Implant Compression Necrosis: Current Understanding and Case Report

Analysis of osseointegration of implants with macrogeometries with healing chambers: a randomized clinical trial

BACKGROUND

To verify the influence of macrogeometry with healing chambers on the osseointegration of dental implants by analyzing implant stability quotient (ISQ) and evaluate the correlation between insertion torque and ISQ insertion with different macrogeometries.

METHODS

In total, 26 implants were installed in the posterior mandible of eight patients with sufficient bone height for the installation of implants measuring 3.5 mm in diameter and 9.0 mm in length. The implants were categorized according to two types of macrogeometry: a test group (GT) with 13 conical implants with healing chambers and a control group (GC) with 13 conical implants with conventional threads. To insert the implants, a bone drilling protocol was used up to a diameter of 3 mm with the last helical bur. The insertion torque of the implants was evaluated, followed by the measurement of ISQ at 0 (T-0), 7 (T-7), 14 (T-14), 21 (T-21), 28 (T-28), and 42 (T-42) days.

RESULTS

The mean insertion torque was 43 Ncm in both groups, without a significant difference. Moreover, no significant difference in the ISQ values was found between the groups at different time points (p > 0.05), except at T-7 (GT = 69.87±1.89 and GC = 66.48±4.49; p = 0.01). Although there was no significant difference, ISQ median values were higher in the GT group than GC group at 28 days (GT = 67.98 and GC = 63.46; p = 0.05) and 42 days (GT = 66.12 and GC = 60.33; p = 0.09). No correlation was found between the insertion torque and ISQ insertion (p > 0.05).

CONCLUSION

Furthermore, implants with a 3.5 mm diameter macrogeometry, with or without healing chambers, inserted with a drilling protocol up to 3 mm in diameter of the last helical bur, led to a similar secondary stability, with no difference in ISQ values. Although, implants with healing chamber demonstrates ascending values in the graph of ISQ, having a trend of faster osseointegration than implants without healing chambers. Both macrogeometries provide a similar primary stability to implants.

TRIAL REGISTRATION

This study was registered retrospectively in ReBec (brazilian registry of clinical trials) under the number RBR-96n5×69, on the date of 19/06/2023.

Fixed prosthodontic rehabilitation using a facially driven fully digital workflow of a patient with syndromic amelogenesis imperfecta associated with a rare form of ectodermal dysplasia, tricho-dento-osseous (TDO) syndrome

Tricho-dento-ossseous (TDO) syndrome is a rare form of ectodermal dysplasia (ED) characterized by defects in the hair, bones, nails, and teeth. Dental findings consistently seen in patients with TDO syndrome include amelogenesis imperfecta and taurodontism, but additional findings such as periapical abscesses, mandibular prognathism, and impacted teeth have been reported. Because of the rarity of this disorder, the prevalence is unknown and limited research is available regarding its dental management. This clinical report describes the fixed prosthodontic implant rehabilitation of an adult patient with TDO syndrome by using a facially driven fully digital workflow. The facially driven digital workflow streamlined the rehabilitation and allowed for functional, esthetic, and psychosocial improvements in a timely manner.

Primary stability and osseointegration comparing a novel tapered design tissue-level implant with a parallel design tissue-level implant. An experimental in vivo study

OBJECTIVES

The aim of the present study was to compare a novel tapered, double-threaded self-tapping tissue-Level design implant (TLC) to a well-established parallel walled tissue-level (TL) implant in terms of primary and secondary stability over time.

MATERIALS AND METHODS

Test TLC (n = 10/per timepoint) and control TL (n = 10/per timepoint) implants were placed in the mandible of minipigs and left for submerged healing for 3, 6, and 12 weeks. Maximum insertion torque and implant stability quotient (ISQ) were measured for each implant at placement. Osseointegration and cortical bone maintenance were histologically evaluated by measuring total bone-to-implant contact (BIC) and first bone-to-implant contact (fBIC).

RESULTS

A significantly higher maximum insertion torque was measured for the test implant TLC compared to the control TL implant (57.83 ± 24.73 Ncm and 22.62 ± 23.16 Ncm, respectively; p < .001). The mean ISQ values were comparable between the two implant types (75.00 ± 6.70 for TL compared to 75.40 ± 3.20 for TLC, p = .988). BIC was comparable between both implant types at each of the evaluated time points. The fBIC was found to be significantly more coronal at 12 weeks for the TLC implant compared to the TL implant (0.31 ± 0.83 mm for TLC compared to -0.22 ± 0.85 for TL, p = .027).

CONCLUSION

The novel tapered tissue level design implant showed improved primary stability and an overall improved crestal bone height maintenance compared to the parallel walled design at 12 weeks.

Numerical study on the three-dimensional temperature distribution according to laser conditions in photothermal therapy of peri-implantitis

PURPOSE

Dental implants have been successfully implemented as a treatment for tooth loss. However, peri-implantitis, an inflammatory reaction owing to microbial deposition around the implant, can lead to implant failure. So, it is necessary to treat peri-implantitis. Therefore, this numerical study is aimed at investigating conditions for treating peri-implantitis.

METHODS

Photothermal therapy, a laser treatment method, utilizes photothermal effect, in which light is converted to heat. This technique has advantage of selectively curing inflamed tissues by increasing their temperature. Accordingly, herein, photothermal effect on peri-implantitis is studied through numerical analysis with using Arrhenius damage integral and Arrhenius thermal damage ratio.

RESULTS

Through numerical analysis on peri-implantitis treatment, we explored temperature changes under varied laser settings (laser power, radius, irradiation time). We obtained the temperature distribution on interface of artificial tooth root and inflammation and determined whether temperature exceeds or does not exceed 47℃ to know which laser power affects alveolar bone indirectly. We defined the Arrhenius thermal damage ratio as a variable and determined that the maximum laser power that does not exceed 47℃ at the AA' line is 1.0 W. Additionally, we found that the value of the Arrhenius thermal damage ratio is 0.26 for a laser irradiation time of 100 s and 0.50 for 500 s.

CONCLUSION

The result of this numerical study indicates that the Arrhenius thermal damage ratio can be used as a standard for determining the treatment conditions to help assisted laser treatment for peri-implantitis in each numerical analysis scenario.

A New Approach to Implant Stability Using a Flexible Synthetic Silicate-Additive Beta-Tricalcium Phosphate-Poly(D,L-lactide-co-caprolactone) Bone Graft: An In Vitro Study

The aim of this study was to evaluate the use of a flexible synthetic polymer bone graft to provide implant stability during implant placement in a dense cortical bone model. In the control group (Group 1), sockets were prepared on polyurethane blocks according to the standard implant socket drilling protocol; both oversizing and deepening were applied in Group 2; and only oversizing was applied in Group 3. In Groups 2 and 3, flexible synthetic polymer bone grafts were placed in the sockets prior to implant placement. The implants were placed at the bone level in all groups. The highest torque value obtained was recorded as the insertion torque. In this study, 75 implant sites were included across three groups. The torque values of the implants in the control group were significantly higher than those of the implants with the oversized and deepened sockets and the oversized-only sockets (p < 0.05; p < 0.01). The torque values of the implants with the oversized and deepened sockets were significantly higher than those of the implants with the oversized-only sockets (p < 0.01). In this study, a flexible synthetic polymer bone graft was shown to be effective in achieving implant stability in the management of implants where there has been a loss of primary stability.

