Oral health-related quality of life (OHRQoL) and implant therapy: A prospective multicenter study of preoperative, intermediate, and posttreatment assessment.

The purpose of this multicenter continuation study was to use high patient numbers in order to generate reliable statements regarding the association between different implant indications and OHRQoL. Patients with various types of indication for dental implants, ranging from single tooth loss to edentulous jaws, were included. Quality of life relating to dental implants was assessed through the oral health impact profile (OHIP-G-21), which has a summary score from 0 to 20 in healthy patients. In total, 16 253 patients from 29 centers (European Centers for Dental Implantology (ECDI)) were involved in the study between 2009 and 2021.8251 patients (50.7%) completed the questionnaire after implant insertion, and 4996 patients (30.7%) after prosthodontic treatment. The average age was 54 years (range 18-88 years). Posterior single-tooth gap (28.5%) and free-end gap (27.8%) were the most frequent indications. The preoperative OHIP-G-21 score for all patients was 32.81 (SD 11.92), while the score during the healing period was 30.00 (SD 10.72), and after completion of treatment 27.24 (SD 9.26) (p < 0.001). The most significant improvements in OHIP-G-21 scores were in the indication of edentulous jaw (phase 1, 41.81 (SD 15.53); phase 2, 35.39 (SD 14.22); phase 3, 29.60 (SD 10.12) (p < 0.001). The study revealed significant improvements in the most frequently reported problems (chewing, serious concerns, appearance) (p < 0.001). Insertion of dental implants and prosthodontic rehabilitation led to an improved OHRQoL for patients with all indications for dental implants. Special attention should be paid to patients with edentulous jaw, since in comparison with other indications it had the greatest impact on improving OHRQoL. The psychological dissatisfaction scale of the OHIP-G-21 represented the most important factors for patients, and these scores were substantially influenced by implant therapy. Thus, treating physicians should increase their focus on these factors, in order to avoid dissatisfaction and increase the likelihood of complete implant therapy success.

Retrospective cohort assessment of survival and complications of zygomatic implants in atrophic maxillae.

OBJECTIVES: To report on zygomatic implant (ZI) survival rate and associated complications through a longitudinal retrospective cohort assessment. MATERIAL AND METHODS: A total of 940 ZIs (rough: 781, machined: 159; immediate loading: 454, delayed loading: 486) and 451 standard implants (rough: 195, machined: 256; immediate loading: 58, delayed loading: 393) were placed in 302 adult patients with atrophic maxilla from December 1998 till September 2020. Following data collection reported complications were grouped based on their origin as infectious/ non-infectious biological and mechanical. Statistical analysis was performed to identify risk factors and preceding complications leading to implant loss (P < 0.05). RESULTS: The survival rate of ZI was found to be 89.9% and the average time between implant placement and an eventual loss was 4.8 years. The mean ZI follow-up period was 7.9 ± 4.9 years. Amongst the infectious biological complications, sinusitis was the most reported (n = 138) occurring at a mean follow-up time-point of 4.5 years, whereas infraorbital nerve hypoesthesia occurred more frequently in the non-infectious biological category (n = 8, meantime: 0.3 years). The prosthetic screw fracture was the most reported complication of mechanical origin (n = 29, meantime: 4 years). Furthermore, sinusitis, standard implant loss, zygomatic/peri-zygomatic region infection, and oroantral communication were significantly associated with ZI loss. CONCLUSIONS: ZI placement offered a high survival rate for the rehabilitation of severely atrophied maxilla with most losses occurring within the first 5 years at follow-up. The most frequently observed complication was sinusitis which tends to develop several years following implant placement.

Clinical assessment of pterygoid and anterior implants in the atrophic edentulous maxilla: a retrospective study.

