenture using Locator abutments. CASE PRESENTATION: A 64-year-old, fully edentulous patient presented with a maxillary complete removable denture. A dual cone beam computed tomography scan was obtained, and the surgical planning was performed. Four 3.3 mm diameter implants were placed at the lateral incisor and second premolar positions, using a guided and flapless approach. Locator abutments were placed, and the denture was connected immediately. The patient was instructed not to remove the prosthesis for 1 week and to follow a soft diet regimen for 2 weeks. Clinical and radiographic evaluation showed positive results at 12 months, with neither prosthetic nor implant complications. CONCLUSION: This is a proof of principle case report, which demonstrates the possibility of immediately loading four guided narrow diameter implants supporting a maxillary overdenture using a Locator retention system.

The effect of implant prosthesis complications on patient satisfaction.

STATEMENT OF PROBLEM: How complications regarding implant prostheses affect patient satisfaction and oral health-related quality of life (OHRQoL) is unclear. PURPOSE: The purpose of this retrospective study was to compare patient satisfaction with implant restorations in patients with or without a history of complications. These data were used to determine whether implant prosthesis complications affected self-reported OHRQoL. MATERIAL AND METHODS: Data were gathered from 176 edentulous and partially dentate patients who had received implant prostheses consisting of implant-supported crowns, implant-supported overdentures, and screw-retained fixed dental prostheses (FDPs) in predoctoral and postdoctoral clinics between January 1, 2010, and December 31, 2014. Demographics and complications were self-reported by means of a survey. Patients rated their OHRQoL using the Quality of Life with Implant-Prostheses (QoLIP-10) questionnaire. Means were compared by using a 1-way ANOVA to compare the variables of prosthesis complications, sociodemographic data, and patient satisfaction. Significantly different variables were further evaluated using a post hoc Tukey-Kramer Honestly Significant Different (HSD) test (α=.05). RESULTS: Statistically significant differences in patient satisfaction were found related to prosthesis complications, gender, and marital status. The most common complication for implant-supported crowns was screw loosening. For implant-supported overdentures and screw-retained FDPs, the most common complication was repair of the prosthesis. Those who had experienced complications reported lower OHRQoL scores than those who had not. Women and widows/widowers overall reported lower OHRQoL scores. The OHRQoL scores of women with and without prosthesis complications were not statistically different (P=.073). No significant differences were found relative to age (P=.937) or education (P=.302). Patients without complications with implant-supported crowns reported the lowest satisfaction because of oral hygiene difficulties. The lowest satisfaction in patients with complications of implant-supported overdentures and screw-retained FDPs was related to worry/concern because of problems with the implant prosthesis. CONCLUSIONS: The results of this survey suggest that patients who experience complications with an implant prosthesis report a lower OHRQoL score than those who do not. Future studies are needed to evaluate patient satisfaction by comparing prosthesis complications with and without implants to determine whether patients who have had complications with implant prostheses are more satisfied than those who have experienced complications with conventional prostheses.

Computer-Guided Surgery Using Human Allogenic Bone Ring With Simultaneous Implant Placement: A Case Report.

INTRODUCTION: The allogenic bone ring technique allows for horizontal and vertical bone augmentation with simultaneous implant placement in severely compromised sites. The aim of this report is to present a modified protocol for simultaneous placement of implant and allogenic bone ring graft using a computer-guided surgery technique. CASE PRESENTATION: Patient's chief complaint was to replace a missing lateral incisor. The implant site presented both vertical and horizontal tissue deficiencies. Study models and wax-ups were digitally scanned to stl files and merged with the existing CBCT data in the implant planning software. A 3D representation of an allogenic bone ring was developed, and two digitally designed guides were created: a 5 mm sleeve guide for the implant site and a 7 mm sleeve guide for the allogenic bone ring trephine. Both the implant site and the allogenic bone ring recipient site were prepared using the computer-generated guides. Once the ring was adapted into the recipient site, the implant was inserted through the allogenic bone ring. The healing was monitored and the implant was restored at 12 months. The accuracy of implant placement was measured and the difference in the final positioning was as follows: 0.6 mm at entry point, 0.55 mm vertical displacement, 1.94 mm at the apex, and angle discrepancy 6.1°. CONCLUSION: The use of computer-guided technology for planning and placement of an allograft bone block with simultaneous implant insertion allows for a prosthetically driven team approach to compromised site grafting in addition to improving precision and accuracy when compared with non-guided techniques.

