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Purpose: To evaluate strain around resilient stud and bar attachments for inclined implants supporting mandibular overdentures during loading and dislodging. Materials and Methods: A mandibular edentulous model was printed using the laser sintering technique. Two vertical implants and two 30-degree distally inclined implants were placed in canine and premolar areas, respectively. Overdentures were attached to the implants with either a resilient stud (Locator, group 1) or a bar/clip (group 2) attachment. Three strain gauges were mounted at the buccal, lingual, and proximal surfaces of each implant. Microstrains were registered during vertical loading and dislodging force applications and compared between attachments (resilient stud and bar) and implant positions (vertical and inclined). Results: For canine implants, bar overdentures recorded significantly higher microstrains than Locator overdentures during vertical loading. For premolar (inclined) implants, Locator overdentures recorded significantly higher microstrains than bar overdentures during vertical dislodging. For both groups (during loading) and the bar overdenture group (during dislodging), canine (vertical) implants showed significantly higher microstrains than premolar (inclined) implants. Conclusion: Within the limitations of this in vitro study, canine (vertical) implants may be at risk of increased stresses during loading if bar attachments are used for vertical and inclined implants supporting mandibular overdentures, and premolar (inclined) implants may be at risk of increased stresses during dislodging if Locator attachments are used. For both attachments, canine implants showed significantly higher microstrains than premolar implants during loading and dislodging. [ABSTRACT FROM AUTHOR]

Purpose: Despite the high clinical accuracy of dynamic navigation, inherent sources of error exist. The purpose of this study was to improve the accuracy of dynamic-navigated surgical procedures in the edentulous maxilla by identifying the optimal configuration of intraoral points that results in the lowest possible registration error for direct clinical implementation. Materials and Methods: Six different four-area configurations (left and right sides; n = 12) were tested by three operators against two negative controls (left and right sides) and one positive control (three-area and eight-area configurations, respectively) using a skull model. The two dynamic navigation systems (X-Guide and Navident) and the two registration methods (bone surface tracing and fiducial markers) produced four registration groups: XG tracing, ND tracing, XG fiducial, and ND fiducial. The accuracy of the registration was checked at the frontal process of the zygoma. Intra- and interoperator reliabilities were reported for each registration group. Multiple comparisons were conducted to find the best configuration with the minimum registration error. Results: Ranking revealed one configuration in the tracing groups (Conf.3) and two configurations in the fiducial groups (Conf.3 and Conf.5) that had the best accuracy. When the inferior surfaces of the zygomatic buttress were excluded, fiducial registration produced better accuracy with both systems (P = .006 and < .0001). However, bilaterally tracing 1-cm areas at these surfaces resulted in similar registration accuracy to placing fiducial markers there (P = .430 and .237). Navident performed generally better (P = .049, .001, and .002), but the values had a wider margin of uncertainty. Changing the distribution of the four tracing areas or fiducial markers had a less pronounced effect with the X-Guide than with the Navident system. Conclusions: For surgery in the edentulous maxilla, four fiducial markers placed according to Conf.3 or Conf.5 resulted in the lowest registration error. Where implants are being placed bilaterally, an additional two sites may further reduce the error. For bilateral zygomatic implant placement, it is optimal to place two fiducial markers on the inferior surfaces of the maxillary tuberosities, two on their buccal surfaces, and another two on the anterior labial surface of the alveolar bone. Utilizing the inferior zygomatic buttress is recommended over the inferior maxillary tuberosities in other types of maxillary surgeries. [ABSTRACT FROM AUTHOR]

Purpose: The goal of this study was to assess the effect of a liquid platelet-rich fibrin (PRF)–coated implant surface (double acid-etched) on osseointegration, analyzing the stability and the possibility of shortening the rehabilitation period. Materials and Methods: Initially, the blood was centrifuged to obtain the liquid PRF (2,000 revolutions per minute [rpm], 10 minutes), dividing a sample to be analyzed by Luminex, and another was applied onto the implant surface. Fifteen patients (30 implants) were divided into two groups (control and liquid PRF). Following the recommendation provided by the manufacturer, within a controlled torque at a maximum of 34 N.mm, the implant was placed. All patients had 1 year of follow-up. Results: Eleven analytes were identified for the sample characterization (IP-10, eotaxin, RANTES, macrophage inflammatory protein 1-beta [MIP-1β], VEGF, PDGF-BB, bFGF, IFN-γ, interleukin [IL]-5, IL-10, and IL-15). Regarding clinical evaluation, for control and liquid PRF groups, respectively, (1) the mean torque for implant placement was 26.67 and 27.27 N.mm; (2) the initial stability (implant stability quotient [ISQ]) was 64.87 (SD ± 6.01) and 67.36 (SD ± 7.21); (3) the final ISQ was 67.67 (SD ± 6.13) and 70.14 (SD ± 6.40); (4) it took an average 73 and 71 days to reestablish the masticatory function; (5) the survival rate was 93.3% and 86.6%; and (6) the marginal bone loss was up to 1.0 mm after 1 year (control)—for two patients, it was between 1.0 and 2.0 mm, and for another two subjects, it was up to 1 mm (liquid PRF). No statistical significance was observed for all parameters analyzed (P > .05). Conclusion: Within the limitations of this study, the results indicated that there was no statistical significance when liquid PRF was applied on the implant surface, for all parameters. [ABSTRACT FROM AUTHOR]

To assess the effects of grade IV titanium ultrasonic tip instrumentation on different grade IV titanium implant surfaces and compare the decontamination of different implant surfaces using chlorhexidine, blue laser, or ozone. Materials and Methods: Profilometry and energy-dispersive x-ray spectroscopy (EDS) analyses were performed on smooth, laser-micropatterned, and sandblasted grade IV titanium sample disks before (t0) and after (t1) ultrasonic instrumentation with an ultrasonic grade IV titanium tip. Samples were also incubated with a Streptococcus sanguinis culture. Each surface type was then treated with chlorhexidine, blue laser, or ozone (three test groups + control group). Scanning electron microscopy (SEM) images were taken after bacterial growth and after decontamination. Results: After ultrasonic instrumentation, surface roughness (Ra) decreased on sandblasted and micropatterned surfaces, whereas it remained substantially unvaried on the smooth surface. SEM images revealed that the laser-micropatterned structure remained substantially unvaried after instrumentation. EDS revealed a minimal quantity of carbon and iron, found in the laser-treated and sandblasted group at t0. A minimal quantity of aluminum and oxygen was found on the sandblasted surface at t0 and t1. Ozone therapy achieved the highest decontaminating effect, regardless of implant surface topography. Conclusion: Among the alternative therapies to ultrasonic instrumentation with titanium tips, ozone appears to be effective regardless of the type of implant surface; it can be used for the decontamination treatment of implants without altering the surface structure. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study was to quantify the probability of implant failure over time from intrinsic patient factors using a population of patients from multiple private practices. Materials and Methods: The records for this retrospective, multicenter cohort study were randomly selected from eight private practices. The primary outcome variable was time to event (implant failure or last known follow-up). The included independent variables were age, sex, diabetes status, smoking status, and arch location. Analyses were performed with Cox proportional hazards on three models: univariate, full multivariate, and systemic factor multivariate. The probability of implant survival at 1, 5, and 10 years was calculated using univariate time-to-event modeling on log-normal distribution with 95% CIs and Cox proportional hazard tests for significance. The Kaplan-Meier survival curve was calculated for patients < 71 years of age. Results: Eight hundred thirty-five implant-level records from 378 patients were collected for analyses. The mean patient age was 60 years, and 48% were men, 15% reported a history of smoking, and 16% reported having diabetes. The follow-up time was as long as 17 years, with a mean of 23.1 months, and a median of 7 months. The hazard ratio (HR) for implant failure due to sex (HR = 1.18; 95% CI: 0.52 to 2.66), smoking (HR = 1.30; 95% CI: 0.49 to 3.46), diabetes (HR = 1.17; 95% CI: 0.35 to 3.86), and arch location (HR = 2.13 to 3.39) failed to reach the threshold within any Cox proportional hazards model (P > .05). Conclusion: The implant survival probability for patients = 70 years of age is 86.4% at 10 years in the course of routine private practice by experienced providers. Cautious interpretation of these results is critical, as the effects of known systemic risk factors are likely tempered by effective modifications in clinical decisions and protocols with short- and long-term follow-up maintenance. [ABSTRACT FROM AUTHOR]