OBJECTIVES: This study aims to evaluate the short-term clinical outcomes and patient satisfaction of anterior and pterygoid implants in the rehabilitation of edentulous maxilla with posterior atrophy. METHODS: Given a minimum follow-up of 1 year, 25 patients with fixed maxillary rehabilitation over anterior and pterygoid implants were enrolled in this retrospective study. The implant survival rates, peri-implant soft tissue status (including probing depth, modified sulcus bleeding index, and plaque index), marginal bone loss, and patient satisfaction were measured. RESULTS: The survival rates for anterior and pterygoid implants at 1-year follow-up were 96.5% and 97.8%, respectively (P>0.05). No statistically significant difference in probing depth, modified sulcus bleeding index, and plaque index was observed between the two types of implants (P>0.05). The marginal bone losses of anterior implants were 0.62 mm± 0.44 mm (mesial) and 0.61 mm± 0.40 mm (distal), and those of pterygoid implants were 0.64 mm± 0.46 mm (mesial) and 0.68 mm± 0.41 mm (distal) mm. These results showed no statistical difference in mesial and distal sites (P>0.05). Patients indicated a high degree of satisfaction with the full-arch prostheses supported by anterior and pterygoid implants. CONCLUSIONS: For the edentulous maxilla with posterior atrophy, full-arch fixed prostheses supported by anterior and pterygoid implants has an acceptable short-term clinical outcome and excellent patient satisfaction. It may be considered as a predictable and feasible method for maxillary rehabilitation.

Cost-effectiveness of three different concepts for the rehabilitation of edentulous mandibles: Overdentures with 1 or 2 implant attachments and hybrid prosthesis on four implants.

BACKGROUND: There are scarce data regarding the combined assessment of the costs and effects of implant treatments for edentulous patients when multiple options are available. AIM: This randomised clinical trial aimed to assess the cost-effectiveness of three different concepts for treatment: mandibular overdenture retained by a single (Group I; n = 11) or two implants (Group II; n = 13) and fixed hybrid prosthesis on four implants (Group III; n = 13). METHODS: Treatment effectiveness was measured as the 1-year before-after changes in patient satisfaction with the mandibular prosthesis. Costs were prospectively quantified from the perspective of the health provider, including all direct cost items attributed to the delivery of treatments and up to the 1-year follow-up, using a "bottom-up" costing estimation method. RESULTS: Patient satisfaction after treatment improved significantly for the three groups. The overall costs were R$ 2370.66, R$ 3185.21 and R$ 5739.52 for Groups I, II and III, respectively (P < .001). Analysis of incremental cost-effectiveness ratios suggested that the overdentures retained by one or two implants were more cost-effective than the fixed implant treatment, considering the mean cost and effectiveness values and the ±20% one-way sensitivity analysis. CONCLUSION: This study suggests that the incremental costs for the fixed hybrid prosthesis, compared to the overdenture treatments, is not proportional to the respective gain in effectiveness. Therefore, although all treatment options had satisfactory outcomes, the use of implants to retain a mandibular overdenture, irrespective of the use of one or two implants, is more cost-effective than the fixed implant treatment for the edentulous mandible.

Quality assessment of systematic reviews regarding the effectiveness of zygomatic implants: an overview of systematic reviews.

BACKGROUND: Oral rehabilitation of atrophic maxillae features high complexity, for which there are several therapeutic modalities reported on scientific literature. Zygomatic implant placement is a viable option that features low morbidity and allows immediate prosthetic loading. The purpose of the present study was to determine the methodological quality of systematic reviews that assessed the effectiveness of zygomatic implants placed in atrophic maxillae. MATERIAL AND METHODS: Searches were conducted on Medline via Pubmed, LILACS, Dare Cochrane, Scopus, and Sigle via Open Grey up to June 2019. RESULTS: Seven systematic reviews were eligible for Overview and comprised a total of 2313 patients, 4812 zygomatic implants, and a 96,72% success rate. Common surgical complications, in decreasing order, were: maxillary sinusitis, peri-implant mucositis, prosthetic fracture, and infections. Methodological quality was assessed using the AMSTAR 2 tool, which revealed that six systematic reviews showed critically low methodological quality and one review was assessed as of low methodological quality. CONCLUSIONS: Zygomatic implants seem to be an adequate option for atrophic maxilla rehabilitation, however, new studies with a higher methodological rigor are needed to provide more reliable results to professionals and patients undergoing this modality of oral rehabilitation.

Outcomes Assessment of Treating Completely Edentulous Patients with a Fixed Implant-Supported Profile Prosthesis Utilizing a Graftless Approach. Part 2: Patient-Related Outcomes.

