Predicting osseointegration by means of implant primary stability

Correlation Between Implant Stability Quotient and Percussion Sound Frequency

OBJECTIVES

To determine the correlation between the primary implant stability quotient and the implant percussion sound frequency.

MATERIALS AND METHODS

A total of 14 pigs' ribs were scanned using a dental cone beam computed tomography (CBCT) scanner to classify the bone specimens into three distinct bone density Hounsfield units (HU) value categories: D1 bone: >1250 HU; D2: 850-1250 HU; D3: <850 HU. Then, 96 implants were inserted: 32 implants in D1 bone, 32 implants in D2 bone, and 32 implants in D3 bone. The primary implant stability quotient (ISQ) was analyzed, and percussion sound was recorded using a wireless microphone connected and analyzed with frequency analysis software.

RESULTS

Statistically significant positive correlations were found between the primary ISQ and the bone density HU value (r = 0.719; p < 0.001), and statistically significant positive correlations between the primary ISQ and the percussion sound frequency (r = 0.606; p < 0.001). Furthermore, significant differences in primary ISQ values and percussion sound frequency were found between D1 and D2 bone, as well as between D1 and D3 bone. However, no significant differences were found in primary ISQ values and percussion sound frequency between D2 and D3 bone.

CONCLUSION

The primary ISQ value and the percussion sound frequency are positively correlated.

Implant stability and clinical outcome between implant placement using internal sinus floor elevation with alloplastic bone material grafting and without grafting: A 1-year randomized clinical trial

OBJECTIVE

To compare implant stability and clinical outcome in implant placement between osteotome sinus floor elevation (OSFE) with biphasic calcium phosphate (BCP) which consisted of 30% of hydroxyapatite (HA) and 70% of beta-tricalcium phosphate (β -TCP) grafting material and OSFE without using bone grafting material. The research questions is whether the BCP provides any benefit in OSFE or not.

MATERIALS AND METHODS

Thirty patients (30 implants) with a single edentulous area of upper premolar or molar were randomly separated into OSFE with BCP (n = 15) and OSFE without grafting (n = 15). The patients were reevaluated 3, 6, 9, and 12 months after implant loading. The clinical assessments (implant stability quotient (ISQ), implant survival-failure rate, and surgical complication) were analyzed. Together with radiographic assessments in 2D (endo-sinus bone gain (ESBG), mean marginal bone change (MMBC)) and 3D (endo-sinus bone gain in CBCT (ESBG-CT)) were evaluated, with a mean follow-up time of at least 12 months of functional loading and prosthetic complication.

RESULTS

20 remaining implants (OSFE with BCP, n = 10; OSFE without grafting, n = 10) were analyzed. Mean ISQ was 79.18 ± 3.43 in 1-year follow-up (ISQ; OSFE with BCP = 78.72 ± 3.46, OSFE without grafting = 79.65 ± 3.52). ISQ in both groups increased steadily without significant differences in each follow-up. (p = 0.56). In radiographic evaluation, at 6-, 9-, and 12-month, OSFE without grafting group showed statistically significant lower MMBC (p < 0.05). The 1-year clinical results showed that 2 implants failed in OSFE with BCP, and 1 implant failed in OSFE without grafting.

CONCLUSIONS

Graft material "BCP" (HA30:TCP70) coupled with OSFE presents no extraordinary benefit in implant stability, clinical and radiographic outcome in 1-year follow-up.

CLINICAL RELEVANCE

Clinically, OSFE with grafting materials provides no additional benefit.

CLINICAL TRIAL REGISTRATION NUMBER

TCTR20210517008 (date of registration: May 17, 2021).

A scoring system to evaluate stability of percutaneous osseointegrated implants for transfemoral amputation with validation in the ITAP clinical trial

Percutaneous osseointegrated implants for individuals with lower limb amputation can increase mobility, reduce socket related pain, and improve quality of life. It would be useful to have an evaluation method to assess the interface between bone and implant. We assessed outpatient radiographs from the Intraosseous Transcutaneous Amputation Prosthesis clinical trial using an interface scoring system which summed and weighted equally measures of implant collar cortical ongrowth and radiolucency along the implant stem/bone interface. Radiographs from 12 participants with unilateral transfemoral amputations (10 males, 2 females, mean age = 43.2, SD = 7.4 years) in the clinical trial from cohort I (implanted in 2008/09) or cohort II (implanted in 2013/14) were collated (mean image span = 7.2, SD = 2.4 years), scale normalised, zoned, and measured in a repeatable way. Interface scores were calculated and then compared to clinical outcomes. Explanted participants received the lowest interface scores. A higher ratio of stem to residuum and shorter residuum's produced better interface scores and there was an association (weak correlation) between participants with thin cortices and the lowest interface scores. A tapered, cemented, non curved stem may provide advantageous fixation while stem alignment did not appear critical. In summary, the interface score successfully demonstrated a non-invasive evaluation of percutaneous osseointegrated implants interfaces when applied to the Intraosseous Transcutaneous Amputation Prosthesis clinical trial. The clinical significance of this work is to identify events leading to aseptic or septic implant removal and contribute to clinical guidelines for monitoring rehabilitation, design and surgical fixation choices.

Influence of Multiple Sterilization on Performance of Titanium Pegs When Measuring Implant Stability With Resonance Frequency Analyses

This in vitro study was conducted to investigate the repeatability of the implant stability quotients (ISQ) measured with multipegs after numerous sterilizations and to detect the exact time when the readings start to deviate. Multipegs were sterilized with 3 different methods (autoclaved, autoclaved + ultrasonic cleaner, chemical disinfection + autoclaved) and grouped according to the method applied. All specimens were put into the autoclave with sealed packages every time they were sterilized. Each specimen was sterilized 50 times according to the technique described in its group after an ISQ measurement was performed. Results of the 2-way analysis of variance showed that neither the sterilization method nor the cycles, nor their interaction, were statistically significant. A multipeg may be reused multiple times after sterilization procedures and may be more cost-effective than a disposable smartpeg for checking implant stability after confirming these results in further investigations.

Combination of leukocyte and platelet-rich fibrin and demineralized bovine bone graft enhanced bone formation and healing after maxillary sinus augmentation: a randomized clinical trial

BACKGROUND AND OBJECTIVE

The resorption of alveolar ridge bone and maxillary sinus pneumatization are challenges to implant-supported prosthetic rehabilitation. Bone regeneration using bone substitutes and growth factors are alternatives for maxillary sinus augmentation (MSA). Therefore, we sought to evaluate the effects of the association between leukocyte and platelet-rich fibrin (L-PRF) and deproteinized bovine bone mineral (DBBM) in MSA procedures.

MATERIALS AND METHODS

Thirty-six maxillary sinuses from 24 individuals were included in this randomized clinical trial. The maxillary sinuses were randomly grafted with LPRF and DBBM (test group) or grafted only with DBBM (positive control). Dental implants were installed in the test group following two periods of evaluation: after 4 (DBBM+LPRF4) and 8 (DBBM+LPFR8) months of sinus graft healing, while the control group received implants only after 8 months. Cone beam computed tomography (CBCT) was taken 1 week after surgery (T1) and before implant placement (T2). Bone samples were collected during implant placement for histomorphometric and immunohistochemical (IHC) analysis. The primary implant stability was assessed by resonance frequency analysis.

RESULTS

CBCT analysis demonstrated a significant decrease in bone volume from T1 to T2 in all groups without differences among them. Histologically, the test group showed significantly increase in bone neoformation in both periods of evaluation (LPRF+DBBM4: 44.70±14.01%; LPRF+DBBM8: 46.56±12.25%) compared to the control group (32.34±9.49%). The control group showed the highest percentage of residual graft. IHC analysis showed increased staining intensity of osteocalcin (OCN), vascular endothelial growth factor (VEGF), and runt related transcription factor 2 (RUNX-2) in LPRF+DBBM4 group, and osteopontin (OPN) in the L-PRF+DBBM8. Primary implant stability was successfully achieved (above 60 in implant stability quotient) in all the evaluated groups.