Prosthodontic Management of Implant Therapy: Esthetic Complications.

The essential promise of implant dentistry is the ability to imperceptibly replace missing teeth. To achieve this, careful planning, execution, and maintenance is required by the dentist and patient to maintain a long-term esthetic and functional result. Unfortunately, as a result of biological, prosthetic, and iatrogenic factors, unesthetic results can occur. This article explores the potential causes for the unesthetic dental implant and the possible solutions that may improve the clinical situation. Whereas relatively simple errors may be corrected through prosthetic means, greater complications may require surgical intervention to achieve the desired result.

Comparison Of Full-Mouth Scaling and Quadrant-Wise Scaling in the Treatment of Adult Chronic Periodontitis.

In the search for the ideal treatment of periodontal disease various non-surgical techniques should be considered. The objective of this study was to evaluate the efficacy of full-mouth scaling (FMS) by clinical and microbiological parameters. 670 individuals were evaluated with 230 subjects meeting the selection criteria and were divided into two groups; 115 subjects treated with FMS and 115 treated with weekly sessions of scaling and root planning (SRP). The patient population had a mean age of 51.67 years, with moderate chronic periodontitis. Subjects were evaluated prior to treatment (T1) and 90 days after execution of therapy (T2), with regards to: probing depth (PD), clinical attachment level (CAL), plaque index (PI), gingival index (GI), and microbial detection for the presence of Porphyromonas gingivalis (P.g.) and Prevotella intermedia (P.i.) by culture method and confirmed by biochemical tests. Subjects treated in the FMS group also rinsed with 0.12% chlorhexidine mouthwash for seven days following treatment. The results were analyzed using statistical Student's t-test and chi-square test. No statistically significant differences were observed for PD and CAL between T1 and T2 in both groups. For GI and PI significant difference was observed between the groups. For the evaluated microbial parameters was observed reduction of P.g. and P.i., but only for P.g. with a significant reduction in both groups. The full mouth scaling technique with the methodology used in this study provided improved clinical conditions and reduction of P.g. in subjects with moderate periodontitis, optimizing the time spent in the therapeutic execution.

Comparison of full-mouth scaling and quadrant-wise scaling in the treatment of adult chronic periodontitis

Abstract In the search for the ideal treatment of periodontal disease various non-surgical techniques should be considered. The objective of this study was to evaluate the efficacy of full-mouth scaling (FMS) by clinical and microbiological parameters. 670 individuals were evaluated with 230 subjects meeting the selection criteria and were divided into two groups; 115 subjects treated with FMS and 115 treated with weekly sessions of scaling and root planning (SRP). The patient population had a mean age of 51.67 years, with moderate chronic periodontitis. Subjects were evaluated prior to treatment (T1) and 90 days after execution of therapy (T2), with regards to: probing depth (PD), clinical attachment level (CAL), plaque index (PI), gingival index (GI), and microbial detection for the presence of Porphyromonas gingivalis (P.g.) and Prevotella intermedia (P.i.) by culture method and confirmed by biochemical tests. Subjects treated in the FMS group also rinsed with 0.12% chlorhexidine mouthwash for seven days following treatment. The results were analyzed using statistical Student's t-test and chi-square test. No statistically significant differences were observed for PD and CAL between T1 and T2 in both groups. For GI and PI significant difference was observed between the groups. For the evaluated microbial parameters was observed reduction of P.g. and P.i., but only for P.g. with a significant reduction in both groups. The full mouth scaling technique with the methodology used in this study provided improved clinical conditions and reduction of P.g. in subjects with moderate periodontitis, optimizing the time spent in the therapeutic execution.