Purpose: To test a novel implant metal-acrylic prosthesis design in comparison to a conventional prosthesis design through simulation of cyclic masticatory loading. The novel design involved digital designing and fabrication of the framework and the matched veneering acrylic resin material. Materials and Methods: Ten prostheses were fabricated for each group. All the prostheses exhibited a similar external design on two implants with a distal cantilever. The conventional group comprised a milled metal framework with mechanically retained acrylic denture teeth via vertical pins. The digital prosthesis group incorporated an inverted T-shape bar and a monolithic milled acrylic resin veneer. The resin veneer was subsequently adhesively attached on the bar. All prostheses were thermally aged and subjected to laboratory cyclic loading at the cantilever region. The load-to-failure and the number of cycles until failure were collected. Furthermore, failed specimens were analyzed to determine the mode of failure. Results: The digital prostheses failed at significantly greater load-to-failure (1,570.0 N ± 116.0 N) and number of cycles (124,857 ± 21,608) than the conventional prostheses (load-to-failure = 1,015.0 N ± 47.4 N; number of cycles = 28,452 ± 6,559). The conventional prostheses failed by fracturing of the acrylic teeth and veneering material that led to exposure of the metal framework. Half of the digital prostheses failed by superficial chipping of the veneering material, while the other half failed by the deformation and fracture of screws. Conclusion: Within the limitations of this study, the digital prostheses with the novel design and monolithic veneering material showed significantly higher strength compared with the conventional prostheses. The mode of acrylic failure of the digital prostheses was more favorable. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this crossover study was to evaluate electromyographic (EMG) connectivity of masseter muscle with different attachments used to retain implant overdentures in patients with atrophied mandibular ridges. Materials and Methods: Twenty-four edentulous participants with atrophic mandibular ridges received conventional dentures (control). Three months after the adaptation period, two implants were placed in the canine areas of the mandible. After osseointegration, each participant was successively given the following prostheses in a crossover manner: (1) ball-retained overdentures, (2) bar-retained overdentures, and (3) Locator-retained overdentures. The EMG parameters (amplitude, chewing area, chewing rate, duration of chewing cycle, duration of chewing burst, and chewing time) were measured 3 months after wearing the following prostheses: conventional dentures, ball overdentures, bar overdentures, and Locator overdentures. Measurements were made during chewing of hard (carrot) and soft (cake) foods. Results: The highest EMG activity/amplitude, chewing area, duration of chewing cycle, and duration of chewing burst were noted with ball overdentures, followed by bar overdentures and Locator overdentures, and the lowest values were observed with conventional dentures. The highest chewing rate and masticatory time were noted with conventional dentures, and the lowest values were observed with ball overdentures. With the exception of chewing area, no significant differences in all tested parameters between bar overdentures and Locator overdentures were observed. Except for duration of chewing cycle, all tested parameters were significantly higher during chewing of hard food than soft food. Conclusion: Within the limitations of this study, twoimplant overdentures recorded higher muscle functions compared to conventional dentures regardless of the type of attachment used. For such overdentures, ball attachment may be recommended over bar and Locator attachments, as it was associated with improved muscle activity and function. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to examine the long-term results of implants in orbital reconstruction after exenteration. Materials and Methods: From 1998 to 2012, patients undergoing implant-supported rehabilitation after subtotal or total exenteration due to a tumor were included in a retrospective study. All the patients were evaluated for soft tissue reconstruction, irradiation, complications, abutments, hygiene index, implant mobility, and long-term success. Results: Forty-eight patients (aged between 27 and 81 years) were selected. A total of 187 implants were inserted. All the patients were supplied with epitheses after implantation in the long term. Of the 187 implants, nine implants placed on five patients were lost. The mean follow-up period was 34 months (ranging from 6 to 144 months). The 5-year survival rate was 88%. Conclusion: On the basis of this retrospective study of 48 patients with 187 implants, the following observations were made: (1) the 5-year survival of implants in nonradiated bone was 92%, and (2) the 5-year survival of implants in radiated bone was 86%. Extraoral implants should be presented as an option in orbital rehabilitation after exenteration. [ABSTRACT FROM AUTHOR]

