Changes in Tooth Mobility and Position in an Established Dentition Following Placement of a New Restoration

The aim of this study is to examine and evaluate physiologic tooth mobility and movement in different groups of patients. Four groups of patients were examined and recordings were taken. Group A1 consisted of 12 undergraduate students under the age of 30, A2 consisted of 11 members of staff over the age of 30 and A3 consisted of 9 patients with periodontal disease between the ages of 40-65 years old. The fourth Group B, 14 patients between 30-70 years old, received single-tooth restorations and recordings were taken immediately after, a month and four months following the cementation of the restoration. Patients in the first 3 groups showed no significant change in tooth mobility and movement between appointments. The fourth group demonstrated a non-statistically significant increase in tooth mobility following the cementation of the restoration due to the force applied on the occlusal surface of the tooth during the cementation process, while tooth movement was not observed beyond that of physiological tooth migration. Regardless of the age or the restorations a patient receives over the years, with careful occlusal consideration, no significant changes in tooth mobility and movement should be observed.

Effect of miniscrew insertion angle in the maxillary buccal plate on its clinical survival: a randomized clinical trial

INTRODUCTION

This study sought to assess the effect of miniscrew insertion angle (vertical and oblique) on its clinical survival under shearing forces in orthodontic patients undergoing canine retraction.

MATERIALS AND METHODS

In this split-mouth randomized controlled clinical trial, 50 miniscrews were placed bilaterally in 25 patients with 45° and 90° insertion angles relative to a line perpendicular to the occlusal plane distal to the maxillary first premolar extraction site. Allocation of insertion angles to the right/left side was random using the Random Allocation Software. The patients, clinician, and statistician were blinded to the allocation of miniscrews to the side of jaw. The patients were followed-up monthly for 6 months. The primary outcome was the clinical survival of miniscrews, which was evaluated at each follow-up session. The secondary outcomes were the miniscrew stability based on the Periotest value (PTV) and the level of pain experienced by patients at 1, 12, and 24 h, and 7 days after miniscrew placement using a visual analog scale (VAS). Data were analyzed using paired t-test, repeated measures ANOVA, and McNemar's test.

RESULTS

The clinical survival rate of miniscrews placed at 90° and 45° angles was 76% and 88%, respectively. This difference was not statistically significant (P = 0.375). No significant difference was noted between the two groups regarding the PTV or the pain score either (P > 0.05).

CONCLUSION

Clinically, the insertion angle of miniscrews (90° versus 45° relative to a line perpendicular to the occlusal plane) has no significant effect on the miniscrew survival rate or stability during orthodontic treatment.

TRIAL REGISTRATION

This trial was registered at www.irct.ir ( IRCT20190901044659N1 ).

PROTOCOL

The protocol was published after trial commencement.

Correlation of Implant Stability Between Two Noninvasive Methods Using Submerged and Nonsubmerged Healing Protocols: A Randomized Clinical Trial

