Brånemark implants and osteoporosis: a clinical exploratory study

Dental Implant Placement in Medically Compromised Patients: A Literature Review

As a discipline of dentistry, oral implantology deals with the diagnosis, design, insertion, restoration, and/or management of alloplastic or autogenous oral structures for the purpose of regaining contour, function, aesthetics, and speech in a partially or completely edentulous patient. The present review aims to provide the currently available knowledge about the impact of certain systemic disorders and the usage of some medications on the survival rate of dental implant therapy and to highlight the importance of patient management under these conditions. Diabetes, osteoporosis, cardiovascular diseases, and the intake of some medications can increase the risk of the failure of a dental implant. Even though there are relatively few medical contraindications to dental implant treatment, certain conditions may increase the risk of failure or complications.

Bone regeneration in implant dentistry: Which are the factors affecting the clinical outcome?

The key factors that are needed for bone regeneration to take place include cells (osteoprogenitor and immune-inflammatory cells), a scaffold (blood clot) that facilitates the deposition of the bone matrix, signaling molecules, blood supply, and mechanical stability. However, even when these principles are met, the overall amount of regenerated bone, its stability over time and the incidence of complications may significantly vary. This manuscript provides a critical review on the main local and systemic factors that may have an impact on bone regeneration, trying to focus, whenever possible, on bone regeneration simultaneous to implant placement to treat bone dehiscence/fenestration defects or for bone contouring. In the future, it is likely that bone tissue engineering will change our approach to bone regeneration in implant dentistry by replacing the current biomaterials with osteoinductive scaffolds combined with cells and mechanical/soluble factors and by employing immunomodulatory materials that can both modulate the immune response and control other bone regeneration processes such as osteogenesis, osteoclastogenesis, or inflammation. However, there are currently important knowledge gaps on the biology of osseous formation and on the factors that can influence it that require further investigation. It is recommended that future studies should combine traditional clinical and radiographic assessments with non-invasive imaging and with patient-reported outcome measures. We also envisage that the integration of multi-omics approaches will help uncover the mechanisms responsible for the variability in regenerative outcomes observed in clinical practice.

Osseointegration of Dental Implants in Patients with Congenital and Degenerative Bone Disorders: A Literature Review

Aims and Objectives

The aim of this study was to describe the mechanism of dental implants osseointegration in patients with congenital and degenerative genetic bone disorders.

Materials and Methods

A PubMed and Scopus documents search was carried out between November 2021 in the, using words such as "osseointegration," "degenerative disease," "congenital disease," and "dental implants."

Results

The thirteen articles selected dealt with dental implants osseointegration in patients with congenital and degenerative bone disorders. The influence and repercussion of these diseases on the bone system, as well as the osseointegration process were described from healing to bone remodeling. In addition, certain articles described some considerations to improve the osseointegration process in patients suffering from these types of conditions.

Conclusions

Within the limitations of this literature review we can conclude that osseointegration in patients with ectodermal dysplasia and osteoporosis could be achieved. However, the planning process for dental implant placement in these patients should be more meticulous and individualized considering the degree of tissue involvement as well as the patient's age and skeletal development compared to systemically healthy patients.

Influence of different surgical techniques on primary implant stability in the posterior maxilla: a randomized controlled clinical trial

BACKGROUND AND OBJECTIVE

Primary stability (PS) is remarkable for secondary stability and implant success. Surgical technique modifications seem to improve primary stability, especially in poor quality bone. The aim of this study was to compare the insertion torque (IT) and implant stability quotients (ISQ) of implants placed with underpreparation, expanders, and standard surgical instrumentation in different bone types.

MATERIAL AND METHODS

This randomized controlled clinical trial enrolled 108 patients (n=108 implants) distributed in three study groups: group 1 (n=36) underpreparation technique, group 2 (n=36) expander technique, and group 3 (n=36) conventional drilling. IT was recorded with a torque indicator. ISQ was recorded with resonance frequency analysis immediately after surgery.

RESULTS

ISQ values were associated with the patient's bone quality and were higher in bone quality type II (76.65) and type III (73.60) and lower in bone quality type IV (67.34), with statistically significant differences (p<0.0001). Lower stability results were obtained when conventional drilling (69.31) was used compared to the use of underpreparation (74.29) or expanders (73.99) with a level of significance of p=0.008 and p=0.005, respectively.

CONCLUSIONS

The surgical technique influences the PS when there is low-quality bone. In low-quality bones, conventional drilling obtains lower ISQ values.

CLINICAL RELEVANCE

Replace the conventional drilling technique for an alternative, underpreparation or expanders, in low-quality bone in order to achieve greater primary stability.

Investigation to Predict Primary Implant Stability Using Frictional Resistance Torque of Tap Drilling

Objectives

The purpose of this experimental study was to investigate the correlation between the frictional resistance torque of tap drilling prior to implant placement and the primary stability after implant placement.

Material and Methods

Solid rigid polyurethane bone blocks of four different densities were used in this study. A computerized surgical implant motor device was utilized to measure the frictional resistance torque of tap drilling. After the tap torque was measured, the dental implants were inserted at the prepared sites. During the implantation, the insertion torque was recorded, and resonance frequency analysis was performed, the value of which was calculated as the implant stability quotient. Thereafter, the correlation between the tap torque and the primary stability of the implant was evaluated and compared with the standard drilling protocol.

Results

A significant positive correlation was found between the tap torque and insertion torque (Pearson's r = 0.88, P < 0.0001). Similarly, there was a positive correlation between the tap torque and implant stability quotient (Pearson's r = 0.69, P < 0.0001).

Conclusions

These results suggest that measurement of the frictional resistance torque of tap drilling prior to implant placement could provide helpful information for implant primary stability.