"Compression Necrosis" - A Cause of Concern for Early Implant Failure? Case Report and Review of Literature

Purpose

Compression necrosis refers to bone tissue damage that can occur when excessive pressure or force is applied to surrounding bone during implant placement. This pressure can compromise blood supply to the bone, leading to necrosis. Compression necrosis is a concern, because it can affect the stability and long-term success of dental implant.

Patients and Methods

This case report highlights a case of early bone loss and implant failure possibly due to compression necrosis. Clinical data, photographs, radiographs, blood examination report and histology were presented to document the early failure of an implant placed in the mandibular left posterior region of a 33-year-old female patient.

Results

Radiograph taken six weeks after implant placement showed severe angular defect. Therefore, the implant was surgically removed. Histological examination of the area showed bony trabeculae with an absence of osteoblastic riming, suggestive of necrotic bone.

Conclusion

Using excessive torque values when placing implants in dense bones can increase the risk of implant failure due to bone over compression. Dental professionals must follow the manufacturer's instructions and employ quality surgical techniques during implant placement into dense cortical bone to minimise risks.

Correlation Between Acquisition of Dental Implant Stability and Hounsfield Units at Dental Implant Placement

Alveolar bone quality at the implantation site affects the initial stability of dental implant treatment. However, the relationship between bone quality and osseointegration has yet to be evaluated. Herein, we aimed to investigate the effect of bone quality on dental implant stability in osseointegration formation changes. Patients underwent computed tomography imaging before dental implantation at the posterior. Hounsfield units were measured at the platform, middle, and tip sites. Implant stability was measured using resonance frequency analysis immediately and at 3 months postoperatively, in which the difference in implant stability quotients (ISQ) was defined as the change between primary and secondary fixation. In multiple regression analysis, the dependent variable was the change between the immediate and secondary fixations. We included 81 implants that conformed to the criteria. Primary fixation yielded the following results: R2 = 0.117, F = 2.529, and P = .047. The difference between the maxilla and mandible of the implantation site (P = .02) and the platform-site Hounsfield units (P = .019) were identified as significant factors. The following results were obtained regarding the change between the immediate and secondary fixation: R2 = 0.714, F = 40.964, and P < .001. The difference between diameter (P = .008) and the immediate ISQ (P < .001) were identified as significant factors. Overall, the bone quality of the implantation site affected initial fixation; however, it had limited effect on secondary fixation. Our findings clarified the period where bone quality affects dental implant treatment and is expected to advance dental implant treatment.

LIMITED EVIDENCE SUGGESTS NO CORRELATION BETWEEN IMPLANT INSERTION TORQUE AND IMPLANT SURVIVAL AND MARGINAL BONE LOSS

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Clinical effect of the high insertion torque on dental implants: A systematic review and meta-analysis. Lemos CA, Verri FR, de Oliveira Neto OB, Cruz RS, Gomes JML, da Silva Casado BG, Pellizzer EP. J Prosthet Dent 2021; 126(4): 490-496.

SOURCE OF FUNDING

Not reported.

TYPE OF STUDY/DESIGN

Systematic review with meta-analysis (SR).

Influence of design implant and apical depth in post-extraction sockets: an in vitro simulated study

BACKGROUND

Implant design and apical stability are principal parameters involved in achieving successful primary stability. Using polyurethane models to simulate post-extraction sockets, we investigated the effects of using differing blade designs on the primary stability of tapered implants and the impact of apical depth.

METHOD

Six polyurethane blocks were used to simulate post-extraction pockets. One of the implants presented self-tapping blades (Group A), while the other (Group B) did not. Seventy-two implants were placed at 3 different depths (5 mm, 7 mm, and 9 mm), and a torque wrench was used to measure the stability of the implants.

RESULTS

When evaluating the implants (placed at 5 mm, 7 mm, and 9 mm apical to the socket), we observed that the torque of the Group B implants was higher than that of Group A implants (P < 0.01). At the 9-mm depth, there was no difference between the groups (Drive GM 34.92 Ncm and Helix GM 32.33 Ncm) (P > 0.001), and considering the same implant groups, those placed at 7-mm and 9-mm depths presented higher torques (p < 0.01) than those placed at 5-mm (p > 0.01).

CONCLUSION

Considering both groups, we concluded that an insertion depth of greater than 7 mm is needed for initial stability, and in situations involving reduced supportive bone tissue or low bone density, a non-self-tapping thread design improves implant stability.

Comparison of Implant Surgery Methods of Cortical Tapping and Cortical Widening in Bone of Various Density: A Three-Dimensional Finite Element Study

PURPOSE

The primary stability of a dental implant is critical for successful osseointegration during immediate loading. The cortical bone should be prepared to achieve enough primary stability, but not overcompressed. In this study, we investigated the stress and strain distribution in the bone around the implant induced by the occlusal force applied during immediate loading at various bone densities by the FEA method to compare cortical tapping and widening surgical techniques.

MATERIALS AND METHODS

A three-dimensional geometrical model of a dental implant and bone system was created. Five types of bone density combination (D111, D144, D414, D441 and D444) were designed. Two surgical methods-cortical tapping and cortical widening-were simulated in the model of the implant and bone. An axial load of 100 N and an oblique load of 30 N were applied to the crown. The maximal principal stress and strain were measured for comparative analysis of the two surgical methods.

RESULTS

Cortical tapping showed lower maximal stress of bone and maximal strain of bone than cortical widening when dense bone was located around the platform, regardless of the direction of the applied load.

CONCLUSIONS

Within the limitations of this FEA study, it can be concluded that cortical tapping is biomechanically more advantageous to the implants under occlusal force during immediate loading, especially when the bone density around the platform is high.

Influence of Insertion Torques on the Surface Integrity in Different Dental Implants: An Ex Vivo Descriptive Study

BACKGROUND

The primary objective of this ex vivo study was to assess the influence of increasing insertion torques on three types of dental implants and possible alterations of their microgeometry after the application of three different torque intensities.

METHODS

27 implants of 3 different implant brands (Groups A, B and C) were placed in cow ribs using 30 Ncm, 45 Ncm and 55 Ncm insertion torques. The implants were subsequently removed using trephine burs, and SEM analysis was carried out in order to detect implant surface and connection changes, as compared to the implant controls.

RESULTS

Surface deformations were predominantly observed on the third apical part of the implants. The alterations presented with increasing insertion torques, with 45 Ncm being the threshold value. Prosthetic connections were also compromised.

CONCLUSIONS

The changes sustained by the implants were proportional to the insertion torque they were subjected to; 45 Ncm and greater insertion torques resulted in more consistent damage, both on the implant surface and the implant connection.

Mandibular bone characteristics, drilling protocols, and final insertion torque for titanium-zirconium mini-implants for overdentures: A cross-sectional analysis

OBJECTIVE

The aim of this study was to assess the final insertion torque values achieved using site-specific drilling protocols for a novel mini implant system for removable complete overdentures. Anatomical and technical factors influencing final insertion torque were recorded and analyzed.