CONCLUSION

Combination of L-PRF and DBBM increased and accelerated new bone formation allowing early implant placement probably due to the higher protein expression of RUNX2, VEGF, OCN, and OPN. These data suggest that the use of L-PRF might be an interesting alternative to use in combination with DBBM for augment the maxillary sinuses allowing the installation of appropriate length implants in shorter period of time.

CLINICAL RELEVANCE

This study showed improvement in bone neoformation and accelerated healing when associating L-PRF and DBBM for maxillary sinus augmentation procedures.

TRIAL REGISTRATION

This study was registered before participant recruitment in Brazilian Registry of Clinical Trials (ReBEC - RBR-95m73t).

Evaluation of Implant Stability According to Implant Placement Site and Duration in Elderly Patients: A Prospective Multi-Center Cohort Study

The aim of this prospective study is to investigate implant stability and the reliability of different measuring devices according to implant placement site and duration in patients aged over 65 years. The study evaluated 60 implants (diameter: 3.5/4.0/4.5/5.0 mm and length: 8.5/10.0/11.5 mm) in 60 patients aged ≥ 65 years. The implant placement sites were divided into six evenly distributed sections (n = 10), i.e., maxillary right-posterior, A; maxillary anterior, B; maxillary left-posterior, C; mandibular right-posterior, D; mandibular anterior, E; mandibular left-posterior, F. Participants visited the hospital six times: implant surgery, 1V; stitch removal, 2V; 1-month follow-up, 3V; 2-month follow-up, 4V; before final restoration delivery, 5V; and after final restoration delivery, 6V. The implant stability was evaluated with the Osstell Mentor (ISQ), Periotest M (PTV), and Anycheck (IST). The mean values of ISQ, PTV, and IST were analyzed (α = 0.05). ISQ, PTV, and IST results of 4V and 5V were significantly higher than those of 1V (p < 0.05). The lowest ISQ results occurred in the E location at 4V and 5V (p < 0.05). In all mandibular locations, IST results of 6V were significantly higher than those of 1V, 2V, 3V, and 4V (p < 0.05). ISQ results were negatively correlated with PTV and positively correlated with IST, and PTV was negatively correlated with IST. By considering various factors affecting the stability of the implant, it is necessary to determine the appropriate implant load application time. This could help increase the implant success rate in elderly patients. And as a diagnostic device for implant stability and the evaluation of osseointegration in elderly patients, Anycheck was also able to prove its relative reliability compared to Osstell ISQ Mentor and Periotest M.

A three-year prospective cohort study evaluating implant stability utilising the osstell® and periotest™ devices

Objectives

To investigate implant stability measurements from two different devices and at three different time points in order to determine their level of correlation. To also evaluate the influence of a range of clinical characteristics on the values produced by the devices at these three time points.

Materials &amp; Methods

Measurements were recorded at implant placement (T1), implant exposure (T2) and at 3 years from implant placement (T3). A range of clinical data was collected including patient demographics and site characteristics. Stability measurements and clinical characteristics were recorded for 29 patients and 68 dental implants at T1, subsequent stability measurements were recorded for 67 implants at T2 and 58 implants at T3. Correlation testing between the Osstell® and Periotest™ devices was carried out utilising Spearman's rank correlation for each time point. Analysis of the difference between clinical factors and stability measurements was compared using Krushal-Wallis test for each variable and time point.

Results

A single dental implant failed shortly after 2nd stage surgery for an overall survival rate of 98% during the study timeline. The median ISQ value was 73.25 (IQR 67–75) at T1 and 74 (IQR 70.5–77) at T3. The median Periotest value was −4 (IQR −6, −2) at T1 and −6 (IQR −7, −5) at T3. The range of ISQ values observed was 50 (39–89) ISQ at T1 and decreased to 21 (61–82) ISQ at T3. The Periotest values ranged from 37 (29 to −8) at T1 and decreased to 6 (−2 to −8) at T3. A weak to moderate correlation was observed between mean ISQ and Periotest values across time-points T1, T2 and T3, (r = −0.26, p = 0.05), (r = −0.35, p &lt; 0.01) and (r = −0.28, p = 0.04) respectively.

Conclusions

Based on the results of this study there was a weak to moderate level of correlation between values recorded between the two measurement devices at implant placement, implant exposure and three years following placement. For both the Osstell® and Periotest™ a narrowing of the range of stability values was observed from T1 to T3. In general, Periotest™ seemed to be more sensitive in highlighting differences in measurements affected by local conditions.

Evaluation of active tactile sensibility in a single-tooth implant opposing a natural tooth with either an immediate or delayed functional loading protocol: A parallel design clinical study

STATEMENT OF PROBLEM

High primary stability makes immediate loading more predictable, but immediately loaded implants are subjected to higher stresses and strains during the healing phase than implants that are left to heal for 3 months. Whether an earlier sensory-motor phenomenon with an immediate loading protocol helps to reduce the risk of overloading at the implant-bone interface is unclear.

PURPOSE

The purpose of this concurrent parallel design clinical study was to evaluate and compare active tactile sensibility for a single-tooth implant opposing a natural tooth in the mandibular posterior region with either a delayed or immediate functional loading -protocol.

MATERIAL AND METHODS

In this parallel group randomized trial, 2 test groups were formed: the DL group comprised 20 participants with the delayed loading protocol (loading after 3 months), and the IL group comprised 20 participants with the immediate loading protocol (loading within 2 days). Natural tooth-to-tooth contact on the side contralateral to the implant site (split mouth) in both test groups was used as a control to evaluate active tactile sensibility, which was evaluated in the test and control sites of both groups by using interocclusal articulating foils of varying thickness in maximum intercuspation. Active tactile sensibility was compared between the DL and IL groups at 3 and 6 months of follow-up. The nonparametric Mann-Whitney test was used for intergroup comparisons (P=.05).

RESULTS

A significant difference was found for 8-μm- and 12-μm-thick articulating foil at 3 months and for 8-μm-thick foil at 6 months (P<.05), indicating a difference in active tactile sensibility between the DL and IL groups. No implant failure was recorded in this short clinical study.

CONCLUSIONS

An immediate loading protocol can be performed in implants with sufficient primary stability. Upon loading, the IL group has shown more active tactile perception than the DL group.

Construction of a Rough Surface with Submicron Ti2Cu Particle on Ti-Cu Alloy and Its Effect on the Antibacterial Properties and Cell Biocompatibility

Titanium-copper (Ti-Cu) alloy is an advanced antibacterial material with excellent mechanical properties, thermodynamic stability, corrosion resistance and biocompatibility. Sandblasting and acid-etching was applied to the Ti-3Cu alloy to construct a rough surface with Ti2Cu phase on the surface in order to improve the antibacterial properties and the osseointegration. The phase constitutes and the physical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and confocal laser scanning microscope (CLSM), and the surface chemical properties were analyzed by X-ray photoelectron spectroscopy (XPS) and electrochemical testing. The antibacterial property was assessed by the plate-count method and the cell compatibility was evaluated by the CCK-8 test in order to reveal the effect of surface characteristics on the antibacterial ability and bioactivity. The results demonstrated a rough and lamellar surface structure with many submicron Ti2Cu particles on the surface of Ti-3Cu, which could enhance the antibacterial ability and promote the cell proliferation and the initial adhesion of osteoblasts. However, the surface treatment also reduced the corrosion resistance and accelerated the Cu ion release.