PURPOSE: To assess outcomes of treating completely edentulous patients with a fixed implant-supported profile prosthesis, utilizing a graftless approach, for the maxilla and for the mandible, with an emphasis on patient-related outcomes, specifically maximum occlusal force, patient satisfaction, and impact on quality of life. MATERIALS AND METHODS: This was a cross-sectional study with the following inclusion criteria: completely edentulous patients rehabilitated with a fixed implant-supported profile denture, utilizing a graftless approach. Patients fulfilling the inclusion criteria were asked to participate in the study during their follow-up visits; hence, a consecutive sampling strategy was used. To measure maximum occlusal force, a digital occlusal force gauge was used. Subjects were asked to answer a paper survey distributed in the clinic. The survey contained general demographic questions, visual analog scale (VAS) categories, and Oral Health Impact Profile-14 (OHIP-14). RESULTS: The mean VAS score was 8.9 out of a possible 10. The mean OHIP-14 score was 7.5 out of a possible 56. The mean maximum occlusal force recorded in the anterior region was 108 Ncm. The mean maximum occlusal force recorded in the posterior region was 205 Ncm. CONCLUSION: Results indicated that patients treated with a graftless approach reported high satisfaction and impact on quality of life. Regarding maximum occlusal force values, significant differences between men and women were reported. The impact on quality of life seemed to improve when patients presented completely edentulous at the time of treatment as opposed to terminal dentition. Finally, significant positive correlations were detected between satisfaction and impact on quality of life, impact on quality of life and posterior maximum occlusal force, anterior and posterior maximum occlusal force, and complications and anterior maximum occlusal force.

Cost minimization analysis of a long-term randomized clinical trial of patients treated with immediately loaded implant-supported fixed prosthesis.

PURPOSE: To document the long-term costs from a randomized controlled clinical trial (RCT) on edentulous patients treated with mandibular 4-implant-supported fixed prosthesis and two loading protocols. METHODS: Taking the perspective of the individual patient, costs associated with treatment, complications, and patients' time from 18 patients who received an immediate-loading protocol and 21 patients treated with a conventional loading protocol were compared over 10 years of observation. All costs are in Canadian dollars and discounted to the RCT base year of 2006 at a rate of 1.5%. RESULTS: The complication rate in both arms was similar and relatively low. No statistically significant difference was observed in the total cost and discounted total cost, along with its five comprising parameters between the two arms. CONCLUSIONS: Over the 10-year time frame, the immediate loading of dental implants with mandibular fixed prosthesis proved to cost similar to the conventional loading protocol, underscoring the feasibility and reliability of this protocol from the patient's perspective. (REB protocol reference # 33395).

Outcomes Assessment of Treating Completely Edentulous Patients with a Fixed Implant-Supported Profile Prosthesis Utilizing a Graftless Approach. Part 1: Clinically Related Outcomes.

PURPOSE: To assess outcomes of treating completely edentulous patients with a fixed implant-supported profile prosthesis utilizing a graftless approach for the maxilla and for the mandible, with emphasis on clinically related outcomes, specifically implant and prosthesis survival. MATERIALS AND METHODS: This was a retrospective study with the following inclusion criteria: completely edentulous patients rehabilitated with a fixed implant-supported profile denture utilizing a graftless approach. Patients fulfilling the inclusion criteria were asked to participate in the study during their follow-up visits, and hence a consecutive sampling strategy was used. Data regarding implant and prosthesis cumulative survival rates (CSRs) were gathered and calculated. RESULTS: Thirty-four patients were identified with a total of 220 implants placed. An overall CSR of 98.2% was recorded with an observation of up to 10 years. For tilted, axial, and zygomatic implants, CSRs of 96.9%, 98.0%, and 100%, respectively, were observed for up to 10 years. For provisional prostheses, CSRs of 92.3% at 1 year, and 84.6% at 2 years were observed. For final prostheses, a CSR of 93.8% was observed at 10 years. CONCLUSION: The results suggest that treating completely edentulous patients with a fixed profile prosthesis utilizing a graftless approach in the maxilla and the mandible can be a reliable treatment option.

Oral health-related quality of life and implant therapy: A prospective multicenter study of preoperative, intermediate, and posttreatment assessment.