Quality of Life in Menopausal Women with Dental Restorations and Implants

Aim:

This multicenter study examined the relationship, possible interactions, and intermittent effects that dental implants and prostheses can have on menopausal women’s quality of life as well as provided information regarding the possible side effects of therapeutic regimens on menopause and osteoporosis or osteopenia.

Materials and Methods:

Questionnaires consisted of selected quality of life questions based on specific and additional medical and dental (mainly prosthodontic) questions, which were administered to 100 Greek menopausal/post-menopausal women (Age: Mean Value=63,62 years old) with osteopenia or with or without osteoporosis, with dental implants and implant restorations, or conventional prosthetic restorations visiting two University Hospitals. Menopausal/post-menopausal status was judged on the basis of either secondary, definitive amenorrhoea or based on follicular stimulation hormone ​​(FSH) values, estradiol, and clinical risk factors.

Results:

Participants had a statistically significantly better “functional” and “psychological” feeling after prosthodontic rehabilitation with and without implants. Three out of four reported that their dentist informed them of the possible implant problems that might arise from osteoporosis and its treatment (medications). Moreover, osteopenia was found to be associated with a very lower problem percentage. The bisphosphonate treatment had the highest rate (80%) of reported implant problems than non-bisphosphonate treatment (30%). The hormone replacement therapy (HRT) for menopause was reported to be more associated with problems in implant placement (19%) than in those without treatment (27.3%).

Conclusion:

The questionnaires revealed a significant improvement concerning women’s life quality and well-documented information about the problems their dental implants and restorations may cause in association with menopause and/or osteoporosis.

Does Low-Magnitude High-Frequency Vibration (LMHFV) Worth for Clinical Trial on Dental Implant? A Systematic Review and Meta-Analysis on Animal Studies

Being as a non-pharmacological medical intervention, low-magnitude high-frequency vibration (LMHFV) has shown a positive effect on bone induction and remodeling for various muscle diseases in animal studies, among which dental implants osteointegration were reported to be improved as well. However, whether LMHFV can be clinically used in dental implant is still unknown. In this study, efficacy, parameters and side effects of LMHFV were analyzed via data before 15th July 2020, collecting from MEDLINE/PubMed, Embase, Ovid and Cochrane Library databases. In the screened 1,742 abstracts and 45 articles, 15 animal studies involving 972 implants were included. SYRCLE's tool was performed to assess the possible risk of bias for each study. The GRADE approach was applied to evaluate the quality of evidence. Random effects meta-analysis detected statistically significant in total BIC (P < 0.0001) and BV/TV (P = 0.001) upon loading LMHFV on implants. To conclude, LMHFV played an active role on BIC and BV/TV data according to the GRADE analysis results (medium and low quality of evidence). This might illustrate LMHFV to be a worthy way in improving osseointegration clinically, especially for osteoporosis.

Systematic Review Registration:https://www.crd.york.ac.uk/PROSPERO, identifier: NCT02612389

An In Vitro Evaluation of Primary Stability Values for Two Differently Designed Implants to Suit Immediate Loading in Very Soft Bone

The achievement of sufficient implant stability in poor quality bone seems to be a challenge. Most manufacturers develop special dental implants, which are claimed to show higher stability even in very soft bone. The aim of this experimental study was to compare two recently introduced dental implants with differing thread designs. A total of 11 implants of each group were inserted in the part of the fresh bovine ribs, corresponding to very soft bone. The primary stability was measured with resonance frequency analysis (RFA) and Periotest; the average of two measurements for each method and for each implant was taken and statistical analysis was applied. The highest stability values were obtained with the ICX Active Master implants, followed by the Conelog^® Progressive-Line implants placed with the very soft bone protocol. The primary stability values of the Conelog^® Progressive-Line implants inserted by the very soft bone protocol and the ICX Active Master implants placed with the standard protocol showed sufficient stability for immediate loading in low-density bone. Within the limitations of this study, the thread design of the implants and underdimensioned implant bed preparation seem to be effective for better primary stability in cancellous bone.

Long-Term Efficacy of Variable-Thread Tapered Implants-A Retrospective, Clinical and Radiological Evaluation

Background and Objective: There is multifaceted evidence that variable-thread tapered implants (VTTIs) offer high primary stability but few regarding the long-term success. This retrospective clinical and radiological cohort study assessed the long-term outcome of VTTIs. Material and Methods: All patients treated in an OMFS practice with NobelActive Internal^® VTTI between October 2007 and September 2011 were invited for clinical examination. The outcome variables were (i) survival rate, (ii) implant success according to the “Health Scale for Dental Implants” and (iii) prevalence of peri-implantitis. Furthermore, the effect of local and systemic risk factors was investigated. Results: In 81 subjects (46 females and 35 males, mean age 65.6 years) 270 implants (157 VTTIs and 113 others as a control group) were analyzed. In 7 out of 81 patients (8.6%), 8 out of 157 VTTIs (5.1%) and 5 out of 113 other implants (4.4%) were lost. Peri-implantitis, defined as (i) presence of bleeding on gentle probing (0.25 N) or exudation and (ii) radiographic bone loss exceeding 0.5 mm since implant insertion to last follow-up, was the most common reason for implant loss (11 out of 13, 84.6%). Sixty-six out of 87 VTTIs (75.9%) were successful. Seventeen out of 42 patients (40.5%) developed peri-implantitis on 29 out of 79 VTTI sites (36.7%). Plaque and missing keratinized peri-implant mucosa were identified as potential risk factors for the development of peri-implantitis. Conclusion: Variable-thread tapered implants showed good long-term results, even in low bone quality. Peri-implantitis was the most common reason for implant failure and may be connected to certain risk factors.

Primary stability and healing outcomes of apically tapered and straight implants placed into fresh extraction sockets. A pre-clinical in vivo study

OBJECTIVES

To compare the stability of apically tapered and straight (non-tapered cylindrical) implants at the time of immediate placement and to histologically evaluate the healing outcomes after 6 weeks.