[Possibilities and prospects for experimental and clinical instrumentation techniques for determining the primary stability of dental implants in comparative analysis]

The high primary stability of dental implants provides a favorable prognosis for orthopedic treatment with implant-supported structures. The importance of assessing the stability and the bone tissue surrounding the implant as a whole is due to the fact that the process of osseointegration is a structural and functional connection between the bone and the loaded surface of the implant. Determination of the dynamics of the stability of dental implants allows timely monitoring of unpredictable changes at the stages of osseointegration and remodeling of bone tissue around the implant. Currently, in addition to clinical and radiation diagnostic methods, there are generally recognized by clinicians frequency resonance analysis and periotestometry. However, there are some scientific discrepancies indicating the lack of objectivity of these methods and the impossibility of their full-fledged application without the support of radiation and clinical diagnostic methods. In addition to these methods, there are many experimental and less common methods in clinical practice for assessing the primary stability of implants, but with reasonable objectivity. Thus, the reasons are given that for a full assessment of the relationship between the efforts exerted on implants and their movements in the space of bone tissue, devices are needed that reflect the stability and density of the contact of the implant with bone tissue in physical quantities. In particular, methods based on lasers, sound, quantitative ultrasound, and others have found experimental practical application. The ultrasound method of assessing the primary stability of the implant is estimated as the most promising, since it allows you to demonstrate the results of studies in certain physical quantities, as well as to compare these results with histomorphological indicators of osseointegration of dental implants.

Efficacy of bone grafting materials in preserving the alveolar ridge in a canine model

Preservation of the alveolar ridge after tooth extraction is an essential component for ideal implant positioning. Furthermore, preservation of bone around the implant after implant placement is an essential component for implant treatment. We aimed to evaluate the efficacy of bone grafting materials in preserving the alveolar ridge after implant placement. Implants were placed in regenerated bone without grafting material or with beta-tricalcium phosphate, bovine bone substitute, or carbonate apatite transplantation. In all groups, the bone healed and the implants were successfully placed within the bone. No significant differences in insertion torque and implant stability quotient values were found. The amount of bone around the implant 5 weeks after implant placement was significantly reduced in the bovine bone substitute group; however, implants placed in regenerated bone achieved sufficient initial fixation and osseointegration.

The Effect of Bone Density Measured by Cone Beam Computed Tomography and Implant Dimensions on the Stability of Dental Implants

ABSTRACT

The aim of this study was to evaluate the effect of bone density value in Hounsfield unit derived from cone beam computed tomography (CBCT), and implant dimensions in relation to implant stability parameters namely the resonance frequency analysis and the insertion torque (IT) value. It included 24 patients who received 42 dental implants (DI). The bone density of the planned implant site was preoperatively measured using cone beam computed tomography. The implant stability was measured using Osstell implant stability quotient (ISQ). The ISQ values were recorded immediately postoperatively and after 16 weeks. The IT value was categorized as 35 N/cm or > 35 N/cm. The mean (standard deviation) primary stability was 79.58 (5.27) ISQ, which was significantly higher than the secondary stability 74.31 (6.34) ISQ (P < 0.0001). There was a significant moderate positive correlation of bone density with primary stability (r = 0.4, P = 0.0099) and no correlation with secondary stability (r = 0.003, P = 0.9867). The bone density of DI with 35 N/cm IT was significantly lower than with > 35 N/cm IT (P = 0.0390). Better stability was recorded with wider implants. Whereas the length of the DI showed a nonsignificant correlation with primary and secondary stability (P = 0.7633 and 0.4670, respectively). The DI dimensions showed a nonsignificant correlation with the IT. Cone beam computed tomography may be considered as a reliable method to assess bone density and predict the implant stability. The diameter of DI affected the implant stability favorably, whereas DI length showed no effect.

One-Abutment One-Time Effect on Peri-Implant Marginal Bone: A Prospective, Controlled, Randomized, Double-Blind Study

Objective: To evaluate the peri-implant hard tissue change at 6 and 12 months after implant placement between definitive abutment placed at the same time of implant surgery, never removing it, and healing abutment disconnected and reconnected three times until the placement of the final rehabilitation. Material and methods: Each partial edentulous patient could receive between 1 and 4 platform-switched implants in the posterior regions. If the implants had primary stability—implant stability quotient (ISQ) equal to or greater than 50, they were randomized to the test group with the abutment inserted at the same time of implant placement (DA) or to the control group, receiving a healing abutment (PA). At 6 and 12 months after surgery, data related with vertical bone level changes (primary outcome) and other clinical parameters (implant mobility, bleeding on probing, probing depth, plaque index) were assessed. Results: 53 implants were included in the trial and completed 12 months follow-up (overall survival rate: 100%). All implants achieved primary stability, with an average ISQ value of 80.9 on the day of surgery. From surgery to 6 months, the mean bone loss was 0.14 ± 0.18 mm for the DA group and 0.23 ± 0.29 mm for the PA group, without statistical significance difference. Between 6 and 12 months, the mean bone loss was 0.14 ± 0.21 mm for the DA group and 0.21 ± 0.27 mm for the PA group, also without statistical significance between the two groups. There were no statistically significant differences (p = 0.330) in total bone loss after 12 months between the control and the study groups. Conclusions: The one abutment one time protocol has at least an equivalent effect on the peri-implant bone level changes when compared with the use of healing abutments that are disconnected and reconnected at least three times.

Comparison of sandblasted and acid-etched surface implants and new hydrophilic surface implants in the posterior maxilla using a 3-month early-loading protocol: a randomized controlled trial

Objectives

In this prospective randomized controlled trial, we measured the primary and secondary stability of two surface-treated implants placed in the posterior maxilla, applied 3-month loading protocols, and compared and analyzed the short-term outcomes of the implants.

Patients and Methods From June 2018 to June 2019, patients with a residual bone height of 4 mm in the posterior maxilla were enrolled and randomly divided into two groups to place SA implants (Osstem Implants, Korea) in Group A and NH implants (Hiossen, USA) in Group B. Finally, 14 implants placed in 13 patients in Group A and 17 implants placed in 14 patients in Group B were analyzed. The measured primary and secondary stability of each implant was represented by implant stability quotient (ISQ), and treatment outcomes were evaluated.

Results

Group A consisted of patients with an average age of 62.2 years (range, 48-80 years), and Group B consisted of patients with an average age of 58.1 years (range, 35-82 years). Primary stability was 73.86±6.40 and 71.24±5.32 in Groups A and B, respectively (P=0.222). Secondary stability was 79.07±5.21 in Group A and 78.29±4.74 in Group B (P=0.667). A steep increase in ISQ during the healing period was observed in Group B, though it was not significant (P=0.265). The mean follow-up period was 378.5±164.6 days in Group A and 385.3±167.9 days in Group B. All implants in each group met the success criteria, and the success rate was 100%.

Conclusion

Two surface-treated implants placed in the posterior maxilla with greater than 4 mm alveolar bone height exhibited successful one-year treatment outcomes if a primary stability of 65 or higher ISQ was obtained and a 3-month early loading protocol was applied.

Osseodensification effect on implants primary and secondary stability: Multicenter controlled clinical trial

Background

Osseodensification (OD) has shown to improve implant stability; however, the influences of implant design, dimensions, and surgical site characteristics are unknown.

Purpose

To compare the insertion torque (IT) and temporal implant stability quotients (ISQ) of implants placed via OD or subtractive drilling (SD).

Materials and Methods

This multicenter controlled clinical trial enrolled 56 patients, whom were in need of at least 2 implants (n = 150 implants). Patients were treated with narrow, regular, or wide implants and short, regular, or long implants in the anterior or posterior region of the maxilla or in the posterior region of the mandible. Osteotomies were performed following manufacturers recommendation. IT was recorded with a torque indicator. ISQ was recorded with resonance frequency analysis immediately after surgery, 3 and 6 weeks.

