Six-year extension results of a randomized trial comparing transcrestal and lateral sinus floor elevation at sites with 3-6 mm of residual bone.

OBJECTIVES: To comparatively evaluate the 6-year outcomes of transcrestal and lateral sinus floor elevation (tSFE and lSFE, respectively). METHODS: The 54 patients representing the per-protocol population of a randomized trial comparing implant placement with simultaneous tSFE versus lSFE at sites with a residual bone height of 3-6 mm were invited to participate in the 6-year follow-up visit. Study assessments included: peri-implant marginal bone level at the mesial (mMBL) and distal (dMBL) aspects of the implant, proportion of the entire implant surface in direct contact with the radiopaque area (totCON%), probing depth, bleeding on probing, suppuration on probing, and modified plaque index. Also, the conditions of the peri-implant tissues at 6-year visit were diagnosed according to the case definitions of peri-implant health, mucositis, and peri-implantitis from the 2017 World Workshop. RESULTS: Forty-three patients (21 treated with tSFE and 22 treated with lSFE) participated in the 6-year visit. Implant survival was 100%. At 6 years, totCON% was 96% (IR: 88%-100%) in tSFE group and 100% (IR: 98%-100%) in lSFE group (p = .036). No significant intergroup difference in patient distribution according to the diagnosis of peri-implant health/disease was observed. Median dMBL was 0.3 mm in tSFE group and 0 mm in lSFE group (p = .024). CONCLUSIONS: At 6 years following placement concomitantly with tSFE and lSFE, implants showed similar conditions of peri-implant health. Peri-implant bone support was high in both groups and was slightly but significantly lower in tSFE group.

Peri-implant tissue conditions following transcrestal and lateral sinus floor elevation: 3-year results of a bi-center, randomized trial.

OBJECTIVES: The present study was performed to comparatively evaluate the peri-implant bone stability and conditions of marginal tissues at 3 years following transcrestal and lateral sinus floor elevation (tSFE and lSFE, respectively). MATERIALS AND METHODS: Patients included in a parallel-arm randomized trial comparatively evaluating tSFE and lSFE were recalled at 3 years post-surgery. Twenty-one and 24 patients in tSFE and lSFE groups, respectively, participated in the follow-up visit. Peri-implant bone support was evaluated as the proportion of the entire implant surface in direct contact with the radiopaque area (totCON%) on 3-year periapical radiographs. The conditions of the marginal peri-implant tissues at 3-year visit were classified as peri-implant health, peri-implant mucositis, or peri-implantitis. RESULTS: At 3 years, both groups showed an implant survival rate of 100%. Median totCON% was stable at 3 years, being 100% in both groups (p = 0.124). Peri-implant health and mucositis were diagnosed in 10 (47.6%) and 11 (52.4%) patients, respectively, in the tSFE group, and in 8 (33.3%) and 16 (66.7%) subjects, respectively, in the lSFE group (p = 0.502). CONCLUSIONS: At 3 years following surgery, implants placed concomitantly with tSFE and lSFE fully maintain peri-implant bone support. Peri-implant mucositis was the most prevalent condition, with a similar prevalence between groups. CLINICAL RELEVANCE: Based on 3-year data on peri-implant bone support and prevalence of peri-implant diseases, the study suggests that tSFE and lSFE represent two equally valid options for the rehabilitation of the posterior maxilla. CLINICALTRIALS: gov ID: NCT02415946.

Immediate versus delayed loading of mandibular implant-retained overdentures: A 60-month follow-up of a randomized clinical trial.

AIM: The purpose of this observational, post-trial follow-up study was to evaluate 60-month outcomes of a randomized controlled clinical trial that compared immediately and delayed loaded two unsplinted implants, supporting a locator-retained mandibular overdenture. MATERIALS AND METHODS: Patients from a randomized controlled clinical trial, treated with either immediate or delayed loading of two implants, supporting a locator-retained mandibular overdenture, were recalled for 60-month evaluation. Patients underwent a clinical and radiographic examination to evaluate the peri-implant soft tissue parameters and bone. Prosthetic maintenance needs and complications were also recorded. RESULTS: Twenty three of the 30 patients were available for the 60-month follow-up. The mean radiographic bone level change measured using standardized periapical radiographs from baseline to 60 months was 0.89 mm (±0.74) and 0.18 (±0.41) for delayed loading and immediate loading groups, respectively. A statistically significant difference was observed at 60 months with a smaller radiographic bone level change in the immediate loading group. No implants were lost between 12 and 60 months. At 60 months, per-protocol implant survival rate was 100% for both the groups. No difference was found in the peri-implant soft tissue parameters and prosthetic needs between the groups. CONCLUSION: Both immediately and delayed loaded implants supporting a locator-retained mandibular overdenture showed similar clinical outcomes.

