Retrospective multicenter analysis of 3i endosseous dental implants placed over a five-year period

Association of Age, Gender, and Site of Implant Placement: An Institution-Based Retrospective Study

Tooth loss is an undesirable condition that leads to functional, esthetic and social damage, having an impact on an individual's quality of life. Dental implants are man-made tooth root replacements that are increasingly used to replace a missing tooth. It is important to gather demographic data in order to take precautions before the possible failures. Hence the objective of this study was to retrospectively determine the association between age, gender, and site of implant placement in patients reporting to a private dental institution. This study was carried out from the data obtained from the case records of 1281 patients who had undergone implant therapy. Chi-square test was applied to see associations of gender, age and implant site. The results show that a maximum number of 348 implants (27.7%) were placed in patients aged between 41-50 years. The patient pool consisted of 705 (55%) females and 576 (45%) males. A maximum of 228 implants (17.80%) were placed in region 46 and 224 implants (17.49%) in region 36. Only 2 implants (0.2%) were placed in region 41. There was a positive association between age, gender and site of implant. In those aged 20-30 years, 20.53% of implants were placed, 26.23% in 31-40 years, 27.1% in 41-50 years, 17.95% in 51-60 years and 8.11% in 61-70 years of age. In male, a maximum of 124 implants (54.4%) were placed in region 46 and only 1 implant (50%) in region 41. In females, region 36 had a maximum of 110 implants (49.1%), and the least number of implants were placed in regions 31 and 41. In this study, it can be concluded that general factors such as age and gender had a significant effect on the site of implant placement.

OII-DS: A benchmark Oral Implant Image Dataset for object detection and image classification evaluation

In recent years, there is been a growing reliance on image analysis methods to bolster dentistry practices, such as image classification, segmentation and object detection. However, the availability of related benchmark datasets remains limited. Hence, we spent six years to prepare and test a bench Oral Implant Image Dataset (OII-DS) to support the work in this research domain. OII-DS is a benchmark oral image dataset consisting of 3834 oral CT imaging images and 15240 oral implant images. It serves the purpose of object detection and image classification. To demonstrate the validity of the OII-DS, for each function, the most representative algorithms and metrics are selected for testing and evaluation. For object detection, five object detection algorithms are adopted to test and four evaluation criteria are used to assess the detection of each of the five objects. Additionally, mean average precision serves as the evaluation metric for multi-objective detection. For image classification, 13 classifiers are used for testing and evaluating each of the five categories by meeting four evaluation criteria. Experimental results affirm the high quality of our data in OII-DS, rendering it suitable for evaluating object detection and image classification methods. Furthermore, OII-DS is openly available at the URL for non-commercial purpose: https://doi.org/10.6084/m9.figshare.22608790.

Mechanical failures of dental implants and supported prostheses: A systematic review

Purpose

Though, mechanical dental implant and supported prosthesis failures are considered significant, a comprehensive evaluation is lacking. A systematic review analyzing different aspects related to such failures was therefore done.

Methods

- Electronic search was carried out in PubMed/MEDLINE and Cochrane Library for articles published between 1981 and 2021. Articles were selected using predefined criteria. Data extraction was based on mechanical complications associated with dental implants, prosthetic implant failures, survival rate of implants, mechanical failure of implants placed in the maxilla and mandible, and mechanical complications associated with implant supported over dentures. Quality of included studies was assessed. Meta-analysis for heterogenicity testing, publication bias and implant failure assessment was conducted using MedCalc® Statistical Software version 19.7.

Results

- Eighteen retrospective and prospective studies were included following PRISMA guidelines. Mechanical complications were more in the initial 9 years but reduced later. Abutment screw loosening was one of the more common mechanical complications (16.21%). Maxillary implant failure was greater compared to mandibular implant failure with an odds ratio of 4.66 (95% CI -3.21- 6.75). Failure of implant supported overdentures due to mechanical complications were 3% in the fixed effect, and 2.9% in the random effect model (P < 0.05). The overall prevalence of mechanical failure was between 5.6% and 7.7% (P < 0.05).

Conclusion

Mechanical failures of implant and supported prosthesis have similar prevalence to biological and esthetic failures, and therefore need to be given due credence. Identifying specific factors contributing to such failures can help reduce incidence.

Effect of dynamic cyclic loading on screw loosening of retightened versus new abutment screw in both narrow and standard implants (in-vitro study)

BACKGROUND

The purpose of this in-vitro study was to evaluate the effect of dynamic cyclic loading on screw loosening of retightened abutment screw versus new abutment screw in both narrow and standard implants.