PURPOSE: Loss of teeth is associated with a significant reduction in quality of life. The aim of this prospective multicenter study was to assess the impact of dental implants on oral health-related quality of life (OHRQoL). MATERIAL AND METHODS: Patients with various kinds of indications for dental implants ranging from single-tooth loss to edentulous jaws were included. Quality of life related to dental implants was assessed through the Oral Health Impact Profile (OHIP-G 21), which has a score from 0 to 20 in healthy patients. RESULTS: In total, 8689 patients from 17 centers from 2009 to 2014 were enrolled in the study. The sex distribution was almost even (53.3% men, 46.7% women). The most frequent indications for the insertion of dental implants were free-end gaps (30.6%) and posterior single-tooth gaps (27%). In all, 12.4% of patients had an edentulous jaw. For all indications, patients reported significant changes in mean OHIP scores after prosthetic reconstruction. The most significant improvements in the OHIP score occurred in the groups of patients with edentulous jaws (pretreatment score: 42.3) after prosthodontic reconstruction (score: 24.8) and in the patient group with an anterior single-tooth gap (pretreatment score: 36.4) after prosthodontic reconstruction (score: 24.8). CONCLUSION: The insertion of dental implants and prosthodontic rehabilitation led to an improved OHRQoL for patients with all indications for dental implants, with the most significant improvements in patients with edentulous jaws and anterior single-tooth gaps.

All-on-4® Treatment Concept for the Rehabilitation of the Completely Edentulous Mandible: A 7-Year Clinical and 5-Year Radiographic Retrospective Case Series with Risk Assessment for Implant Failure and Marginal Bone Level.

BACKGROUND: Studies are needed to evaluate long-term outcomes of the All-on-4® treatment concept (Nobel Biocare AB) for rehabilitation of edentulous mandibles by assessing marginal bone levels and risk indicators for implant failure. PURPOSE: To evaluate 7-year clinical outcomes and 5-year radiographic outcomes of the All-on-4 treatment concept. MATERIALS AND METHODS: This retrospective case series included patients admitted for implant rehabilitations in the mandible, who were followed for 7 years clinically and 5 years radiographically. Primary outcome measures were cumulative prosthetic and implant survival using patient as the unit of analysis (Kaplan-Meier product limit estimator). Secondary outcome measure was marginal bone level (MBL) at 5 years. Variables associated with implant failure were analyzed using the Cox proportional hazards regression model to calculate hazard ratios (HRs) with 95% confidence intervals (CIs). Binary logistic regression was used to compute odds ratio (OR) with 95% CIs for variables associated with MBL ≥2.8 mm at 5 years. RESULTS: A total of 324 patients (194 women, 130 men, average age = 58.9 years) were rehabilitated with 1,296 implants supporting 324 full-arch fixed immediately loaded mandibular prostheses. Sixty-four patients (19.8%) were lost to follow-up. Prosthetic survival was 323/324 (99.7%), and 14 patients lost 18 implants, with an estimated cumulative survival rate of 95.4% at 7 years. Variables associated with implant failure were smoking (HR = 5.28; 95% CI: 1.33, 20.91]) and the learning curve effect (0.69 < HR < 0.33 for more experienced levels). Mean MBL at 5 years was 1.81 mm (95% CI: 1.70, 1.92), and smoking was associated with MBL ≥2.8 mm (OR = 2.4; 95% CI: 1.02, 5.62). CONCLUSIONS: The high implant and prosthetic survival rates and excellent MBL outcome confirm the predictability and safety of the All-on-4 treatment concept over a longer term than previously reported.

Assessment of the correlation between implant stability and bone density by computed tomography and resonance frequency analysis in fresh cadavers.