MATERIALS AND METHODS

The second maxillary incisors were extracted bilaterally in nine dogs. After randomization, apically tapered and straight implants with a 3.3 mm shoulder diameter were inserted into the extraction sockets. The implant stability quotient (ISQ) of the implants was recorded after placement. Peri-implant defects on the buccal aspect were filled with deproteinized bovine bone mineral and covered with resorbable type I/III porcine collagen matrix. After 6 weeks of healing, sections were prepared for histological and morphometric analysis.

RESULTS

All implant sites healed uneventfully. The apically tapered implants had significantly higher ISQ values compared to straight implants at placement (p = .009). The histomorphometric outcomes 6 weeks following implant placement in both experimental groups were similar, except in the apico-palatal region. Apically tapered implants demonstrated significantly less percentage bone-to-implant contact (p = .035) in the apico-palatal region. At both implant types, substantial corono-apical resorption of the buccal bone wall was noted in the coronal 2 mm of the implant.

CONCLUSION

Apically tapered implants had significantly higher ISQ values at immediate placement compared to straight implants. The healing outcomes and remodelling of the buccal bone wall were similar for both implant designs. In the apico-palatal region, there was less %BIC at the implant surface at apically tapered implants compared to straight implants.

Combined effect of undersized surgical technique and axial compression on the primary implant stability and host bone architecture

Aim

The aim of this study was to investigate the combined effect of the lateral-compression of host-bone (undersized-osteotomy-preparation) and axial-compression of host-bone (not drilling the full length of the implant) on the primary-implant-stability and the host-bone-architecture.

Materials and Methods

In this experimental-study, 44 dental implants (diameter-4.2 mm; length-10 mm; Dyna®) were installed in the femoral-condyles of four cadaver-goats using four different surgical approaches (11 implant/surgical approach; n = 11). Approach-1: Standard preparation according to the manufacturer's guidelines. The bone-cavity was prepared up to 10 mm in depth and 4 mm in diameter. Approach-2: Preparation up to 8 mm in depth and 4 mm in diameter. Approach-3: Preparation up to 10 mm in depth. Approach-4: The bone-cavity was prepared up to 8 mm in depth and 3.6 mm in diameter. Insertion torque (n = 11), removal torque (n = 7) and % bone-implant contact (n = 4) measurements were recorded. Bone architecture was assessed by micro-computer tomography and histological analysis (n = 4).

Results

For approaches 2, 3, and 4 (P < .05), insertion-torque values were significantly higher as compared to approach 1. Regarding the bone-implant-contact percentage (%BIC), approach 3 and 4 were significantly higher compared to approach 1 and 2 (P<.05). For approach 2, the %bone volume (%BV) was significantly higher as compared to approach 1 (P<.05) for the most the inner zone of host bone in proximity of the implant.

Conclusion

Lateral and axial compression improved the primary-implant-stability and therefore this new surgical-technique should be considered as an alternative approach especially for placing implants in low-density bone. Nevertheless, additional in vivo studies should be performed.

Influence of different implant placement techniques to improve primary implant stability in low-density bone: A systematic review

Aim:

The aim of this study is to assess the influence of different implant placement techniques to improve primary implant stability (PIS) in the low-density bone.

Materials and Methods:

Citations published in English and those available in full text were searched from electronic databases (PubMed and Google Scholar) from the year 2000–2017 by which 75 manuscripts were revealed. After applying inclusion and exclusion criteria, seven were selected for the present review. The whole process was conducted by the following preferred reporting items for systematic reviews and meta-analyses guidelines.

Results:

The measurement of primary stability showed significant correlations with different bone densities and with implant outcome; however, these two parameters have not been investigated at the same time frequently. Of the seven manuscripts, three discussed standard drilling protocol, two used undersized drilling, one used guided drilling, and one compared standard drilling with undersized drilling. Several intraoperative methods of jaw bone-density assessment were reported, and resonance frequency analysis, periotest, and insertion torque values were used to quantify PIS.

Conclusion:

The use of undersized drilling has proven advantageous for increasing initial implant stability in the low-density bone. Although the PIS may be lower, the secondary implant stability is found to be correlated to acceptable values.

Can Osseointegration Be Achieved Without Primary Stability?

The osseointegration and survival of dental implants are linked to primary stability. Good primary stability relies on the mechanical friction between implant surface and surrounding bone with absence of mobility in the osteotomy site immediately after implant placement. Several factors have been found to affect implant primary stability, including bone density, implant design, and surgical technique. Various methods have been used to assess implant primary stability including insertion torque and resonance frequency analysis. This article aims to evaluate the success of osseointegration in the absence of primary stability and to propose recommendations to manage implants that lack primary stability.

The effect of undersizing and tapping on bone to implant contact and implant primary stability: A histomorphometric study on bovine ribs

PURPOSE

Implant site preparation may be adjusted to achieve the maximum possible primary stability. The aim of this investigation was to study the relation among bone-to-implant contact at insertion, bone density, and implant primary stability intra-operatively measured by a torque-measuring implant motor, when implant sites were undersized or tapped.

MATERIALS AND METHODS

Undersized (n=14), standard (n=13), and tapped (n=13) implant sites were prepared on 9 segments of bovine ribs. After measuring bone density using the implant motor, 40 implants were placed, and their primary stability assessed by measuring the integral of the torque-depth insertion curve. Bovine ribs were then processed histologically, the bone-to-implant contact measured and statistically correlated to bone density and the integral.

RESULTS

Bone-to-implant contact and the integral of the torque-depth curve were significantly greater for undersized sites than tapped sites. Moreover, a correlation between bone to implant contact, the integral and bone density was found under all preparation conditions. The slope of the bone-to-implant/density and integral/density lines was significantly greater for undersized sites, while those corresponding to standard prepared and tapped sites did not differ significantly.