METHODS

Separate acrylic resin blocks containing implant assembly (fixture, abutment, abutment screw, metal tube capping the abutment). Samples were divided into two main groups according to the diameter of implant: group 1 (GI 4.5-mm diameter) and group 2 (GII 3-mm diameter). Each group is subdivided into two subgroups according to the suggested option to manage screw loosening either by retightening (GIA, GIIA) or using new screws (GIB, GIIB). One hundred thousand cycles of eccentric dynamic cyclic loading (DCL) were applied before and after retightening or replacing the screw; then, removal torque loss (RTL) ratio was calculated, tabulated, and analyzed by t-student, ANOVA, pair wise Tukey's tests.

RESULTS

There were differences between GI and GII regarding the incidence of screw loosening process. Removal torque loss ratio was higher in GIB and GIIB where the old abutment screws were replaced by new screws for both standard implants (SIs) and narrow diameter implants (NDIs). There was significant effect of retightening and replacing the abutment screws after exposure to DCL.

CONCLUSIONS

Within the limitations of this in-vitro study, it can be conclude that screw loosening process occurred in both SIs and NDIs but with higher values in NDIs. It is better to retighten the screw of NDIs and SIs than replacing it with a new screw.

Molecular mechanisms of painful traumatic trigeminal neuropathy-Evidence from animal research and clinical correlates

Painful traumatic trigeminal neuropathy (PTTN) may occur following major craniofacial or oral trauma, or may be subsequent to relatively minor dental interventions. Following injury, pain may originate from a peripheral nerve, a ganglion, or from the central nervous system. In this review, we focus on molecular mechanisms of pain resulting from injury to the peripheral branch of the trigeminal nerve. This syndrome has been termed painful traumatic trigeminal neuropathy (PTTN) by the International Headache Society and replaces previous terms including atypical odontalgia, deafferentation pain, traumatic neuropathy and phantom toothache. We emphasize the scientific evidence supporting the events purported to lead to PTTN by reviewing the pathophysiology of PTTN based on relevant animal models. Additionally, we briefly overview clinical correlates and pathophysiological manifestations of PTTN.

Short Implants Versus Standard Implants: Midterm Outcomes of a Clinical Study

INTRODUCTION

The aim of this study was to evaluate the midterm survival rate, marginal bone resorption (MBR), and stability of short implants and to compare the results with standard length implants.

MATERIALS AND METHODS

A total of 38 patients were included. In total, 147 implants (Nucleoss Implants, Izmir, Turkey) were placed (86 short implants and 61 standard implants). Cement-retained metal-ceramic prostheses were fabricated. MBR was evaluated on periapical radiographs taken at implant placement, at the time of crown insertion and annually thereafter. The stability of the implants was evaluated by resonance frequency analysis.

RESULTS

The 3- and 5-year cumulative survival rates for standard implants was 98.4% and for short implants was 96.5% (P = 0.644). The MBR of the short implants was significantly lower than that of the standard implants after 1, 2, and 3 years of loading (P < 0.05). No significant differences were found between 2 groups after 6 and 12 months of loading in terms of implant stability (implant stability quotient values) (P > 0.05).

CONCLUSION

Within the limits of this study, it is concluded that short implants achieved similar results as standard implants after 3 to 5 years of loading.

Use of narrow-diameter implants in the posterior jaw: a systematic review

STATEMENT OF PROBLEM

Evidence is limited on the efficacy of narrow-diameter implants (NDIs) in the posterior jaw.

PURPOSE

The purpose of this systematic review was to assess the survival of NDIs and provide guidelines for their safe use.

MATERIALS AND METHODS

Electronic search of the English-language literature enriched by hand search to identify suitable publications was made. Only peer-reviewed clinical studies published from January 1990 through March 2014 were included.

RESULTS

Seventeen studies with a total of 1644 implants met the inclusion criteria, with an observation period from 1 up to 12 years. The mean survival rate of 98.6% was reported. Technical and other complications were observed.

CONCLUSION

Short-term clinical data suggest that NDIs may serve in the posterior jaw as an alternative to standard-diameter implants. However, certain clinical conditions must be observed to assure long-term success.

A New Detection Method for Submerged Implants: Oral Tattoo

PURPOSE

To evaluate the marking potential of tattoo ink in determining the definitive locations of submerged implants at the time of surgical exposure of the implants.

MATERIALS AND METHODS

In total, 104 implants in 32 patients were included in this study. After placement of the implants, cover screws were inserted. Overlying mucosa was marked with tattoo ink using a 20 g needle through the center of the cover screw. At the time of surgical exposure the tattoo marks were evaluated relative to visibility.

RESULTS

At the time of the surgical exposures, tattoo ink was clearly visible at 91 implants, slightly visible at 8 implants, and not visible at 5 implants. After detection and classification of tattoo ink, the overlying mucosa was gently removed by tissue punch under local anesthesia.

CONCLUSION

The results of this study seemed to indicate that marking the location of implants with tattoos at the time of implant placement can be an inexpensive, easy, healthy, and practical way to identify the location of marked submerged dental implants.