Purpose: This within-subject comparison tested the null hypothesis that there is no difference in patient satisfaction and oral health–related quality of life when an individual with an edentulous mandible is rehabilitated with a two-implant overdenture or a three-implant–supported fixed dental prosthesis. Materials and Methods: Twelve subjects with an edentulous mandible or failing dentition were rehabilitated with the use of endosseous dental implants. Three implants were placed, and were immediately loaded with a provisional fixed prosthesis with minimal cantilever. After healing for 4 months, two Locator attachments were inserted and an overdenture was trialed; then, after a further 4 months, a fixed prosthesis was placed on the three implants. The fixed prosthesis was fabricated using computer-assisted design, and a titanium framework was manufactured with a resin base and teeth. Patient satisfaction and oral health–related quality of life was assessed before treatment, after wearing the provisional, and after each treatment option using a seven-item visual analog scale and a modified version of the 49-item oral health impact profile. Results: Of the 12 subjects, 11 chose the fixed over the removable prosthesis. A statistically significant (P < .05) and positive effect on the overall score of both assessment tools was reported for both treatment modalities (when compared with pretreatment scores). Although no significant difference (P > .05) was found between the two options in overall scores of both surveys or in any of the seven domains of the modified oral health impact profile, the fixed prosthesis had a statistically higher score for stability, retention, and ease of chewing on a visual analog scale. Conclusion: Both treatment modalities provided a significant and similar improvement in patient satisfaction and oral health–related quality of life compared with a conventional complete mandibular removable dental prosthesis; however, a statistically significant higher score was reported for stability, retention, and ease of chewing for the fixed dental prostheses. Based on the 12 participants in this study, greater stability and ease of chewing with the fixed prosthesis likely influenced patient preference in most but not all subjects. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the use of chemically unchanged tooth material in lateral alveolar ridge augmentation or for the filling of jaw defects. Materials and Methods: A total of 20 patients underwent either lateral augmentation of the alveolar process (11 patients) or filling of jaw defects (6 patients) with autogenous unaltered tooth material in a longitudinal 2-year study. In three patients, the jaw defect was so marked that a bone block graft had to be used for augmentation in addition to particulate dental material. In four patients, an autogenous tooth block was exclusively used; in seven, crushed tooth material was exclusively used; and in the remaining six, dystopic teeth that had been extracted were removed, crushed, and reinserted into the defect in particulate form. Fully impacted teeth served as autogenous donor teeth. Results: After a healing time of 3 to 6 months, 28 implants could be placed (10 immediate implants, 18 delayed implants). At 6, 12, and 24 months postrestoration, peri-implant bone loss as assessed by x-ray was 0 mm, 0.4 mm, and 0.6 mm, respectively. Peri-implant probing depth was 1 mm after 1 year and 2 mm after 2 years. Bleeding on probing was not seen in any of the implants after 2 years. Conclusion: Autogenous tooth material appears to be suitable for the restoration of lateral and intraosseous defects of the alveolar ridge with both complete blocks and in particulate form. However, additional long-term studies with higher case numbers will be required for substantiating these results. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to assess the effect of local application of growth hormone on osseointegration of dental implants inserted in osteoporotic bones. Materials and Methods: Twenty female New Zealand rabbits were used in this study. Ten were ovariectomized and fed a low-calcium diet for 6 weeks, and the others remained intact. A titanium implant was inserted into each tibia, in both groups. In half of the rabbits, 2 IU of growth hormone was placed into the ostectomy prior to the implant insertion. Two weeks after implant surgery, all animals were sacrificed. Tibiae were dissected from soft tissues, and included in methacrylate to be studied under light microscopy. Bone-to-implant contact (BIC) and bone mineral density (BMD) were measured by morphometric and densitometric analysis, respectively. Multifactorial analysis of variance (ANOVA) was used for statistical evaluation. P < .05 was considered to be significant. Results: Ovariectomy induced less BIC and BMD in regions closer to the implant compared with the control group. Local application of growth hormone was able to increase the BIC in the ovariectomized group, with statistically significant differences with respect to the control group (P < .01). Regarding the BMD, no statistically significant differences were found. Conclusion: Within the limitations of this experimental study, local application of 2 IU of recombinant human growth hormone at the moment of titanium implant insertion in rabbit tibiae significantly enhanced the BIC around titanium implants 15 days after the implantation in this experimental osteoporotic animal model, without affecting the BMD. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this prospective study was to determine platform and angle accuracy for dental implants using dynamic navigation, a form of computer-assisted surgery. Three hypotheses were considered: (1) the overall accuracy for implant placement relative to the virtual plan is similar to that of static tooth-borne computerized tomography (CT)–generated guides; (2) the dynamic system is more accurate than freehand methods; and (3) there is a learning curve associated with this method. Materials and Methods: This study involved three surgeons placing implants in the mandible and maxilla of patients using a dynamic navigation system (X-Guide, X-Nav Technologies). Virtual implants were placed into planned sites using the navigation system computer. Post–implant placement cone beam CT scans were taken on all patients. For each patient, this scan was mesh overlayed with the virtual plan and used to determine platform and angular deviations to the virtual plan. The primary outcome variables were platform and angular deviations comparing the actual placement to the virtual plan. Secondary analyses included determination of accuracy related to case experience and freehand placement of implants. Comparisons to published accuracy studies were made for implant placement using static guides. Results: Accuracy deviations from the virtual plan were similar to those reported for static tooth–based guides using literature references as the comparison. The accuracy of dynamic navigation was superior compared to freehand implant placement. The three surgeons had similar accuracies after their learning curve was achieved. Proficiency based on case series was achieved by the 20th surgical procedure. Conclusion: Dynamic navigation can achieve accuracy of implant placement similar to static guides and is an improvement over freehand implant placement. In addition, there was a learning curve to achieve proficiency. [ABSTRACT FROM AUTHOR]

Purpose: Compared with the general population, a poorer quality of bone-implant osseointegration occurs and at a higher failure rate in patients with type 2 diabetes mellitus. The aim of this study was to analyze the effects of local injection of nerve growth factor at the bone-implant interface after implantation in type 2 diabetic rats. Materials and Methods: Goto-Kakizaki (GK) rats (n = 30) were used as a model of type 2 diabetes mellitus, and Wistar rats were used as a control (n = 15). GK rats were assigned randomly into two groups (n = 15/group): the diabetes mellitus group (saline only) and the nerve growth factor group (received nerve growth factor treatment). One titanium implant was placed in each rat's left tibia. Immediately postoperatively, nerve growth factor group rats were injected with nerve growth factor (0.4 µg/ day) intramuscularly around the implant, daily for 7 days. Diabetes mellitus and control group rats received normal saline in an identical manner. Rats were sacrificed at 2, 4, and 8 weeks following implant surgery. Results: Traditional light and confocal laser scanning microscopy were used on nondecalcified sections to investigate fluorochrome labeling changes and histologic features of bone adjoining the implants. Bone-toimplant contact and bone volume percentage in the diabetes mellitus group were significantly less than in the control and nerve growth factor groups, with no statistically significant differences between the control and nerve growth factor groups. Confocal laser scanning microscopy showed a significant increase in marked bone around the nerve growth factor group implant at 4 weeks (P < .01) and 8 weeks (P < .05) compared with the diabetes mellitus group. Conclusion: This study showed that local injection of nerve growth factor could improve implant-bone osseointegration in diabetic rats and may have important clinical implications. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate whether photofunctionalization of titanium mesh enhances its osteoconductive capability. Materials and Methods: The titanium mesh (0.2 mm thickness) used in this study was made of commercially pure grade-2 titanium and had hexagonal apertures (2 mm width). Photofunctionalization was performed by treating titanium mesh with UV light for 12 minutes using a photo device immediately before use. Untreated or photofunctionalized titanium mesh was placed into rat femurs, and bone generation around titanium mesh was profiled using three-dimensional (3D) microcomputed tomography (micro-CT). A set of in vitro experiments was conducted using bone marrow-derived osteoblasts. Results: Photofunctionalized titanium mesh surfaces were characterized by the regenerated hydrophilicity and significantly reduced surface carbon. Bone generation profiling at week 3 of healing showed that the hexagonal apertures in photofunctionalized mesh were 95% filled, but they were only 57% filled in untreated mesh, particularly with the center zone remaining as a gap. Bone profiling in slices parallel to the titanium surface showed that photofunctionalized titanium mesh achieved 90% bone occupancy 0 to 400 μm from the surface, compared with only 35% for untreated mesh. Bone occupancy remained as high as 55% 800 to 1,200 μm from photofunctionalized titanium mesh surfaces, compared with less than 20% for untreated mesh. In vitro, photofunctionalized titanium mesh expedited and enhanced attachment and spread of osteoblasts, and increased ALP activity and the rate of mineralization. Conclusion: This study may provide novel and advanced metrics describing the osteoconductive property of photofunctionalized titanium mesh. Specifically, photofunctionalization not only increased the breadth, but also the 3D range, of osteoconductivity of titanium mesh, enabling space-filling and far-reaching osteoconductivity. Further translational and clinical studies are warranted to establish photofunctionalized titanium mesh as a novel clinical tool for better bone regeneration and augmentation. [ABSTRACT FROM AUTHOR]

Inferior alveolar nerve repositioning is an option for treating the edentulous posterior mandible with insufficient bone height above the inferior alveolar canal. This report presents a case in which inferior alveolar nerve medialization was performed for placing dental implants. In the second postoperative week, mandibular fracture occurred after biting on a relatively solid piece of food, which was treated conservatively. [ABSTRACT FROM AUTHOR]

Purpose: The authors conducted a meta-analysis to determine the effect of a history of periodontitis on the long-term survival of dental implants. Materials and Methods: An electronic search of PubMed and a supplemental manual search were conducted. Studies published in English through March 2013 were included in the meta-analysis. Survival rates, success rates, periodontal status, types of periodontitis, most recent followup time, and other information were extracted and analyzed. Results: Thirteen studies involving 2,011 patients and 6,802 implants were included in the meta-analysis. The results revealed that a history of periodontitis, especially aggressive periodontitis, is associated with significantly higher risks of long-term implant failure versus a healthy periodontium (risk ratio [RR] = 1.03, 95% confidence interval [CI] = 1.02 to 1.04). Based on the limited number of included articles, a subgroup analysis showed that a history of periodontitis had no statistically significant effect on implant survival up to 100 months of follow-up (RR = 1.03, 95% CI = 0.99 to 1.06); however, it did significantly affect implant survival within a period of 101 to 200 months (RR = 1.03, 95% CI = 1.02 to 1.04). Some implant systems also significantly influenced the correlation between a history of periodontitis and implant survival. Conclusion: Within the limitations of this meta-analysis, a history of periodontitis is estimated to be a statistical risk factor for the long-term survival of dental implants. This negative effect would be most evident in patients with aggressive periodontitis, severe periodontitis, or after a longer follow-up. [ABSTRACT FROM AUTHOR]