Various invasive and noninvasive methods have been used for measuring primary implant stability. Periotest damping device and resonance frequency analysis with the Osstell device have been classified as noninvasive methods. Primary and secondary implant stability measurements using both devices have given reproducible quantitative values. In this clinical randomized trial, a general correlation was evaluated between the implant stability recorded using both Osstell and Periotest devices on the day of implant installation and 3 months after healing for the submerged and nonsubmerged loading protocols. The present study also investigated whether the difference in gender of the included patients would have an effect on the correlation between the two devices. Eighty completely edentulous patients were recruited, and all patients ranged from 50 to 69 years of age. Overall, 56 men and 24 women were included, with a mean age of 62.5 years for men and 59.6 years for women. A single implant was installed in the midline of the completely edentulous mandible to improve retention of the patient's lower denture. After implant installation, one implant stability quotient (ISQ) value at the buccal surface was recorded, and then the Periotest M device was used to measure the damping effect (Periotest value [PTV]) of the installed implant using the smart peg screwed to the implant. Patients were then randomized into 2 groups using sealed envelopes: the submerged and nonsubmerged groups. For both groups, all ISQ and Periotest readings were recorded in the patient's case report file on the day of implant installation and 3 months after healing. When the ISQ of the buccal surface was correlated to the PTV, there was a moderate negative statistically significant correlation between the 2 readings (correlation coefficient = -.466, P = .000). There tended to be a weak negative correlation between the 2 devices in the male group (correlation coefficient = .395, P = .046) during implant installation, although there tended to be no correlation between the 2 devices in the female group (correlation coefficient = -.367, P = .342). After 3 months of healing, when correlating the readings of the buccal surface of the Osstell with that of the Periotest within each group (submerged and nonsubmerged), there was no statistically significant correlation between the readings within each group (correlation coefficient = -.014, -.430, P = .942, P = .052, respectively). However, there was a strong negative statistically significant correlation between the 2 devices for the female group for both the nonsubmerged group (correlation coefficient = -.823, P = .003) and submerged group (correlation coefficient = -.857, P = .014), whereas there was no statistically significant correlation within the male group for both the nonsubmerged group (correlation coefficient = -.377, P = .123) and submerged group (correlation coefficient = -.022, P = .940). The correlation between the Osstel and Periotest device remains controversial. The present study concluded that there is a significant negative correlation between the 2 devices when recording primary implant stability, although this significance is lost after 3 months of loading when recording secondary implant stability. Gender also affects the implant stability recording, which is mainly due to the difference in bone density between men and women.

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.

Evaluations of miniscrew type-dependent mechanical stability

BACKGROUND

Miniscrew has been widely used as an absolute anchorage in orthodontic treatment. Types of miniscrew with different diameter, length, shape, and thread dimensions may have a substantial effect on mechanical stability of the miniscrew system. Thus, the objective of this study was to evaluate miniscrew type-dependent mechanical stability to assess mechanical properties of miniscrew systems in various thickness of artificial bone block using different measurement tools.

METHODS

Two types of miniscrews (15 Tomas and 15 AbsoAnchor) were placed in artificial bone block with different thickness of 1.5, 2.0, 3.0 mm. Values of maximum insertion torque, removal torque, Periotest, implant stability quotient, static stiffness, dynamic stiffness, and energy dissipation ability were assessed for each miniscrew system.

FINDINGS

The maximum insertion torque, removal torque, implant stability quotient, static and dynamic stiffness values significantly increased when the miniscrews were placed in thicker bone block while Periotest values decreased. The static stiffness, Periotest and implant stability quotient values were significantly correlated each other and also with other mechanical properties (p < 0.001) except tan δ (p > 0.35). However, the slopes of some correlations and absolute values of measurement were significantly different dependent on the miniscrew types (p < 0.025).

INTERPRETATION

The current findings suggest that miniscrew type-dependent calibrations are required to estimate mechanical stability of the miniscrew systems despite the utilization of same measurement tool.

Clinical and Radiographic Outcomes of Apical Surgery: A Clinical Study

Background

Endodontic treatment is usually indicated when teeth with periapical lesions are encountered. However, sometimes root canal treatment results in failure. In that case, one of the treatment choices is retreatment by an orthograde approach. Surgical endodontic therapy is also an alternative to preserve the tooth. Various techniques have been suggested in the literature which has more predictable results. The introduction of modern surgical techniques have enhanced the results of apical surgery procedures. Operating microscopes, magnifying loupes, microinstruments, ultrasonic tips, and biologically acceptable root-end filling materials (such as MTA and SuperEBA) have been introduced to this field with the modern technique, thus the success rates of modern apical surgery has increased significantly.

Objective

The aim of the present study was to evaluate the clinical and radiographic outcomes and periotest values of apical surgery treatment.

Methods

A total of 112 teeth were included. SuperEBA and MTA were used as root-filling materials. The recorded parameters were gender, age, location of the tooth, the presence/absence of a post, coronal restoration of the tooth, previous surgical/nonsurgical treatment of the tooth, the size of periapical lesions, histopathology of periapical lesions, smoking habits. Also the periotest values were recorded.