Resumo Na busca do tratamento ideal da doença periodontal varias são técnicas não-cirúrgicas que podem ser consideradas. O objetivo deste estudo foi avaliar a eficácia da técnica de desinfecção total de boca (FMD, na sigla em Inglês) por parâmetros clínicos e microbiológicos. Foram avaliados 670 indivíduos com 230 indivíduos atendendo aos critérios de seleção e divididos em dois grupos; 115 indivíduos tratados com FMD e 115 tratados com sessões semanais de raspagem e alisamento corono radicular (SRP, na sigla em Inglês). A população avaliada tinha idade média de 51,67 anos, com periodontite crônica moderada. Os sujeitos foram avaliados antes do tratamento (T1) e 90 dias após a execução da terapia (T2), quanto à profundidade de sondagem (PS), nível de inserção clínica (NIC), índice de placa (IP), índice gengival (IG) e detecção microbiana da presença de Porphyromonas gingivalis (P.g.) e Prevotella intermedia (P.i.) por método de cultura e confirmada por testes bioquímicos. Os indivíduos tratados no grupo FMD também realizaram bochechos com clorexidina 0,12% durante sete dias após o tratamento. Os resultados foram analisados ​​utilizando o teste estatístico t de Student e o teste de qui-quadrado. Não foram observadas diferenças estatisticamente significativas para PS e NIC entre T1 e T2 em ambos os grupos. Para IG e IP observou-se diferença significativa entre os grupos. Para os parâmetros microbianos avaliados foi observada redução de P.g. e P.i., mas apenas para P.g. com uma redução significativa em ambos os grupos. A técnica FMD com a metodologia utilizada neste estudo proporcionou condições clínicas melhoradas e redução da P.g. Em indivíduos com periodontite moderada, otimizando o tempo gasto na execução terapêutica.

The soft tissue immunologic response to hydroxyapatite-coated transmucosal implant surfaces: a study in humans.

OBJECTIVE: To evaluate the soft tissue response in humans immunologically and histologically after placement of mini-implants coated with or without nano-size hydroxyapatite coatings. MATERIAL AND METHODS: Commercially pure (cp) titanium mini-implants (n = 13) or nano-hydroxyapatite-coated ones (n = 12) were randomly placed into partially edentulous jaws. Crevicular fluid was sampled 1 week after placement and subjected to quantitative polymerase chain reaction analysis to explore the inflammatory markers. After 8 weeks, implants and surrounding soft and hard tissue were trephined, and undecalcified ground sections were prepared. Inflammatory cell accumulation within a defined region of interest in the soft tissue was quantified histomorphometrically. RESULTS: No statistically significant differences in immunological response to the different implant surfaces were found for IL-6 (p = .438), TGF-ß2 (p = .467), MMP-8 (p = .758), CCL-3 (p = .758), IL-8 (p = .771), and IL-1ß (0.771). Histomorphometric evaluation presented no statistically significant difference between the two mini-implant surfaces with regards to number of inflammatory cells (p = .669). CONCLUSION: Nano-hydroxyapatite-coated surfaces in the transmucosal region yielded similar inflammatory response and is suggested to be as biocompatible as commercially pure titanium surfaces.

The influence of 1α.25-dihydroxyvitamin d3 coating on implant osseointegration in the rabbit tibia.

OBJECTIVES: This study aims to evaluate bone response to an implant surface modified by 1α,25-dihydroxyvitamin D3 [1.25-(OH)2D3] in vivo and the potential link between 1.25-(OH) 2D3 surface concentration and bone response. MATERIAL AND METHODS: Twenty-eight implants were divided into 4 groups (1 uncoated control, 3 groups coated with 1.25-(OH)2D3 in concentrations of 10(-8), 10(-7) and 10(-6) M respectively), placed in the rabbit tibia for 6 weeks. Topographical analyses were carried out on coated and uncoated discs using interferometer and atomic-force-microscope (AFM). Twenty-eight implants were histologically observed (bone-to-implant-contact [BIC] and new-bone-area [NBA]). RESULTS: The results showed that the 1.25-(OH)2D3 coated implants presented a tendency to osseointegrate better than the non-coated surfaces, the differences were not significant (P > 0.05). CONCLUSIONS: The effect of 1.25-(OH)2D3 coating to implants suggested possible dose dependent effects, however no statistical differences could be found. It is thought that the base substrate topography (turned) could not sustain sufficient amount of 1.25-(OH)2D3 enough to present significant biologic responses. Thus, development a base substrate that can sustain 1.25-(OH)2D3 for a long period is necessary in future studies.

Radiographic stents: integrating treatment planning and implant placement.