Results

Data complied as a function of osteotomy indicated significantly higher IT for OD relative to SD. OD outperformed conventional SD for all pairwise comparisons of arches (maxilla and mandible) and areas operated (anterior and posterior), diameters and lengths of the implants, except for short implants. Overall, ISQ data also demonstrated significantly higher values for OD compared to SD regardless of the healing period. Relative to immediate readings, ISQ values significantly decreased at 3 weeks, returning to immediate levels at 6 weeks; however, ISQ values strictly remained above 68 throughout healing time for OD. Data as a function of arch operated and osteotomy, area operated and osteotomy, implant dimensions and osteotomy, also exhibited higher ISQ values for OD relative to SD on pairwise comparisons, except for short implants.

Conclusions

OD demonstrated higher IT and temporal ISQ values relative to SD, irrespective of arch and area operated as well as implant design and dimension, with an exception for short implants. Future studies should focus on biomechanical parameters and bone level change evaluation after loading.

Short Dental Implants (≤8.5 mm) versus Standard Dental Implants (≥10 mm): A One-Year Post-Loading Prospective Observational Study

Background: Recent data have shown that short dental implants can be the preferred treatment in most of cases of posterior atrophic alveolar ridges, offering higher survival and lower complication rates than long implants. The survival rates, stability, and marginal bone level changes were compared between short implants (7 and 8.5 mm) and standard-length implants (≥10 mm). Methods: Prospective observational study in which adult patients requiring ≥1 osseointegrated implants to replace missing teeth were recruited consecutively. A clinical examination was performed on the day the definitive prosthesis was placed and after 6 and 12 months. Implant stability quotient (ISQ), marginal bone level (MBL) changes, and the correlation between these parameters and the characteristics of the implants were evaluated. Results: A total of 99 implants were inserted (47 short, 52 standard) in 74 patients. The 12-month survival rate was 100%. ISQ values showed a similar pattern for both types of implants. No correlation was found between ISQ changes after one year and MBL values, nor between the latter and the characteristics of the implants. Conclusions: With clinical treatment criteria, shorter implants (7 and 8.5 mm in length) can be just as useful as standard-length implants in atrophic alveolar ridges, demonstrating similar rates of survival, stability, and crestal bone loss.

The Influence of the Implant Macrogeometry on Insertion Torque, Removal Torque, and Periotest Implant Primary Stability: A Mechanical Simulation on High-Density Artificial Bone

Background: The primary stability is a determinant clinical condition for the success of different dental implants macro-design in different bone density using a validated and repeatable in vitro technique employing solid rigid polyurethane blocks. Materials and Methods: Five implants 3.8 × 13 mm2 for each macro-design (i.e., IK—tapered; IC—cylindric; and IA—active blade shape) were positioned into 20- and 30- pounds per cubic foot (PCF) polyurethane blocks. Bucco-lingual (BL) and mesial-distal (MD) implant stability quotient score (ISQ) was assessed by resonance frequency analysis while, insertion/removal torques were evaluated by dynamometric ratchet. Results: IC implants shown better primary stability in terms of ISQ compared to IA and IK in lower density block (20 PCF), while IK was superior to IA in higher density (30 PCF). IC shown higher removal torque in 30-PCF compared to IA and IC. Conclusions: The study effectiveness on polyurethane artificial bone with isotropic symmetry structure showed that the implants macro-design might represent a key factor on primary stability, in particular on low-density alveolar bone. Clinicians should consider patients features and implant geometry during low-density jaws rehabilitation. Further investigations are needed to generalize these findings.

Prognosis of single tooth implants following alveolar ridge preservation with two recombinant human bone morphogenetic protein-2 delivery systems

Background

We previously reported similar efficacies of alveolar ridge preservation (ARP) on single extraction socket with two different E. coli derived recombinant human bone morphogenetic protein-2 (rhBMP-2) delivery systems (Cowell BMP, Cowell medi Co, Busan, Korea; β-tricalcium phosphate and hydroxyapatite particle & O-BMP, Osstem Implant Co, Busan, Korea; absorbable collagen sponge). After the trial, we completed implant therapy and observed over an average of 3 years. This follow-up study was performed retrospectively to compare result of implant treatment at the preserved alveolar ridge site.

Methods

Patients who underwent extraction of single tooth and received ARP with one of two rhBMP-2 delivery systems from October 2015 to October 2016 were enrolled. Twenty-eight patients (Group 1: Cowell BMP 14; Group 2: O-BMP 14) who underwent implant therapy and prosthetic treatment were included in study. Stability and marginal bone loss (MBL) of each implant were collected from medical charts and radiographs, and analyzed. The survival and success rates of implants were calculated.

Results

The primary implant stability represented by implant stability quotient (ISQ) for Groups 1 and 2 was 69.71 and 72.86, respectively. The secondary implant stability for Groups 1 and 2 was 78.86 and 81.64, respectively. Primary and secondary stabilities were not statistically different (P = 0.316 and 0.185, respectively). MBL at the latest follow-up was 0.014 mm in Group 1 over 33.76 ± 14.31 months and 0.021 mm in Group 2 over 40.20 ± 9.64 months, with no significant difference (P = 0.670). In addition, the success rate of implants was 100% (14/14) in Group 1 and 92.9% (13/14) in Group 2, with survival rate of 100% (14/14) in Group 1 and 92.9% (13/14) in Group 2.

Conclusions

We confirmed good prognosis in both groups as a result of implant therapy after ARP with each of two rhBMP-2 carriers.

Influence of Smoking on Dental Implant Osseointegration: A Radiofrequency Analysis of 194 Implants

Although many studies have related smoking to peri-implantitis and marginal bone loss, little is known of its potential impact on dental implant osseointegration. The present clinical study explores the influence of smoking on secondary stabilization based in radiofrequency analysis. A total of 194 implants in 114 patients were included. Implant stability was evaluated on the day of surgery and at a minimum of 90 days after implantation, when osseointegration is considered to have been completed. The evolution of implant stability was compared between 2 groups: smokers and nonsmokers. The following variables were also analyzed: implant brand and model, length, diameter, insertion torque, bone density according to the Misch classification, location of the implant, and patient age and gender. The results showed that smoking did not affect the primary stability of the implant, although it was associated with a marked decrease in secondary stability. The nonsmokers showed a gain of 2.69 points (95% confidence interval [CI]: 1.529-3.865; P < .001) in the osseointegration process. However, in the smokers group, implant stability was seen to decrease 0.91 points (95% CI: -3.424 to 1.600; P < .004), generating a difference of 3.61 points between smokers and nonsmokers. Smoking is thus concluded to be an important factor that must be taken into account when seeking good implant osseointegration outcomes.

A Radiographic and Clinical Comparison of Immediate vs. Early Loading (4 Weeks) of Implants with a New Thermo-Chemically Treated Surface: A Randomized Clinical Trial

Background: Implant dentistry has evolved over time, resulting in better treatment outcomes for both patients and clinicians. The aim of this trial was to test whether the immediate loading of implants with a platform-switching design influences the marginal bone level, compared to four-week loading, after one year of follow-up. Moreover, a comparison of clinical data regarding implant survival, implant stability, and patient-reported outcome measures (PROMs) was conducted. Methods: Klockner^® VEGA^® implants with a ContacTi^® surface were placed in partially edentulous patients in the posterior areas. Group A received an immediately loaded prosthesis (one week) and Group B received an early-loaded prosthesis (four weeks). All abutments were placed at the time of surgery. Radiographic and clinical data were recorded. Results: Twenty-one patients were treated (35 implants). No implants were lost during the study. The final marginal bone level did not show differences between groups. The bone loss at 12 months at the implant level was 0.00 mm for both groups (median). The final implant quotient stability (ISQ) values did not differ between groups (median 73 and 70.25), nor did the other clinical parameters or PROMs. Conclusions: The results suggest that neither of the loading protocols with the implants used influenced the marginal bone level—not the osseointegration rate, clinical conditions, or PROMs.