Results

The overall success rate was 88.4%. With regard to the evaluated variables, only one parameter (tooth type) was found statistically significant. Although the periotest values were decreased after 6 months compared to immediately postoperative measurements, the values were still significantly higher than preoperative measurements.

Conclusion

In this study, apical surgery performed with the modern instruments has significantly successful results with 88.4% success rate.

Effects of implant length and 3D bone-to-implant contact on initial stabilities of dental implant: a microcomputed tomography study

Background

The influences of potential bone-to-implant contact (BIC) area (pBICA), BIC area (BICA), and three dimensional (3D) BIC percentage (3D BIC%; defined as BICA divided by pBICA) in relation to the implant length on initial implant stability were studied. Correlations between these parameters were also evaluated.

Methods

Implants with lengths of 8.5, 10, 11.5, and 13 mm were placed in artificial bone specimens to measure three indexes of the initial implant stability: insertion torque value (ITV), Periotest value (PTV), and implant stability quotient (ISQ). The implants and bone specimens were also scanned by microcomputed tomography, and the obtained images were imported into Mimics software to reconstruct the 3D models and calculate the parameters of 3D bone-to-implant contact including pBICA, BICA, and 3D BIC%. The Kruskal-Wallis test, Wilcoxon rank-sum test with Bonferroni adjustment, and Spearman correlations were applied for statistical and correlation analyses.

Results

The implant length affected ITV more than PTV and ISQ, and significantly affected pBICA, BICA, and 3D BIC%. A longer implant increased pBICA and BICA but decreased 3D BIC%. The Spearman coefficients were high (>0.78) for the correlations between the three 3D BIC parameters and the three indexes of the initial implant stability.

Conclusions

pBICA, BICA, and 3D BIC% are useful when deciding on treatment plans related to various implant lengths, since these 3D BIC parameters are predictive of the initial implant stability.

Er:YAG laser, piezosurgery, and surgical drill for bone decortication during orthodontic mini-implant insertion: primary stability analysis-an animal study

It is important to identify factors that affect primary stability of orthodontic mini-implants because it determines the success of treatment. We assessed mini-implant primary stability (initial mechanical engagement with the bone) placed in pig jaws. We also assessed mini-implant insertion failure rate (mini-implant fracture, mini-implants to root contact). A total of 80 taper-shaped mini-implants (Absoanchor® Model SH1312-6; Dentos Inc., Daegu, Korea) 6 mm long with a diameter of 1.1 mm were used. Bone decortication was made before mini-implant insertion by means of three different methods: Group G1: Er:YAG laser (LiteTouch®, Light Instruments, Yokneam, Israel) at energy of 300 mJ, frequency 25 Hz, fluence 38.2 J/cm2, cooling 14 ml/min, tip 1.0 × 17 mm, distance 1 mm, time of irradiation 6 s; Group G2: drill (Hager & Meisinger GmbH, Hansemannstr, Germany); Group G3: piezosurgery (Piezotom Solo, Acteon, NJ, USA). In G4 group (control), mini-implants were driven by a self-drilling method. The primary stability of mini-implants was assessed by measuring damping characteristics between the implant and the tapping head of Periotest device (Gulden-Medizinteknik, Eschenweg, Modautal, Germany). The results in range between − 8 to + 9 allowed immediate loading. Significantly lower Periotest value was found in the control group (mean 0.59 ± 1.57, 95% CI 0.7, 2.4) as compared with Er:YAG laser (mean 4.44 ± 1.64, 95% CI 3.6, 5.3), piezosurgery (mean 17.92 ± 2.73, 95% CI 16.5, 19.3), and a drill (mean 5.91 ± 1.52, 95% CI 5.2, 6.6) (p < 0.05). The highest failure rate (33.3%) during mini-implant insertion was noted for self-drilling method (G4) as compared with G1, G2, and G3 groups (p < 0.05). The small diameter decortication by Er:YAG laser appeared to provide better primary stability as compared to drill and piezosurgery. Decortication of the cortical bone before mini-implant insertion resulted in reduced risk of implant fracture or injury of adjacent teeth. The high initial stability with a smaller diameter of the mini-implant resulted in increased risk of fracture, especially for a self-drilling method.