CONCLUSION

The integral of the torque-depth curve provided reliable information about bone-to-implant contact and primary implant stability even in tapped or undersized sites. The linear relations found among the parameters suggests a connection between extent and modality of undersizing and the corresponding increase of the integral and, consequently, of primary stability. These results might help the physician determine the extent of undersizing needed to achieve the proper implant primary stability, according to the planned loading protocol.

A stepwise under-prepared osteotomy technique improves primary stability in shallow-placed implants: a preliminary study for simultaneous vertical ridge augmentation

Simultaneous vertical ridge augmentation (VRA) can reduce treatment procedures and surgery time, but the concomitant reduction in primary stability (PS) of a shallow-placed implant imparts risk to its prognosis. Although several studies have reported improvements in PS, there is little information from any simultaneous VRA model. This study aimed to evaluate whether tapered implants with stepwise under-prepared osteotomy could improve the PS of shallow-placed implants in an in vitro model of simultaneous VRA. Tapered implants (Straumann^® Bone Level Tapered implant; BLT) and hybrid implants (Straumann^® Bone Level implant; BL) were investigated in this study. A total of 80 osteotomies of different depths (4, 6, 8, 10 mm) were created in rigid polyurethane foam blocks, and each BLT and BL was inserted by either standard (BLT-S, BL-S) or a stepwise under-prepared (BLT-U, BL-U) osteotomy protocol. The PS was evaluated by measuring maximum insertion torque (IT), implant stability quotient (ISQ), and removal torque (RT). The significance level was set at P < 0.05. There were no significant differences in IT, ISQ or RT when comparing BLT-S and BL-S or BLT-U and BL-U at placement depths of 6 and 8 mm. When comparison was made between osteotomy protocols, IT was significantly greater in BLT-U than in BLT-S at all placement depths. A stepwise under-prepared osteotomy protocol improves initial stability of a tapered implant even in a shallow-placed implant model. BLT-U could be a useful protocol for simultaneous VRA.

Dental implants in patients with osteoporosis: a systematic review with meta-analysis

There is currently no consensus regarding the survival rate of osseointegrated implants in patients with osteoporosis. A systematic review with meta-analysis was performed to evaluate the survival rate of implants in such patients. The PubMed/MEDLINE, Web of Science, Cochrane Library, and SciELO databases were used to identify articles published up to September 2016. The systematic review was performed in accordance with PRISMA/PICO requirements and the risk of bias was assessed (Australian National Health and Medical Research Council scale). The relative risk (RR) of implant failure and mean marginal bone loss were analyzed within a 95% confidence interval (CI). Fifteen studies involving 8859 patients and 29,798 implants were included. The main outcome of the meta-analysis indicated that there was no difference in implant survival rate between patients with and without osteoporosis, either at the implant level (RR 1.39, 95% CI 0.93-2.08; P=0.11) or at the patient level (RR 0.98, 95% CI 0.50-1.89; P=0.94). However, the meta-analysis for the secondary outcome revealed a significant difference in marginal bone loss around implants between patients with and without osteoporosis (0.18mm, 95% CI 0.05-0.30, P=0.005). Data heterogeneity was low. An increase in peri-implant bone loss was observed in the osteoporosis group. Randomized and controlled clinical studies should be conducted to analyze possible biases.

The effects of implant topography on osseointegration under estrogen deficiency induced osteoporotic conditions: Histomorphometric, transcriptional and ultrastructural analysis

Compromised bone quality and/or healing in osteoporosis are recognised risk factors for impaired dental implant osseointegration. This study examined the effects of (1) experimentally induced osteoporosis on titanium implant osseointegration and (2) the effect of modified implant surface topography on osseointegration under osteoporosis-like conditions. Machined and micro-roughened surface implants were placed into the maxillary first molar root socket of 64 ovariectomised and sham-operated Sprague-Dawley rats. Subsequent histological and SEM observations showed tissue maturation on the micro-rough surfaced implants in ovariectomised animals as early as 3days post-implantation. The degree of osseointegration was also significantly higher around the micro-rough implants in ovariectomised animals after 14days of healing although by day 28, similar levels of osseointegration were found for all test groups. The micro-rough implants significantly increased the early (day 3) gene expression of alkaline phosphatase, osteocalcin, receptor activator of nuclear factor kappa-B ligand and dentin matrix protein 1 in implant adherent cells. By day 7, the expression of inflammatory genes decreased while the expression of the osteogenic markers increased further although there were few statistically significant differences between the micro-rough and machined surfaces. Osteocyte morphology was also affected by estrogen deficiency with the size of the cells being reduced in trabecular bone. In conclusion, estrogen deficiency induced osteoporotic conditions negatively influenced the early osseointegration of machined implants while micro-rough implants compensated for these deleterious effects by enhancing osteogenic cell differentiation on the implant surface.

STATEMENT OF SIGNIFICANCE

Lower bone density, poor bone quality and osseous microstructural changes are all features characteristic of osteoporosis that may impair the osseointegration of dental implants. Using a clinically relevant trabecular bone model in the rat maxilla, we demonstrated histologically that the negative effects of surgically-induced osteoporosis on osseointegration could be ameliorated by the biomaterial's surface topography. Furthermore, gene expression analysis suggests this may be a result of enhanced osteogenic cell differentiation on the implant surface.