MATERIAL AND METHODS

Participants were randomized to two surgical protocol groups (flapped or flapless) and all received four mini implants (Straumann® mini implant system; Straumann AG) in the anterior mandible, using a 1.6 mm needle drill and a 2.2 mm pilot drill for the implant bed site preparation. The final insertion torque was recorded as the main outcome variable during surgery. Bone type, radiographical bone density, ridge form, implant length, and the drilling protocol were considered as independent variables. Descriptive statistics, generalized estimating equations (GEE) regression, and heatmap charts were used for data analyses.

RESULTS

A total of 296 mini implants were placed in 74 patients (mean age = 64.1 ± 8.0; 64.9% female) using flapless (n = 37) or flapped (n = 37) surgeries. Mean final insertion torque was 55.8 ± 18.4 Ncm (10.5% > 35 Ncm, 48.9% between 35 and 65 Ncm, and 40.6% > 65 Ncm). The needle drill was used in only 43.9% of the implant bed sites. Higher final torque values were observed for higher bone densities (bone type I > II > III, and D1-D2 > D3-D4), highly resorbed ridge forms (5-6 > 3-4), flapped surgeries, and male patients. However, regression models showed that the likelihood of achieving optimal insertion torque (≥35 and ≤65 Ncm) was higher for females (OR = 2.14; 95%CI = 1.14-4.01; p = 0.018), ridge forms 3-4 (OR = 2.87; 95%CI = 1.05-7.85; p = 0.040), and flapless surgeries (OR = 1.96; 95%CI = 1.09-3.51; p = 0.024).

CONCLUSIONS

Sufficient primary stability for immediate loading was achieved for the majority of the mini implants placed. Surgical implant bed preparation should be site-specific to achieve optimal primary stability for immediate loading while avoiding excessive insertion torque.

Clinical effects of conventional and underprepared drilling preparation of the implant site based on bone density: A systematic review and meta-regression

PURPOSE

There is no clinical consensus to determine the right balance between underpreparation and marginal bone level changes. The purpose of this systematic review and meta-regression was to investigate the influence of the type of drilling preparation of the implant site in relation to the bone mineral density on the clinical success, expressed in terms of the MBL and implant failure rate.

STUDY SELECTION

A thorough search was performed using the digital databases MEDLINE PubMed, EMBASE, and Cochrane Central Register of Controlled Trials by entering research lines or various combinations of free words. The main keywords used were "dental implants", "bone density", and "torque".

RESULTS

The mean bone resorption in the conventional preparation group was -0.43 (± 0.28) mm, whereas it was -0.80 (± 0.37) mm in the underprepared group. For the D1/D2/D3 bone group, the slope was significantly different from zero and linearity; the D4 bone group slope was not significantly different from zero and was almost parallel, although it was significantly different from linearity. The box and whiskers plot shows that the MBL in underprepared sites tended to be significantly higher with a higher variation than that in conventionally prepared sites.

CONCLUSIONS

Within its limits, our meta-regression analysis showed that MBL is influenced by the type of drilling preparation and bone mineral density. In particular, a lower MBL was observed in the D1 bone with conventional preparation than with underpreparation. Moreover, a greater implant-to-osteotomy site mismatch was positively associated with greater MBLs in the bone densities of D1/D2/D3.

Temperature Changes during Implant Osteotomy Preparations in Fresh Human Cadaver Tibiae, Comparing Straight with Tapered Drills

The success of osseointegration depends on many factors. With temperatures beyond a 47 °C threshold over 1 min, bone survival may be impaired. The purpose of the study was to evaluate, in fresh human cadaver tibiae, the temperature changes during osteotomy preparations using two straight and two tapered implant systems’ drills, external irrigation, and varying revolutions per minute (RPM). The tibiae from a fresh female cadaver were harvested bilaterally. Two tapered and two straight design drills were assessed. Two-hundred and forty osteotomies were prepared at 6 mm depth following the drill sequence of the manufacturers’ protocol for each drilling speed. Difference in temperature (ΔΤ) was calculated by subtracting the baseline from the maximum temperature (ΔT = T_max − T_base). Drill design and drill diameter, as independent variables or synergistically, had a significant effect on ΔΤ. Tapered drills: As the drill diameter increased, ΔΤ increased at all RPM. Straight drills: As the drill diameter increased, ΔΤ remained constant or slightly decreased at all RPM. Drill diameter and design had a significant effect on ΔΤ in human tibiae, which never exceeded the critical threshold of 47 °C. Tapered drills caused significantly greater heat production compared to straight drills.

Immediate Loading of a Fully Tapered Implant with Deep Apical Threads Placed in Healed Alveolar Ridges vs. Immediate Extraction Sockets

OBJECTIVES

Immediate implant placement and loading is a practice that continues to gain traction in implant dentistry because it reduces treatment time and improves satisfaction. Novel implant designs that facilitate increased primary stability, while not compromising osseointegration and long-term survival are important to offer immediate solutions for missing teeth. Here, we hypothesize that fully tapered implants can obtain successful osseointegration with high survival rates after immediate loading in fresh extraction sockets and healed sites.

MATERIALS AND METHODS

13 swine with 73 implants were evaluated. Fully tapered or apically tapered implants were placed in extraction sockets and healed sites. Insertion torque and resonance frequency analysis were determined at placement and euthanasia. Animals were evaluated at: placement, and 1-week and 12-weeks after placement. Bone to Implant Contact (BIC), Bone Area / Total Area (BA/TA), and first BIC (fBIC) analyses was conducted.

RESULTS

The fully tapered implant achieved similar primary stability with lower insertion torque at placement (Fig. 2). Apically and fully tapered implants had comparable BIC (50.1% vs 59.4%) and ISQ (82.5 vs 80.3) values by 12 weeks in healed sites. In extraction sockets, BIC and ISQ for the apically tapered implant was 35.8% and 73.2 and 37.8% and 79.2 for the fully tapered implants, respectively (Fig. 2, 5).

CONCLUSIONS

In this short-term study, immediately loaded fully tapered implants obtained high survival with similar osseointegration ability as apically tapered implants when placed in healed sites and fresh extraction sockets. Fully tapered implants show promise for use in immediate loading and immediate placement.

Biological mechanisms underlying complications related to implant site preparation

Implant site preparation is a critical stage of implant surgery that may underpin various complications related to implant surgery. This review discusses the latest available scientific information on risk factors related to implant site preparation. The role of the drilling process in relation to the density of the available alveolar bone, the effects of insertion torque on peri-implant osseous healing, and implant-related variables such as macrodesign and implant-abutment connection are all factors that can influence implant success. Novel information that links osteotomy characteristics (including methods to improve implant initial stability, the impact of drilling speed, and increase of the implant insertion torque modifying the bone-implant interface) with the appropriate instrumentation techniques will be discussed, as well as interactions at the bone-biomaterial interface that may lead to biologic complications mediated by implant dissolution products.