Narrow-diameter implants with conical connection for restoring the posterior edentulous region

Background

The objective of this retrospective study was to show results from platform-switched narrow-diameter implants in the posterior edentulous region, which we followed up for more than 1 year after functional loading.

Methods

Ninety-eight narrow implants were inserted into 66 patients. After healing, fixed implant-supported prostheses were delivered to the patients, and Periotest and radiographic examinations were performed. After the first year of loading, the implant outcome was again evaluated clinically and radiographically using the Periotest analysis. Crestal bone loss and Periotest values (PTVs) were used to evaluate the effect of surgery, prosthesis, implant, and a host-related factor. A general linear model was used to statistically detect variables statistically associated with crestal bone loss and Periotest value.

Results

We followed up on the implants over 1 to 4 years after loading; their survival rate was 100 %, and pronounced differences from PTVs were noted among jaw location, bone quality, and loading period. No difference was detected in bone loss among the variables studied. Bone loss after functional loading was 0.14 ± 0.39 mm. The stability value from the Periotest was −3.29 ± 0.50.

Conclusions

Within the limitations of this study, judicious use of platform-switched narrow implants with a conical connection must be considered an alternative for wide-diameter implants to restore a posterior edentulous region.

Does the time of osseointegration in the maxilla and mandible differ?

OBJECTIVES

The objectives of the present study were to measure the implant stability quotient (ISQ) values at 3 different time points after the surgical insertion and to determine whether the time of osseointegration differs in the maxilla and mandible.

MATERIALS AND METHODS

To measure implant stability, resonance frequency analysis (RFA) was performed in 44 patients (40 women, 4 men) with a total of 100 Implacil De Bortoli implants; the patients were divided into 2 groups: group 1, implants in the maxilla (22 in the anterior maxilla and 37 in the posterior maxilla); and group 2, implants in the mandible (41 posterior mandibles). Using RFA, implant stability was measured immediately after implant placement to assess the immediate stability (time 1) and at 90 (time 2) and 150 (time 3) days.

RESULTS

Overall, the mean (SD) ISQ was 63.3 (6.63) (95% confidence interval [CI], 39-79) for time 1, 70.5 (6.32) (95% CI, 46-88) for time 2, and 73.5 (6.03) (95% CI, 58-88) for time 3. In group 1, the mean (SD) ISQ was 61.8 (6.56) (95% CI, 39-79) for time 1, 68.8 (5.19) (95% CI, 57-83) for time 2, and 72.3 (5.91) (95% CI, 58-85) for time 3. In group 2, the mean (SD) ISQ was 65.5 (6.13) (95% CI, 44-75) for time 1, 72.9 (7.02) (95% CI, 46-88) for time 2, and 75.3 (5.80) (95% CI, 60-88) for time 3.

CONCLUSIONS

The stability of the implants placed in the maxilla and mandible showed a similar evolution in the ISQ values and, consequently, on osseointegration; however, the implants in the mandible presented superior values at all time points.

Stability of implants placed in fresh sockets versus healed alveolar sites: Early findings

OBJECTIVES

The present study measured implant stability quotient (ISQ) values at three different time points after surgical procedures to compare whether the stability values differed between implants placed in fresh extraction sockets versus healed alveolar sites.

MATERIALS AND METHODS

To measure implant stability, resonance frequency analysis (RFA) was performed in 77 patients (53 women, 24 men) with a total of 120 dental implants. These implants were divided into two groups: Group 1 included 60 implants in healed alveolar sites (22 in the maxilla, 38 in the mandible), and Group 2 included 60 implants in fresh sockets (41 in the maxilla, 19 in the mandible). Implant stability was measured immediately at implant placement (baseline), 90, and 150 days later. Statistical analysis was made using a multivariate regression linear model at implant level (α = 0.05).

RESULTS

Overall, the means and standard deviations of the ISQ values were 62.7 ± 7.14 (95% confidence interval [CI], 39-88) at baseline, 70.0 ± 6.22 (95% CI, 46-88) at 90 days, and 73.4 ± 5.84 (95% CI, 58-88) at 150 days. In Group 1, the ISQs ranged between 64.3 ± 6.20 and 75.0 ± 5.69, while in Group 2, presented lower values that ranged between 61.2 ± 8.09 and 71.9 ± 5.99 (P = 0.002). Anatomic location and times periods were the only identified variables with an influence on ISQ values at implant level (P < 0.0001).

CONCLUSIONS

The stabilities of the implants placed in the fresh sockets and in healed sites exhibited similar evolutions in ISQ values and thus osseointegration; however, the implants in the healed alveolar sites exhibited superior values at all time points.

Implant Stability Measurements in the Long-Term Follow-up of Dentis Implants: A Retrospective Study With Periotest

PURPOSE

The purpose of this study was to evaluate retrospectively the stability of Dentis implant with the Periotest.