Effects on primary stability of three different techniques for implant site preparation in synthetic bone models of different densities

Preparation of implant sites affect the primary stability of implants that is necessary for osseointegration. We have investigated the effect on the primary stability of implants of three techniques used to prepare the site for implants in synthetic bone models of different densities. A total of 540 implants of varying diameters (3.3 (narrow), 4.1 (standard), and 4.8 (wide) mm) and lengths (8 or 12mm) were inserted into three artificial bone blocks (the density of which decreased from D2, D3, to D4), and we compared conventional, fully-guided, and condensing preparation of the site. After insertion, primary stability was measured using resonance frequency analysis. There were significant differences between conventional and condensing procedures (p <0.0001 in all cases) and between fully-guided and condensing procedures (p<0.01 in all cases), but there were no differences between fully-guided and conventional procedures when short implants were used, with a standard or wide diameter in low-density bone blocks (D3 and D4). In low-density bone blocks (D3 and D4) wide implants (4.8mm) compared with narrow (3.3mm) resulted in significantly better primary stability (p<0.0001 in all cases). Fully-guided preparation of the implant site is associated with increased primary stability, but is not an alternative to bone condensing. Use of longer or wider implants can increase primary stability, but the effect is less pronounced after bone condensing.

Alveolar bone loss in osteoporosis: a loaded and cellular affair?

Maxillary and mandibular bone mirror skeletal bone conditions. Bone remodeling happens at endosteal surfaces where the osteoclasts and osteoblasts are situated. More surfaces means more cells and remodeling. The bone turnover rate in the mandibular alveolar process is probably the fastest in the body; thus, the first signs of osteoporosis may be revealed here. Hormones, osteoporosis, and aging influence the alveolar process and the skeletal bones similarly, but differences in loading between loaded, half-loaded, and unloaded bones are important to consider. Bone mass is redistributed from one location to another where strength is needed. A sparse trabeculation in the mandibular premolar region (large intertrabecular spaces and thin trabeculae) is a reliable sign of osteopenia and a high skeletal fracture risk. Having dense trabeculation (small intertrabecular spaces and well-mineralized trabeculae) is generally advantageous to the individual because of the low fracture risk, but may imply some problems for the clinician.

Bone stability around implants in elderly patients with reduced bone mineral density - a prospective study on mandibular overdentures

OBJECTIVE

The purpose of this prospective clinical study was to determine whether reduced bone mineral density (BMD) is correlated with a higher risk for dental implant therapy in an elderly patient population.

MATERIAL AND METHODS

Seventy-nine patients recruited at the Prince Philip Dental Hospital were provided with 2-implant-supported mandibular overdentures. Skeletal BMD was recorded before the implant therapy. The World Health Organization Osteoporosis Diagnosis Classification (femoral neck score) was utilized to define the osteoporosis status of patients. Periapical radiographs were taken with a special radiographic holder at the time of implant loading (baseline) and at follow-up examinations. The mesial and distal marginal bone levels of each implant were measured. The mean marginal bone loss (mMBL) and greatest marginal bone loss (GBL) of four implant sites at patient level were recorded for data analysis. Clinical examination including plaque score (PI) and bleeding on probing (BOP) was recorded.

RESULTS

Of the 79 patients recruited in the study, the survival rate of implant was 98.7%. Sixty-three patients (79.7%) were finally available for data collection and statistical analyses. The mean follow-up time was 62.9 (SD = 15.2) months with the mean MBL 0.65 mm (SD = 0.67) and mean GBL 1.25 mm (SD = 0.83), respectively. The average BOP and PI of patients were 49.6% (SD = 30.8) and 47.4% (SD = 37.4). Only BOP was found significantly correlated with mMBL (r = 0.321, P = 0.01). Skeletal BMD was not associated with marginal bone loss (mean MBL: r = -0.094, P = 0.466; mean GBL: r = 0.04, P = 0.761).

CONCLUSIONS

Within the limits of this study, osteoporosis was not a contraindication for implant therapy, and reduced skeletal BMD was not associated with increased marginal bone loss around implants or other complications in an elderly population.

Improved Bone Micro Architecture Healing Time after Implant Surgery in an Ovariectomized Rat

The present animal study investigated whether oral intake of synthetic bone mineral (SBM) improves peri-implant bone formation and bone micro architecture (BMA). SBM was used as an intervention experimental diet and AIN-93M was used as a control. The SBM was prepared by mixing dicalcium phosphate dihydrate (CaHPO4·2H2O) and magnesium and zinc chlorides (MgCl2 and ZnCl2, respectively), and hydrolyzed in double-distilled water containing dissolved potassium carbonate and sodium fluoride. All rats were randomly allocated into one of two groups: a control group was fed without SBM (n = 18) or an experimental group was fed with SBM (n = 18), at seven weeks old. At 9 weeks old, all rats underwent implant surgery on their femurs under general anesthesia. The implant was inserted into the insertion socket prepared at rats' femur to a depth of 2.5 mm by using a drill at 500 rpm. Nine rats in each group were randomly selected and euthanized at 2 weeks after implantation. The remaining nine rats in each group continued their diets, and were euthanized in the same manner at 4 weeks after implantation. The femur, including the implant, was removed from the body and implant was pulled out by an Instron universal testing machine. After the implant removal, BMA was evaluated by bone surface ratio (BS/BV), bone volume fraction (BV/TV), trabecular thickness (TbTh), trabecular number (TbN), trabecular star volume (Vtr), and micro-CT images. BS/BV, BV/TV, TbTh and Vtr were significantly greater in the rats were fed with SBM than those were fed without SBM at 2 and 4 weeks after implantation (P < 0.05). The present results revealed that SBM improves the peri-implant formation and BMA, prominent with trabecular bone structure. The effect of SBM to improve secondary stability of the implant, and shortening the treatment period should be investigated in the future study.