Radiographic outcomes of transcrestal and lateral sinus floor elevation: One-year results of a bi-center, parallel-arm randomized trial.

OBJECTIVES: To comparatively evaluate the radiographic outcomes of transcrestal and lateral sinus floor elevation (tSFE and lSFE, respectively) when applied concomitantly with implant placement. MATERIALS AND METHODS: Patients with at least 1 edentulous site with residual bone height (RBH) of 3-6 mm were enrolled in a bi-center, parallel-arm, randomized trial. Both tSFE and lSFE were associated with a bovine-derived xenograft, and implants were inserted concomitantly. In lSFE group, the antrostomy was covered with a resorbable collagen membrane. Marginal bone loss and the maturation of the grafted area were evaluated on periapical radiographs at 6 and 12 months. Twelve-month CT/CBCT was used to assess the effect of grafting procedures circumferentially around the implant. A per-protocol analysis was performed. RESULTS: The per-protocol study population consisted of 26 patients in the tSFE group and 28 patients in the lSFE group. At 12 months, the median proportion of the implant surface in contact with the peri-implant radiopaque area was 100% in both groups, with no significant inter-group difference. Suboptimal bone-to-implant contact was observed in 13% and 3.6% of tSFE and lSFE cases, respectively. In both groups, marginal bone loss was minimal (≤1 mm) and infrequent, and the radiographic aspect was suggestive of an advanced stage of maturation. CONCLUSIONS: At sites with RBH of 3-6 mm where implants are placed concomitantly with sinus floor elevation, tSFE and lSFE are both highly predictable in obtaining an implant surface completely embedded in a radiopaque area at 12 months post-surgery. (ClinicalTrials.gov ID: NCT02415946).

Morbidity following transcrestal and lateral sinus floor elevation: A randomized trial.

AIM: To comparatively evaluate the morbidity following maxillary sinus floor elevation according to either transcrestal (tSFE) or lateral (lSFE) approach with concomitant implant placement. MATERIALS & METHODS: Patients with ≥1 edentulous maxillary posterior site with residual bone height (RBH) of 3-6 mm were enrolled. tSFE was performed in association with a xenograft and a collagen matrix. For lSFE, the sinus was grafted with the xenograft, and the antrostomy was covered with a membrane. Implants were inserted concomitantly. The postoperative course was assessed through questionnaires. Pain level (VASpain ) was recorded using a 100-mm visual analogue scale. RESULTS: Twenty-nine and 28 patients were included in tSFE and lSFE group, respectively. On the day of surgery, VASpain was significantly higher for tSFE compared to lSFE, and similar from day 1 to 14. tSFE was characterized by significantly lower incidence of swelling, bruising and nasal discharge/bleeding. Significantly less severe limitation in swallowing, continuing daily activities, eating, speaking, opening the mouth and going to school/work was found for tSFE only at specific postsurgery intervals. CONCLUSIONS: lSFE was associated with lower pain on the day of surgery, and tSFE revealed lower postoperative morbidity as well as more tolerable postoperative course.

Alveolar ridge dimensions in mandibular posterior regions: a retrospective comparative study of dentate and edentulous sites using computerized tomography data.