The Effect of Coronal Implant Design and Drilling Protocol on Bone-to-Implant Contact: A 3-Month Study in the Minipig Calvarium

Background: Stress concentrated at an implant’s neck may affect bone-to-implant contact (BIC). The objective of this study was to evaluate four different implant neck designs using two different drilling protocols on the BIC. Methods: Ninety-six implants were inserted in 12 minipigs calvarium. Implants neck designs evaluated were: type 1–6 coronal flutes (CFs), 8 shallow microthreads (SMs); type 2–6 CFs,4 deep microthreads (DMs); type 3–4 DMs; type 4–2 CFs, 8 SMs. Two groups of forty-eight implants were inserted with a final drill diameter of 2.8 mm (DP1) or 3.2 mm (DP2). Animals were sacrificed after 1 and 3 months, total-BIC (t-BIC) and coronal-BIC (c-BIC) were evaluated by nondecalcified histomorphometry analysis. Results: At 1 month, t-BIC ranged from 85–91% without significant differences between implant types or drilling protocol. Flutes on the coronal aspect impaired the BIC at 3 m. c-BIC of implant types with 6 CFs was similar and significantly lower than that of implant types 3 and 4. c-BIC of implant type 4 with SMs was highest of all implant types after both healing periods. Conclusions: BIC was not affected by the drilling protocol. CFs significantly impaired the -BIC. Multiple SMs were associated with greater c-BIC.

Potential of Using an Implant Fixture as a Ridge Expander for Minor Ridge Augmentation: An Ex Vivo Randomized Controlled Study

To place implants with minimal trauma is what the patient and clinician are seeking. Hence, the aim of this study was to quantify the potential of using an implant fixture as a ridge expander in an underprepared osteotomy. Thirty-eight edentulous sites in 12 human cadaver jaws with ridge widths ranging from 4 to 6 mm and with type 3 or type 4 bone density were randomly assigned into 2 groups. In the ridge expansion group (RE), each osteotomy was drilled to a width of 2.8 mm and depth of 11.5 mm. In the non-ridge expansion (NE) control group, each osteotomy was drilled to a width of to 3.4 mm and depth of 11.5 mm. A 3.7 mm × 11.5 mm tapered implant was inserted into each site. The ridge width before (RW1) and after (RW2) implant placement as well as the buccal plate thickness (BPT) post-insertion were measured and analyzed. In the RE group, the average RW1 and RW2 were 4.69 ± 0.45 mm and 5.54 ± 0.35 mm, respectively, corresponding to a statistically significant ridge expansion of 0.85 mm (P < .01). In the NE group, no ridge width gain was observed (RW1: 4.79 ± 0.40 mm, RW2: 4.88 ± 0.42 mm). Compared to NE, RE resulted in a statistically greater BPT (1.08 ± 0.28 mm after RE vs 0.71 ± 0.37 mm after NE, P < .001). Our study determined that it was physically possible to widen a ridge by an average of 0.85 mm by osteotomy underprepation in ridge with type 3 or type 4 bone density, which effectively turned the implant upon insertion into a ridge expander. The physiological consequences of this method of ridge expansion in a living person must be established before drawing further conclusions about its clinical indications or efficacy.

Treatment of Early Developed Peri-Implantitis in Fibula Graft Site

The fibula microvascular free flap technique and placement of dental endosseous implants seem to be viable options for reconstructing the mandible, following a resective jaw surgery. The causes of early failures of implants include bone overheating, latent infection by surgical trauma, the factors related with the implant, and overcompression. This case report reviews the mechanisms of early post-implantation bone loss, and suggests the course of treatment for early peri-implantitis for implants that show no mobility. Radiographs and clinical data presented have shown that the surgical treatment of early developed peri-implantitis using GBR methods in free fibula graft sites offers promising and stabile results.

Effects of Different Undersizing Site Preparations on Implant Stability

As immediate loading protocols are becoming more frequent, the primary stability of implants has become an essential criterion for the osseointegration of dental implants. Based on this, the objective of this study was to understand the influence of different undersized surgical preparation sites on the insertion torque (IT) and implant stability quotient (ISQ). Four different site-preparation protocols were performed on fresh humid type III bovine bone: one control, the standard protocol recommended by the manufacturer (P1), and three variations of undersized techniques (P2, P3 and P4). The implant used was VEGA by Klockner Implant System. The sample size was n = 40 for each of the four groups. A torquemeter was used to measure the IT, and the ISQ was measured with a Penguin RFA. Both variables showed a tendency to increase as the preparation technique was reduced, although not all the values were statistically significant (p < 0.05) when comparing with the standard preparation. The preparations without a cortical drill, P2 and P4, showed better results than those with a cortical drill. Given the limitations of this study, it can be concluded that reducing the implant preparation can increase both the IT and ISQ. Removing the cortical drill is an effective method for increasing implant stability, although it should be used carefully.

Comparison of nonself-tapping tapered implant and self-tapping hybrid implant in terms of implant stability at initial and second fixation: A prospective randomized clinical trial

BACKGROUND

Various features are provided in dental implants to improve initial fixation.

PURPOSE

To compare the implant stability of the nonself-tapping tapered implant and self-tapping hybrid implant over a 3-month healing period.

MATERIALS AND METHODS

A randomized controlled trial was conducted. Patients were randomly divided into tapered and self-tapping groups. Patients in the tapered group received NobelReplace Tapered (Nobel Biocare, Sweden) implants, while those in the self-tapping group received NobelSpeedy (Nobel Biocare, Sweden) implants. Implant stability was measured by resonance frequency analysis at surgery and 3 months following implant insertion. Data were analyzed using an independent t-test.

RESULTS

Forty-three patients (tapered group: 21, self-tapping group: 22) received a total of 88 implants. Initial stability in the tapered group was significantly higher (mean: 60.14, SD: 12.40) than that in the self-tapping group (mean: 54.72, SD: 7.92). Implant stability significantly increased 3 months after implantation in the tapered group (mean: 66.61, SD: 9.00) and self-tapping group (mean: 64.01, SD: 5.78). No significant intergroup difference in implant stability was noted 3 months after surgery.

CONCLUSIONS

The tapered shape affected initial fixation more than the self-tapping function. However, during the second fixation, both implants showed good stability, and the difference disappeared.

A novel system exploits bone debris for implant osseointegration

BACKGROUND

Bone debris generated during site preparation is generally evacuated with irrigation; here, we evaluated whether retention of this autologous material improved the rate of peri-implant bone formation.

METHODS

In 25 rats, a miniature implant system composed of an osseo-shaping tool and a tri-oval-shaped implant was compared against a conventional drill and round implant system. A split-mouth design was used, and fresh extraction sockets served as implant sites. Histology/histomorphometry, immunohistochemistry, and microcomputed tomography (μCT) imaging were performed immediately after implant placement, and on post-surgery days 3, 7, 14, and 28.

RESULTS

Compared with a conventional drill design, the osseo-shaping tool produced a textured osteotomy surface and viable bone debris that was retained in the peri-implant environment. Proliferating osteoprogenitor cells, identified by PCNA and Runx2 expression, contributed to faster peri-implant bone formation. Although all implants osseointegrated, sites prepared with the osseo-shaping tool showed evidence of new peri-implant bone sooner than controls.

CONCLUSION

Bone debris produced by an osseo-shaping tool directly contributed to faster peri-implant bone formation and implant osseointegration.

Clinical effect of the high insertion torque on dental implants: A systematic review and meta-analysis

STATEMENT OF PROBLEM

A consensus on the clinical performance in dental implants placed with different insertion torques is lacking.

PURPOSE

The purpose of this systematic review and meta-analysis was to evaluate the effect of high insertion torque compared with regular or low torques during dental implant placement in terms of implant survival rate and marginal bone loss.