Low Skeletal Bone Mineral Density Does Not Affect Dental Implants

The aim of this case-control study (n = 30) was to evaluate the effects of osteoporosis/osteopenia on the success of dental implants. Twenty healthy females ages 50–80 with confirmed osteoporosis or osteopenia, and 10 age- and gender-matched subjects with normal bone density (controls) received dental implants. Dual-energy X-ray absorptiometry (DXA) scans at 5 standard sites (total body, hip, spine [lateral and anterior-posterior] and radius) were measured at baseline and 24 months. Periapical and panoramic radiographs were taken at baseline before implant placement; 1 periapical radiograph was taken immediately after placement of the dental implant. Since implants are standard sizes, periapical bone loss was measured from the first implant thread to the level of alveolar bone at baseline, 12 months, and 24 months via 1 periapical radiograph. All subjects received implants of the same manufacturer (NobelBiocare). One subject was a smoker. Three subjects with osteoporosis had received prior treatment with Fosamax, 1 received Fortical, and 1 Forteo. In all 3, there was slight improvement in DXA after 24 months. All implants remained successful with no evidence of bone loss after 24 months. These investigators conclude that implants placed in individuals with confirmed skeletal osteoporosis can be successful, with no clinical differences to implants placed in healthy individuals. Although 3 subjects with osteoporosis had treatment with oral bisphosphonates, no side effects were noted and no bone necrosis of the jaw was observed. Further investigation with larger sample sizes and longer periods of time for treatment with oral bisphosphonates is recommended to confirm these results.

Immediate Implant Placement in a Patient With Osteoporosis Undergoing Bisphosphonate Therapy: 1-Year Preliminary Prospective Study

The purposes of this preliminary study are to assess the risk of developing bisphosphonate-related osteonecrosis of the jaw (BRONJ) in a patient with osteoporosis using zoledronic acid and to report the results of a 1-year prospective clinical study regarding 5 immediately inserted implants in the anterior mandible. For this comparative prospective study, 24 female patients, aged ≥54 years, were chosen, all with partially edentulous mandibles. Group A consisted of 12 patients with osteoporosis taking zoledronic acid receiving a once-yearly intravenous infusion of zoledronic acid (5 mg). Control group B consisted of 12 other patients without osteoporosis and not taking drugs. In both groups, the remaining teeth were extracted before 120 implants, 3.7-mm wide and 16-mm long, were immediately installed in the interforaminal region of the mandibles. The 1-year implant survival rate was 100%. No apparent necrotic bone was observed among patients receiving zoledronic acid (group A) after implant surgery. Immediate implant osseointegration can be successful in a patient with osteoporosis using bisphosphonates, suggesting the safety of implantology as a treatment modality.

Five-year alveolar bone level changes in women of varying skeletal bone mineral density and bone trabeculation

OBJECTIVES

To investigate alveolar bone level changes in women with varying skeletal bone mineral density (BMD) and bone trabeculation.

STUDY DESIGN

In a prospective, longitudinal study of 128 women (22-75 years of age), BMD (dual x-ray absorptiometry), and periapical radiography were performed in 1996 and 2001. The mandibular trabecular bone was assessed as dense, mixed, or sparse. Mandibular alveolar bone level was measured with a Schei ruler and related to BMD (osteoporotic, osteopenic, or normal) and trabeculation.

RESULTS

After 5 years, the total bone level score was significantly decreased (P = .001). No significant differences were found in the total bone level scores between the different BMD groups. The greatest decreased total bone level score in 1996 was found in the group with dense trabeculation (0.71 in the dense group vs. 0.31 in the nondense group, P = .005), and similarly in 2001 (0.75 in the dense group vs. 0.39 in the nondense group, P = .020). Five-year changes in the total bone level scores did not differ between trabeculation groups (P = .37).

CONCLUSIONS

The small group of women with dense mandibular trabecular bone seems to suffer a greater decrease in alveolar bone height compared with other women, including women with osteoporosis.

Does HIV infection have an impact upon dental implant osseointegration? A systematic review

OBJECTIVE

A systematic review is made to determine whether human immunodeficiency virus (HIV) infection has an impact upon dental implant osseointegration.

STUDY DESIGN

A PubMed (MEDLINE) literature search was made of articles published up until 14 April 2014. The systematic review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA). The quality of the studies included in the review was assessed using the Methodological Index for Nonrandomized Studies (MINORS) and levels of evidence (based on the University of Oxford's Center for Evidence Based Medicine criteria).

RESULTS

The combinations of search terms resulted in a list of 132 titles. Nine studies finally met the inclusion criteria and were selected for inclusion in the systematic review. A total of 173 dental implants were placed in 80 patients (135 implants in 56 HIV-positive subjects and 38 implants in 24 HIV-negative patients), and a single loss of dental implant osseointegration was recorded in an HIV-positive patient.

CONCLUSIONS

Our results suggest that dental implant placement in HIV-positive patients does not increase the dental implant failure rate. Prophylactic antibiotic treatment, the administration of highly active antiretroviral therapy, and control of the CD4+ T lymphocyte counts appear to be the main influencing factors in this respect. Given the few studies included in our systematic review, further prospective studies involving larger sample sizes and longer durations of follow-up are required in order to confirm the results obtained.

Osteoporosis and bisphosphonate-related osteonecrosis in a dental school implant patient population

PURPOSE

Studies have demonstrated an inconsistent association between implant failure and bone mineral density. The prevalence of osteoporosis in US adults has been reported to range from 5% to 10% in women and from 2% to 4% in men. The prevalence of bisphosphonate (BP)-related osteonecrosis of the jaw (BRONJ) has been reported to range from 0% to 4.3% of patients taking oral BPs. The purpose of this study was to calculate the risk of dental implant loss and the incidence of BRONJ in patients with osteoporosis at the University of Kentucky College of Dentistry (UKCD).

MATERIALS AND METHODS

This study analyzed data collected from patients who had implants placed between 2000 and 2004 at UKCD. Data were gathered from patient interviews regarding implant survival and patient-satisfaction parameters, and interviews were conducted either chairside at a scheduled maintenance appointment or by telephone interview.

RESULTS

Among 203 patients who received 515 implants, the prevalence of osteoporosis was 23.3% for women and 1.2% for men. None of the 20 patients who reported a history of oral BP use exhibited BRONJ, and there were no implant failures in patients with a history of osteoporosis.