Purpose: To study the relation between irretrievable abutment healing caps (AHCs), temperature, and the torque required to remove the AHCs from implants. Materials and Methods: Twenty implants, 13 mm long and 4.2 mm in diameter, were inserted into four acrylic boxes and covered with acrylic resin. An AHC was screwed into each implant, using a 30 N/cm torque. The acrylic blocks were placed in a 37°C water bath, and subsequently, a block was removed from the bath, the AHCs were cooled, and the torque needed to release each AHC from the implant was measured using a torque wrench. The cooling methods applied were contact with an ice cube for 10 or 25 seconds or spraying of endodontic refrigerant spray for 3 seconds. The control abutments were similarly tested, but without prior cooling. Results: The application of ice cubes for 10 seconds reduced the mean releasing torque from 29.60 ± 1.22 N/cm to 28.55 ± 1.96 N/cm (P = .01). Cooling the AHCs with ice cubes for 25 seconds reduced the mean required releasing torque from 29.6 N/cm to 27.85 ± 1.22 N/cm (P < .001). Cooling the same abutments using endodontic refrigerant spray for 3 seconds reduced the mean releasing torque to 27.74 ± 2.13 N/cm (P < .001). Conclusion: Within the limitations of this study, it is possible to conclude that cooling the AHC reduces the torque required for its release from the implant. This finding may also be relevant to the removal of prosthetic abutments with irretrievable screws. [ABSTRACT FROM AUTHOR]

Purpose: Recent clinical studies have shown that implant placement is highly predictable with computer-generated surgical guides; however, the reliability of these guides has not been compared to that of conventional guides clinically. This study aimed to compare the accuracy of reproducing planned implant positions with computer-generated and conventional surgical guides using a split-mouth design. Materials and Methods: Ten patients received two implants each in symmetric locations. All implants were planned virtually using a software program and information from cone beam computed tomographic scans taken with scan appliances in place. Patients were randomly selected for computer-aided design/computer-assisted manufacture (CAD/CAM)-guided implant placement on their right or left side. Conventional guides were used on the contralateral side. Patients underwent operative cone beam computed tomography postoperatively. Planned and actual implant positions were compared using three-dimensional analyses capable of measuring volume overlap as well as differences in angles and coronal and apical positions. Results were compared using a mixed-model repeated-measures analysis of variance and were further analyzed using a Bartlett test for unequal variance (α = .05). Results: Implants placed with CAD/CAM guides were closer to the planned positions in all eight categories examined. However, statistically significant differences were shown only for coronal horizontal distances. It was also shown that CAD/CAM guides had less variability than conventional guides, which was statistically significant for apical distance. Conclusion: Implants placed using CAD/CAM surgical guides provided greater accuracy in a lateral direction than conventional guides. In addition, CAD/CAM guides were more consistent in their deviation from the planned locations than conventional guides. [ABSTRACT FROM AUTHOR]

Purpose: To show the presence and direction of the collagen fiber orientation around platform-switched (PS) and non-platform switched (NPS) implants at the crestal bone level. Materials and Methods: Twelve implants (six PS and six NPS implants) were placed with single-stage surgery in three dogs. The implant abutments were disconnected and reconnected after 8, 10, 12, and 14 weeks. The animals were sacrificed in the 18 week. The specimens were stained with hematoxylin and eosin and examined using polarized light microscopy. Results: The PS implant specimens showed circular fiber orientation at the implant platform level and the NPS implants showed similar fiber orientation at the bone level of the first implant thread. All specimens demonstrated a circular fiber orientation of the collagen fibers at the crestal bone level. Conclusions: The discrepancy in implant-abutment diameter involving a change from a wider implant platform to a smaller abutment diameter, described as platform switching, seems to provoke a circular fiber orientation at the implant platform level. Similar circular fiber orientation was found at the first implant thread bone level for regular implants without platform switching. The histologic results support the hypothesis that platform switching can reduce crestal bone loss and can serve as a "mechanical retention factor" for periodontal fiber orientation. More clinical and histologic studies are needed to corroborate this preliminary finding. [ABSTRACT FROM AUTHOR]

Purpose: The aims of the present study were to compare a novel biphasic calcium phosphate (BCP) with deproteinized bovine bone (DBB) for maxillary sinus floor augmentation in a split-mouth design and to perform a clinical follow-up of dental implants placed in the augmented sinuses. Materials and Methods: Partially or completely edentulous patients requiring bilateral sinus augmentation were included in the study. The patients were randomized for augmentation with BCP (test) and DBB (control) in the contralateral side. Eight months after grafting, dental implants were placed. After 3 years of graft healing, core biopsy specimens were obtained from the grafted areas for histologic and histomorphometric analyses. After 3 years of functional implant loading, implant survival/success rates and clinical indices were assessed and radiographic examination and resonance frequency analysis were performed. Results: Nine completely edentulous patients and two partially edentulous patients (mean age, 67 years) who required bilateral sinus augmentation were included in the study, and 62 implants were placed. The mean values for the area of newly formed bone in the retrieved specimens were 29% ± 14.3% and 32% ± 18.0% for BCP and DBB, respectively; the percentage of graft particles in contact with bone was 38% ± 10.9% in the BCP group and 44% ± 12.1% in the DBB group (no statistical significant differences between groups). The mean values for the area of BCP particles and DBB particles were 20% ± 7.5% and 24% ± 13.5%, respectively (difference not significant). One dental implant was lost from each group, resulting in an overall implant survival rate of 96.8% after 3 years of loading. Conclusion: After 3 years, a similar amount of newly formed bone was present regardless of the biomaterial used. The choice of biomaterial did not seem to influence implant survival rates. [ABSTRACT FROM AUTHOR]

Purpose: To determine the change in stability of three different implant systems using resonance frequency analysis (RFA) and to correlate RFA measurements with factors related to implant design, length, and diameter, patient gender, and dental arch. Clinical and radiologic evaluations were performed up to 1 year after loading. Materials and Methods: Three different types of implants from three different manufacturers were inserted in the posterior maxilla and mandible. RFA measurements were performed at implant placement and weekly up to 8 weeks postoperatively and were compared with respect to implant type, length, and diameter and dental arch. The implants were loaded after 8 weeks. All implants were examined radiographically at baseline and at 6 and 12 months. Plaque Index, Sulcus Bleeding Index, peri-implant probing depths, and marginal bone loss were recorded. Repeated-measurements analysis of variance, two-tailed mixed-model analysis of variance, the Least Significant Differences and Mann-Whitney U tests were used for statistical analyses. Results: All the groups showed high stability values at all time points (above 71). There were statistically significant differences between groups at all time points except 1 and 2 weeks. Mandibular implants showed statistically higher stability values than maxillary implants. Wide implants showed statistically higher stability values than narrow implants. Mean marginal bone loss was 0.22 ± 0.47 mm after 1 year. Conclusions: All three implant systems showed clinically acceptable stability values prior to early loading. The success rates and bone loss were similar to the values reported in the literature. [ABSTRACT FROM AUTHOR]