PURPOSE: To evaluate ridge dimensions at edentulous, mandibular posterior sites, and contralateral dentate sites. METHODS: Computerized tomography scans of 24 patients with one fully edentulous and one fully dentate mandibular posterior region were retrospectively selected. Relative ridge position (rRP), bone height (BH), alveolar canal height (ACH), basal bone height (BBH), and bone width (BW) at 1, 3, and 5 mm apically to the most coronal point of the alveolar crest (BW1mm, BW3mm, and BW5mm, respectively) were measured at posterior dentate sites and contralateral edentulous sites. The proportion of edentulous sites with BH ≥ 9 mm and BW1mm ≥ 6 mm and/or BH ≥ 11 mm and BW3mm ≥ 6 mm was calculated. RESULTS: When compared to dentate sites, edentulous sites showed lower BH, a more apical position of the ridge, lower BW1mm, lower ACH, and similar BBH. The difference in rRP, BH, ACH, BBH, BW1mm, BW3mm, and BW5mm between edentulous and contralateral dentate sites was not significantly different between females and males. The prevalence of edentulous sites with BH ≥ 9 mm and BW1mm ≥ 6 mm and/or BH ≥ 11 mm and BW3mm ≥ 6 mm was higher in females (83.3%) compared to males (58.3%) at second premolar, while was higher in males compared to females at the first molar (83.3 vs 66.6%) and second molar (83.3 vs 75.0%). CONCLUSIONS: In the posterior mandible, edentulous sites show a reduced height and bucco-lingual ridge width compared to contralateral dentate sites. Gender seems to have a limited impact on the extent of ridge resorption following the loss of posterior mandibular teeth.

Single versus double flap approach in periodontal regenerative treatment.

AIM: to compare the outcomes of a regenerative strategy based on recombinant human platelet-derived growth factor-BB (rhPDGF-BB, 0.3 mg/ml) and ß-tricalcium phosphate (ß-TCP) in the treatment of intraosseous defects accessed with the Single Flap Approach (SFA) versus Double Flap Approach based on papilla preservation techniques (DFA). MATERIALS AND METHODS: Fifteen and 13 defects, randomly assigned to SFA or DFA, respectively, were grafted with rhPDGF-BB + ß-TCP. Probing parameters were assessed before and 6 months after surgery. Pain (VAS(pain)) was self-reported using a visual analogue scale. RESULTS: Twelve SFA sites and DFA 6 sites showed complete flap closure at 2 weeks post-surgery. No significant differences in 6-month changes in probing parameters and radiographic defect fill were found between groups. Significantly lower VAS(pain) was observed in SFA group compared to DFA group at day +1, +2 and +6. A significantly greater number of analgesics were consumed in the DFA group compared to the SFA group at day +1. CONCLUSIONS: When combined with rhPDGF-BB and ß-TCP, the SFA may result in similar clinical outcomes, better quality of early wound healing, and lower pain and consumption of analgesics during the first postoperative days compared to the DFA.

Randomized controlled multicentre study comparing short dental implants (6 mm) versus longer dental implants (11-15 mm) in combination with sinus floor elevation procedures. Part 1: demographics and patient-reported outcomes at 1 year of loading.

AIM: To test whether or not the use of short dental implants (6 mm) results in an implant survival rate similar to long implants (11-15 mm) in combination with sinus grafting. METHODS: This multicentre study enrolled 101 patients with a posterior maxillary bone height of 5-7 mm. Patients randomly received short implants (6 mm) (group short) or long implants (11-15 mm) with sinus grafting (group graft). Six months later, implants were loaded with single crowns and patients re-examined at 1 year of loading. Outcomes included treatment time, price calculations, safety, patient-reported outcome measures (OHIP-49 = Oral Health Impact Profile) and implant survival. Statistical analysis was performed using a non-parametric approach. RESULTS: In 101 patients, 137 implants were placed. Mean surgical time was 52.6 min. (group short) and 74.6 min. (group graft). Mean costs amounted to 941EUR (group short) and 1946EUR (group graft). Mean severity scores between suture removal and baseline revealed a statistically significant decrease for most OHIP dimensions in group graft only. At 1 year, 97 patients with 132 implants were re-examined. The implant survival rate was 100%. CONCLUSIONS: Both treatment modalities can be considered suitable for implant therapy in the atrophied posterior maxilla. Short implants may be more favourable regarding short-term patient morbidity, treatment time and price.

Randomized controlled multicenter study comparing short dental implants (6 mm) versus longer dental implants (11-15 mm) in combination with sinus floor elevation procedures. Part 2: clinical and radiographic outcomes at 1 year of loading.