MATERIAL AND METHODS

Two independent reviewers searched electronic databases for studies published until April 2019. The population, intervention, comparison, outcome (PICO) question was "Do patients who receive implants with a high torque (equal or higher than 50 Ncm) show similar implant survival rates and marginal bone loss as compared with those who receive implants with a regular or low torque (less than 50 Ncm)?". The meta-analysis was based on the Mantel-Haenszel (MH) and the inverse variance (IV) methods (α=.05).

RESULTS

The search yielded 6 articles, which included 389 patients (mean age: 55.28 years) who had received 651 dental implants (437 with high torque and 214 with low or regular torque). Most studies evaluated delayed loading, except 1 study that evaluated immediate implant loading (n=50 for each group). Low or regular insertion torque had a high failure rate (4.2%) compared with high insertion torque (1.1%), chiefly because of immediate loading. However, the meta-analysis indicated no significant difference between high- and regular- or low-torque implant placement in implant survival rate (P=.52, risk ratio [RR]: 0.51, 95% confidence interval [CI]: 0.06-4.06) and marginal bone loss (P=.30, mean difference [MD]: 0.15, 95% CI: -0.14 to 0.44).

CONCLUSIONS

A high insertion torque during implant placement does not affect implant survival rate or marginal bone loss. However, further research is recommended to reassess this clinical performance.

Effect of insertion factors on dental implant insertion torque/energy-experimental results

Anchorage of dental implants is quantified with a mechanical engagement to insertion, for example maximum insertion torque (MIT) and insertion energy (IE). Good anchorage of dental implants highly correlates to positive clinical outcomes. However, it is still unclear how bone density, drill protocol, surface finish and cutting flute affect anchorage. In this study, effects of the insertion factors on both MIT and IE were investigated using a full-factorial experiment at two levels: bone surrogate density (0.32 g/cm³ versus 0.48 g/cm³), drill protocol (Ø2.4/2.8 versus Ø2.8/3.2 mm), implant surface finish (machined versus anodized surface) and cutting flute (with versus without). Osteotomies were prepared on rigid polyurethane foam blocks with dimensions of 40 × 40 × 8 mm. Screw shaped dental implants with variable tapered body were consecutively inserted into and removed from the polyurethane foam blocks three times under constant axial displacement and rotational speed. Axial force and torque were recorded synchronously. Insertion energy was calculated from the area under the torque-displacement curve. In this study, we found the main insertion mechanics were thread forming for the first insertion. For the second and third insertions, the main mechanics shifted to thread tightening. Maximum insertion torque (MIT) responded differently to the four insertion factors in comparison to IE. Bone surrogate density, drill protocol and surface finish had the largest main effects for first MIT. For the first IE, drill protocol, surface finish and cutting flute were significant contributors. These results suggest that MIT and IE are influenced by different mechanics: the first MIT and the first IE were sensitive to thread tighten and forming, respectively. Together MIT and IE provide a complete assessment of dental implant anchorage.

De Aza P. Can changes in implant macrogeometry accelerate the osseointegration process?: An in vivo experimental biomechanical and histological evaluations

OBJECTIVES

The propose was to compare this new implant macrogeometry with a control implant with a conventional macrogeometry.

MATERIALS AND METHODS

Eighty-six conical implants were divided in two groups (n = 43 per group): group control (group CON) that were used conical implants with a conventional macrogeometry and, group test (group TEST) that were used implants with the new macrogeometry. The new implant macrogeometry show several circular healing cambers between the threads, distributed in the implant body. Three implants of each group were used to scanning electronic microscopy (SEM) analysis and, other eighty samples (n = 40 per group) were inserted the tibia of ten rabbit (n = 2 per tibia), determined by randomization. The animals were sacrificed (n = 5 per time) at 3-weeks (Time 1) and at 4-weeks after the implantations (Time 2). The biomechanical evaluation proposed was the measurement of the implant stability quotient (ISQ) and the removal torque values (RTv). The microscopical analysis was a histomorphometric measurement of the bone to implant contact (%BIC) and the SEM evaluation of the bone adhered on the removed implants.

RESULTS

The results showed that the implants of the group TEST produced a significant enhancement in the osseointegration in comparison with the group CON. The ISQ and RTv tests showed superior values for the group TEST in the both measured times (3- and 4-weeks), with significant differences (p < 0.05). More residual bone in quantity and quality was observed in the samples of the group TEST on the surface of the removed implants. Moreover, the %BIC demonstrated an important increasing for the group TEST in both times, with statistical differences (in Time 1 p = 0.0103 and in Time 2 p < 0.0003).

CONCLUSIONS

Then, we can conclude that the alterations in the implant macrogeometry promote several benefits on the osseointegration process.

Primary stability of self-tapping dual etched implants

BACKGROUND

The aims of this study were to enumerate the primary implant stability quotient (ISQ) value of self-tapping dual etched implants and to explore the influence of parameters such as implant length, implant diameter, age, gender, implant location and osteotomy preparation on the ISQ value.

METHODS

Retrospective data from clinical worksheets given to participants during two implant courses held between the periods of 2013 to 2014 were evaluated. A total of 61 implants were considered based on the inclusion criteria. The effects of parameters such as implant diameter, implant length, age, gender, implant location and osteotomy protocol on ISQ values were analyzed.

RESULTS

Mean ISQ value for all implants was 67.21±9.13. Age of patients (P=0.016) and location of implants (P=0.041) had a significant linear relationship with the ISQ values. Within the age limit of the patients in this study, it was found that an increase in one year of patient's age results in 0.20 decrease in ISQ value (95% CI: -0.36, -0.04). However, placing an implant in the posterior maxilla may negatively affect the ISQ with a likely decrease in primary stability by 6.76 ISQ value (95% CI: -13.22, -0.30).

CONCLUSIONS

The results suggest that the mean ISQ achieved by the participants were comparable with the range reported for this particular type of implants. The patient's age and location of implants were elucidated as the determinant factors of primary implant stability.

Modified surgical drilling protocols influence osseointegration performance and predict value of implant stability parameters during implant healing process

OBJECTIVE

The aim of this study was to evaluate the effects of three different surgical drilling protocols on changes of implant stability parameters and osseointegration performance during the healing period in rabbit femoral condyles.

MATERIAL AND METHODS

Thirty New Zealand white rabbits were used in this study. Three experimental groups according to different surgical drilling protocols (undersized, standard and oversized preparation) were designed. Measurements of implant stability parameters were performed immediately after implant insertion and then at 1, 2, 4, and 8 weeks after the operation. After the animals were sacrificed, the bone blocks with implant were prepared for histological evaluation and histomorphometric analysis.

RESULTS

The results demonstrated that the ISQ values of each group increased gradually through the whole healing period, while the damping factor showed the opposite tendency. The histomorphometric analysis revealed that BIC (bone-implant contact) values gradually increased with time until 8 weeks of healing at each group. In addition, the undersized group has the highest initial BIC (25.16% ± 7.25%) and the lowest values were found in oversized group (9.13% ± 5.89%). Moreover, a higher correlation (R² = 0. 9817) between ISQ and BIC values in oversized group and moderate correlations between DF and BIC values in undersized group (R² = 0.823) were demonstrated.

CONCLUSIONS

The undersized drilling protocol group presented the highest implant stability and BIC values in the whole healing period, while the similar tendency of results was found between standard and oversized drilling protocol groups.