Rheumatoid polyarthritis is a systemic autoimmune disease characterized by chronic synovitis and bone damage associated with significant functional disability and morbidity. This case report describes a 4-year follow-up of a 56-year-old female receiving polymedication for severe rheumatoid polyarthritis and osteoporosis with a fully edentulous maxilla treated with two osseointegrated implants supporting a removable mandibular prosthesis. No practitioner wanted to use implants to stabilize her mandibular prosthesis because of the health risks involved. This report encourages the dental practitioner to be familiar with the symptoms and oral manifestations of rheumatoid polyarthritis in order to help manage this disease when patients lose all of their teeth. [ABSTRACT FROM AUTHOR]

Purpose: Pneumatized sinuses in the posterior maxilla often make implant placement difficult or impossible. A sinus lifting procedure can reliably augment the bone height, with the highest success rates reported when two-stage implants are placed 6 to 9 months later. The aim of this study was to evaluate the clinical reliability of a shortened approach in which nonsubmerged implants were placed at the time of sinus augmentation. Materials and Methods: All patients treated with sinus floor elevation and simultaneous implant placement at the authors' institution from 1999 to 2004 were retrospectively selected for a long-term follow-up study. Sinus elevation was considered when the remaining subantral bone height did not reach 6 mm in one or more implant sites. The lateral window technique was performed using bovine hydroxyapatite as a filler, and nonsubmerged implants were placed immediately. Implant and prosthodontic survival rates, as well as biologic and prosthodontic complications, were evaluated 2 to 6 years after loading. Results: In a sample of 40 patients, 50 subantral bone augmentations were performed and 102 implants were placed using the one-stage approach. One implant remained submerged because of a lack of primary stability. No sinusitis was noted. Only two implants were lost before loading. No implants failed after the definitive restorations were placed, leading to a 98% implant survival rate and 100% prosthodontic survival rate after 2 to 6 years. Conclusions: Subantral bone regeneration with bovine hydroxyapatite as a space filler is an effective and safe procedure allowing high survival rates of implants placed in the posterior maxilla. If the remaining bone is sufficient to ensure primary stability, implant placement can be performed simultaneously with sinus lifting, and even in a nonsubmerged fashion. [ABSTRACT FROM AUTHOR]

Purpose: Osteoporosis and diabetes are physiologic determinants that affect the process of osseointegration. The demand for dental implants is high in these patients, who have benefited from progress in preclinical research. Osseointegration has been extensively studied in rat models of osteoporosis and diabetes. The aim of this study is to present an assessment of the published data and provide consideration for future studies. Materials and Methods: The present study summarizes information through a systematic review of the literature from 1997 to 2008 available through PUBMED. The authors found 20 and 13 articles that report on osseointegration of implants in osteoporotic and diabetic rats, respectively. The survey was extended to recent publications on relevant aspects related to species, strains, and quality of endpoint data. Results: Differences in experimental variables such as timing of implant insertion, location of implants, or duration of disease prior to implant placement were reported and can be justified based on the experimental questions. Moreover, heterogeneity was further caused by variations in the age of rats and in reporting of the main parameters of osseointegration in the cortical and medullary compartments. Regardless of these differences, the evidence indicates consistently that ovariectomy results in reduced osseointegration, while there is only moderate evidence for impaired osseointegration in diabetic rats. Conclusions: Selection of the appropriate protocol is critical when studying implant osseointegration in rats. This overview highlights the demand for quality endpoint data related to animal numbers, data collection, and the way to establish osseointegration. Because of the differences in research questions, general recommendations for uniform models for osteoporosis and diabetes cannot be made. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate the effect of an electrochemically deposited nanohydroxyapatite (EDHA) coating on the bone bonding of sandblasted and dual acid-etched titanium implants. Materials and Methods: One hundred EDHA-coated and uncoated sandblasted/dual acidetched implants (3 mm in diameter, 10 mm long) were inserted into the femoral condyles of 50 rabbits. The osteotomy sites were enlarged to 3 mm in diameter via a sequence of drills. After 2, 4, 6, 8, and 12 weeks of bone healing, removal torque testing was performed to evaluate the interfacial shear strength of each implant type. The removed implants were prepared and observed with an electron microscope equipped with an energy dispersive electron probe x-ray microanalyzer. Results: The mean removal torque values for the EDHA-coated implants were 39.6 Ncm at 2 weeks and 40.4 Ncm at 4 weeks; corresponding values for the control implants were 21.1 Ncm and 24.1 Ncm. Removal torque values of the EDHA-coated implants were 87% higher than those of control implants after 2 weeks of healing (P = .015). However, the mean removal torque values for both types of implants were similar after 6, 8, or 12 weeks of healing (no significant differences between the implant surfaces; P > .05). Conclusions: The EDHA nanocrystal coating had a beneficial effect on interfacial shear strength during the early stages of bone healing. [ABSTRACT FROM AUTHOR]

Purpose: Zirconia ceramics, a biocompatible material with favorable mechanical properties, has been suggested for use in the manufacture of dental implants instead of the commonly used titanium. Not much data exist on the early healing response around zirconia dental implants. The aim of this study was to give a descriptive histologic assessment of the degree of early bone apposition around zirconia dental implants at 2 and 4 weeks after insertion compared to surface-modified titanium implants. Materials and Methods: Four zirconia and 4 titanium implants were placed in New Zealand white male rabbits. One implant was inserted in the condyle of each distal femur. Specimens were harvested at 2 and 4 weeks and processed with light microscopic analysis. The area of bone-implant contact was evaluated histomorphometrically. Results: A high degree of bone apposition could be observed on all implants at both time points. Differences in the percentage of implant surface covered with bone were noted between the 2 time points, with comparable results for the 2 materials. Conclusion: The results of this limited histologic study demonstrate a similar rate of bone apposition on zirconia and surfacemodified titanium implant surfaces during early healing. To confirm these results, further studies need to be conducted, involving larger sample size at more time points. [ABSTRACT FROM AUTHOR]

Implant-based prosthetic restoration and oral rehabilitation is a very popular modality of treatment, with excellent success rates. Although a relatively safe procedure, implant insertion has its risks, which have been described in the literature. This article describes an as-yet unreported complication following implant insertion-salivary gland injury. The characteristics of salivary gland injury are examined, and 4 cases in which the salivary apparatus was injured or obstructed during 1 of the phases of implant therapy are presented. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study was to determine changes in interdental papillae, alveolar bone loss, esthetics, and initial healing survival when 1-piece narrow-diameter implants were immediately loaded in sites with limited tooth-to-tooth spacing. Materials and Methods: One-piece titanium alloy implants with a maximum diameter of 3.0 mm and a resorbable blast surface texture on a squarethread form were evaluated. Digital photographs were made at each clinical visit to assess soft tissue healing. Interproximal soft tissue fill of the embrasure was assessed with a modified Jemt index. Standardized radiographs were made at baseline (implant placement) and at 6 and 12 months postsurgery. Radiographic bone height was measured from a consistent landmark on the implant. A 1- sided t test was used to determine statistical differences of bone height. Results: Thirty-one implants were placed in 17 subjects. One implant had clinical mobility and was removed, for an overall survival rate of 96.7%. Mean bone height on the day of placement and restoration was 2.33 + 0.73 mm above the first thread. Mean bone height was 1.75 ± 0.78 mm at 6 months postrestoration and 1.63 ± 0.81 mm at 12 months postrestoration. There was a statistically significant loss of bone support over the initial 6 months (0.58 mm; P < .01), with no significant progression thereafter (0.12 mm; NS). Complete fill of papillae was found in 92% of maxillary lateral incisor sites and 60% of mandibular incisor sites. Conclusion: The use of 1-piece narrow-diameter immediately loaded implants appears to be an effective prosthetic treatment for areas of limited space. [ABSTRACT FROM AUTHOR]