AIM: To compare, clinically and radiographically, short dental implants (6 mm) to long implants (11-15 mm) placed with sinus grafting. METHODS: Participants with 5-7 mm of bone height in the posterior maxilla were randomly allocated to receive short implants (GS) or long implants with sinus grafting (GG). Implants were loaded with single crowns 6 months after placement (PR). Patients were re-evaluated 12 months after loading (FU-1). Outcome variables included: Implant survival rate (CSR), marginal bone level alteration (MBL), periodontal probing depth (PPD), bleeding on probing (BoP), plaque control record (PCR) and crown-to-implant ratios (C/I). Statistical analysis was performed using parametric tests. RESULTS: In 97 subjects, 132 implants were re-evaluated at FU-1. The CSR was 100%. The MBL from implant placement (IP) to (PR) was -0.22 ± 0.4 mm for GG and -0.3 ± 0.45 mm for GS (p < 0.001). MBL from IP to FU-1 was -0.37 ± 0.59 mm for GG and -0.22 ± 0.3 mm for GS (p < 0.001). Intergroup comparisons showed non-significant differences for MBL (p > 0.05), PPD (p = 1) and PCR (p = 0.09). BoP was higher in the GS (p = 0.04). The C/I was 0.99 ± 0.17 for GG and 1.86 ± 0.23 for GS (p < 0.001). No correlation was observed between C/I and MBL, (GG: p = 0.13; GS: p = 0.38). CONCLUSIONS: Both treatment modalities provided similar outcomes.

Artifacts in Cone Beam Computed Tomography Image Volumes: An Illustrative Depiction.

INTRODUCTION: The evolution of cone beam computed tomography (CBCT) has brought about a paradigm shift in radiographic evaluation of the maxillofacial skeleton. Because of its low cost, high resolution, and relatively low-radiation dose, CBCT is fast becoming the 3-D imaging modality of choice in dentistry. The ubiquitous availability of this new imaging modality poses unique challenges in understanding this technology and recognizing the associated artifacts that present themselves in the acquired image volumes. There are several artifacts that are inherent to CBCT scans by virtue of the physics behind their acquisition and image reconstruction algorithms. BACKGROUND: An image artifact may be defined as a visualized structure in the reconstructed data that was not originally present in the object or the imaged area of interest. It can be explained as any distortion or error in the image that is unrelated to the subject being studied. Artifacts are induced by discrepancies between the physical conditions of the measuring setup, which is usually the CBCT scanner's technical composition and position of the object under investigation. OBJECTIVE: The objective of this study is to present an illustrative depiction of the most commonly encountered CBCT artifacts with an explanation of how each artifact is caused and how it presents itself in CBCT image volumes. CONCLUSION: Because these artifacts cause significant image degradation and often misrepresent the region of interest, they should be recognized, understood, and taught along with normal CBCT anatomy to facilitate accurate evaluation of the image volumes and prevent inaccurate diagnoses.

Gingival pedicle with split-thickness tunnel technique: A retrospective case series for single mandibular anterior recessions.

INTRODUCTION: Gingival recessions in the mandibular anterior sextant are a common clinical finding, but mucogingival treatment in this location is particularly challenging, due to several anatomical and surgical difficulties. In the present case series, a novel technique, called gingival pedicle with split-thickness tunnel (GPST), was retrospectively evaluated. CASE SERIES: Fifteen patients presenting with a single buccal RT1 or RT2 gingival recession of a depth of ≥3 mm in the mandibular anterior sextant were treated by means of the GPST technique. Clinical periodontal parameters at baseline and at the last follow-up evaluation visit (6-84 months) were compared. Early healing was uneventful in all cases, and no complications such as flap dehiscence or loss of connective tissue graft were observed. Mean root coverage (mRC) was 98.1% ± 7.38%, corresponding to a statistically significant recession reduction (ΔRD) of 4.53 ± 1.19 mm. Complete root coverage was achieved in 14 of 15 cases. The gain in keratinized tissue width amounted to 3.13 ± 0.99 mm and was statistically significant, whereas no significant change in periodontal probing depth was observed after treatment. CONCLUSION: In conclusion, treatment with GPST technique seems to achieve a favorable and predictable clinical improvement in gingival recessions on mandibular anterior teeth. Why are these cases new information? Limited information is available about the management of isolated deep labial recessions in the mandibular anterior teeth. A novel surgical approach, called GPST technique, is described in a case series to specifically address this type of defect. What are the keys to successful management of these cases? Horizontal incision ≥ RECwidth Cut-back preparation helps to mobilize the flap without tension. CTG width ≥ 3 times RECwidth CTG height ≥ RECdepth Proper graft and flap stabilization need to be achieved. What are the primary limitations to success in these cases? Limited mesio-distal dimensions, which do not allow to obtain a pedicle with adequate horizontal width Very thin biotype may not be suitable because of the risk of inadequate flap vascularization.