METHODS

In total, 36 patients and 88 implants were investigated. Periotest was used to measure implant stability, and a periapical view was taken immediately after surgery and again immediately after, 3 months after, 6 months and 5 years after prosthesis placement. Bone loss on the periapical view, bone quality according to tactile sensation, and area of implant installation were assessed.

RESULTS

The mean Periotest value (PTV) immediately after surgery was -1.02, and the mean bone loss rate (bone loss/fixture length × 100) at 6 months after prosthesis placement was 8.42%. PTV was higher with more bone loss (types III, IV vs types I, II bone). The lowest mean PTV was in the lower molar area (-1.48), followed by the lower anterior (-1.41), upper molar (0.11), and upper anterior area (5). One implant failed and survival rates were 98.9%.

CONCLUSION

Implant stability was lower in cases with more bone loss and poor bone quality and in the maxilla versus the mandible.

Reasons for failures of oral implants

This study reviews the literature regarding the factors contributing to failures of dental implants. An electronic search was undertaken including papers from 2004 onwards. The titles and abstracts from these results were read to identify studies within the selection criteria. All reference lists of the selected studies were then hand-searched, this time without time restrictions. A narrative review discussed some findings from the first two parts where separate data from non-comparative studies may have indicated conclusions different from those possible to draw in the systematic analysis. It may be suggested that the following situations are correlated to increase the implant failure rate: a low insertion torque of implants that are planned to be immediately or early loaded, inexperienced surgeons inserting the implants, implant insertion in the maxilla, implant insertion in the posterior region of the jaws, implants in heavy smokers, implant insertion in bone qualities type III and IV, implant insertion in places with small bone volumes, use of shorter length implants, greater number of implants placed per patient, lack of initial implant stability, use of cylindrical (non-threaded) implants and prosthetic rehabilitation with implant-supported overdentures. Moreover, it may be suggested that the following situations may be correlated with an increase in the implant failure rate: use of the non-submerged technique, immediate loading, implant insertion in fresh extraction sockets, smaller diameter implants. Some recently published studies suggest that modern, moderately rough implants may present with similar results irrespective if placed in maxillas, in smoking patients or using only short implants.

Role of primary stability for successful osseointegration of dental implants: Factors of influence and evaluation

A secure implant primary (mechanical) stability is positively associated with a successful implant integration and long-term successful clinical outcome. Therefore, it is essential to assess the initial stability at different time-points to ensure a successful osseointegration. The present study critically reviews the factors that may play a role in achieving a successful initial stability in dental implants. Databases were searched from 1983 up to and including October 2013 using different combinations of various keywords. Bone quality and quantity, implant geometry, and surgical technique adopted may significantly influence primary stability and overall success rate of dental implants.

Assessment of demographic and clinical data related to dental implants in a group of Turkish patients treated at a university clinic

PURPOSE

This retrospective study analyzed the distribution of the dental implants with regards to age and gender of the patients and type of indication for the implant therapy, as well as the location, dimension and type of the implants.

MATERIALS AND METHODS

The data of demographics (age and gender), type of indication for implant therapy, anatomical location, dimensions (length and diameter) and type (bone and tissue level) of 1616 implants were recorded from patient charts between January 2000 and January 2010. Descriptive statistics were analyzed using a chi-squared test for demographic parameters, type of indication, tooth position, anatomical location, implant dimensions and type (α=.05).

RESULTS

The patient pool comprised of 350 women and 266 men, with a mean age of 52.12 ± 13.79 years. The difference in n% of the implants of the age groups was statistically significant between the types of indications. The difference in the position of the implants was statistically significant between the n% of the implants of all age groups. Gender did not significantly vary, except that the diameter of the implants was significantly higher for the standard diameter implants in males. The difference between the implant positions was statistically significant when considered according to indication. The relationship between implant length and anatomical location was statistically significant.

CONCLUSION

The indication for dental implant use is age dependent and the type and size of the implant seems to be strongly related to the location of the implant.

The influence of implant diameter on its survival: a meta-analysis based on prospective clinical trials

BACKGROUND

The use of narrow-diameter implants has been proposed to restore small edentulous spans, thus avoiding extensive bone augmentation procedures and reducing the surgical complexity of implant rehabilitations. Although success rates of narrow-diameter implants have already been analyzed in the literature, to the best of the authors' knowledge, no meta-analysis based on prospective and randomized controlled trials has been performed. The aim of this study is to analyze the survival rates of narrow-diameter implants compared with standard or wide-diameter implants.

METHODS

An electronic search from three databases and a hand search in implant-related journals of studies published in English before September 1, 2012 were performed. Prospective human clinical studies with at least 10 implants and a follow-up period of 1 year were included in the meta-analysis. Implants were divided into two groups based on their diameters.