Purpose: Misfit of implant components has been linked to restorative complications such as screw loosening. Although previous studies have shown a correlation between rotational misfit and screw loosening, the impact of casting procedures on rotational misfit is lacking. The aim of this in vitro study was to evaluate the effect of casting procedures on rotational misfit of cast abutments when compared to machined titanium abutments. Materials and Methods: Forty-eight external hexagonal implants and 48 abutments were placed in 4 groups of 12 samples each: (1) machined titanium abutments, (2) premachined palladium abutments cast-on with palladium, (3) plastic burnout abutments cast with nickel chromium, and (4) plastic burnout abutments cast with cobalt chromium. Rotational misfit between the external hexagon of the implant and the internal hexagon of the abutment was measured using standardized techniques and recorded in degrees. Mean values for each group were analyzed with analysis of variance and Tukey test. Results: The mean rotational misfit was 1.21 ± 0.57 degrees for machined titanium abutments, 1.77 ± 130 degrees for cast-on abutments, 1.98 ± 0.72 degrees for cast NiCr abutments, and 2.79 ± 1.13 degrees for cast CoCr abutments. Significantly greater rotational misfit was recorded with cast CoCr abutments when compared to machined titanium abutments (P < .05). Conclusion: Rotational misfit was less than 2 degrees for all groups except for cast CoCr abutments, which demonstrated a significantly greater rotational misfit. [ABSTRACT FROM AUTHOR]

Purpose: Current implant systems with screw-retained abutments permit direct laboratory fabrication of castings. Computer aided drafting systems further enhance the fabrication of computer-milled abutments (CMAs) and castings. The purpose of this study was to compare marginal accuracy, as measured by gap size, of castings made directly on CMAs with those made indirectly on epoxy and stone dies. Materials and Methods: Castings were made directly for 10 CMAs. Marginal gap measurements were made with the castings seated on the abutments (group A). Castings were also made indirectly on stone and epoxy dies obtained from impressions of the abutments. Marginal gap measurements were made with these indirectly made castings seated on their CMAs (groups B and E). In addition, the directly made castings were transferred between CMAs and marginal gap measurements made (group D). Marginal gap measurements of the groups were compared with analysis of variance (ANOVA) and pair-wise comparisons (Scheffé test). Results: Groups A and D had marginal gaps of less than 100 μm. These marginal gaps were significantly smaller (P < .05) than the gaps of groups B and E, made on dies, which were approximately 200 to 500 μm. Discussion and Conclusions: With CMAs, it is possible to make an exact duplicate of the abutment. This permits the laboratory to make castings on duplicate abutments with greater precision than can be obtained using the indirect technique. Direct fabrication of castings resulted in smaller marginal gaps, which in turn allows a better marginal seal and improved retention of castings. [ABSTRACT FROM AUTHOR]

Purpose: Osteoporosis and osteopenia are characterized by reductions in bone mass and may lead to skeletal fragility and fracture. The latest generation of oral bisphosphonate drugs, including alendronate and risendronate, has been approved for the prevention and treatment of osteoporosis. These medications are chemically absorbed into bone, decreasing osteoclast number and activity and thereby decreasing bone resorption. The purpose of this report is to present safety data from 2 controlled studies in patients receiving oral bisphosphonates. Materials and Methods: Study 1 tested the effect of alendronate, an inhibitor of bone resorption, on alveolar bone. A total of 335 patients (162 men and 173 women, aged 30 to 79 years) with moderate or severe periodontal disease were randomized to either placebo or 70 mg alendronate once weekly. Alveolar bone height and safety were assessed over a 2-year period. Study 2 was a longitudinal single-blind controlled design comparing implant success in 50 consecutive patients (210 implants), 25 patients who received bisphosphonate therapy and 25 age-matched control subjects. Implant success and safety, including incidence of osteonecrosis of the jaws (ONJ), was blindly assessed for at least 3 years. Results: In study 1, no cases of ONJ were observed in either treatment group. Furthermore, a trend toward lower incidences of infection and tooth loss was observed in the alendronate group. In study 2, no cases of ONJ were observed in either group, and implant success was greater than 99% in both groups. Conclusion: On the basis of 2 controlled clinical studies, oral bisphosphonate usage was not associated with occurrence of ONJ. [ABSTRACT FROM AUTHOR]

Purpose: One-stage implant placement in the grafted maxillary sinus has traditionally been limited to patients with at least 5 mm of residual bone to ensure complete implant stabilization. The aim of this prospective study was to determine the long-term survival rates of implants with roughened surfaces placed immediately into maxillary sinus grafts in patients with 1 to 5 mm of residual bone. Materials and Methods: A total of 2432 microtextured screw-type (n = 1,374) or hydroxyapatite-coated cylindertype (n = 758) implants were immediately placed into the grafted sinuses of 731 patients. The implants were restored and monitored for up to 9 years of clinical follow-up. Results: Cumulative survival at 9 years was 97.9% (n = 2,091 implants); 20.4% of the implants were placed in 1 to 2 mm of residual bone. Discussion: Initial implant stability and parallelism were achieved through a combination of meticulous condensation of the particulate bone graft material around the implants, the frictional interface of the roughened implant surfaces and the host tissues, and selection of an appropriate graft material. Conclusions: Simultaneous implant placement into sinus floor grafts can be a predictable treatment option for patients with at least 1 to 2 mm of vertical residual bone height when careful case planning and meticulous surgical techniques are used. [ABSTRACT FROM AUTHOR]

Purpose: The primary goal of this study was to compare bone-to-implant contact (BIC) in alveolar bone augmented by distraction osteogenesis with BIC in alveolar bone augmented by onlay iliac crest grafting. Materials and Methods: Alveolar bone defects were created bilaterally in 5 American foxhounds, and after healing, bone augmentation was accomplished using distraction osteogenesis on 1 side of the jaw and onlay grafting on the other. Twelve weeks after consolidation, implants were placed in augmented and control sites. The animals were sacrificed and the jaws harvested for histologic analysis after an additional 8 weeks. Results: The mean BIC was 54.7% ± 14.6% for implants placed in distracted sites, 53.8% ± 11.8% for sites where an onlay graft was used, and 51.2% ± 14.4% for control sites. Significant differences in BIC were noted between experimental and control sites only at the apical third of the implant (19.8 ± 1.8 for distracted sites; 15.5 ± 1.5 for grafted sites; 8.0 ± 0.5 for control sites; P < .05). Discussion: The data showed that both distraction osteogenesis and onlay grafting produce sufficient bone for implant placement. There were no differences between procedures in regard to BIC after 8 weeks. Conclusion: These data suggest that both onlay grafting and vertical distraction are appropriate methods for bone augmentation prior to implant placement. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study was to evaluate whether the local administration of growth hormone (GH) would influence the formation of peri-implant bone around titanium sheets placed in the tibiae of young rabbits. Materials and Methods: Thirty-two New Zealand rabbits were randomly placed in 1 of 2 groups: the experimental group, in which 4 IU (1.2 mg) of lyophilized powder (GH) was added to a surgically created defect at implant placement, or the control group, in which an implant sheet was placed without hormonal treatment. Animals were sacrificed at 1, 2, 3, and 6 weeks after surgery, and histologic sections were stained with Masson, Alcian blue, picrosirius, and hematoxylin-eosin and observed under light microscopy. The sections were analyzed morphometrically and densitometrically to calculate the amount of newly formed bone. Results: At week 2, GH-group sections showed enhanced growth of the trabeculae from the periosteal tissue, with thicker and more irregular trabeculae than those observed in control group specimens. A tendency toward greater bone area and lesser density was observed in the GH group, although the groups did not differ significantly. Nevertheless, bone-to-implant contact in weeks 2 and 6 was significantly greater in the GH group (P < .05). Discussion: An increase in the cortical response from periosteal and endosteal reactions was observed with the high local administration of GH, in disagreement with most authors. In the first phases of bone repair, the osteons were more disorganized; they were more organized by the sixth week. Conclusion: Local administration of GH could stimulate the first phases of the bone remodeling process in this experimental model. [ABSTRACT FROM AUTHOR]