CLINICAL RELEVANCE

These results suggested that undersized drilling protocol is mechanically and biologically beneficial in low-density bone. The modifications of surgical drilling protocols would influence the predictive value of implant stability parameters for osseointegration performance.

Under-Drilling versus Hybrid Osseodensification Technique: Differences in Implant Primary Stability and Bone Density of the Implant Bed Walls

The goal of this study was to evaluate the effects of two implant bed preparation techniques on the implant primary stability (IPS) and the bone density of the implant site. We completed 40 implant bed osteotomies in pig ribs using two techniques: osseodensification (OD) plus under-drilling (UD) with universal osseodensification drills (Test A), and under-drilling alone with drills of the same implant system (Test B). Implants with a 4.1 mm diameter and 10 mm length were inserted, and the IPS was evaluated with three methods: (insertion torque (IT), periotest (PTV), and resonance frequency analysis (RFA). The bone density was evaluated using micro-computed tomography. ANOVA and Tukey’s post-hoc test were used for comparison of the IPS values, and Kruskal–Wallis was used to evaluate the bone density. Statistical significance was set at p < 0.05. The tested B technique (UD) achieved a higher IPS compared to the Test A technique (OD + UD) for all the evaluation methods (p < 0.05). Bone density was higher at the apical and middle region in Test A compared to Test B and control sites (p < 0.05). We concluded that although the bone density increased with the hybrid OD technique with universal drills, implant beds prepared with UD using drills with geometry similar to that of the implant are more efficient at increasing IPS values.

Peri-implantitis

OBJECTIVES

This narrative review provides an evidence-based overview on peri-implantitis for the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions.

METHODS

A literature review was conducted addressing the following topics: 1) definition of peri-implantitis; 2) conversion from peri-implant mucositis to peri-implantitis, 3) onset and pattern of disease progression, 4) characteristics of peri-implantitis, 5) risk factors/indicators for peri-implantitis, and 6) progressive crestal bone loss in the absence of soft tissue inflammation.

CONCLUSIONS

1)Peri-implantitis is a pathological condition occurring in tissues around dental implants, characterized by inflammation in the peri-implant connective tissue and progressive loss of supporting bone. 2)The histopathologic and clinical conditions leading to the conversion from peri-implant mucositis to peri-implantitis are not completely understood. 3)The onset of peri-implantitis may occur early during follow-up and the disease progresses in a non-linear and accelerating pattern. 4a)Peri-implantitis sites exhibit clinical signs of inflammation and increased probing depths compared to baseline measurements. 4b)At the histologic level, compared to periodontitis sites, peri-implantitis sites often have larger inflammatory lesions. 4c)Surgical entry at peri-implantitis sites often reveals a circumferential pattern of bone loss. 5a)There is strong evidence that there is an increased risk of developing peri-implantitis in patients who have a history of chronic periodontitis, poor plaque control skills, and no regular maintenance care after implant therapy. Data identifying "smoking" and "diabetes" as potential risk factors/indicators for peri-implantitis are inconclusive. 5b)There is some limited evidence linking peri-implantitis to other factors such as: post-restorative presence of submucosal cement, lack of peri-implant keratinized mucosa and positioning of implants that make it difficult to perform oral hygiene and maintenance. 6)Evidence suggests that progressive crestal bone loss around implants in the absence of clinical signs of soft tissue inflammation is a rare event.

Effect of impaction energy on dynamic bone strains, fixation strength, and seating of cementless acetabular cups

Seating a cementless acetabular cup via impaction is a balancing act; good cup fixation must be obtained to ensure adequate bone in-growth and cup apposition, while acetabular fracture must be avoided. Good impaction technique is essential to the success of hip arthroplasty. Yet little guidance exists in the literature to inform surgeons on "how hard" to hit. A drop rig and synthetic bone model were used to vary the energy of impaction strikes in low and high-density synthetic bone, while key parameters such as dynamic strain (quantifying fracture risk), implant fixation, and polar gap were measured. For high energy impaction (15 J) in low-density synthetic bone, a peak tensile strain was observed during impaction that was up to 3.4× as large as post-strike strain, indicating a high fracture risk. Diminishing returns were observed for pushout fixation with increasing energy. Eighty-five percent of the pushout fixation achieved using a 15 J impaction strike was attained by using a 7.5 J strike energy. Similarly, polar gap was only minimally reduced at high impaction energies. Therefore it is suggested that higher energy strikes increase fracture risk, but do not offer large improvements to fixation or implant-bone apposition. It may difficult be for surgeons to accurately deliver specific impaction energies, suggesting there is scope for operative tools to manage implant seating. © 2019 The Authors. Journal of Orthopaedic Research^® published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 37:2367-2375, 2019.

Peri-implantitis

OBJECTIVES

This narrative review provides an evidence-based overview on peri-implantitis for the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions.

METHODS

A literature review was conducted addressing the following topics: 1) definition of peri-implantitis; 2) conversion from peri-implant mucositis to peri-implantitis, 3) onset and pattern of disease progression, 4) characteristics of peri-implantitis, 5) risk factors/indicators for peri-implantitis, and 6) progressive crestal bone loss in the absence of soft tissue inflammation.

CONCLUSIONS

1)Peri-implantitis is a pathological condition occurring in tissues around dental implants, characterized by inflammation in the peri-implant connective tissue and progressive loss of supporting bone. 2)The histopathologic and clinical conditions leading to the conversion from peri-implant mucositis to peri-implantitis are not completely understood. 3)The onset of peri-implantitis may occur early during follow-up and the disease progresses in a non-linear and accelerating pattern. 4a)Peri-implantitis sites exhibit clinical signs of inflammation and increased probing depths compared to baseline measurements. 4b)At the histologic level, compared to periodontitis sites, peri-implantitis sites often have larger inflammatory lesions. 4c)Surgical entry at peri-implantitis sites often reveals a circumferential pattern of bone loss. 5a)There is strong evidence that there is an increased risk of developing peri-implantitis in patients who have a history of chronic periodontitis, poor plaque control skills, and no regular maintenance care after implant therapy. Data identifying "smoking" and "diabetes" as potential risk factors/indicators for peri-implantitis are inconclusive. 5b)There is some limited evidence linking peri-implantitis to other factors such as: post-restorative presence of submucosal cement, lack of peri-implant keratinized mucosa and positioning of implants that make it difficult to perform oral hygiene and maintenance. 6)Evidence suggests that progressive crestal bone loss around implants in the absence of clinical signs of soft tissue inflammation is a rare event.