The pivotal point in treatment planning for dental implants occurs when the location of bone is viewed radiographically in the context of the planned prosthesis. Radiographic planning for dental implant therapy should be used only after a review of the patient's systemic health, imaging history, oral health, and local oral conditions. The radiological diagnostic and planning procedure for dental implants can only be fully achieved with the use of a well-designed and -constructed radiographic guide. This article reviews several methods for construction of radiographic guides and how they may be utilized for improving implant surgery planning and performance.

Patient selection and treatment planning for implant restorations.

Dental implants are an indispensible tool for the restoration of missing teeth. Their use has elevated the practice of dentistry by improving both our technical ability to rehabilitate patients and general quality of life. To routinely achieve the associated high expectations, diligent attention to details must be observed and addressed from the outset. Of central concern is the attainment of osseointegration and the location of implants to ideally support the intended restoration. The pivotal point in treatment planning for dental implants occurs when the location of bone is viewed radiographically in the context of the planned prosthesis. This most often requires diagnostic waxing or tooth arrangement using mounted diagnostic casts.

Prosthodontic management of implant therapy.

Implant-supported dental restorations can be screw-retained, cement-retained, or a combination of both, whereby a metal superstructure is screwed to the implants and crowns are individually cemented to the metal frame. Each treatment modality has advantages and disadvantages. The use of computer-aided design/computer-assisted manufacture technologies for the manufacture of implant superstructures has proved to be advantageous in the quality of materials, precision of the milled superstructures, and passive fit. Maintenance and recall evaluations are an essential component of implant therapy. The longevity of implant restorations is limited by their biological and prosthetic maintenance requirements.

Osteoblastic and cytokine gene expression of implant-adherent cells in humans.

OBJECTIVES: Implant surface topography is a key determinant affecting osteoblastic differentiation and cell-cell signaling of implant-adherent cells. MATERIALS AND METHODS: To assess the early osteoinductive and cell-cell signaling events in adherent cells, commercially pure titanium implants (2.2 × 5 mm) with nanotopography (HF-treated TiO2 grit-blasted) were compared with micron-scale topography TiO2 grit-blasted (micron-scale, control) implants in vivo. Six implants (n = 3/surface) were placed in 10 systemically healthy subjects and removed by reverse threading at 1, 3, and 7 days. Gene expression profiles of adherent cells were interrogated using low-density RT-PCR arrays. RESULTS: Osteoinduction was not observed at day 1 on either surface. At 3 days, elevated levels of BMP6, osteopontin, and osterix (OSX) were observed in RNA of cells adherent to both micron-scale and nanotopography surfaces. Both surfaces supported osteoinductive gene expression at 7 days; however, modest elevations of most mRNAs and significantly higher OSX mRNA levels were measured for cells adhered to nanotopography implants. Further, chemokine and cytokine profiles including CXCL10, CXCL14, IL-9, IL-22, and TOLLIP were upregulated on nanotopographic surfaces as compared with microtopographic surfaces. CONCLUSIONS: Implants with superimposed nanoscale topography generate a greater induction of genes linked to osteogenesis and cell-cell signaling during the early phases of osseointegration.

Surface characterization and clinical review of two commercially available implants.

PURPOSE: To characterize topographically and chemically the surfaces of 2 commercially available implants. Furthermore, to gather an overview of the clinical results of these implant systems. MATERIALS AND METHODS: Two commercially available oral implants were analyzed using optical interferometry, scanning electron microscopy, and energy dispersive spectroscopy. In addition, a literature search for all the clinical articles on the same implants was performed. RESULTS: No significant differences of topographical parameters were found between the 2 implants, except for the hybrid parameter Sdr presenting significant higher values for the Ankylos implants. Both surfaces had a homogenous microporosity. At higher magnifications of scanning electron microscope images, evenly distributed nanostructures (approximately 10 nm) were visible. Chemically, mainly titanium, oxygen and carbon were detected. Fifty-six clinical articles were included for the review. The implant survival rates (minimum follow-up: 5 years) ranged between 87.7% and 100%. CONCLUSIONS: The examined commercially available implants showed a moderately rough surface, with a homogenous microporosity. Nanofeatures were detected on the surface of both implants. The clinical performances of these implants were comparable to that of other commercialized implant systems.

Evaluation of bone regeneration after three different lateral sinus elevation procedures using micro-computed tomography of retrieved experimental implants and surrounding bone: a clinical, prospective, and randomized study.