A preliminary report

BACKGROUND

The implant primary stability is a fundamental prerequisite for a success of osseointegration process which determines the prosthetic reconstruction time.

OBJECTIVES

The aim of the present study was to assess the quality and precision of modern conical bone computer tomography (CBCT) software in preparing root analog zirconia implants (RAZIs) by measuring its primary stability by means of the Periotest device.

MATERIAL AND METHODS

Thirteen pig jaws with proper erupted first premolar (P1) teeth were used in the study. The CBCT examination was conducted in the area of the P1 tooth in each mandible. The 3-dimensional (3D) view of each tooth was designed from CBCT scan. The created 3D images were used to prepare root analog zirconia implants milled from a medical-grade zirconia block by means of laboratory milling. The RAZIs and titanium implants were placed into an alveolar socket after the tooth had been removed. The primary stability of the teeth before their extraction (G1), RAZIs (G2) and titanium implants (G3) were checked by Periotest devices.

RESULTS

The mean results in PTV were: 15.9, 3.35, 12.7 for G1, G2 and G3 group, respectively. RAZIs during immediate loading achieved a significantly higher primary stability (lower Periotest value) as compared to the teeth and implants.

CONCLUSIONS

The modern CBCT device allows us to design a precise image of an extracted tooth for the purpose of manufacturing a root analog implant. The additional feature of the surgical protocol using RAZI is the possibility of avoiding the augmentation procedure, which reduces the whole cost of the treatment.

Six-implant-supported immediate fixed rehabilitation of atrophic edentulous maxillae with tilted distal implants

Background

The aim of this retrospective study was to evaluate the treatment outcome of six Bredent blueSky™ implants (Bredent GmbH, Senden, Germany) immediately loaded with a fixed full-arch prosthesis (two tilted posterior and four axial frontal and premolar implants).

Methods

All 10 patients with atrophic edentulous maxillae being treated with a standardized procedure from 09/2009 to 01/2013, who had a follow-up of at least 3 years, were included. Sixty implants were placed to support 10 screwed prostheses. Twenty-one of them were inserted in fresh extraction sockets. Lab-side-prepared provisional fixed prostheses were placed at the day of implantation. Periotest (PT) values and implant stability quotient (ISQ) were measured after implant surgery and after 3 months of healing in all patients.

Results

The analyzed implants were in function in mean 64 ± 13 months (range 42 to 84 months). One axial and two tilted implants failed in three patients. The mean PT values decreased, and ISQ increased significantly after the first 3 months at the osseointegrated tilted and axial implants. With an area under the curve of 0.503 and 0.506 in the receiver operating characteristic, the PT values and the ISQ were unspecific parameters and unsuitable as a predictor for the risk of non-osseointegration.

Conclusions

Within the limits of this small group (n = 10 patients/60 implants), the failure rate of the analyzed implant system (n = 3 respective 5% implant loss) seems to be comparable with other immediate-loading protocols. The failure rate of tilted implants in the atrophic upper jaw was quite high, but the aimed treatment concept could be achieved in every patient. The rehabilitation of the posterior region in edentulous maxilla remains a challenge.

Impacts of 3D bone-to- implant contact and implant diameter on primary stability of dental implant

BACKGROUND/PURPOSE

This study investigated the effects of three three-dimensional (3D) bone-to-implant contact (BIC) parameters-potential BIC area (pBICA), BIC area (BICA), and 3D BIC percentage (3D BIC%; defined as BICA divided by pBICA)-in relation to the implant diameter on primary implant stability, as well as their correlations were also evaluated.

METHODS

Dental implants with diameters of 3.75, 4, 5, and 6 mm and artificial bone specimens were scanned by microcomputed tomography to construct 3D models for calculating pBICA, BICA, and 3D BIC%. Indexes of the primary implant stability including the insertion torque value (ITV), Periotest value (PTV), and implant stability quotient (ISQ) were measured after implants with various diameters were placed into bone specimens. The Kruskal-Wallis test, Wilcoxon rank-sum test with Bonferroni adjustment, and Spearman correlations were all performed as statistical and correlation analyses.