Effect of leukocyte and platelet rich fibrin (L-PRF) on stability of dental implants. A systematic review and meta-analysis

The aim of this study was to assess the impact, if any, of L-PRF application in an implant bed prior to implant placement, focusing on stability by means of implant stability quotient (ISQ) values. The literature was searched in a systematic way by means of the main databases and hand searching of the most relevant journals. The inclusion and exclusion criteria were used to determine the eligible studies included in this review. Only randomised controlled trials (RCT) and controlled clinical trials (CCT) were included. A total of four RCTs were included for data extraction. The risk of bias was deemed moderate to unclear. Meta-analysis was performed to assess the effect of L-PRF, on implant stability, immediately post-insertion in three studies, after one week from the implant placement in three studies and after four weeks for all the included studies. The fixed effects model has shown Hedges g statistic for the one week varying from 0.380 to 1.401 with a pooled figure of 0.764 (95% CI 0.443 to 1.085) and for four weeks varying between 0.74 and 1.1 with a combined effect of 0.888 (95% CI 0.598 to 1.177). The results for both intervals were in favour of the use of L-PRF while the statistical difference immediately post-insertion was not statistically significant. The present systematic review, though acknowledging its limitations, suggests that L-PRF has a positive effect on secondary implant stability and that needs to be correlated to the clinical practice to measure the actual clinical effect by means of reducing treatment times.

Biomechanical analysis of the press-fit effect in a conical Morse taper implant system by using an in vitro experimental test and finite element analysis

STATEMENT OF PROBLEM

The press-fit (Morse taper) implant system is commonly used to restore edentulous areas. However, abutment screws in this system may be damaged because of the 2- or 3-piece design, consequently causing complications. How these damaging situations occur is unclear.

PURPOSE

The purpose of this in vitro and finite element analysis (FEA) study was to elucidate the mechanisms of the press-fit implant system underlying abutment screw damage.

MATERIAL AND METHODS

The ANKYLOS implant system was used as a simulation model and for experimental test specimens. The experimental test was performed by using a material test system, and the obtained data were used to validate the FEA outcome. In the FEA simulation, the bilinear material property and nonlinear contact conditions were applied to simulate the process of tightening the abutment screw between the abutment and implant. A force of 300 N was then applied to the abutment to investigate the stress distribution and deformation of the implant system.

RESULTS

In the experimental test, the fracture site of all specimens was observed at the abutment-screw thread. All implants and abutments exhibited permanent bending deformation. The results of the FEA simulation generally concurred with the experimental outcomes.

CONCLUSIONS

The abutment torque used to generate the press-fit contact interface between the abutment and implant induced stresses within the implant components, substantially increasing the failure probability of the conical implant system during function.

PRIMARY STABILITY IN VARIOUS-LEVELS IMPACTED IMPLANTS: AN EX-VIVO STUDY

The aim of this study was to examine the primary stabilization of different vertically impacted bone implants. Implant stability was measured by resonance frequency analysis. Forty-five dental implants were used and divided into three groups. Group 1 was placed 4 mm (1/3 impacted), Group 2 was placed 8 mm (2/3 impacted), and Group 3 was placed 12 mm (fully impacted). Implant stability quotient values were measured on the longitudinal and transversal axis by two independent researchers. The fully-impacted group showed the significantly highest value among the groups (p < 0.05). There were statistically varying implant-stability quotient values between researchers. None of the 1/3 impacted implants' value reached a 70 implant-stability quotient value.

Factors Influencing Primary and Secondary Implant Stability—A Retrospective Cohort Study with 582 Implants in 272 Patients

The success rate of dental implants depends on primary and secondary stability. We investigate predictive factors for future risk stratification models. We retrospectively analyze 272 patients with a total of 582 implants. Implant stability is measured with resonance frequency analysis and evaluated based on the implant stability quotient (ISQ). A linear regression model with regression coefficients (reg. coeff.) and its 95% confidence interval (95% CI) is applied to assess predictive factors for implant stability. Implant diameter (reg. coeff.: 3.28; 95% CI: 1.89–4.66, p < 0.001), implant length (reg. coeff.: 0.67, 95% CI: 0.26–1.08, p < 0.001), and implant localization (maxillary vs. mandibular, reg. coeff.: −7.45, 95% CI: −8.70–(−6.20), p < 0.001) are significant prognostic factors for primary implant stability. An increase in ISQ between insertion and exposure is significantly correlated with healing time (reg. coeff.: 0.11, 95% CI: 0.04–0.19). Patients with maxillary implants have lower ISQ at insertion but show a higher increase in ISQ after insertion than patients with mandibular implants. We observe positive associations between primary implant stability and implant diameter, implant length, and localization (mandibular vs. maxillary). An increase in implant stability between insertion and exposure is significantly correlated with healing time and is higher for maxillary implants. These predictive factors should be further evaluated in prospective cohort studies to develop future preoperative risk-stratification models.

Biomechanical and histomorphometric analysis of endosteal implants placed by using the osseodensification technique in animal models: A systematic review and meta-analysis

STATEMENT OF PROBLEM

Osseodensification, a counterclockwise drilling technique for the placement of endosseous implants is a popular clinical technique. However, the effect of the osseodensification technique on primary implant stability, bone-implant contact, and bone area frequency occupancy is unclear.

PURPOSE

The purpose of this systematic review and meta-analysis was to investigate the biomechanical and histomorphometric outcomes of endosteal implants placed by using the osseodensification technique in animal models.

MATERIAL AND METHODS

An electronic search through Medline/PubMed, Lilacs, and Science Direct databases, and an additional manual search of the reference list of included articles was conducted by using specific keywords and Medical Subject Headings (MeSH) terms for articles in the English language and published up to April 31, 2020. Only animal studies comparing the biomechanical and histomorphometric outcomes of endosteal implants placed by using the osseodensification and conventional drilling protocol were included. The SYstematic Review Center for Laboratory animal Experimentation (SYRCLE) tool was used to determine the risk of bias assessment, and the quality of included studies was assessed by using Animal Research: Reporting in Vivo Experiments (ARRIVE) guidelines.

RESULTS

Nine studies were included. The results of the meta-analysis showed that the pooled weighted mean difference of the insertion torque value for the primary implant stability of endosseous dental implants placed by using the osseodensification technique was 2.270 (95% confidence interval [CI]=1.147 to 3.393; P<.001), the weighted mean difference of the percentage of bone-implant contact at 3 weeks was 0.487 (95% CI=0.220 to 0.754; P=.114), the weighted mean difference of the percentage of bone-implant contact at 6 weeks was 0.565 (95% CI=0.219 to 0.911; P=.448), the weighted mean difference of the percentage of bone area frequency occupancy at 3 weeks was 0.679 (95% CI=0.265 to 1.093; P=.073), and the weighted mean difference of the percentage of bone area frequency occupancy at 6 weeks was 0.391 (95% CI=-0.204 to 0.986; P=.027).

CONCLUSIONS

Limited data from animal studies suggest that the primary implant stability, bone-implant contact, and bone area frequency occupancy significantly improved for the endosteal implants placed by using the osseodensification technique compared with conventional drilling protocol. However, additional laboratory and clinical studies are recommended to provide stronger evidence.

Comparison of Measurements of Implant Stability by Two Different Radio Frequency Analysis Systems: An In Vitro Study

Aim:

To compare and evaluate the implant stability quotient (ISQ) measurements by two different radio frequency analysis (RFA) machines, Osstell Mentor and PenguinRFA.

Materials and Methods:

Twenty bone-level implants (3.7 × 10 mm2) were placed on a bovine bone in this in vitro study. The ISQ measurements were performed with the PenguinRFA and Osstell Mentor machines using the multipeg of the Penguin system. The measurements were repeated three times for each direction and an average ISQ value was calculated. The results were averaged (mean ± SD) and the intraclass correlation coefficient (ICC) was calculated to assess the relationship between the measurements.

Result:

The mean ISQ values for the Osstell and Penguin machines were 77.60 + 2.11 and 78.05 + 2.04, respectively. The ICC was 0.958. The ISQ values obtained from the Osstell and Penguin machines were significantly compatible ( P < .05).