RESULTS

The initial search yielded 484 articles, of which 49 were evaluated in full text for eligibility. Finally, 16 studies were chosen and separated into two groups: 1) implants of diameter <3.3 mm (group 1) and 2) implants of diameter ≥3.3 mm (group 2). A meta-analysis performed for groups 1 and 2 showed survival rates of 75% and 87%, respectively.

CONCLUSIONS

This meta-analysis showed that narrower implants (<3.3 mm) had significantly lower survival rates compared with wider implants (≥3.3 mm). Other variables, such as type of prosthesis, implant surface, and timing of prosthetic loading, were found to have influenced the implant survival rates.

Radiographic Evaluation of Narrow-Diameter Implants After 5 Years of Clinical Function: A Retrospective Study

The use of regular-sized dental implants is generally recommended to ensure adequate bone to implant contact. However, when the width of the edentulous crest is insufficient for the placement of a regular-sized implant, the use of a narrow-diameter implant (NDI) should be considered to prevent the need for invasive reconstruction techniques such as grafting procedures. The aim of the present study was to evaluate the survival and marginal bone levels of NDIs 5 years after prosthetic loading. A total of 159 NDIs belonging to 4 brands (Straumann, Astra Tech, Biolok, Xive) were evaluated in 71 patients. Clinical and radiographic evaluations using digital panoramic radiography were carried out. Two implants failed and no progressive bone loss or periapical lesions were detected in the remaining 157 implants, which is an overall success rate of 98.74%. Mean marginal bone loss (MBL) was found 1 mm on the mesial side and 0.98 mm on the distal side of the implants. No statistically significant relationship was detected between patient age, gender, implant location, implant length, type of the prosthesis, and MBL (P &gt; .05). Among the 4 brands used, the MBL was highest around the Biolok implants but this was significant only compared with the Astra Tech implants (P &lt; .05). The results of the present study indicate that NDIs can be a good solution for specific clinical situations where regular-sized implants are not suitable.

Influence of the implant abutment types and the dynamic loading on initial screw loosening

PURPOSE

This study examined the effects of the abutment types and dynamic loading on the stability of implant prostheses with three types of implant abutments prepared using different fabrication methods by measuring removal torque both before and after dynamic loading.

MATERIALS AND METHODS

Three groups of abutments were produced using different types of fabrication methods; stock abutment, gold cast abutment, and CAD/CAM custom abutment. A customized jig was fabricated to apply the load at 30° to the long axis. The implant fixtures were fixed to the jig, and connected to the abutments with a 30 Ncm tightening torque. A sine curved dynamic load was applied for 10⁵ cycles between 25 and 250 N at 14 Hz. Removal torque before loading and after loading were evaluated. The SPSS was used for statistical analysis of the results. A Kruskal-Wallis test was performed to compare screw loosening between the abutment systems. A Wilcoxon signed-rank test was performed to compare screw loosening between before and after loading in each group (α=0.05).

RESULTS

Removal torque value before loading and after loading was the highest in stock abutment, which was then followed by gold cast abutment and CAD/CAM custom abutment, but there were no significant differences.

CONCLUSION

The abutment types did not have a significant influence on short term screw loosening. On the other hand, after 10⁵ cycles dynamic loading, CAD/CAM custom abutment affected the initial screw loosening, but stock abutment and gold cast abutment did not.

A multidisciplinary approach for the management of hypodontia: case report

Hypodontia is the congenital absence of one or more teeth and may affect permanent teeth. Several options are indicated to treat hypodontia, including the maintenance of primary teeth or space redistribution for restorative treatment with partial adhesive bridges, tooth transplantation, and implants. However, a multidisciplinary approach is the most important requirement for the ideal treatment of hypodontia. This paper describes a multidisciplinary treatment plan for congenitally missing permanent mandibular second premolars involving orthodontics, implantology and prosthodontic specialties.

Histological Evaluation of Peri-Implant Soft Tissues in Immediately Loaded Implants Featuring Different Implant-Abutment Connections: A Preliminary Study

The aim of the present study is to evaluate the peri-implant soft tissues and the amount of inflammatory cells around two different implant-abutment connections (self-locking conical connection with platform switching and screwed connection with standard abutment and internal anti-rotational system). Histological analysis was made of 14 implants, 7 with self-locking Morse tapered connection (experimental group A) and 7 with screw-retained anti-rotational connection (control group B). Sixty days after non-functional immediate loading, peri-implant tissue biopsies were performed. In the samples taken from the experimental group the peri-implant connective tissue consisted of a greater density of collagen and fibroblasts compared to the connective tissue of the control group. The experimental group specimens showed less inflammatory infiltrate close to the self-locking tapered connection compared to the tissues around the screw-retained connection. The SEM observations showed less microgap in the self-locking conical connection than in the screw connections with standard abutment and internal anti-rotational system. The presence of connective tissue with few inflammatory cells and the absence of inflammatory infiltrate, in self-locking conical connection implants is due to the minimal size of the implant-abutment microgap that does not allow the passage of fluids and bacteria from the oral cavity to the implant thus preventing tissue inflammation.