RESULTS

The implant diameter significantly influenced pBICA and BICA, but not 3D BIC%. ITV and PTV were more sensitive to implant diameter than was ISQ. The coefficients of determination were high (>0.92) for the correlations between pBICA (or BICA) and indexes of the primary implant stability.

CONCLUSION

This study revealed how the implant diameter and the three-dimensional (3D) BIC influence the primary stabilities of dental implant. ITV and PTV were more sensitively influenced by the implant diameter than ISQ. The pBICA and BICA seem to be more important than 3D BIC % for using wider implant in treatment plan, since those two parameters are highly predictive of variations in the primary stability of dental implant.

Evaluation of Hi-Tec Implant Restoration in Mandibular First Molar Region- A Prospective Clinical Study

BACKGROUND AND AIMS

Missing teeth lead to loss of structural balance, inefficient function, poor aesthetics and psychological effects on human beings, which needs restoration for normal contour, function and aesthetics. Several natural or synthetic substitutes are being used for replacement of missing tooth since centuries. Implants are the latest modality of replacement. So, the study was aimed to assess clinical success rate of Hi-Tec implant; which is economical and new in market. Results of the study will help clinician for appropriate implant selection.

MATERIALS AND METHODS

The study included 10 patients from 19 to 31 years and needed restoration of missing mandibular first molar. Restoration had done using Hi Tec Single-tooth implants with metal-ceramic single crown prosthesis after three months of osseointegration. The implants were evaluated clinically (bleeding on probing, probing depth, implant mobility- periotest) and radiographically (marginal bone loss and peri-implant radiolucency) for six years. The observers were blinded for the duration of the study to prevent bias.

RESULTS

All the patients had uneventful post-surgical healing. No bleeding on probing, Implant mobility, peri-implant radiolucency with minimal marginal bone loss and constant probing depths were observed well within the normal range during follow-up periods.

CONCLUSION

Two stage single-tooth Hi Tec implant restoration can be used as a successful treatment modality for replacing mandibular first molar in an economic way. However, these results were obtained after 6 years of follow up with a smaller sample size, so long term multi center studies with a larger sample size is recommended for the predictability of success rate conclusively.

Evaluation of the value of bone training (progressive bone loading) by using the Periotest: A clinical study

Aim:

The aim of this clinical study was to determine if progressive bone loading was effective in improving bone density and rigidity of implants.

Materials and Methods:

11 implants were placed with conventional loading and 14 implants were placed with progressive loading. The Periotest instrument was used to assess implant mobility. Mean difference of values were recorded in both qualities of bone.

Results:

Conventional loading in poor quality bone showed a significant decrease in rigidity of the bone as compared to conventional loading in good quality of bone. Progressive loading in both poor and good quality bone showed a significant increase in bone rigidity.

Conclusion:

Implants should not be loaded conventionally in poor quality bone but should be progressively loaded to prevent decrease in density and rigidity around implants.

Effect of Platelet-Rich-Plasma (PRP) and Implant Surface Topography on Implant Stability and Bone

PURPOSE

To evaluate the effect of Platelet-Rich-Plasma (PRP) and different implant surface topography on implant stability and bone levels around immediately loaded dental implants.

MATERIALS AND METHODS

Dental implants were placed in subjects divided into two groups and four subgroups on basis of implant treatment with PRP and implant surface topography used. A total of 30 implants were placed, 15 in each group. For PRP group, implants were placed after surface treatment with PRP. Temporization was done within two weeks and final prosthesis was given after three months. Implant stability was measured with Periotest at baseline, one month and three months. Bone height was measured on mesial & distal side on standardized IOPA x-rays.

RESULTS

A statistically significant difference was noticed in implant stability with PRP at baseline. The effect of PRP on bone height changes was not statistically significant. A synergistic effect of PRP and square thread-form was observed on improved implant stability and bone levels; however, no such effect is seen with PRP and reverse buttress thread-form.