Immediate Loading of Four Guided Unsplinted Narrow Implants Supporting a Maxillary Overdenture: A Minimally Invasive Approach.

INTRODUCTION: Little evidence is available on the loading protocols for implant-supported overdentures in the treatment of the edentulous maxilla. There are only a few case-reports available to document the feasibility of immediate loading for maxillary overdenture, and the majority of the publications include the use of splinted implants. This paper presents a case report of immediately loaded narrow diameter implants supporting a maxillary overdenture using Locator abutments. CASE PRESENTATION: A 64-year-old, fully edentulous patient presented with a maxillary complete removable denture. A dual cone beam computed tomography scan was obtained, and the surgical planning was performed. Four 3.3 mm diameter implants were placed at the lateral incisor and second premolar positions, using a guided and flapless approach. Locator abutments were placed, and the denture was connected immediately. The patient was instructed not to remove the prosthesis for 1 week and to follow a soft diet regimen for 2 weeks. Clinical and radiographic evaluation showed positive results at 12 months, with neither prosthetic nor implant complications. CONCLUSION: This is a proof of principle case report, which demonstrates the possibility of immediately loading four guided narrow diameter implants supporting a maxillary overdenture using a Locator retention system.

Computer-Guided Surgery Using Human Allogenic Bone Ring With Simultaneous Implant Placement: A Case Report.

INTRODUCTION: The allogenic bone ring technique allows for horizontal and vertical bone augmentation with simultaneous implant placement in severely compromised sites. The aim of this report is to present a modified protocol for simultaneous placement of implant and allogenic bone ring graft using a computer-guided surgery technique. CASE PRESENTATION: Patient's chief complaint was to replace a missing lateral incisor. The implant site presented both vertical and horizontal tissue deficiencies. Study models and wax-ups were digitally scanned to stl files and merged with the existing CBCT data in the implant planning software. A 3D representation of an allogenic bone ring was developed, and two digitally designed guides were created: a 5 mm sleeve guide for the implant site and a 7 mm sleeve guide for the allogenic bone ring trephine. Both the implant site and the allogenic bone ring recipient site were prepared using the computer-generated guides. Once the ring was adapted into the recipient site, the implant was inserted through the allogenic bone ring. The healing was monitored and the implant was restored at 12 months. The accuracy of implant placement was measured and the difference in the final positioning was as follows: 0.6 mm at entry point, 0.55 mm vertical displacement, 1.94 mm at the apex, and angle discrepancy 6.1°. CONCLUSION: The use of computer-guided technology for planning and placement of an allograft bone block with simultaneous implant insertion allows for a prosthetically driven team approach to compromised site grafting in addition to improving precision and accuracy when compared with non-guided techniques.

Novel Surgical Approach for Root Coverage of Single Deep Recessions on Mandibular Incisors: Gingival Pedicle With Split-Thickness Tunnel Technique.