PURPOSE: To compare three different lateral sinus elevation procedures concerning new bone formation by using micro-computed tomography (micro-CT) of retrieved implants. MATERIALS AND METHODS: Twenty-four consecutive partially dentate patients with a mean age of 64 years were included in the study and provided with 30 sinus elevation procedures. Three procedures for lateral sinus elevation were used: lateral sinus elevation with replacement of bone window and without bone graft (BW), lateral sinus elevation and covering osteotomy site with a collagen membrane and without bone graft (CM), and lateral sinus elevation with autogenous bone graft (ABG). Experimental implants were retrieved after 7 months of healing and analyzed by micro-CT. RESULTS: One implant was found not to be integrated at the time of implant retrieval. This implant belonged to group CM and was excluded when calculating bone-to-implant contact (BIC) and intrasinus bone levels. The integrity of the lateral sinus bony wall was determined at the time of implant removal. In group ABG, all lateral sinus walls were ossified. In group BW, one lateral sinus wall was not completely ossified and in group CM, two lateral sinus walls. There were no statistical differences in %BIC between the groups: 93.5% (BW), 92.0% (CM) and 93.5% (ABG). Additionally, no statistical differences were found in apical intrasinus bone levels between the groups. When surfaces were compared within the same implant, a statistical difference was found between the apicobuccal distance and the apicolingual distance. The mean apicobuccal distances/apicolingual distances were 0.6 mm/1.2 mm for the BW group, 0.5 mm/0.8 mm for the CM group, and 0.6 mm/0.8 mm for the ABG group (P = .003). CONCLUSIONS: All three procedures were statistically equal when new bone formation was compared. Most of the examined implants' apices were not covered with bone at the time of retrieval.

The influence of nano hydroxyapatite coating on osseointegration after extended healing periods.

OBJECTIVE: Studies observing early wound healing periods around dental implants demonstrate an implants ability to enhance osseointegration, the bone-implant interactions for extended healing periods though have not been thoroughly studied. METHODS: Twenty threaded titanium alloy (Ti6Al4V, Grade 5) implants were inserted bilaterally, half prepared to impart stable hydroxyapatite nanoparticles onto a sand blasted and acid etched surface (HA) and half with a non-coated control surface with only heat treatment (HT), into eighteen rabbit femurs. At 12 weeks, the bone-implant blocks were retrieved for micro computed tomography (µCT), histologic processing and histomorphometric evaluation. RESULTS: The bone-to-implant contact for the entire threaded portion of the implant revealed 57.1% (21.0) for the HT group and 38.8% (17.7) for the HA group with a total bone area within the threads 72.5% (13.9) (HT) and 59.7% (12.5) (HA). The 3D reconstructed µCT image corresponded to the histomorphometric results. SIGNIFICANCE: It is suggested that multiple factors such as the change in topography and chemistry may have influenced the outcomes.

Ubiquitin/proteasome-dependent degradation of D-type cyclins is linked to tumor necrosis factor-induced cell cycle arrest.

Tumor necrosis factor-alpha (TNF) is well known for its cytotoxic effect on malignant cells. Its role in cell cycle control is relatively less known. In this study, we found that TNF induced G(1) arrest of TF-1 and MV4-11 cells while simultaneously causing apoptosis. Treatment of the cells with TNF for 48 h caused cell cycle arrest, accompanied by dephosphorylation of pRb and reduction in D-type cyclin expression. The down-regulation of the D-type cyclins resulted in approximately 50-80% decrease of the cyclin-dependent kinase activities. Cells treated with calpain-dependent inhibitor ALLN and apoptosis inhibitor zVAD-FMK suppressed degradation of IkappaBalpha and activation of caspase 3, respectively. However, treatment of cells with these two inhibitors was not able to prevent TNF-induced down-regulation of the D-type cyclins. In contrast, proteasome inhibitor MG-132 and lactacystin blocked both TNF-induced degradation of IkappaBalpha and down-regulation of D-type cyclins. These data suggest that down-regulation of D-type cyclins by TNF may be proteasome-proteolysis dependent. Additional support for this conclusion was obtained from experiments showing an increase of proteasome activity in TNF-treated cells and in vitro degradation of cyclin D3 by 26 S proteasome.