CONCLUSION

Within the limitation of this study, enhancement on implant stability and bone healing was observed with PRP treated implant surfaces, and with use of implant with square thread-form.

The Evaluation of the Reliability of Periotest for Implant Stability Measurements: An In Vitro Study

Periotest (Medizintechnik Gulden, Modautal, Germany) is a widely accepted implant stability measurement method, although the reliability is not well known. The aim of this in vitro study was to investigate the reliability of the Periotest in implant stability measurements. Thirty implants were placed in 3 cow ribs. The stability of each implant was measured by insertion torque, resonance frequency analyses, and Periotest and then compared. The Periotest values (PTVs) were measured by 4 different examiners. The measurements were repeated twice in both the buccal and mesial directions, for each implant at 2-hour intervals and the intra- and interobserver reliability of Periotest was measured. Results showed that the intraobserver reliability of the Periotest was excellent for the buccal PTVs but fair to poor for the mesial PTVs. The interobserver reliability of the Periotest was excellent for the buccal PTVs but poor for the mesial PTVs. No significance was found between the PTVs and IT values (P = .803) and PTVs and ISQ values, whereas a 47.1% significant correlation was detected between the IT values and ISQ values (P = .009). The present study indicates that only Periotest measurements from buccal result in excellent intra- and interobserver reliability for the quantification of the implant stability.

Comparison of implant stability before prosthetic loading of two dental implant systems

Dental implantology is the state of the art technique to replace missing teeth. Implant stability of implant jeopardizes its longevity and success of treatment. This study evaluates the implant stability of implant before and after 4 months of the implant placement, but before prosthetically loading it. Ten two-stage implants of Life care and Nobel Biocare dental implants were placed in 20 patients. Digital OPG was taken on the day of implant placement. After 4 months, at the time of second stage surgery, the implant stability was evaluated by the Periotest instrument. Four months after the implant placement, Periotest evaluation showed a mean of 1.9, which indicated that implants were well osseointegrated and stable. Even before prosthetically loading the two-stage implant, crestal bone loss of 0.6-0.9 mm occurred around the implant. The smooth polished collar design of the implant may have contributed to crestal bone loss.

Comparative evaluation of bone in mandibular implant retained overdentures using delayed and immediate loading protocol: an in-vivo study

The aim of the present study was to evaluate the changes in periimplant bone quality, crestal bone level and the implant stability (periotest) for mandibular implant retained overdentures with ball attachments using delayed and immediate loading protocols. Ten completely edentulous patients had two alpha bio dental implants placed in the anterior part of the mandible. The loading protocols for the patients was chosen randomly by drawing lots. Five patients were loaded under immediate loading protocols and other five following delayed. Crestal bone loss and bone quality were assessed around each implant. Periotest values were recorded for each implant at 3, 6 and 12 months after loading. Two implants were lost and were excluded from the study. However mean crestal bone loss around implants was 0.81 mm from the time of prosthetic loading to 12 months after prosthetic loading was seen and no significant result was found between the two groups for the crestal bone loss and the periotest values. Though the periotest value decreased (indicates increased stability) over the time period. The bone density changes were significant for both the groups at coronal level at all time intervals but at middle level significant only after 12 months of prosthetic loading, although individual variation was high. This study concluded that the changes in crestal bone level and periotest values were insignificant for the two groups. But the implant stability increased over the time and the crestal bone loss was evident with decreased rate over the period of time. There was wide individual variation for the bone density changes but overall increase in the density was seen.