INTRODUCTION: Gingival recession is a very common mucogingival defect in the adult population, with mandibular central and lateral incisors being the most frequently affected teeth. Limited information is available about the management of isolated deep recession lesions in the mandibular anterior area, where the predictability of the root coverage is reduced by unfavorable anatomical conditions. The purpose of this case report is to present a novel surgical technique for deep labial recessions on mandibular incisors, based on a gingival pedicle with split-thickness tunneling (GPST), in combination with connective tissue graft (CTG). CASE PRESENTATION: A 25-year-old female patient presented with a Class II Miller isolated buccal recession on #24, 5 × 3 mm. The recipient site design consisted of a laterally positioned flap with a width of 4 mm, in combination with a split-thickness tunnel preparation that reached the mesial line angle of #25 and extended beyond the mucogingival junction. A CTG (13 × 7 mm) was harvested from the palate and properly adapted over the root surface. Graft and flap were secured with internal mattress and single-interrupted sutures. Complete root coverage was obtained and maintained at 6 months with excellent esthetic outcomes. CONCLUSION: This novel surgical approach, based on the combination of laterally displaced pedicle flap and tunneling in addition to CTG, seems to lead to promising results for the treatment of single deep mandibular anterior recessions.

Replacement of mandibular molars with single-unit restorations supported by wide-body implants: immediate versus delayed loading. A randomized controlled study.

PURPOSE: This prospective randomized controlled trial aimed to compare single implant-supported mandibular molar restorations using either an immediate or a delayed loading protocol. MATERIALS AND METHODS: Thirty subjects requiring single mandibular molar replacement were consecutively treated. One implant was placed in each patient. Fifteen subjects were assigned to delayed loading protocol and 15 to immediate loading protocol according to a randomization table. After insertion, the delayed loaded implants were connected to a healing abutment and restored after 3 to 4 months of healing without loading. The immediately loaded implants were loaded within 24 hours of surgery with a provisional restoration. The interim prosthesis was placed in centric occlusion. All contacts in lateral excursions were eliminated. At implant placement the maximum value of insertion torque was recorded. Radiographic bone level change was measured on periapical radiographs obtained at the time of implant placement and 12 months after loading. Means of the 2 groups were compared by Student t test and analysis of variance (ANOVA). The level of significance was set at .05. RESULTS: No implants were lost in the delayed loading group (0/15), whereas 1 implant failed (1/15) in the immediate loading group. No differences were observed in relation to implant length or insertion torque between the groups. The average radiographic bone level change after 1 year of function was 1.2 +/- 0.55 mm (range, 0.5 to 2.6 mm) and 0.77 +/- 0.38 mm (range, 0.29 to 1.23 mm) for the delayed loaded and the immediately loaded implants, respectively. The difference in radiographic bone level change between the delayed and immediate loading groups was statistically significant (P = .022; CI = -0.79 to -0.06; Student t test). CONCLUSIONS: Immediate loading of wide-diameter implants supporting single restorations in mandibular molar sites seems to be a suitable clinical option. Moreover, the radiographic bone level change observed after 12 months of loading was significantly less for immediately loaded implants.

Immediate loading of two implants supporting a ball attachment-retained mandibular overdenture: a prospective clinical study.

BACKGROUND: A prospective clinical study was conducted to evaluate clinically and radiographically the performance of two implants immediately loaded supporting a ball attachment-retained mandibular overdenture. MATERIALS AND METHODS: Seventeen completely edentulous patients were included in the study. Each patient received two implants inserted after a minimal flap reflection and no vestibular extension in order to reduce the postoperative swelling and facilitate immediate prosthesis connection. After implant placement, a mandibular complete denture was connected to the implants using ball attachments of appropriate height according to the depth of the peri-implant tissue. Patients were asked not to remove the denture for 1 week. No limitations to chewing function were given. At implant placement, the maximum value of insertion torque was recorded. Patients were examined at 1, 2, 4, 12, and 52 weeks postsurgery. At postoperative visit, occlusion was checked and the need for any prosthesis maintenance was recorded. The radiographic bone level (RBL) change was measured on periapical radiographs at baseline and 12 months after loading. RESULTS: After 12 months of loading, no implant failure was reported and the survival rate was 100%. Average RBL change was 0.7 mm +/- 0.5 mm. Of the 17 cases, two had major prosthetic complications and five patients required minor extra maintenance appointments. CONCLUSIONS: The immediate loading of two implants by means of ball attachment-retained mandibular complete denture may be a predictable treatment option. This clinical approach offers increased stability and comfort, while keeping a high implant success rate.