Small Diameter Implants: Specific Indications and Considerations for the Posterior Mandible: A Case Report

The field of implant dentistry continues to grow globally as clinicians embrace the evolution of various endosseous implant technologies and the array of enhanced surgical and prosthetic products. The utilization of small diameter implants in limited osseous regions increases patients' ability to choose implants as a viable restorative option. Although small diameter implants have been indicated in the incisor region for the maxilla and mandible primarily, their usage should be considered in select posterior regions. These 2 case reports demonstrate the incorporation of small diameter implants to replace missing mandibular posterior teeth.

Implant insertional torque values predict outcomes

PURPOSE

To study the relationships between insertional torque values (ITVs) recorded during implant placement and implant healing times and cumulative survival rates.

MATERIALS AND METHODS

This retrospective study evaluated 174 Osseotite 6.0-mm-diameter, straight-wall, threaded dental implants (BIOMET 3i, Palm Beach Gardens, FL) placed in 172 consecutive patients by the primary author. All implants were placed immediately into mandibular first or second molar extraction sockets after extraction. ITVs were recorded at placement. Implants were evaluated 3 months after surgery before discharge to restorative dentists for restoration. The post-restorative follow-up ranged from 2 years 1 month to 4 years 8 months (median and mean of 3 years 1 month [SD, 4.95]).

RESULTS

Of the implants, 3% (n = 5) were removed at the time of surgical placement because of perceived clinical mobility of the implants within the osteotomies. The implants that were stable at the time of implant placement (n = 169) were placed into 1 of 3 groups relative to the specific ITVs at implant placement: group 1, low ITV, 29% (n = 49); group 2, medium ITV, 23% (n = 39); and group 3, high ITV, 48% (n = 81). Cumulative survival rates for each group were 86% for low ITV, 90% for medium ITV, and 96% for high ITV (P = .0302). At the scheduled 3 months' follow-up visit, 33% of the low ITVs, 21% of the medium ITVs, and 5% of the high ITVs required an additional 3 months of healing.

CONCLUSION

In this study ITVs measured through surgical handpieces during implant placement provided meaningful real-time feedback that aided the surgeon regarding implant survival and determining unloaded healing times on a case-by-case basis.

Survival Rate of Immediately vs Delayed Loaded Implants: Analysis of the Current Literature

Immediate loading of oral implants has been reported as a beneficial treatment protocol in implant dentistry that increases the comfort of the patient. However, documentation in the literature is poor regarding the clinical outcome and the peri-implant bone response of immediately loaded implants compared with the conventional loading protocol placed in different bone qualities. The aim of this report was to present the role of bone quality in the survival rate of implants using conventional or immediate loading according to the literature. A literature search analysis was performed to demonstrate the survival rate of immediately loaded implants, as well as data from the histologic and histomorphometric evaluation in comparison with conventional loaded implants. This analysis showed high survival rates of immediately loaded implants along with osseointegration, with high percentages of bone-to-implant contacts based on histologic evaluation from human and animal studies of immediately and conventionally loaded implants. This study may provide histologic and clinical evidence of the immediate loading protocol for different bone qualities.

Variations in bone density at dental implant sites in different regions of the jawbone

The survival rate of dental implants is markedly influenced by the quality of the bone into which they are placed. The purpose of this study was to determine the trabecular bone density at potential dental implant sites in different regions of the Chinese jawbone using computed tomography (CT) images. One hundred and fifty-four potential implant sites (15 in the anterior mandible, 47 in the anterior maxilla, 55 in the posterior mandible, and 37 in the posterior maxilla) were selected from the jawbones of 62 humans. The data were subjected to statistical analysis to determine any correlation between bone density (in Hounsfield units, HU) and jawbone region using the Kruskal-Wallis test. The bone densities in the four regions decreased in the following order: anterior mandible (530 +/- 161 HU, mean +/- s.d.) approximately equal anterior maxilla (516 +/- 132 HU) > posterior mandible (359 +/- 150 HU) approximately equal posterior maxilla (332 +/- 136 HU). The CT data demonstrate that trabecular bone density varies markedly with potential implant site in the anterior and posterior regions of the maxilla and mandible. These findings may provide the clinician with guidelines for dental implant surgical procedures (i.e., to determine whether a one-stage or a two-stage protocol is required).

Osseotite implants inserted into fresh frozen bone grafts

BACKGROUND

In the last decade, several investigators have reported that double etched implants have achieved excellent results. However, no report regarding double etched implants inserted into fresh frozen bone is available.