Conclusion:

Both of the RFA devices provided similar and reliable ISQ measurements.

Morphological Evaluation of Bone by CT to Determine Primary Stability-Clinical Study

Background: Primary stability is an important prognostic factor for dental implant therapy. In the present study, we evaluate the relationship between implant stability evaluation findings by the use of an implant stability quotient (ISQ), an index for primary stability, and a morphological evaluation of bone by preoperative computed tomography (CT). Subjects and methods: We analyzed 98 patients who underwent implant placement surgery in this retrospective study. For all 247 implants, the correlations of the ISQ value with cortical bone thickness, cortical bone CT value, cancellous bone CT value, insertion torque value, implant diameter, and implant length were examined. Results: 1. Factors affecting ISQ values in all cases: It was revealed that there were significant associations between the cortical bone thickness and cancellous bone CT values with ISQ by multiple regression analysis. 2. It was revealed that there was a significant correlation between cortical bone thickness and cancellous bone CT values with ISQ by multiple regression analysis in the upper jaw. 3. It was indicated that there was a significant association between cortical bone thickness and implant diameter with ISQ by multiple regression analysis in the lower jaw. Conclusion: We concluded that analysis of the correlation of the ISQ value with cortical bone thickness and values obtained in preoperative CT imaging were useful preoperative evaluations for obtaining implant stability.

The reliability of Anycheck device related to healing abutment diameter

PURPOSE

The purpose of this in vitro study was to examine the reliability of the Anycheck device and the effect of the healing abutment diameter on the Anycheck values (implant stability test, IST).

MATERIALS AND METHODS

Thirty implants were placed into three artificial bone blocks with 10 Ncm, 15 Ncm, and 35 Ncm insertion torque value (ITV), respectively (n = 10). (1) The implant stability was measured with three different kinds of devices (Periotest M, Osstell ISQ Mentor, and Anycheck). (2) Five different diameters (4.0, 4.5, 4.8, 5.5, and 6.0 mm) of healing abutments of the same height were connected to the implants and the implant stability was measured four times in different directions with Anycheck. The measured mean values were statistically analyzed.

RESULTS

The correlation coefficient between the mean implant stability quotient (ISQ) and IST value was 0.981 (P<.01) and the correlation coefficient between the meant periotest value (PTV) and IST value was −0.931 (P<.01). There were no statistically significant differences among the IST values with different healing abutment diameters.

CONCLUSION

There was a strong correlation between the Periotest M and Anycheck values and between the ISQ and IST. The diameter of the healing abutment had no effect on the Anycheck values.

Next-Day Loading of a Bone-Anchored Hearing System: Preliminary Results

OBJECTIVES

To demonstrate the feasibility and efficacy for next-day loading of a percutaneous bone-anchored hearing device.

STUDY DESIGN

Multicenter prospective cohort study.

SETTING

Tertiary neurotologic referral centers.

SUBJECT AND METHODS

In this multicenter prospective study, a 4.5-mm laser-etched bone-anchored hearing device was implanted in adult subjects who had conductive/mixed hearing loss or single-sided deafness. One day following implantation, the surgical site was assessed for soft tissue reaction per the Holgers Scale, and implant stability was evaluated by manual palpation and resonance frequency analysis. On the same day, subjects were fitted with the processor. Follow-up evaluations were at 1 week, 4 weeks, 3 months, 6 months, and 12 months. The Glasgow Benefit Inventory and Abbreviated Profile of Hearing Aid Benefit questionnaires were completed postoperatively.

RESULTS

Fourteen devices were implanted in 12 subjects. Two subjects underwent bilateral implantation. Implant stability was rated as firm at every interval for all ears, and the Implant Stability Quotient values at 3 months were stable or increased as compared with day 1 measurements. Skin irritation was limited to Holgers grade 0 and 1, with the majority having no skin irritation. The mean Glasgow Benefit Inventory global score was +43.8, and the mean Abbreviated Profile of Hearing Aid Benefit global benefit score was 60.2%. All 14 implants have remained firmly anchored.

CONCLUSIONS

Next-day loading of this 4.5-mm-diameter percutaneous bone-anchored hearing device appears to be a feasible alternative to the original 3-month delayed loading. Although this is a preliminary study, the results support continued investigation of a next-day loading strategy.

Initial Stability Measurements of Implants Using a New Magnetic Resonance Frequency Analyzer With Titanium Transducers: An Ex Vivo Study

The establishment of dental implant stability is mandatory for successful osseointegration. Resonance frequency analysis (RFA) is the most frequently used method for the clinical measurement of implant stability. The purpose of the present study was to evaluate the reliability of the recently developed RF analyzer Penguin RFA and to compare it with the traditional RF analyzer Osstell ISQ. Sixty implants were inserted into fresh steer vertebrae and pelvis. Implant stability was measured using Penguin RFA by its transducers (multipegs) and Osstell ISQ by its transducers (smartpegs). Additionally, stability was measured by multipegs with Osstell ISQ and by smartpegs with Penguin RFA. The intraobserver and interobserver reliability of Penguin RFA were estimated by the intraclass coefficient (ICC). Mean implant stability quotients (ISQs) measured with Osstell ISQ were higher than the ISQs measured with Penguin RFA (P < .05). The intra- and interobserver reliability of Penguin RFA were considered as excellent (ICC > 0.7). For Osstell ISQ, no significance in ISQs was detected between the readings by smartpegs and multipegs (P > .05), while for Penguin RFA ISQs by smartpegs were significantly higher than the ISQs by multipegs (P <.05). The recently developed Penguin RFA is reliable and can be used in clinical practice for the measurement of dental implant stability regardless of the bone type. The multipegs originally manufactured for the Penguin RFA is also compatible with Osstell ISQ.

Influence of cortical bone and implant design in the primary stability of dental implants measured by two different devices of resonance frequency analysis: An in vitro study

Background

This study aimed to evaluate the effect of the implant design and the presence of cortical bone in the primary stability, as well as analyze the differences between the stability measurements obtained by two different resonance frequency analysis (RFA) devices.

Material and Methods

A total of 80 Klockner implants of two different models [40 Essential Cone implants (group A) and 40 Vega implants (group B)] were used. The implants were placed in two polyurethane blocks that simulated the mechanical properties of the maxillary bone. One block featured a layer of cortical bone that was absent from the other block. The primary stability of all implants was measured by insertion torque and RFA using two different devices: Penguin RFA and Osstell IDX.

Results

Primary stability was superior in the cortical bone in both torque and RFA. In the block containing cortical bone, group A implants obtained a greater insertion torque than did group B. The insertion torque was lesser in the bone lacking cortex. Regarding the ISQ of the implants, group A presented higher values in the block with cortical bone, but the values were lower in the block without cortical bone. There were no significant differences between the values obtained from the Osstell IDX and Penguin RFA.

Conclusions

The presence of cortical bone positively influences the primary stability of dental implants. The design of the implant also has a statistically significant influence on implant primary stability, although the impact depends on whether there is coronal cerclage or not. There were no statistically significant differences in the implant stability measurements obtained by two different devices.

Key words:Implant stability, resonance frequency analysis, torque, osstell, penguin, cortical.

Preliminary study of clinical outcomes for single implant-retained mandibular overdentures

This study evaluated marginal bone loss and prosthetic complications associated with single implant-retained mandibular overdentures (1-IODs) with locator attachments. The 1-IOD was placed in the mandibular midline by using a conventional loading protocol in 22 patients with an edentulous mandible. Marginal bone loss at the start of loading and 12 months postoperatively was assessed by radiographic and crestal bone evaluation. The crestal bone was defined as the distance between the customized abutment shoulder and the top of the bone, as indicated by probing. In addition, implant stability quotient and prosthetic complications were recorded. The cumulative implant survival rate was 95.5%. Median implant stability quotient remained greater than 80, and median radiographic bone loss was 0.56 mm. Crestal measurement showed a median crestal bone loss of 0.16, 0.43, 0.39, and 0.52 mm on the buccal, right, lingual, and left sides, respectively. Both radiographic and crestal bone loss values significantly differed between the start of implant loading and 12 months postoperatively (except on the buccal and lingual sides; P < 0.05). The need to replace the nylon insert was the most common complication. Conventional loading of a 1-IOD with a locator attachment resulted in a high survival rate, good implant stability, and acceptable marginal bone loss.

