Alveolar bone remodeling in virtually planned, bone-grafted vs non-grafted guided flapless implant surgery in the anterior maxilla: a cross-sectional retrospective follow-up study

PURPOSE

In patients who underwent virtual planning and guided flapless implant surgery for teeth missing in the anterior maxilla, we compared buccal bone loss between those treated with and without autogenous bone augmentation.

METHODS

Of 22 patients with teeth missing because of trauma or aplasia, 10 (18 implant sites) were reconstructed with buccally placed bone graft harvested from the mandibular ramus, and 12 were non-reconstructed (16 sites). Baseline cone-beam computed tomography allowed for implant planning using the NobelClinician® software and was performed again at 1 year after functional loading. The marginal bone level was assessed radiographically at post-implant baseline and at follow-up.

RESULTS

At follow-up, buccal bone loss differed significantly between groups at the central level of the implant (p = 0.0005) but not at the coronal level (p = 0.329). The mean marginal bone level change was 0.6 mm, with no significant between-group difference (p = 0.876). The actual implant position often deviated in the vertical or sagittal plane by an average of 0.3-0.6 mm from the planned position.

CONCLUSION

Compared with non-reconstructed patients, reconstructed patients experienced significantly more buccal bone loss at the central level of implants. The groups did not differ at the coronal level or in marginal bone loss, possibly because of the more augmented bone at the central level among reconstructed patients. Differences between planned versus actual implant positions should be considered in situations of limited bone volume at the planned implant site.

Comparison between immediate vs. delayed lateral expansion technique to augment narrow alveolar ridges for placement of implants - A pilot study

Objective

Narrow alveolar ridges pose a serious challenge for successful placement of endosseous implants and alveolar ridge widening procedure is indicated in cases of crest thickness of ≤4.0 mm. The study evaluated and compared, immediate and delayed techniques of implant placement using split crest technique to augment atrophic narrow alveolar ridges.

Methods

The study was carried out in 10 patients randomly divided into two groups of five each for immediate or delayed placement of implants. Implants were placed simultaneously after split crest procedure in immediate technique and after 3-4 weeks of healing in delayed technique. Data collected was statistically analyzed by SPSS version 22 using unpaired t-test, ANOVA and Pearson's correlation with p value = 0.05.

Results

Statistically significant (p = 0.000) difference was observed for implant stability at intra-op, 4 months and 6 months post-op between the two groups, however there was no statistically significant difference in amount of augmentation achieved between the two groups.

Conclusion

We observed that both the techniques were comparable on the basis of augmentation achieved, implant success and survival rates, whereas implant stability was significantly higher in delayed technique group.

Comparative evaluation of implant stability in two different implant systems at baseline and 3-4 months intervals using RFA device (OSSTELL ISQ)

Introduction

Osseointegration as formulated by Alberktson is crucial for implant survival and success. Osseointegration is a measure of implant stability. Measuring implant stability helps to arrive at decisions as to loading of an implant, allows protocol choice on a patient to patient basis and provides enhanced case documentation. The RFA technique provides with clinically relevant information about the state of the implant-bone interface at any stage after implant placement.

Aim

Evaluation of primary and secondary stability between implants of two different systems by resonance frequency analysis device.

Methodology

This study was conducted among 17 patients divided into two groups. Group 1 (n = 10) receiving 20 MIS seven implants and Group 2 (n = 7) received 20 Alphadent active implants. The primary implant stability was measured at the time of implant placement and secondary stability is measured at 3-4 months interval using RFA device OSSTELL ISQ. Statistical analysis was performed using paired t test for intra group and independent sample test for intergroup comparisons.

Results

No statistically significant differences in primary and secondary stabilities were found between the implant systems at either time intervals (P > 0.05). A positive correlation was noticed between mesiodistal stability and implant diameter in MIS seven group (P < 0.05). A positive correlation was noticed between mesiodistal, labiolingual stabilities and implant diameter in Alphadent group (P = 0.03). A positive correlation was noticed between mesiodistal, labiolingual stabilities and implant length in Alphadent group (P = 0.03).

Conclusion

From the present data, it can be concluded that within the limitations of study, implant systems used and their design features showed no significant correlation to implant stability between the groups. More studies are required to assess the effect of implant designs and surface conditions on implant stability on a long-term basis.