AIMS

We planned to perform a retrospective study on double etched implants inserted into fresh frozen bone grafts.

SETTING AND DESIGN

28 patients (17 females and 11 males with a median age of 52 years) were operated on and 114 double etched implants inserted. Implant diameter and length ranged from 3.25 to 5.0 mm and from 10.0 to 15 mm, respectively. Implants were inserted to replace 14 incisors, 5 cuspids, 47 premolars and 48 molars.

RESULTS

Since only 4 out of 114 implants were lost (i.e. Survival Rate SVR = 96.5%) and no statistical differences were detected among the studied variables. The type of prosthetic restoration (i.e. fixed prostheses) correlated with a statistically significant lower delta Implant Abutment Junction (i.e. reduced crestal bone loss) and thus a better clinical outcome.

CONCLUSION

Double etched implants inserted into fresh frozen bone had a high survival and success rate similar to those reported in previous studies of two-stage procedures in non-grafted bone, although a higher marginal bone loss has to be expected when removable prosthetic restorations are used.

In vitro reaction of human osteoblasts on alumina-toughened zirconia

OBJECTIVES

Alumina toughening enhances the mechanical properties of zirconia ceramics but the biocompatibility of this material has rarely been addressed. In this study, we examined the osteoblast response to alumina-toughened zirconia (ATZ) with different surface topographies.

MATERIAL AND METHODS

Human osteoblasts isolated from maxillary biopsies of four patients were cultured and seeded onto disks of the following substrates: ATZ with a machined surface, airborne-particle abraded ATZ, airborne-particle abraded and acid etched ATZ. Airborne-particle abraded and acid etched titanium (SLA) and polystyrene disks served as a reference control. The surface topography of the various substrates was characterized by profilometry (R(a), R(p-v)) and scanning electron microscopy (SEM). Cell proliferation, cell-covered surface area, alkaline phophatase (ALP) and osteocalcin production were determined. The cell morphology was analyzed on SEM images.

RESULTS

The surface roughness of ATZ was increased by airborne-particle abrasion, but with the R(a) and R(p-v) values showing significantly lower values compared with SLA titanium (Mann-Whitney U-test P<0.05). The proliferation assay revealed no statistically significant differences between the ATZ substrates, SLA titanium and polystyrene (Kruskal-Wallis test, P>0.05). All substrates were densely covered by osteoblasts. ALP and osteocalcin production was similar on the examined surfaces. Cell morphology analysis revealed flat-spread osteoblasts with cellular extensions on all substrates.

CONCLUSIONS

These results indicate that ATZ may be a viable substrate for the growth and differentiation of human osteoblasts. Surface modification of ATZ by airborne-particle abrasion alone or in combination with acid etching seems not to interfere with the growth and differentiation of the osteoblasts.

The Procera Maryland Bridge: a case report

Although congenital partial hypodontia is widespread, and a variety of solutions for treating this condition in adolescents have been devised, all have had one or more significant drawbacks. A new treatment option that has recently become available, the Procera Maryland Bridge, appears to deliver excellent esthetics and strength. This article discusses that option and presents a case in which it was used successfully.

CLINICAL SIGNIFICANCE

Congenitally missing lateral incisors always present a treatment dilemma for restorative dentists. Numerous treatment options exist; none of which are totally satisfactory. This article presents a potential alternative for these patients using a novel all-ceramic Maryland Bridge.

Multivariate study of factors influencing primary dental implant stability

OBJECTIVES

The purpose was to determine by multivariate analysis in a large series of dental implants the variables associated with primary endosseous dental implant stability (DIS).

MATERIAL AND METHODS

A 10-year retrospective study was conducted of 1084 Brånemark implants placed in 316 patients. Clinical variables (age, gender, smoking habit, and periodontal status), implant diameter, implant length, and Periotest values (PTVs) were analyzed in bivariate and multivariate studies in order to determine their influence on DIS, using a cut-off PTV value of -2.

RESULTS

The site of implant insertion showed the strongest association with primary DIS failure among the study variables. Implants in the anterior mandible had a 6.43-fold lower risk of primary DIS risk vs. those at other sites [95% confidence interval (CI) 3.28-12.61], and implants in the maxillary had a 2.70-fold higher risk of primary DIS failure vs. those in the mandible (95% CI 1.82-4). Among other variables, females had a 1.54-fold higher risk of primary DIS failure vs. males (95% CI 1.88-2.22) and implants <15 mm in length had a 1.49-fold higher risk of failure vs. longer implants (95% CI 1.09-2.04).

CONCLUSION

According to these findings, primary DIS failure is more likely in females, at sites other than the anterior mandible, and with dental implants shorter than 15 mm, at least when non-threaded titanium implants are used. These data may be of value in the identification of patients at a high risk of primary DIS failure with immediate implant loading.