CONCLUSIONS

In this study, osteoporosis conferred no risk of implant failure, and oral BP therapy was not associated with BRONJ.

High-frequency loading positively impacts titanium implant osseointegration in impaired bone

High-frequency loading via whole body vibration promotes bone formation and increases bone strength. Whether this translates to positive titanium implant osseointegration in osteoporotic bone was explored in this animal study. An anabolic effect of not only bisphosphonate treatment but also high-frequency loading on implant osseointegration in osteoporotic bone was observed.

INTRODUCTION

The present study investigated the impact of high-frequency (HF) loading, applied via whole body vibration (WBV), on titanium implant osseointegration in healthy versus ovariectomy-induced compromised versus pharmacologically treated compromised bone.

METHODS

A custom-made Ti implant was inserted into the metaphyseal tibia of 59 rats and left to heal for either 4 or 14 days. Rats were divided into six groups according to their hormonal and mechanical status. WBV, consisting of 10 consecutive frequency steps at an acceleration of 0.3 g, was applied daily for either 4 or 14 days. Tissue samples were processed for quantitative histology at the tibial cortical and medullar level. Data were analyzed by three-way ANOVA and by post hoc pairwise comparisons.

RESULTS

The bone healing response at the interface and surrounding titanium implants was negatively influenced by osteoporotic bone conditions, mainly at the trabecular bone level. Furthermore, the administration of bisphosphonates for preventing the ovariectomy-induced impaired peri-implant response was successful. Finally, the effect of HF WBV loading on the peri-implant bone healing was dependent on the bone condition and was anabolic solely in untreated osteoporotic trabecular bone when applied for an extended period of time.

CONCLUSIONS

The bone healing response to implant installation is compromised in osteoporotic bone conditions, in particular at the trabecular bone compartment. Meanwhile, not only pharmacological treatment but also mechanical loading via HF WBV can exert a positive effect on implant osseointegration in this specific bone micro-environment. The peri-implant cortical bone, however, seems to be less sensitive to HF WBV loading influences.

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.

Dental implants in the medically compromised patient

OBJECTIVE

It has been suggested that some local and systemic factors could be contraindications to dental implant treatment. The objective of this paper was to evaluate whether success and survival rates of dental implants are reduced in the medically compromised patient.

DATA/SOURCES

An extensive literature search was conducted using PubMed/Medline, Scopus, Scirus and Cochrane databases up to November 8, 2012.

CONCLUSIONS

There are very few absolute medical contraindications to dental implant treatment, although a number of conditions may increase the risk of treatment failure or complications. The degree of systemic disease-control may be far more important that the nature of the disorder itself, and individualized medical control should be established prior to implant therapy, since in many of these patients the quality of life and functional benefits from dental implants may outweigh any risks.

Identification of the risk for osteoporosis in dental patients

This article describes how dentists can recognize osteoporosis before fractures develop, and discusses whether osteoporosis affects tooth loss or inhibits implant osseointegration. Some success in diagnosing osteoporosis has been obtained using clinical questionnaires that attempt to identify those who have strong risk factors for the disease, and analysis of the sparse trabeculation and thinning of the mandibular cortex often seen in dental panoramic radiographs. The role of osteoporosis in periodontal disease is unclear as there are many conflicting reports, but the evidence suggests that tooth loss may be more prevalent in patients with osteoporosis.

PTH [1-34] enhances bone response around titanium implants in a rabbit model of osteoporosis

INTRODUCTION

Dental implant osseointegration can be impaired in medical conditions with low bone mass, such as glucocorticoid-induced osteoporosis. Intermittent human parathyroid hormone (PTH) [1-34] administration has shown relevant anabolic bone activity in various animal models of osteoporosis. Therefore, we studied the effects of intermittent PTH [1-34] on bone response around titanium implants in experimental osteoporosis induced by ovariectomy and glucocorticoid administration.

METHODS

Titanium dental implants were placed in the proximal tibia metaphysis in 38 animals. Twenty-eight rabbits had undergone bilateral ovariectomy and further methylprednisolone administration for 4 weeks to induce osteoporosis. Ten healthy rabbits were used as controls. At week 8, osteoporotic rabbits started saline vehicle or intermittent PTH administration for 12 weeks. Bone mineral density (BMD) was assessed in peri-implant area, lumbar spine, and global and subchondral knee bone at baseline, and weeks 6 and 20. Animal sacrifice was carried out at week 21. Afterward, tibiae were removed for μCT morphometry and undecalcified sections were evaluated by light and scanning electron microscopy.

RESULTS

PTH increased bone-to-implant contact compared with control rabbits or vehicle administration in osteoporotic rabbits (P < 0.005). PTH-induced new bone formation around external and internal surfaces of titanium implants led to a significant increase of BMD at peri-implant area in osteoporotic rabbits at week 20, when compared with vehicle (P < 0.005). Likewise, PTH increased BMD in other analysed regions.

CONCLUSIONS

Intermittent administration of PTH [1-34] enhances the bone response around titanium implants in a rabbit model of ovariectomy and glucocorticoid-induced osteoporosis.

Patient-related risk factors for implant therapy. A critique of pertinent literature

BACKGROUND

Treatment planning for dental implants involves the assessment of patient-related risk factors prior to formulation of a treatment plan. The aim of this review was to assess relevant literature and provide evidence-based information on the successful surgical placement of dental implants.

METHODS

An electronic search of Medline, PubMed and the Cochrane Databases of Systematic Reviews was undertaken using a combination of MeSH terms and keywords. A handsearch was also performed and cross-referenced with articles cited in papers selected. The primary study parameter was implant failure.

RESULTS

Forty-three studies were selected based on specific inclusion criteria. Many studies contain confounding variables, numbers in subcategories are often too small for meaningful statistical analysis, and follow-up times vary and are often short-term.