PURPOSE: Because of the immediate loading implant process, clinicians must consider implant primary stability issues before initiating surgery. The aim of this study was to assess the correlation between the bone density assessed by computed tomography (CT) images and the primary stability of two implant designs, as determined by resonance frequency analysis (RFA). MATERIALS AND METHODS: Sixty implants (30 NobelActive, 30 NobelSpeedy [Nobel Biocare]) were placed in five totally edentulous fresh cadaver maxillae. Before surgery, CT images were analyzed and bone densities measured. Implant primary stabilities (measured in implant stability quotient [ISQ] units) were determined along the buccolingual and mesiodistal axes by RFA. Correlations were assessed using the Pearson correlation test. RESULTS: Bone densities were similar near NobelActive and NobelSpeedy implants: 434.67 (± 220.53) versus 479.87 (± 209.05) Hounsfield Units (HU). Bone densities and NobelActive primary stabilities were highly correlated with ρ = 0.74 (P = .000) and ρ = 0.78 (P = .000) for the buccolingual and mesiodistal axes, respectively. An association was found between the 350 HU and 50 ISQ values, confirming good primary stabilities. For NobelSpeedy implants, no correlation was found regardless of the axis, with ρ = -0.07 (P = .72) (buccolingual) and ρ = -0.10 (P = .59) (mesiodistal). However, poor and good stabilities were observed in the anterior and posterior areas, respectively. CONCLUSION: This study revealed variations in primary stabilities depending on the implant design. The primary stability of conical implants with a double-lead thread design (NobelActive) seemed bone density-dependent regardless of the area of the maxilla, whereas the primary stability of nearly parallel-wall implants with a classical thread design (NobelSpeedy) seemed dependent on anatomical morphology. These results raise questions about the specific roles of the implant shape and thread design depending on the bone density and alveolar morphology.

An economic evaluation of maxillary implant overdentures based on six vs. four implants.

BACKGROUND: The purpose of the present study was to assess the value for money achieved by bar-retained implant overdentures based on six implants compared with four implants as treatment alternatives for the edentulous maxilla. METHODS: A Markov decision tree model was constructed and populated with parameter estimates for implant and denture failure as well as patient-centred health outcomes as available from recent literature. The decision scenario was modelled within a ten year time horizon and relied on cost reimbursement regulations of the German health care system. The cost-effectiveness threshold was identified above which the six-implant solution is preferable over the four-implant solution. Uncertainties regarding input parameters were incorporated via one-way and probabilistic sensitivity analysis based on Monte-Carlo simulation. RESULTS: Within a base case scenario of average treatment complexity, the cost-effectiveness threshold was identified to be 17,564 € per year of denture satisfaction gained above of which the alternative with six implants is preferable over treatment including four implants. Sensitivity analysis yielded that, depending on the specification of model input parameters such as patients' denture satisfaction, the respective cost-effectiveness threshold varies substantially. CONCLUSIONS: The results of the present study suggest that bar-retained maxillary overdentures based on six implants provide better patient satisfaction than bar-retained overdentures based on four implants but are considerably more expensive. Final judgements about value for money require more comprehensive clinical evidence including patient-centred health outcomes.

Functional jaw muscle assessment in patients with a full fixed prosthesis on a limited number of implants: a review of the literature.

BACKGROUND: Full fixed prosthesis on a limited number of implants (FFP) are a viable treatment option for edentulous patients with a reduced amount of residual bone. Jaw muscular function in FFP patients has been evaluated in several studies, however heterogeneous data emerge from literature. PURPOSE: The aim of this review of the literature was to assess the function of jaw muscles in edentulous patients restored with full fixed prostheses on a limited number (≤ 6) of implants, as compared to dentate subjects and edentulous subjects wearing dentures, implant-supported overdentures or full fixed prostheses supported by more than six implants. MATERIALS AND METHODS: An electronic search of databases up to December 2013 was performed. The articles were selected using specific inclusion criteria, independent of the study design. RESULTS: A total of 1598 records were identified. After removing the duplicates and excluding records based on title and abstract, only 37 eligible records were identified. After full-text review, seventeen studies were selected for analysis according to the inclusion criteria. From the included studies, only one evaluated masseter muscle thickness in a cross sectional study by means of ultrasound, while the 16 remaining papers evaluated muscular function by using electromyography (EMG). Those studies analysed several heterogeneous parameters throughout the execution of five functional tests and were therefore described and pooled according to the following task categories: clenching; swallowing; reflex and fatigue for statics; and chewing for dynamics. CONCLUSIONS: The results of selected studies seem to indicate that, compared to dentate controls, FFP patients display a global satisfactory neuromuscular equilibrium in static activities, but still have some impairment during chewing.

Use of implant-supported prostheses in edentulous mandibles among prosthodontists in Sweden.