Use of resonance frequency analysis to evaluate the effects of surface properties on the stability of different implants

OBJECTIVES

We performed a randomized clinical study evaluating the stability of implants with different surfaces (alkali-modified or sandblasted) via resonance frequency analysis (RFA).

MATERIALS AND METHODS

Fourteen patients who were bilaterally edentulous in terms of their mandibular molars were enrolled. Implants with alkali-modified (bioactive) and sandblasted surfaces were randomly placed in either hemi-arch; the 50 implants used were identical in terms of diameter and length. RFA was used to measure the implant stability quotient (ISQ) immediately after placement (to assess primary stability) and 2, 6, and 12 weeks later.

RESULTS

The average RFA value for alkali-modified implants was significantly higher than that for sandblasted implants immediately after implantation, but the ISQs fell rapidly and were similar in the two groups at 2 and 6 weeks (p > .05); ISQ values were the same in the two groups at 3 months (p > .05).

CONCLUSIONS

Implants with alkali-modified surfaces were more stable than implants with sandblasted surfaces at all times after placement. The ISQs of bioactive implants exhibiting high-level primary stability fell to greater extents than did those of implants with sandblasted surfaces at 2 and 6 weeks postoperatively; both types of implant yielded similar clinical results at 12 weeks postoperatively.

Biomechanical Effects of a New Macrogeometry Design of Dental Implants: An In Vitro Experimental Analysis

The purpose of the present study was to measure and compare the insertion torque, removal torque, and the implant stability quotient by resonance frequency analysis in different polyurethane block densities of two implant macrogeometries. Four different polyurethane synthetic bone blocks were used with three cortical thickness: Bone 1 with a cortical thickness of 1 mm, Bone 2 with a cortical thickness of 2 mm, Bone 3 with a cortical thickness of 3 mm, and Bone 4, which was totally cortical. Four groups were created in accordance with the implant macrogeometry (n = 10 per group) and surface treatment: G1—regular implant design without surface treatment; G2—regular implant design with surface treatment; G3—new implant design without surface treatment; G4—new implant design with surface treatment. All implants used were 4 mm in diameter and 10 mm in length and manufactured in commercially pure titanium (grade IV) by Implacil De Bortoli (São Paulo, Brazil). The implants were installed using a computed torque machine, and following installation of the implant, the stability quotient (implant stability quotient, ISQ) values were measured in two directions using Osstell devices. The data were analyzed by considering the 5% level of significance. All implant groups showed similar mean ISQ values without statistical differences (p > 0.05), for the same synthetic bone block: for Bone 1, the value was 57.7 ± 3.0; for Bone 2, it was 58.6 ± 2.2; for Bone 3, it was 60.6 ± 2.3; and for Bone 4, it was 68.5 ± 2.8. However, the insertion torque showed similar higher values for the regular macrogeometry (G1 and G2 groups) in comparison with the new implant macrogeometry (G3 and G4 groups). The analysis of the results found that primary stability does not simply depend on the insertion torque but also on the bone quality. In comparison with the regular implant macrogeometry, the new implant macrogeometry decreased the insertion torque without affecting the implant stability quotient values.

Influence of Mucosal Thickness, Implant Dimensions and Stability in Cone Morse Implant Installed at Subcrestal Bone Level on the Peri-Implant Bone: A Prospective Clinical and Radiographic Study

The objective of this observational clinical study was to analyze the behavior of peri-implant tissues around cone Morse dental implants installed in the subcrestal bone position considering different clinical variables: Mucosal thickness, implant diameter, and implant length. Thirty patients were selected and included in the present study. Initially the thickness of the mucosa was measured by periapical radiographic and clinically (after the mucosal displaced). According to the planning for each treatment, implants with different dimensions (in length and diameter) were selected and used. Periapical radiographs were obtained at different times: Immediate postoperative (time t1) and 90 days after implantation (time t2). The initial stability of the implants (ISQ) was measured immediately of the implant insertion and 90 days after. The means and standard deviations of the ISQ values were in time t1 was 63.2 ± 6.99 (95% confidence interval (CI): 41 to 83) and in time t2 was 69.7 ± 7.09 (95% CI: 61 to 87). Overall mean of mesial and distal bone loss 90 days after the implantations were 1.11 ± 1.16 mm and 1.11 ± 1.15 mm, respectively. When the variables were considered, in all situations proposed, the bone loss showed differences statistically significant. In conclusion, the implant diameter and mucosal thickness variables showed an important effect on bone loss values. However, the implant length did not show an effect on the peri-implant behavior.

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.

Predictive values of resonance frequency analysis as a diagnostic tool in palatal implant loss

OBJECTIVES

To determine the diagnostic value of resonance frequency analysis (RFA) in predicting palatal implant (PI) loss.

MATERIALS AND METHODS

RFA values of 32 patients (study center at Mainz and Dresden) were evaluated in a prospective randomized controlled trial addressing clinical performance of two loading concepts on PI (Orthosystem, Straumann, Basel, Switzerland). Group 1: conventional loading after a 12-week healing period vs group 2: immediate loading within one week after insertion. Stability was assessed by RFA after surgical insertion (T1), one week (T2), and 12 weeks (T3) later.

RESULTS

All 32 PI were clinically stable after surgical insertion; 14 PI were loaded conventionally and 18 immediately. One implant in group 1 was lost 6 weeks after insertion. One drop-out was registered in group 2. One false positive and three false negative implant stability quotients (ISQ) were observed. ISQ values of clinically stable PI in group 1 were 67.2 (SD ± 9.5) at T1, 62.3 (SD ± 11.7) at T2, and 68.2 (SD ± 5.5) at T3. Group 2 showed 67.1 (SD ± 11.7) at T1, 65.4 (SD ± 10.4) at T2, and 72.3 (SD ± 5.6) at T3. Differences between groups were not statistically significant for starting time (P = .88) and change from T1 to T2: 0.08 but were significant from T1 to T3: P = .04; (regression analysis).

CONCLUSIONS

RFA had no sensitivity for prediction of stability. General decrease after primary stability and increase with secondary stability gives support for specificity. Within the limits of the study, only the diagnostic value of RFA identifying stable palatal implants could be confirmed.

Enhanced osteoconductivity on electrically charged titanium implants treated by physicochemical surface modifications methods

Biomimetic design is a key tenet of orthopedic device technology, and in particular the development of responsive surfaces that promote ion exchange with interfacing tissues, facilitating the ionic events that occur naturally during bone repair, hold promise in orthopedic fixation strategies. Non-bioactive nanostructured titanium implants treated by shot-blasting and acid-etching (AE) induced higher bone implant contact (BIC=52% and 65%) compared to shot-blasted treated (SB) implants (BIC=46% and 47%) at weeks 4 and 8, respectively. However, bioactive charged implants produced by plasma (PL) or thermochemical (BIO) processes exhibited enhanced osteoconductivity through specific ionic surface-tissue exchange (PL, BIC= 69% and 77% and BIO, BIC= 85% and 87% at weeks 4 and 8 respectively). Furthermore, bioactive surfaces (PL and BIO) showed functional mechanical stability (resonance frequency analyses) as early as 4 weeks post implantation via increased total bone area (BAT=56% and 59%) ingrowth compared to SB (BAT=35%) and AE (BAT=35%) surfaces.