Intraosseous Temperature Change during Installation of Dental Implants with Two Different Surfaces and Different Drilling Protocols: An In Vivo Study in Sheep

Background: The intraosseous temperature during implant installation has never been evaluated in an in vivo controlled setup. The aims were to investigate the influence of a drilling protocol and implant surface on the intraosseous temperature during implant installation, to evaluate the influence of temperature increase on osseointegration and to calculate the heat distribution in cortical bone. Methods: Forty Brånemark implants were installed into the metatarsal bone of Finnish Dorset crossbred sheep according to two different drilling protocols (undersized/non-undersized) and two surfaces (moderately rough/turned). The intraosseous temperature was recorded, and Finite Element Model (FEM) was generated to understand the thermal behavior. Non-decalcified histology was carried out after five weeks of healing. The following osseointegration parameters were calculated: Bone-to-implant contact (BIC), Bone Area Fraction Occupancy (BAFO), and Bone Area Fraction Occupancy up to 1.5 mm (BA1.5). A multiple regression model was used to identify the influencing variables on the histomorphometric parameters. Results: The temperature was affected by the drilling protocol, while no influence was demonstrated by the implant surface. BIC was positively influenced by the undersized drilling protocol and rough surface, BAFO was negatively influenced by the temperature rise, and BA1.5 was negatively influenced by the undersized drilling protocol. FEM showed that the temperature at the implant interface might exceed the limit for bone necrosis. Conclusion: The intraosseous temperature is greatly increased by an undersized drilling protocol but not from the implant surface. The temperature increase negatively affects the bone healing in the proximity of the implant. The undersized drilling protocol for Brånemark implant systems increases the amount of bone at the interface, but it negatively impacts the bone far from the implant.

New Implant Macrogeometry to Improve and Accelerate the Osseointegration: An In Vivo Experimental Study

A new implant design with healing chambers in the threads was analyzed and compared with a conventional implant macrogeometry, both implants models with and without surface treatment. Eighty conical implants were prepared using commercially pure titanium (grade IV) by the company Implacil De Bortoli (São Paulo, Brazil). Four groups were performed, as described below: Group 1 (G1), traditional conical implants with surface treatment; group 2 (G2), traditional conical implants without surface treatment (machined surface); group 3 (G3), new conical implant design with surface treatment; group 4 (G4), new conical implant design without surface treatment. The implants were placed in the two tibias (n = 2 implants per tibia) of twenty New Zealand rabbits determined by randomization. The animals were euthanized after 15 days (Time 1) and 30 days (Time 2). The parameters evaluated were the implant stability quotient (ISQ), removal torque values (RTv), and histomorphometric evaluation to determine the bone to implant contact (%BIC) and bone area fraction occupancy (BAFO%). The results showed that the implants with the macrogeometry modified with healing chambers in the threads produced a significant enhancement in the osseointegration, accelerating this process. The statistical analyses of ISQ and RTv showed a significative statistical difference between the groups in both time periods of evaluation (p ≤ 0.0001). Moreover, an important increase in the histological parameters were found for groups G3 and G4, with significant statistical differences to the BIC% (in the Time 1 p = 0.0406 and in the Time 2 p < 0.0001) and the BAFO% ((in the Time 1 p = 0.0002 and in the Time 2 p = 0.0045). In conclusion, the result data showed that the implants with the new macrogeometry, presenting the healing chambers in the threads, produced a significant enhancement in the osseointegration, accelerating the process.

Effect of Primary Stability and Soft- and Hard-Tissue Thickness on Marginal Bone Loss: A Prospective Pilot Study

OBJECTIVE

To compare prospectively the effect of different insertion torques (ITs) on marginal bone stability and study the effect of soft-tissue and buccal bone thickness as confounding factors while using a 3-dimensional radiographic evaluation.

MATERIALS AND METHODS

Thirty-nine implants were placed in 22 patients. IT, soft-tissue thickness, and buccal bone thickness were recorded at implant placement. Marginal bone loss was evaluated on individualized periapical radiographs and cone-beam computed tomography at 1 year after loading.

RESULTS

Three groups of implants emerged based on their IT: group I (<30 Ncm), group II (between 30-45 Ncm), and group III (>45 Ncm). Soft-tissue thickness was ≤2 mm in 10 implants (25.6% thin biotype) and more than 2 mm in 29 implants (74.4% thick biotype). No significant difference in marginal bone loss was found for different IT and different soft-tissue thickness. A significant correlation was found between initial buccal bone thickness (≥2 mm or <2 mm) and marginal bone loss at 1 year.

CONCLUSIONS

IT and mucosal tissue thickness did not influence marginal bone loss. Buccal bone thickness of ≥2 mm was associated with a minimal marginal bone remodeling.

Stability of tapered and parallel-walled dental implants: A systematic review and meta-analysis

BACKGROUND

Clinical trials have suggested that dental implants with a tapered configuration have improved stability at placement, allowing immediate placement and/or loading. The aim of this systematic review and meta-analysis was to evaluate the implant stability of tapered dental implants compared to standard parallel-walled dental implants.

MATERIALS AND METHODS

Applying the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement, randomized controlled trials (RCTs) were searched for in electronic databases and complemented by hand searching. The risk of bias was assessed using the Cochrane Collaboration's Risk of Bias tool and data were analyzed using statistical software.

RESULTS

A total of 1199 studies were identified, of which, five trials were included with 336 dental implants in 303 participants. Overall meta-analysis showed that tapered dental implants had higher implant stability values than parallel-walled dental implants at insertion and 8 weeks but the difference was not statistically significant. Tapered dental implants had significantly less marginal bone loss compared to parallel-walled dental implants. No significant differences in implant failure rate were found between tapered and parallel-walled dental implants.

CONCLUSIONS

There is limited evidence to demonstrate the effectiveness of tapered dental implants in achieving greater implant stability compared to parallel-walled dental implants. Superior short-term results in maintaining peri-implant marginal bone with tapered dental implants are possible. Further properly designed RCTs are required to endorse the supposed advantages of tapered dental implants in immediate loading protocol and other complex clinical scenarios.

Anatomic Customization of Root-Analog Dental Implants With Cone-Beam CT and CAD/CAM Fabrication: A Cadaver-Based Pilot Evaluation

Existing root-analog dental implant systems have no standardized protocols regarding retentive design, surface manipulation, or prosthetic attachment design relative to the site's unique anatomy. Historically, existing systems made those design choices arbitrarily. For this report, strategies were developed that deliberately reference the adjacent anatomy, implant and restorable path of draw, and bone density for implant and retentive design. For proof of concept, dentate arches from human cadavers were scanned using cone-beam computed tomography and then digitally modeled. Teeth of interest were virtually extracted and manipulated via computer-aided design to generate root-analog implants from zirconium. We created a stepwise protocol for analyzing and developing the implant sites, implant design and retention, and prosthetic emergence and connection all from the pre-op cone-beam data. Root-analog implants were placed at the time of extraction and examined radiographically and mechanically concerning ideal fit and stability. This study provides proof of concept that retentive root-analog implants can be produced from cone-beam data while improving fit, retention, safety, esthetics, and restorability when compared to the existing protocols. These advancements may provide the critical steps necessary for clinical relevance and success of immediately placed root-analog implants. Additional studies are necessary to validate the model prior to clinical trial.

Ex Vivo Evaluation of Cementless Acetabular Cup Stability Using Impact Analyses with a Hammer Instrumented with Strain Sensors

The acetabular cup (AC) implant stability is determinant for the success of cementless hip arthroplasty. A method based on the analysis of the impact force applied during the press-fit insertion of the AC implant using a hammer instrumented with a force sensor was developed to assess the AC implant stability. The aim of the present study was to investigate the performance of a method using a hammer equipped with strain sensors to retrieve the AC implant stability. Different AC implants were inserted in five bovine samples with different stability conditions leading to 57 configurations. The AC implant was impacted 16 times by the two hammers consecutively. For each impact; an indicator I_S (respectively I_F) determined by analyzing the time variation of the signal corresponding to the averaged strain (respectively force) obtained with the stress (respectively strain) hammer was calculated. The pull-out force F was measured for each configuration. F was significantly correlated with I_S (R² = 0.79) and I_F (R² = 0.80). The present method has the advantage of not modifying the shape of the hammer that can be sterilized easily. This study opens new paths towards the development of a decision support system to assess the AC implant stability.