The aim of this study was to investigate the production of mandibular implant-supported fixed and removable prostheses among prosthodontic specialists in Sweden and to compare the results with findings in a similar study made in 2001 (17). Questionnaires regarding treatment with mandibular implant prostheses during 20011 were mailed to all specialists in prosthodontics in Sweden (n = 156, according to available data). Of the 156 questionnaires, 129 (83%) were returned and of those 114 were completed. The reported number of treatments with mandibular implant-supported prostheses varied much among the specialists. Fixed implant prostheses were more common than overdentures (means 11 and 3, median values 8 and 2, respectively). However, the range was large for both alternatives. Ten (9%) of the specialists reported no treatment with fixed implant prostheses while 29 (25%) had not made any implant overdenture during 2011. The most common anchorage system for overdentures in 2011 (as well as in 2001) was two un-splinted implants with ball attachments or Locator abutments. The most common reasons for choosing overdenture treatment instead of a fixed implant prosthesis in 2011 were the reduced cost and the patient's main wish to improve denture retention. A majority of the prosthodontists (58%) reported that patients with implant overdentures were as satisfied as those with fixed implant-supported prostheses, whereas 40% claimed they were less satisfied. Two respondents (2%) considered that overdenture patients were more satisfied than those with a fixed prosthesis. It can be concluded that the general attitude among Swedish prosthodontists towards implant overdentures has not changed much during the 10-year period between the present and the previous investigation.An overdenture is still a seldom-used option in implant treatment of patients with edentulous mandibles in Sweden. Instead, a fixed implant-supported prosthesis continues to be the preferred option,

Assessment of rehabilitation in edentulous patients treated with an immediately loaded complete fixed mandibular prosthesis supported by three implants.

PURPOSE: Conventionally, in patients with completely edentulous mandibles, fixed prostheses have been supported by four or more implants. However, an alternative protocol employing three implants and immediate loading has been developed. The objective of the present study was to assess the rehabilitation of edentulous patients treated with a complete fixed mandibular prosthesis with immediate loading and supported by three implants. MATERIALS AND METHODS: In this observational study, a total of 99 implants placed in 33 patients was evaluated after 18 months in use. Panoramic radiographs were digitized to measure bone loss at the mesial and distal surfaces of each implant. RESULTS: Mean peri-implant bone loss was 0.66 ± 0.51 mm for the left implant, 0.92 ± 0.61 mm for the central implant, and 0.82 ± 0.53 mm for the right implant. The bone loss observed around the distal implants was similar to that seen around the central implant, and there were no statistically significant differences in peri-implant bone loss between the three implant locations. There was no significant correlation between implant length and bone loss. The results were compatible with the peri-implant bone loss that has been described for prostheses of the same type supported by larger numbers of implants. CONCLUSIONS: The use of a complete fixed mandibular prosthesis with immediate loading supported by three implants proved to be an adequate option for the rehabilitation of edentulous patients. The protocol allowed simplification of treatment while maintaining similar bone loss to that reported for the same type of treatment supported by a larger number of implants.

Immediate load on the edentulous mandible: treatment planning considerations.

Immediate load protocols for the edentulous mandible offer the patient many advantages in terms of decreased number of visits, improved early function, and reduction of surgical exposure; however, this treatment modality is not universally appropriate for all patients. The available evidence will assist the clinician in developing a customized and comprehensive informed consent. Patient selection and patient-mediated factors will dictate the suitability of not only a fixed or removable prosthesis, but also whether immediate loading would enhance the cost/benefit ratio. The indications, objective and subjective patient considerations, and design strategies are discussed for the immediate load scenario.

Patient satisfaction and oral health-related quality of life outcomes of implant overdentures and fixed complete dentures.