CONCLUSIONS

There are many risk factors which the clinician is required to know and understand to advise patients, and consider in planning and treatment provision. Consistent evidence exists to show an increased failure rate with smokers, a history of radiotherapy and local bone quality and quantity. Weaker evidence exists to show a higher incidence of peri-implant disease in patients with a history of periodontitis-related tooth loss. Lack of evidence precludes definitive guidelines for patients with autoimmune disorders where expert opinion recommends caution. Osteoporotic patients show acceptable survival rates; however patients on oral bisphosphonates show a small incidence but high morbidity from osteonecrosis of the jaw. Emerging evidence suggests that there is a correlation between genetic traits and disruption of osseointegration.

The effect of hierarchical micro/nanosurface titanium implant on osseointegration in ovariectomized sheep

Hydrofluoric etching and anodized hierarchical micro/nanotextured surface titanium implant was placed in mandibles of ovariectomized sheep for 12 weeks, and it showed improved osseointegration by resonance frequency analysis (RFA), microcomputed tomography (micro-CT) evaluation, histomorphometry, and biomechanical test.

INTRODUCTION

This study aimed to investigate the effects of micro/nanotextured titanium implant on osseointegration in ovariectomized (OVX) sheep.

METHODS

The hierarchical micro/nanotextured surface of titanium implant was fabricated by acid in 0.5% (w/v) hydrofluoric (HF) and anodized in HF acid electrolytes with a DC power of 20 V, and the machined surface implants with no treatment served as control group. The implants were placed in mandibles of OVX sheep, respectively. Twelve weeks after implantation, RFA, microcomputed tomography, histomorphometry, and biomechanical tests were applied to detect the osseointegration of the two groups.

RESULTS

The implant stability quotient (ISQ) values, the maximum pull-out forces, and the bone-implant contact (BIC) were 65.5 ± 6.3, 490.6 ± 72.7 N, and 58.31 ± 5.79% in the micro/nanogroup and 58.3 ± 8.9, 394.5 ± 54.5 N, and 46.85 ± 5.04% in the control group, respectively. There was no significant difference between the two groups in ISQ values (p > 0.05), but in the micro/nanogroup, the maximal pull-out force and the BIC were increased significantly (p < 0.05 or p < 0.01). Micro-CT analysis showed that the bone volume ratio and the trabecular number increased significantly (p < 0.01), and the trabecular separation decreased significantly (p < 0.05) in the micro/nanogroup.

CONCLUSION

Implant modification by HF acid etching and anodization to form a hierarchical micro/nanotextured surface could improve titanium implant osseointegration in OVX sheep 12 weeks after implantation.

Influence of estrogen deficiency on bone around osseointegrated dental implants: an experimental study in the rat jaw model

PURPOSE

The aim of this study was to evaluate the influence of estrogen deficiency on bone around osseointegrated dental implants in a rat jaw model.

MATERIALS AND METHODS

This study used 16 female rats that had the first molars bilaterally extracted and were allowed to heal for 30 days before implant placement. Sixty days after implant placement, the animals were randomly subjected to sham surgery or ovariectomy (OVX). The animals were euthanized 90 days after OVX. Bone-to-implant contact, bone area fraction occupancy between implant threads, mineral density, turnover markers, and cells positive for tartrate-resistant acid phosphatase were assessed for the 2 groups.

RESULTS

The results showed that OVX group presented a decrease of systemic bone density, alterations in bone turnover markers, and an increase of cells positive for tartrate-resistant acid phosphatase compared with the sham-surgery group. However, no difference relative to bone-to-implant contact and bone area fraction occupancy was observed between groups.

CONCLUSIONS

The findings of this study demonstrate that estrogen deficiency may not be considered a risk factor for osseointegrated implant failure in jaw bone.

Influence of surgical technique, implant shape and diameter on the primary stability in cancellous bone

Achievement of primary stability during surgical placement of dental implants is one of the most important factors for successful osseointegration depending on various anatomical, surgical and implant-related factors. Resonance frequency analysis (RFA) has been shown as a non-invasive and objective technique for measuring the stability of implants. The aim of this study was to evaluate the effect of some surgical and implant-related factors in enhancing primary stability and to estimate a correlation between RFA and insertion torque (IT) in proximal regions of cow ribs representing cancellous bone. Fifteen implant beds were prepared in the most proximal region of six fresh cow ribs. Ninety implants with three different shapes and two different diameters were placed with two different surgical techniques, and the primary stability was compared using RFA and IT. Significantly higher RFA and IT values were achieved when under-dimensioned drilling was used as the surgical method (P<0·01); significantly higher IT values were obtained with the use of wider implants (P<0·01) and partially conical Astra Tech implants showed the highest IT values (P<0·01). When all the implants were considered, significant correlations between the IT and RFA values were noted (%40·6, P<0·05). Partially conical implants with a wide diameter to be placed with the modified surgical technique proposed appear to be useful in enhancing the primary stability in cancellous bone.

Bone Particles and the Undersized Surgical Technique

During the installation of implants, osteogenic bone particles are translocated along the surface. These particles may contribute to peri-implant bone healing. Based on this phenomenon, it is hypothesized that implants placed with undersized drilling, besides showing higher primary-implant stability, also enhance the amount and osteogenic responses of these bone particles. Biocomp® implants were inserted into bicortical fresh-cadaver bone by a press-fit or an undersized surgical technique, and peak-insertion torque values (ITV) were measured. After explantation, the implants were incubated in culture medium up to 24 days. Histology, bone-implant contact (BIC), micro-CT, scanning electron microscopy (SEM), and calcium (Ca) measurements were performed. ITV were significantly higher for implants placed with an undersized technique. Moreover, histology, BIC, micro-CT, SEM, and Ca measurements confirmed the presence of more bone-like tissue on implants inserted with an undersized technique. The undersized surgical technique not only results in higher primary-implant stability, but also induces more translocated bone particles, thus having a positive influence on the osteogenic response.