Relationship between implant stability measurements obtained by insertion torque and resonance frequency analysis: A systematic review

BACKGROUND

The primary stability of dental implants can be evaluated by insertion torque (IT) and resonance frequency analysis (RFA).

OBJECTIVE

Assess the supposed relationship between the IT and RFA.

MATERIALS AND METHODS

A systematic review was performed based on the PRISMA. The electronic search was performed in the PubMed, Web of Science, SCOPUS, Cochrane Library electronic, OVID, and Scielo databases. Manual searches were also performed. There was no restrictions regarding year of publication or language. The articles identified were assessed independently by 3 trained researchers. Clinical trials reporting the RFA values by means of implant stability quotient (ISQ) and IT were included.

RESULTS

The electronic and manual searches yielded 2017 studies. Twelve studies were included in the systematic review. There was no statistically significant correlation between ISQ and IT (r_s  = .366; P = .079). The quality of the evidence was downgraded by risk of bias and indirectness; and the certainty of the evidence was low.

CONCLUSION

IT and RFA are independent and incomparable methods of measuring primary stability. Is important for clinicians to define only one method of evaluation for each implant.

Incidence and Determinants of Dental Implant Failure: A Review of Electronic Health Records in a U.S. Dental School

The aim of this study was to use electronic health care records (EHRs) to examine retrospectively the incidence of and attributes associated with dental implant failures necessitating implant removal in a large cohort of patients treated in the student clinics of a U.S. dental school over three and a half years. EHRs were searched for all patients who received dental implants between July 1, 2011, and December 31, 2014. Characteristics of patients and implants that were actively removed due to irrevocable failure of any etiology ("failure cohort") during this period were compared to those of all other patients who received dental implants during the same time frame ("reference cohort"). Differences in the frequency distribution of various characteristics between the failure and reference cohorts were compared. Of a total 6,129 implants placed in 2,127 patients during the study period, 179 implants (2.9%) in 120 patients (5.6%) were removed. In the multivariate analysis, presence of a removable (OR=2.86) or fixed temporary prosthesis (OR=3.71) was statistically significantly associated with increased risk for implant failure. In contrast, antibiotic coverage (pre- and post-surgery OR=0.16; post-surgery only OR=0.38) and implants of certain manufacturers were associated with lower risk of implant failure. In this sizeable cohort of patients receiving care in dental student clinics, the review of EHRs facilitated identification of multiple variables associated with implant failure resulting in removal; however, these findings do not suggest causative relationships. The adopted analytical approach can enhance quality assurance measures and may contribute to the identification of true risk factors for dental implant failure.

Parameters to Define Peri-Implantitis: A Review and a Proposed Multi-Domain Scale

Peri-implant diseases have received much attention since dental implants are generally used in contemporary dentistry. Several contributing factors associated with the development of peri-implant diseases have also been investigated. The prevalence of peri-implantitis has been reported but with great heterogeneity because of a lack of a universally accepted classification system that could define the extent and severity of peri-implantitis. Several parameters-including radiographic bone loss, probing depth, bleeding on probing, and suppuration-have been introduced in these reports to assist with clinical diagnosis. This article provides an objective evaluation of these parameters based on currently available evidence, offers further recommendations, and proposes a multidomain scale for diagnosis of peri-implantitis. Future investigations and modifications may be needed to develop a comprehensive, evidence-based classification system that addresses the multifactorial etiology of peri-implant diseases.

Tapered Implants in Dentistry: Revitalizing Concepts with Technology: A Review

The most common approach to lessen treatment times is by decreasing the healing period during which osseointegration is established. Implant design parameters such as implant surface, primary stability, thread configuration, body shape, and the type of bone have to be considered to obtain this objective. The relationship that exists between these components will define the initial stability of the implant. It is believed implant sites using a tapered design and surface modification can increase the primary stability in low-density bone. Furthermore, recent experimental preclinical work has shown the possibility of attaining primary stability of immediately loaded, tapered dental implants without compromising healing and rapid bone formation while minimizing the implant stability loss at compression sites. This may be of singular importance with immediate/early functional loading of single implants placed in poor-quality bone. The selection of an implant that will provide adequate stability in bone of poor quality is important. A tapered-screw implant design will provide adequate stability because it creates pressure on cortical bone in areas of reduced bone quality. Building on the success of traditional tapered implant therapy, newer tapered implant designs should aim to maximize the clinical outcome by implementing new technologies with adapted clinical workflows.

Comparison Between Cortical Drill and Cortical Tap and Their Influence on Primary Stability of Macro-Thread Tapered Implant in Thin Crestal Cortical Bone and Low-Density Bone

OBJECTIVE

To evaluate the effect of different surgical techniques on primary stability, particularly in poor-quality bone with or without a crestal cortical bone.

MATERIALS AND METHODS

Three implant site preparation techniques-undersized drilling (UD), undersized drilling and coronal widening with a cortical drill (UD + CD), undersized drilling and coronal tapping with a cortical tap (UD + CT)-were compared in 2 different low-density polyurethane bone models either with or without the crestal cortical bone. Insertion torque values (ITVs) for each technique was recorded.

RESULTS

Statistically significant difference was observed for all 3 surgical techniques. In the presence of a crestal cortical bone, the peak ITV for UD was the highest, UD + CT the second, and UD + CD the lowest. All peak ITVs remained significantly lower in the absence of a crestal cortical bone.

CONCLUSION

Our findings suggested that UD + CTmay be the most effective implant surgical technique to achieve an ideal primary stability in low-density bone with a thin crestal cortical bone layer. Also, this technique may prevent compression necrosis of the dense cortical bone.

Primary stability and osseointegration of dental implants in polylactide modified bone - A pilot study in Goettingen minipigs

The present study aimed to evaluate primary stability (PS) and osseointegration of dental implants in polylactide [70/30 poly(l-lactide-co-d, l-lactide); (PLDLA)] modified bone in 30 Goettingen minipigs. Each animal received three implants per jaw quadrant. In a split-mouth design, one side of the maxilla and mandible was randomly allocated to the experimental treatment (PLDLA applied into the drill hole before implantation), while the contralateral sides served as intraindividual controls (no PLDLA applied). The required insertion torque and the implant stability quotient (ISQ) were measured during implantation. ISQ, volume density (VD) of new bone formation (NBF), and the bone-implant contact (BIC) were evaluated at the end of the observation period (1, 3, 6, 12, and 24 months, respectively) in six animals each. Across all study groups, the PLDLA treatment resulted in a) a comparable insertion torque, b) an equivalent ISQ, c) a reduced BIC, and d) a reduced VD of NBF, as opposed to the untreated controls. In conclusion, the PLDLA treatment did not affect the PS, but rather led to an impaired osseointegration, which was particularly strong in the compact mandibular bone, and decreased in the spongious maxillary bone. PLDLA induced anchoring in spongious bone should be evaluated in further investigations.