PURPOSE: To assess and compare patient satisfaction and oral health-related quality of life (OHQOL) in patients treated with implant-supported overdentures and complete implant fixed prostheses. MATERIALS AND METHODS: From a database of patients who had undergone implant treatment over a 6-year period, a study population of 62 patients was identified; every patient had at least four implants placed in one edentulous arch and was restored with either an overdenture or a fixed prosthesis. Patients were examined and a self-administered, structured multiple-response questionnaire, including the Oral Health Impact Profile-14 measurement tool and a patient satisfaction survey, was used to evaluate patient-centered treatment outcomes. RESULTS: Generally, patient satisfaction was very high in both the implant overdenture and fixed prosthesis groups, although the subjects in the overdenture group, who had mostly maxillary prostheses, reported significantly lower overall satisfaction and lower satisfaction with chewing capacity and esthetics. In just three categories--cost, satisfaction with treating doctor, and ability to perform oral hygiene measures--the fixed prosthesis group was less satisfied than the removable overdenture group, but the difference was not significant. Similarly, the overall OHQOL was high, although patients receiving a fixed prosthesis demonstrated significantly lower psychologic discomfort and psychological disability compared to the overdenture group. CONCLUSIONS: Among all patients who had similar numbers of implants placed, those who received an implant overdenture were less satisfied and had lower OHQOL than the patients who had a fixed prosthesis. Since patient and dentist preferences influenced the type of prosthesis provided, it is likely that subjective, patient-related factors are major determinants of satisfaction and treatment outcomes.

Virtual variation simulation of CAD/CAM template-guided surgeries performed on human cadavers: Part II.

STATEMENT OF PROBLEM: CAD/CAM template-guided surgery has gained attention as a method of improving the predictability of dental implant placement. However, due to possible variations during the manufacturing process and in the robustness of the template design, a virtual prediction of the potential positioning of the implants is needed. PURPOSE: The purpose of this study was to perform virtual variation simulations on virtually planned implant placements and to compare them with corresponding results from actual surgeries performed on human cadavers in a previous study. MATERIAL AND METHODS: Seventeen computer-aided plans were used for virtual variation simulation of surgeries conducted on 17 human cadavers and 145 implants placed in the cadavers. For each surgery, 10,000 virtual surgeries were performed, resulting in 1,450,000 implant placements. The results from the virtual variation simulations were statistically compared with the results from the actual surgeries. The Mann-Whitney U test was used to compare the implant distributions (alpha=.05). RESULTS: In the maxillae, the difference between the simulated average mean of the mean and the compared surgical average of the median was 0.22 mm (apex) and -0.35 mm (hex), and for the mandible, the corresponding values were -0.19 mm (apex) and -0.69 mm (hex). The simulated average mean of the range compared to the mean range of the maximum deviation results from the surgeries of the maxillae was 2.96 mm (apex) and 0.44 mm (hex), and 2.3 mm (apex) and 0.26 mm (hex) for the mandible. The implant distributions between the simulations and the surgeries were significantly different at both the hex (P<.001) and apex (P<.001). CONCLUSIONS: The implant distributions were neither static nor normally distributed. Thus, within the limitations of this study, the definitive geometrical variations of the implants were not static, as they depend on the individual anatomy of the jaws and the ability to place the CAD/CAM-guided surgical template in the proper position.

Bone density at implant sites and its relationship to assessment of bone quality and treatment outcome.

PURPOSE: To investigate the relationship between bone mineral density (BMD) before implant placement, implant stability measures at implant placement, and marginal bone loss of immediately loaded implants after 1 year in situ. MATERIALS AND METHODS: Consecutively recruited patients received Straumann SLActive implants loaded with fixed provisional prostheses within 24 hours. BMD was measured from computed tomographic images before implant placement. Alveolar bone quality was assessed during surgery. Implant stability-both rotational and as measured with resonance frequency analysis-and marginal bone height were assessed at implant placement and after 1 year. The Pearson correlation coefficient was used to calculate correlations, and significance was considered when P < .05. RESULTS: Twenty-one patients received 137 implants (87 in maxillae and 50 in mandibles). BMD was significantly correlated with bone quality classification in both arches (P < .001). Mean BMD was also significantly correlated with stability values (P < .001). Mean marginal bone loss at implant surfaces differed, but not significantly, at the 1-year follow-up, regardless of BMD values (P = .086) and measured stability (rotational stability P = .34, resonance frequency analysis P = .43) at implant placement. CONCLUSION: Within the limits of this study, it can be concluded that computed tomographic examination can be used as a preoperative method to assess jawbone density before implant placement, since density values correlate with prevailing methods of measuring implant stability. However, in the short time perspective of 1 year, there were no differences in survival rates or changes in marginal bone level between implants placed in bone tissue of different density.