Oral rehabilitation using Camlog�screw?cylinder implants with a particle-blasted and acid-etched microstructured surface. Results from a prospective study with special consideration of short implants

OBJECTIVES

The purpose of the present clinical study was to report on the clinical performance of screw-cylinder implants with special consideration of the survival rate of short implants.

MATERIAL AND METHODS

In this prospective study with consecutive patient recruitment, Camlog screw-cylinder implants with a particle-blasted and acid-etched microstructured surface and a triple-cam tube-in-tube implant-abutment connection have been used only. Two groups of implants were evaluated: implants of 9 and 11 mm in length were considered short, those of 13 and 16 mm were considered long. Besides clinical and radiographic parameters, data of complications, patients' subjective evaluation of treatment outcome, general medical history and smoking habits were recorded.

RESULTS

Three hundred and thirty-three Camlog screw-cylinder implants were inserted in 133 patients. One hundred and twenty-nine patients were available for follow-up, representing 325 implants. The median observation period was 33 months (Q(25%) 26; Q(75%) 38). After a maximum observation period of 55 months, the Kaplan-Meier-survival analysis revealed no significant difference between the mean survival probabilities of 98.3% (n=59, patient-related) of short implants, and of 95.7% of long implants (n=70, patient-related) (P=0.162). No significant difference was found between implant survival rates considering maxilla (98.7%) and mandible (98.2%). A stratified analysis of short implants revealed a significant influence of premature cover screw exposures (P=0.02) and smoking (P=0.008) on implant survival. These influences were not found significant for long implants.

CONCLUSIONS

The prognosis of short Camlog implants is comparable with that of long implants. Therefore, their clinical use instead of performance of sophisticated vertical augmentation procedures before installation of long implants might be considered as alternative treatment option. In smokers, the use of short implants should be considered cautiously, however. The risk of premature cover screw exposure should be minimized.

Clinical and radiographic evaluation of small-diameter (3.3-mm) implants followed for 1-7 years: a longitudinal study

Implants with a small diameter may be used where bone width is reduced or in single-tooth gaps with limited mesiodistal space, such as for the replacement of lateral maxillary or mandibular incisors. The purpose of the present longitudinal study was to compare the prognosis of narrow implants (3.3-mm-diameter) to standard (4.1-mm-diameter) implants. Over a 7-year period, 122 narrow implants were inserted in 68 patients to support 45 partial fixed prostheses (PFD) and 23 single-tooth prostheses (ST). Furthermore, 120 patients received 208 standard implants and were restored with 70 PFD and 50 ST, respectively. Clinical and radiographic assessment data were provided. Six (1.8%) out of 330 implants failed. Cumulative survival and success rates were calculated with life-table analyses processed by collecting clinical and radiographic data. For narrow implants, the cumulative survival rate was 98.1% in the maxilla and 96.9% in the mandible. The cumulative success rate was 96.1% in the maxilla and 92% in the mandible. Conversely, standard-diameter implants showed a cumulative survival rate of 96.8% in the maxilla and 97.9% in the mandible. The cumulative success rate was 97.6% in the maxilla and 93.8% in the mandible. Cumulative survival and success rates of small-diameter implants and standard-diameter implants were not statistically different (P > 0.05). Type 4 bone was a determining failure factor, while marginal bone loss was not influenced by the different implant diameters. The results suggest that small-diameter implants can be successfully used in the treatment of partially edentulous patients.

Influence of cortical bone thickness and implant length on implant stability at the time of surgery--clinical, prospective, biomechanical, and imaging study

This clinical study is the first to quantitatively evaluate both regional bone structure by computed tomography preoperatively and dental implant stability by resonance frequency analysis at the time of surgery to explore the relation between local bone structure and dental implant stability in humans. Implant stability at the time of installation is often difficult to achieve in lower density bone and implant stability might influence treatment efficacy. Few clinical studies have reported detailed bone characteristics obtained using computed tomography prior to surgery and comprehensive implant stability measurements at the time of surgery. We hypothesized that thicker cortical bone would improve the stability of the dental implant at the time of placement. Before radiographic examination, diagnostic radiographic templates were made by incorporating radiopaque indicators. Computed tomography scans were obtained for 50 edentulous subjects prior to surgery. Preoperatively, the thickness of the cortical bone at the sites of implant insertion was measured digitally, and then implant insertion surgery was performed. A total of 225-implant stability measurements were made using a resonance frequency analyzer. There was a strong linear correlation between cortical bone thickness and resonance frequency (r = 0.84, P < 0.0001). The implant length had a weak negative correlation with stability (r = -0.25, P < 0.0005). These results suggest that the initial stability at the time of implant installation is influenced more by cortical bone thickness than by implant length. The cortical and cancellous ratio of local bone is extremely important for implant stability at the time of surgery and determining the local bone condition is critical for treatment success.