The influence of fixation in formalin on the measurement of stability of implants using resonance frequency analysis and Periotest M®: a study in a dog

Resonance frequency analysis (RFA) and Periotest® have been widely used to evaluate measurements of the stability of implants in clinical studies and animal experiments. In animals, these measurements are often made after bone has been fixed in formalin. However, it is not yet clear how this fixation influences RFA and Periotest®, and our aim was to clarify this using the implant stability quotient (ISQ) and Periotest® value (PTV). Six titanium implants were placed, 3 into each femur, of one male dog (a beagle/labrador cross). After 2 months blocks of bone were harvested, each block containing 3 implants, and were fixed in 10% neutral formalin. Measurements were made before fixation (time 0) then at 4h, and 1, 7, 14, 21, and 28 days. ISQ values of 6 implants were evaluated 3 times on the short and long axes, as were PTV. ISQ ranged from 67.5 to 79.3 and tended to increase with time. ISQ at 7-28 days were significantly higher than that at time 0. PTV ranged from -7.7 to -7.8 and did not differ significantly among fixation times. These results suggest that fixation of bony tissue in formalin might affect ISQ, so it might be preferable to measure ISQ during the early stages of fixation.

Clinical evaluation of early loaded and unloaded implants in edentulous mandible

OBJECTIVES

The aim of this study is to compare and evaluate the clinical outcome of early loaded and unloaded implants in the interforaminal region of anterior mandible.

MATERIALS AND METHODS

Five completely edentulous patients aged between 45 and 65 years were selected satisfying certain criteria. Four implants were placed in 33, 43, 35 and 45 regions; implants in 33 and 43 regions were loaded by a Dolder bar supported overdenture at 7th day. The implants at 35 and 45 regions were connected to 33 and 43 regions, respectively after 4 months. The implants were divided into two groups. Group I consisted of early loaded implants (implants in the region of 33 and 43) and Group II consisted of delayed loaded implants (implants in the region of 35 and 45). The implants were evaluated for various clinical parameters at 2, 4 and 6 month intervals after initial placement.

RESULTS

There was significant increase in the bone to implant contact for unloaded implants as compared to early loaded at the end of 6 months of implant placement. There was increased marginal bone loss around early loaded implants as compared to unloaded implants at the end of 6 months. Clinical stability of early loaded implants was lower as compared to the unloaded implants at the end of 6 months. Survival rate for early loaded and unloaded implants was 100% at the end of 6 months with all implants in function.

CONCLUSION

Early loading of interforaminal mandibular implants demonstrated a highly acceptable clinical success at the end of 6 months. However, the bone density, marginal bone level and clinical stability were significantly lower for the early loaded implants as compared to unloaded implants.

Assessment of Osstell™ and Periotest® systems in measuring dental implant stability (in vitro study)

OBJECTIVES

The objectives of this in vitro study were to investigate the sensitivity and reliability of the Osstell™ systems (Resonance Frequency Analysis - RFA) compared to the Periotest® system in implant bone simulated conditions. Three conditions were simulated: (1) the direct fixture-bone contact and fibrous tissue fixture contact, (2) The different levels of horizontal bone loss, and (3) The hardening implant-bone interface.

MATERIALS AND METHODS

Forty-nine dental implant fixtures were placed in the center of acrylic cubes. In Part I seven fixtures were placed in direct contact with acrylic and another seven were placed in contact with polyvinyl siloxane impression material as soft interface. Part II: four sets of 0, 2, 4 and 6 mm horizontally exposed fixture samples were made (seven fixtures in each set). Part III: seven fixtures were placed in contact with a thin mix of autopolymerizing resin. The stability of these fixtures was measured using Osstell™ and Periotest® systems.

RESULTS

The mean Periotest® value(PTV) and Osstell™ measurements showed a significant difference between the direct contact and soft interface (P < 0.001). These values also showed statistically significant difference between the different levels of horizontally exposed fixture groups (P < 0.001). The level of horizontal fixture exposure was strongly correlated with the PTVS (r = 0.967) and strongly negatively correlated with Implant Stability Quotient (r = -0.946). A strong correlation was found between the Osstell™ readings and the change in the stiffness of the autopolymerizing resin fixture interface group (r = 0.986).

CONCLUSIONS

Both Osstell™ and Periotest® systems proved to be sensitive in measuring dental implant stability in hard and in soft interfaces. Osstell™ also proved to be sensitive in detecting changes in the fixture interface stiffness. Osstell™ system proved to be more reliable compared to Periotest® system in measuring dental implant stability in hard and in soft interfaces.