Immediate loading of dental implants supporting fixed partial dentures in the posterior mandible: a randomized controlled split-mouth study--machined versus titanium oxide implant surface.

PURPOSE: A split-mouth study was conducted to compare dental implants with either machined or titanium oxide (TiO) surfaces immediately loaded with fixed partial dentures in the posterior mandible. MATERIALS AND METHODS: Ten patients with bilateral partial edentulism in the posterior mandible received 42 implants; 20 on the test (TiO) and 22 on the control (machined) side. The implants were loaded within 24 hours postsurgery. At implant placement the maximum insertion torque (IT) was recorded. Implant stability quotient (ISQ) was also evaluated at baseline (day 0) and 1, 2, 4, 12, 24, and 52 weeks following implant placement. The radiographic bone level (RBL) change was measured on periapical radiographs at baseline and 12 months after loading. Means for the 2 groups were compared by paired t test. RESULTS: The overall implant success rate was 95%. No implants were lost in the test group; 2 failed in the control group. The difference between the groups in RBL change after 1 year of function was not statistically significant (P = .224). However, average RBL change for machined implants in distal positions was significantly higher than for TiO surface implants in the same position (post-hoc comparison; P = .048). ISQ and peak IT values did not differ between the groups (P = .414 and P = .762, respectively). The high IT necessary to insert the implants did not seem to affect the RBL change (P = .203). CONCLUSIONS: No significant difference was observed between machined and TiO implant surface in terms of RBL change or ISQ, although TiO implants may provide a lower RBL change compared to machined implants when utilized in the distal position. Immediate loading of implants using fixed partial dentures in posterior mandible may be considered as a treatment option if implants are inserted with IT > or = 20 Ncm and ISQ > or = 60 into nonaugmented bone and loaded with light centric occlusal contact.

Osteogenesis During Early Healing Around Titanium and Roxolid Implants: Evaluation of Bone Markers by Immunohistochemistry and RT-PCR Analysis in Miniature Pigs: A Pilot Study.

PURPOSE: A novel approach for the study of early bone formation around dental implants in the miniature pig was evaluated. In addition to the traditional histologic and histomorphometric analysis, the expression of the osteogenic genes was analyzed both at the messenger ribonucleic acid (mRNA) and protein level. MATERIALS AND METHODS: Mandibular premolars and the first molar were extracted in six miniature pigs. After 3 months of healing, 36 specially designed bone chamber implants were placed. Three different implant surface configurations were used: titanium SLA, titanium SLActive, and titanium zirconium SLActive (Roxolid). Each hemi-mandible received three randomly allocated implants (one for each surface type) on both sides of the arch, in a split-mouth design. Three animals were sacrificed after 3 days and another three after 2 weeks of healing post-implant insertion. For each animal the right hemi-mandible underwent qualitative histologic and quantitative histomorphometric analysis. The left hemi-mandible underwent immunohistofluorescence (IHF) analysis. ß-catenin, Runx2, osteopontin, and osteocalcin were analyzed by IHF; osterix, and osteocalcin mRNA expression was also evaluated by quantitative reverse transcription polymerase chain reaction (qRT-PCR). RESULTS: At 3 days after the implantation, all implants were surrounded by blood clot. No provisional matrix or bone was observed inside the chamber. Infection or degenerative lesions were absent. At 2 weeks, the histomorphometric analysis showed no significant difference between the groups concerning the bone area. qRT-PCR showed that Ti SLActive had the highest osteocalcin mRNA expression followed by Ti SLA and Roxolid SLActive. Osterix mRNA expression was higher on Ti SLA and Roxolid SLActive compared to Ti SLActive. The differences were not statistically significant. IHF was only found positive for osteocalcin at 2 weeks. At 3 days, osteocalcin was detected only on native bone. At 2 weeks, osteocalcin was expressed highest by Ti SLActive followed by Roxolid SLActive and TiSLA; however, there was no statistically significant difference between the groups in the osteocalcin expression level. CONCLUSION: The present methodology allowed evaluation of changes in gene expression during the early phase of osteogenesis that seem to be related to the quality of the surface. Further studies with higher power and more specific antibodies are needed to confirm these preliminary findings.