Purpose: This study was intended to provide a report of experience and results with Frialit-2 implants used for single-tooth replacement. Materials and Methods: Over a 7-year period (1994-2000), 146 single-tooth implants (84 maxilla, 62 mandible) were placed in 112 patients (67 females, 45 males; 31.2 ± 16.4 years). The sites included maxillary anterior teeth (n = 38) as well as the mandibular premolars and molars (n = 57). Ninety-three crowns were cemented and 53 crowns were screw mounted (22 with vertical, 31 with horizontal screws) on standard abutments. The follow-up time varied between 3 and 80 months (35.8 ± 16.5 months). Results: Two implants (1.4%) were lost, 1 during early loading and the other after 6 years. The most frequent prosthetic complication was isolated crown loosening of cemented crowns requiring recementation of 9 crowns (9.9%). Crowns with vertical screws showed no crown and/or screw loosening. Four crowns (2.8%) were replaced because of ceramic fracture. Discussion: Peri-implant soft tissue condition, bone resorption, and Periotest values indicated satisfactory results. The cumulative implant survival rate during the follow-up period was 97.3%, and that of the crowns 96.4% (total cumulative survival rate 93.7%). Conclusions: With the low number of abutment screw loosenings (3.5%), the deep internal hexagonal retention compared favorably to external retention methods. The predominant use of long implants (98.4% ≥ 13 mm) allowed a favorable implant/crown ratio with the potential for problem-free, long-term results. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of particulate dentin-plaster of Paris with and without platelet-rich plasma (PRP) on bone healing and new bone formation around titanium dental implants in a canine model. Histologic sections and histomorphometric analysis of the defects were obtained at 6 and 12 weeks after surgery. Materials and Methods: Three circular bone defects were surgically prepared in iliac crest sites in each of 10 animals. A total of 30 Avana dental implants were placed in the animals. They were self-tapping, screw-type implants, 10 mm in length and 4 mm in diameter, all made of commercially pure titanium. A titanium implant was placed centrally in each defect. In each dog, the defects were treated with 1 of the following 3 treatment modalities: (1) no treatment (control); (2) grafting with particulate dentin-plaster of Paris; (3) grafting with particulate dentin-plaster of Paris and PRP. Results: Histologic analysis showed that all of the bone defects surrounding the implants that were treated with particulate dentin-plaster of Paris, with and without PRP, were filled with new bone. The defects that were not treated (control) demonstrated new bone formation only in the inferior threaded portion of the implants. Discussion: Histomorphometric results revealed a higher percentage of bone contact with particulate dentin-plaster of Paris and PRP compared to the control and particulate dentin-plaster of Paris. Conclusions: These results suggested that bone defects around titanium implants can be treated successfully with particulate dentin-plaster of Paris, and that the outcome can be improved if PRP is also used. [ABSTRACT FROM AUTHOR]

Purpose: A technique is presented which utilizes a trephine with a 3.0-mm external diameter followed by an osteotome to implode a core of maxillary posterior alveolar bone prior to immediate implant placement. Materials and Methods: The technique and its indications and contraindications are described in detail. Results: One hundred sixteen implants were placed and uncovered utilizing this technique. Two implants were mobile at the time of uncovering. Discussion: One hundred fourteen implants were restored and have been functioning successfully for up to 4 years according to the Albrektsson criteria, yielding a success rate of 98.3%. Conclusion: No implants have been lost or are failing in function. [ABSTRACT FROM AUTHOR]

The purpose of this study was to estimate the quantity of dental implant literature available on MEDLINE for evidence-based clinical decision-making and to identify its location. A search strategy based on Medical Subject Headings for dental implants was developed to examine MEDLINE using the Ovid Web Gateway search engine. Sensitive and specific methodologic search filters identified 4 categories of information: etiology, diagnosis, therapy, and prognosis. The results were then subdivided by year to identify trends and sorted to identify the sources of publications. The searches identified 4,655 articles published in English between 1989 and 1999 on human dental implants on MEDLINE. The mean number of articles ( ±SD) per year ranged from 15 ±11 for specific searches to 107 ±50 for sensitive searches. The number of articles increased by 14% to 43% each year for the sensitive search. When subdivided by clinical category, the mean numbers of articles per year for sensitive and specific searches were, respectively: diagnosis 12 ±7.5 and 1.5 ±1.6, etiology 58 ±33 and 1.9 ±2.5, therapy 23 ±15 and 0.3 ±0.5, and prognosis 67 ±33 and 12 ±8.3. Four dental journals account for approximately half of these publications. These results provide 6 key central findings: (1) there appears to be a substantial literature of clinically relevant information on implants upon which to base clinical decisions; (2) the implant literature is significantly biased toward articles addressing prognosis; (3) to stay current, one would need to read between 1 and 2 articles per week 52 weeks per year, and this number increases significantly each year; (4) approximately 50% of the articles were published in 4 journals, whereas the remainder reside in approximately 97 other journals, making it difficult to stay current; (5) these trends reaffirm the need for lifelong learning; (6) these trends also suggest the need for computer-based clinical knowledge systems. [ABSTRACT FROM AUTHOR]

Although dental implants continue to provide consistent and predictable treatment options for most patients, some people with uncontrolled systemic disease may be denied implant treatment. Diabetes is one such disease. According to the U.S. Centers for Disease Control and Prevention, diabetes is a leading cause of blindness, kidney failure, and amputations of the lower extremities. These complications result from microvascular disturbances associated with diabetes. The effect of diabetes on the healing of titanium implants has not been well established. In this study of 32 rats, diabetes was induced in 16 animals by injection of streptozotocin (65 mg/kg); the remaining 16 animals served as controls. Titanium alloy implants were placed in the tibiae of all 32 rats using standard surgical techniques. Implants healed for 14 days. Blood samples were obtained for serum glucose, osteocalcin, and alkaline phosphatase analyses. Implants were retrieved and processed for histomorphometric analyses. Three quantities were measured using light microscopy, video capture, and computer analysis: percent osseointegration (ie, linear bone interface), associated bone volume percent, and contact frequency. Diabetic animals demonstrated significantly less osseointegration than controls. However, bone volume percent in diabetic animals was about 4 times greater than controls. Biochemical analyses were mixed; diabetic animals demonstrated increased serum osteocalcin levels compared to controls but decreased alkaline phosphatase. Based on the results of this study, it was concluded that the bone response associated with titanium alloy implants in the tibiae of diabetic rats is uniquely different from controls. [ABSTRACT FROM AUTHOR]