Is clinical experience important for obtaining the primary stability of dental implants with aggressive threads? An ex vivo study

Background

The aim of this study was to investigate the clinicians’ experience on maintaining the primary stability of implants with aggressive threads belonging to a novel dental implant system.

Material and Methods

Three hundred implants with aggressive threads were inserted in fresh bovine ribs mimicking Type IV bone by five clinicians which were classified according to their previous experience of total number of implant insertion. An independent examiner measured the primary stability of all implants after insertion by using resonance frequency analysis (RFA), electronic percussive testing (EPT) and removal torque methods.

Results

No significant differences were detected between the stability values measured by the clinicians (p< 0.05) except the Periotest values (PTVs) of the non-experienced clinician. PTVs of the non-experienced clinician were significantly higher than the PTVs of the expert and good clinicians (p >0.05). Significantly higher stability values were detected in the secondary insertion of the non-experienced clinician as compared to her initial insertion values (p >0.05). No significant differences were detected between the first and second measurements of the other clinicians (p< 0.05).

Conclusions

Within the limitations of this ex-vivo study, it may be concluded that experience does not play an important role in maintaining the stability of implants with aggressive threads.

Key words:Implantology, experimental design, osseointegration.

Factors Influencing Resonance Frequency Analysis (RFA) Measurements and 5-Year Survival of Neoss Dental Implants

BACKGROUND

Diagnostic instruments based on resonance frequency analysis (RFA) can be utilised to assess dental implant stability during treatment and follow-up.

AIM

The aim of the present study was to investigate the influence of patient- and implant-related factors on implant stability and the 5-year implant survival. In addition, the influence of stability (ISQ value) at placement and abutment connection on implant survival was evaluated.

MATERIALS AND METHODS

RFA measurements from a total of 334 consecutive patients with 745 dental implants (Neoss Ltd., Harrogate, UK) were retrospectively analysed after at least 5 years in function. Statistics were used to evaluate the influence of the different variables on implant stability and implant survival. Odds ratio calculations were performed to compare the risk for implant failure using 60, 65, 70, and 75 ISQ as threshold levels at placement and loading.

RESULTS

A total of 20 implant failures in 14 patients were noted during the 5 years of follow-up, giving an overall cumulative survival rate (CSR) of 97.3% at the implant level and 95.8% at the patient level. Gender, jaw, position, bone quality, and implant diameter had an influence on implant stability at placement. Jaw, bone quality, and implant diameter had an influence on stability after 3-4 months of healing. More failures were observed in full than in partial rehabilitations. Age, gender, jaw, position, bone quantity, bone quality, implant diameter, and implant length had no influence on implant survival. Implants with ISQ values below the threshold levels showed lower survival rates compared to implants with values above these levels.

CONCLUSIONS

The present study showed a significantly higher risk for implant failure, showing an ISQ value below 70 and 75 at placement or after 3-4 months of healing. The results indicate that RFA measurements can be used to identify implants with increased risk for failure.

Relationship between cortical bone thickness and implant stability at the time of surgery and secondary stability after osseointegration measured using resonance frequency analysis

Purpose

It has been suggested that resonance frequency analysis (RFA) can measure changes in the stability of dental implants during osseointegration. This retrospective study aimed to evaluate dental implant stability at the time of surgery (primary stability; PS) and secondary stability (SS) after ossseointegration using RFA, and to investigate the relationship between implant stability and cortical bone thickness.

Methods

In total, 113 patients who attended the Tohoku University Hospital Dental Implant Center were included in this study. A total of 229 implants were placed in either the mandibular region (n=118) or the maxilla region (n=111), with bone augmentation procedures used in some cases. RFA was performed in 3 directions, and the lowest value was recorded. The preoperative thickness of cortical bone at the site of implant insertion was measured digitally using computed tomography, excluding cases of bone grafts and immediate implant placements.

Results

The mean implant stability quotient (ISQ) was 69.34±9.43 for PS and 75.99±6.23 for SS. The mandibular group had significantly higher mean ISQ values than the maxillary group for both PS and SS (P<0.01). A significant difference was found in the mean ISQ values for PS between 1-stage and 2-stage surgery (P<0.5). The mean ISQ values in the non-augmentation group were higher than in the augmentation group for both PS and SS (P<0.01). A weak positive correlation was observed between cortical bone thickness and implant stability for both PS and SS in all cases (P<0.01).

Conclusions

Based on the present study, the ISQ may be affected by implant position site, the use of a bone graft, and cortical bone thickness before implant therapy.

Impact of a zoledronate coating on early post-surgical implant stability and marginal bone resorption in the maxilla-A split-mouth randomized clinical trial

OBJECTIVES

The objective of this clinical study was to evaluate the effect of a bisphosphonate coating on a titanium implant on the implant stability quotient (ISQ) and the radiographic marginal bone levels at implants during early healing (2-8 weeks).

MATERIALS AND METHODS

In a randomized double-blind trial with internal controls, 16 patients received a dental implant coated with zoledronate and one uncoated implant as a control. The coated and uncoated implants which were visually indistinguishable were bone level titanium implants with a moderately rough surface and a microthreaded neck. ISQ values were obtained at insertion and at 2, 4, 6, and 8 weeks. Radiographs were obtained at insertion and at 8 weeks. The primary outcome was the difference in ISQ values between the coated implants and the control implants at 4 and 6 weeks, corrected for insertion values. The secondary outcome was loss of marginal bone level from insertion to 8 weeks.

RESULTS

Implant stability quotient values remained largely constant over the 8 weeks, and there was no significant difference between coated and uncoated implants at any time point. There was 0.12 (SD 0.10) mm marginal bone loss at the control implants and 0.04 (SD 0.08) mm at the coated implants. The difference was 0.17 mm; SD 0.14; p < 0.006). On blind qualitative scoring, 13 of the 15 control implants and two of 15 coated implants showed small marginal bone defects (p = 0.003).

CONCLUSIONS

There were no statistically significant differences observed in ISQ values between the coated and uncoated implants during the early healing. There was less marginal bone loss at the coated implants.

Short vs. Standard Laser-Microgrooved Implants Supporting Single and Splinted Crowns: A Prospective Study with 3 Years Follow-Up

PURPOSE

The aim of this study was to compare survival rates, marginal bone loss (MBL), and peri-implant soft tissue parameters between short and standard laser-microgrooved implants supporting single or splinted crowns 3 years after loading.

MATERIALS AND METHODS

30 subjects received 1 short ( ≤ 7 mm ) and 1 standard length ( ≥ 9 mm ) laser-microgrooved implant in adjacent sites of the premolar and molar regions of the mandible or maxilla. Peri-implant soft tissue parameters and intraoral radiographs were recorded at the delivery of definitive crowns (baseline) and 3 years later. Cumulative survival rate (CSR) and marginal bone loss (MBL) in relation to crown/implant (C/I) ratio, implant length, location, type of antagonist, and type of prosthetic design (single or splinted), were evaluated.

RESULTS

CSR of short implants was 98%, compared to 100% for standard implants, without significant statistical difference. MBL was not significantly different over the observation period, with an average of 0.23 ± 0.6 mm and 0.27 ± 0.3 mm for short and standard implants, respectively. No statistical differences were found between short and standard implants regarding plaque (14.7% vs. 15.7%), number of sites BOP (8.3% vs. 5.9%), probing depth (1.13 ± 0.6 mm vs. 1.04 ± 0.8 mm), and mean mucosal recession (0.18 ± 0.3 mm vs. 0.22 ± 0.3 mm). Analyzing MBL in relation to the C/I ratio, implant length, location, type of antagonist, and type of prosthetic design, no statistically significant differences were found.

CONCLUSION

Regardless of C/I ratio, implant length, location, type of antagonist, and type of prosthetic design, short and standard laser-microgrooved implants had similar survival rates, MBL, and peri-implant soft tissue conditions over the observation period of 3 years.