Fibular Reconstruction of the Maxilla and Mandible with Immediate Implant-Supported Prosthetic Rehabilitation: Jaw in a Day

The fibula free flap is a workhorse flap used to reconstruct ablative, osseous defects in the upper and lower jaws. Traditionally, the fibula free flap is inset into the defect freehand; dental implants are placed secondarily; and final prosthetic rehabilitation often occurs more than 1 year after ablative surgery. Virtual surgical planning and rapid prototyping of cutting guides and guide stents for head and neck reconstruction have facilitated improved accuracy in fibular transfer. This article describes the Jaw in a Day technique, allowing maxillary or mandibular resection, fibular free flap reconstruction, immediate implant placement, and prosthetic rehabilitation in a single operation.

Comparative evaluation of soft and hard tissue changes following endosseous implant placement using flap and flapless techniques in the posterior edentulous areas of the mandible-a randomized controlled trial

BACKGROUND

Dental implant-supported restorations have long been used as a successful modality for replacing missing teeth. There are two well-established methods of implant placement. The traditional approach to implant surgery involves raising a mucoperiosteal flap and the alternative approach does not involve reflecting a flap, each having its own advantages and disadvantages. The purpose of the present study was to compare and evaluate the soft and hard tissue changes around endosseous implants placed using flap and flapless surgery in mandibular posterior edentulous sites over a period of time.

MATERIALS AND METHODS

A total of 20 systemically healthy patients with a single edentulous site in the posterior mandible were enrolled in this study and 20 endosseous implants were placed (10 in the flap group and 10 in the flapless group). The peri-implant probing depth was assessed. Radiographic assessment was done for changes in the marginal bone levels at the mesial and distal side of the implant with measurements made at baseline, 6 months, and 12 months. Patient-centered outcomes were assessed by using the visual analogue scale (VAS). All these parameters were statistically analyzed using the Wilcoxon signed-rank test, paired Student t test, and two-way ANOVA test and were considered to be significant if the p value was ≤ 0.05.

RESULTS

Twenty patients were enrolled in the present study and endosseous implants were placed. Eighteen subjects were followed up throughout the study period and two patients were excluded from the study. The mean PD in the flapless group was comparatively less than the flap group at 12 months and was found to be statistically significant. During the observation period of 12 months, reduction of crestal bone height around the implants placed by flapless and flap surgery were statistically significant. The flapless group showed less change in the crestal bone height which was statistically significant compared to the flap group. The mean VAS score on day 0 in the flap and flapless group was statistically significant. The flapless group showed significantly less pain when compared to the flap group.

CONCLUSION

Although the flapless technique of endosseous implant placement had statistically significant less PD, bone loss, and pain than the flap technique, the difference was found to have uncertain clinical significance.

Sinus Augmentation and Simultaneous Implant Placement Success: Pilot Study (2008-2011)

OBJECTIVE

1) To describe implant success in the posterior maxillary when a sinus augmentation procedure was performed simultaneously with implant placement and then compare differences in success when sinus augmentation was delayed in patients attending the maxillofacial surgery clinic of the University of Puerto Rico, 2008 through 2011. 2) To determine sociodemographic characteristics, ASA classification, graft material, and final restoration and, using a questionnaire, determine as well patient satisfaction.

METHODS

A retrospective cohort study was conducted (approved by IRB) with 172 patients, using medical records. A total of 102 implants were placed in grafted maxillary areas, 55 placed simultaneously and 47 delayed. Patients were contacted, invited to participate, and, upon agreement, instructed to sign an informed consent.

RESULTS

A total of 45 implants were evaluated clinically (22 immediate and 23 delayed), all with 100% success (according to Buser and Weber criteria). In the sample group, 72.5% of the participants were women and 26.8% were men; their ages ranged from 42 to 87 years, with a mean age of 57 years. Patient participation was low (44%). The categories of appearance and esthetics and function were both rated at 86.2%; cost of restoration came in at 86.1%, and maintenance was rated at 71.2%.

CONCLUSION

Implant placement with simultaneous sinus augmentation was successful, and no differences were found between implants that were placed immediately and those that were delayed, which is similar to what has been found by previous studies. Patients reported being satisfied with the final cost of the implant restoration.

An Evaluation of the Stress Distribution in Screw Retained Implants of Different Crown Implant Ratios in Different Bone Densities Under Various Loads-A FEM Study

INTRODUCTION

Studies on stress distribution around screw retained implants in different bone densities are limited. In clinical situations crowns of different heights are placed on the implants and the effect of varying crown implant ratio on the bone is not understood properly.

AIM

To evaluate and compare the stress distribution in different screw retained implants for different crown-implant ratios in different bone densities under various occlusal loads using three dimensional finite element analyses.