The fabrication of a complete maxillary implant-supported prosthesis in a patient with slight resorption of the alveolar ridge and a high lip line presents a professional challenge. The implants must be placed with high precision to achieve good esthetics, phonetics, and function. A fixed surgical template using microimplants has been developed for this purpose. The objective of this investigation was to compare a fixed surgical template (FST) to a conventional movable surgical template (MST) for the precise placement of implants in the slightly resorbed edentulous maxilla. Three patients (28 implants), edentulous in the maxilla, with slight ridge resorption, in whom the implants were placed with an FST, were compared with 5 controls having the same characteristics and implants placed with an MST (35 implants). After completion of the prosthesis, occlusal photographs (1:1) were taken, and these images were scanned and transferred to a drawing program in which the contours of the teeth, the ideal emergence position of the occlusal hole of the abutment screw, and its real position were drawn. A blind evaluation was made using the following variables: frequency of location of the abutment screw hole outside of the tooth contour, and the relative measurements of the area of coincidence between the circle that represents the ideal position and real position. A significantly smaller frequency of implants outside the tooth contour was seen with the FST (7%) than with the MST (46%) (P < .0008). Also, a significantly higher relative area of coincidence was observed between ideal position and real position in the FST (0.61) than in the MST (0.38) (P < .003). This s tudy revealed that considerably higher precision was associated with the use of an FST. [ABSTRACT FROM AUTHOR]

The survival rate of implants placed in the maxillary molar area in a 2-stage procedure was evaluated. Between 1990 and 1997, 60 consecutive patients (32 females and 28 males, mean age 51 years) received 87 implants to replace missing maxillary molar teeth. Radiographs were evaluated preoperatively for bone quantity (mesiodistal width, potential implant length not compromising the integrity of adjacent vital structures). Second-stage surgery was performed in a mean of 7.9 months postimplantation. The 5-year cumulative implant survival rate and the influence of implant characteristics (type, length, diameter, and coating) on implant failure and complication rates (between the 2 stages of surgery) were evaluated. The total 5-year cumulative survival rate was 95.4% (4 implants were lost). There were a total of 17 "complications" (premature spontaneous implant exposure) in non-failing implants, 11 with high and 6 with flat cover screws, respectively. Implantation in the edentulous maxillary molar area is a predictable procedure with a considerably high survival rate. The type of implant cover screw used can affect the complication rate. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate whether a new periodontal ligament attachment will form on titanium implants when they are implanted with cultured periodontal ligament cells. Periodontal ligament cells obtained from the teeth of 3 dogs were cultured and attached to the surface of titanium implants. The implants with the cultured autologous periodontal ligament cells were placed in the mandibles of the dogs. After 3 months of healing, histologic examination revealed that, on some implant surfaces, a layer of cementum-like tissue with inserting collagen fibers had been achieved. These results demonstrated that cultured periodontal ligament cells can form tissue resembling a true periodontal ligament around implants. [ABSTRACT FROM AUTHOR]

Transposition of the inferior alveolar nerve was performed in an experimental dog model. Four adult greyhounds were used in the study. Surgical transposition of the nerve was made bilaterally, and 3 implants were placed on each side while the nerve was lateralized. On one side, the nerve was repositioned in contact with the implants, while on the contralateral side a resorbable membrane was positioned between the implant surface and the neurovascular bundle. Histologic section after 4 months of healing showed an intimate contact between implants and nerve tissue in all cases without an interpositional membrane, in contrast to cases with membranes. Histomorphometric measurements of the distance between the implants and the nerve tissue showed that the membrane side had a considerably larger distance between the implant and the nerve, although not with concomitant bone formation. [ABSTRACT FROM AUTHOR]

Bone resorptive patterns may prevent the ideal placement of endosseous implants. Numerous techniques have been described to create a more favorable surgical site for implant placement. This retrospective review was conducted to determine the frequency of need for implant site preparation in an outpatient clinical setting. In addition, different techniques of surgical site preparation were evaluated to determine their frequency of use and surgical outcome. A history review was conducted of all consecutively treated partially edentulous patients between January 1993 and December 1997. This review evaluated the number of implants placed, the age and gender of the patient, the type of graft used, and the status of the implant. In all, 542 patients were seen in this time interval, with a total of 1,313 implants placed. Implant site preparation was needed in 4.4% of the patients, with the requirement for grafts occurring more frequently in the maxilla. Implant site preparation is a relatively infrequent requirement in the general population. Grafts are required more frequently in the maxilla than in the mandible. Complications following grafting were relatively infrequent and were not severe. [ABSTRACT FROM AUTHOR]

A surgical procedure for the rehabilitation of severely resorbed maxillae is described. Twenty-five patients, made up of a development group of 5 and a routine group of 20, were treated with Le Fort I osteotomy using interpositional bone grafts from the iliac crest and, in a second stage, titanium implants. Altogether, 181 Brånemark implants were placed, and the patients were followed for up to 5 years. The implant survival rate for the development group was 60.0% after 5 years. Life table analysis for the routine group showed a 5-year survival rate of 85.6%. Twenty-two patients received fixed prostheses and 2 received overdentures. One patient lost all implants and was rehabilitated with a prong denture. [ABSTRACT FROM AUTHOR]

A technique is described for accomplishing both localized sinus augmentation and guided bone regeneration at the time of maxillary molar extraction. One hundred nine sites were treated in 92 patients. Of these, 102 procedures (94.0%) were successful and 7 (6.0%) were partially successful. Success was defined as the ability to ideally position an implant at least 10 mm in length and 4.8 mm in width without perforating the floor of the sinus or generating an implant fenestration or dehiscence. Partially successful procedures required an additional osteotome sinus lift at the time of implant placement. [ABSTRACT FROM AUTHOR]

The expanded experience with oral implants and supplementary augmentation techniques has opened new possibilities for treating patients with oligodontia or anodontia with fixed prostheses. A problem in treating such patients is the need to place implants in growing maxillae or mandibles, as many of these patients are children or adolescents. When implant treatment is postponed until the patient is full grown, dysfunctions become manifest, which necessitates extensive surgical measures to achieve a fixed prosthetic restoration. This report illustrates the problems associated with different concepts for the treatment of multiple aplasia with implants. The results are based on the findings of 22 patients with oligodontia who underwent surgical treatment and were followed over a period of 5 years. Two controversially treated cases are presented. [ABSTRACT FROM AUTHOR]

The torque output of the Nobelpharma electric torque controller was determined using a special setup on an Instron test machine. The devices were held in a vice and oriented so that activation of the drivers caused a pure torsion effect. Measured torque levels generally varied significantly between individual devices. Further, significant differences generally existed between the nominal torque levels and the corresponding measured values. Torque application errors varied from target values by 1% to 165%. For the clinician to deliver appropriate torque levels, these data indicate that a simple means for chairside calibration and adjustment should be available. [ABSTRACT FROM AUTHOR]

The quality of the tissue-implant interface was evaluated using light and scanning electron microscopy with morphometric analysis. Nine dogs were implanted with 3 types of dental implants (titanium, zirconia, or alumina). A total of 24 dental implants was placed in mandibular bone previously filled with coral carbonate calcium (corail) or hydroxyapatite. The study results in breaking the concept of osseointegration into 2 phases: "osseocoaptation," which concerns only the interface (physical contact between the implants and the bone without interpenetration process), and "osseocoalescence," which relies on an interpenetration of the bioactive material, which almost entirely disappears, being substituted by newly formed bone. There was no significant statistical difference between the 3 types of implants. Both fillings showed good ossecoalescence properties. However, hydroxyapatite led to fibrous encystment, preventing osseocoaptation of implants, in contrast with calcium carbonate filling. [ABSTRACT FROM AUTHOR]

The recent announcement of the discovery of a first or second century AD Roman example of a dental implant appears to fall into a category of spurious claims regarding ancient dentistry. Several earlier claims of the discovery of impressive examples of ancient dentistry are reviewed, followed by a discussion of the recent discovery from France. This survey of all of these claims regarding finds of ancient dental implants, plus data from the modern and rapidly evolving field of implant dentistry, suggests that these "ancient implants" are the product of the imaginations of 20th-century archaeologists. [ABSTRACT FROM AUTHOR]