MATERIALS AND METHODS

In this invitro study the stress distribution was evaluated and compared between two different crown heights (7.5mm, 10mm) retained on implants by using different screw materials (commercially pure titanium, titanium alloy) in two different densities of bone D2, D3 under various load (100N, 200N) applications by using finite element analysis.

RESULTS

For crown height of 7.5mm, in D2 bone density when vertical load of 200N was applied, the maximum stress concentration was 1780N/cm(2), for oblique load of 100N it was 2936N/cm(2) respectively and in D3 bone density when vertical load of 200N was applied, the maximum stress concentration was 1820N/cm(2), for oblique load of 100N it was 3477N/cm(2) respectively. When the crown height is increased to 10mm, the maximum stress concentration in D2 bone was 1875N/cm(2) for vertical load, 4015N/cm(2) for oblique load and in D3 bone the maximum stress concentration was 2123N/cm(2) for vertical load and 4236N/ cm(2) for oblique load. In case of titanium screws for crown height of 7.5 mm, when vertical load was applied, stress concentration was 1603 N/cm(2) where as for titanium alloy screw it was 1820N/cm(2). In case of 10mm crown height stress concentration was 1904N/cm(2) for titanium screw and 2123N/cm(2) for titanium alloy screw. In case of oblique loading for 7.5mm crown height stress concentration was 3155N/cm(2) for titanium screw 3477N/cm(2) for titanium alloy screw. For 10mm crown height stress concentration was 4236N/cm(2) for titanium screw, 4663N/cm(2) for titanium alloy screw.

CONCLUSION

Stress concentration was less and stress distribution was better in D2 bone density than in D3 bone density. Stress concentration was less and stress distribution was better in commercially pure titanium screw than in titanium alloy screw. With the increase in the height of crown (i.e., from 7.5mm to 10mm) stress concentration and stress distribution also increased.

Successful long-term mandibular reconstruction and rehabilitation using non-vascularised autologous bone graft and recombinant human BMP-7 with subsequent endosseous implant in a patient with bisphosphonate-related osteonecrosis of the jaw

We describe a case of extensive osteonecrosis of the mandible after a dental extraction in a 71-year-old woman who was taking alendronic acid (Fosamax(®), Merck) for osteoporosis. Bone damaged by bisphosphonate-related osteonecrosis of the jaw (BRONJ), also now known as medication-related osteonecrosis of the jaw (MRONJ), can be regenerated and filled with endosseous implants using non-vascularised autologous grafts.

Effects of the nanotopographic surface structure of commercially pure titanium following anodization-hydrothermal treatment on gene expression and adhesion in gingival epithelial cells

The long-term stability and maintenance of endosseous implants with anodized-hydrothermally treated commercially pure titanium surfaces and a nanotopographic structure (SA-treated c.p.Ti) depend on the barrier function provided by the interface between the transmucosal portion of the implant surface and the peri-implant epithelium. This study investigated the effects of extracellular and intracellular gene expression in adherent gingival epithelial cells cultured for 1-7 days on SA-treated c.p.Ti implant surfaces compared to anodic oxide (AO) c.p.Ti and c.p.Ti disks. Scanning electron microscopy (SEM) showed filopodium-like extensions bound closely to the nanotopographic structure of SA-treated c.p.Ti at day 7 of culture. Gene expressions of focal adhesion kinase, integrin-α6β4, and laminin-5 (α3, β3, γ2) were significantly higher on SA-treated c.p.Ti than on c.p.Ti or AO c.p.Ti after 7 days (P<0.05). Our results confirmed that gingival epithelial cells adhere to SA-treated c.p.Ti as the transmucosal portion of an implant, and that this interaction markedly improves expression of focal adhesion molecules and enhances the epithelial cell phenotype. The cellular gene expression responses driving extracellular and intracellular molecular interactions thus play an important role in maintenance at the interface between SA-treated c.p.Ti implant surfaces and the gingival epithelial cells.

Osseointegration: an update

Osseointegration, defined as a direct structural and functional connection between ordered, living bone and the surface of a load-carrying implant, is critical for implant stability, and is considered a prerequisite for implant loading and long-term clinical success of end osseous dental implants. The implant-tissue interface is an extremely dynamic region of interaction. This complex interaction involves not only biomaterial and biocompatibility issues but also alteration of mechanical environment. The processes of osseointegration involve an initial interlocking between alveolar bone and the implant body, and later, biological fixation through continuous bone apposition and remodeling toward the implant. The process itself is quite complex and there are many factors that influence the formation and maintenance of bone at the implant surface. The aim of this present review is to analysis the current understanding of clinical assessments and factors that determine the success & failure of osseointegrated dental implants.