Influence of controlled immediate loading and implant design on peri-implant bone formation

AIM: Tissue formation at the implant interface is known to be sensitive to mechanical stimuli. The aim of the study was to compare the bone formation around immediately loaded versus unloaded implants in two different implant macro-designs. MATERIAL AND METHODS: A repeated sampling bone chamber with a central implant was installed in the tibia of 10 rabbits. Highly controlled loading experiments were designed for a cylindrical (CL) and screw-shaped (SL) implant, while the unloaded screw-shaped (SU) implant served as a control. An F-statistic model with alpha=5% determined statistical significance. RESULTS: A significantly higher bone area fraction was observed for SL compared with SU (p<0.0001). The mineralized bone fraction was the highest for SL and significantly different from SU (p<0.0001). The chance that osteoid- and bone-to-implant contact occurred was the highest for SL and significantly different from SU (p<0.0001), but not from CL. When bone-to-implant contact was observed, a loading (SL versus SU: p=0.0049) as well as an implant geometry effect (SL versus CL: p=0.01) was found, in favour of the SL condition. CONCLUSIONS: Well-controlled immediate implant loading accelerates tissue mineralization at the interface. Adequate bone stimulation via mechanical coupling may account for the larger bone response around the screw-type implant compared with the cylindrical implant.     

Randomized controlled trial comparing immediate loading with conventional loading using cone-anchored implant-supported screw-retained removable prostheses: A 2-year follow-up clinical trial

Statement of problem

Implant-based prosthetic solutions can be time consuming. If implants can be loaded immediately, treatment time can be reduced.

A randomized clinical trial comparing two mandibular implant overdenture designs: 3-year prosthetic outcomes using a six-field protocol

PURPOSE: This clinical trial tested the null hypothesis that there would be no difference in prosthetic maintenance for two-implant mandibular overdentures retained by either a bar-clip mechanism or ball attachments. Prosthetic outcomes are reported over 3 years using a six-field protocol. MATERIALS AND METHODS: One hundred edentulous participants received new maxillary complete dentures and a mandibular two-implant overdenture (IOD), with random assignment to either a bar and metal clip or two ball attachments (titanium alloy matrix and spring) for retention. Eighty-seven subjects were available for follow-up after 3 years. RESULTS: Almost three times as many bar-clip dentures (63%) were rated successful compared to the ball attachment design. Two percent of the participants in each group died over the course of the study, while 15% of the bar-clip and 8% of the ball IOD subjects were lost to follow-up. More than three times as many ball attachment IODs (60%) required retreatment in the form of excessive repairs, and twice as many of the ball attachment design (8%) required replacement. The ball attachment IOD was significantly more likely to require patrix tightening or matrix replacement, while the bar-clip design was more likely to require activation of the matrix. CONCLUSION: Using the criteria of a six-field protocol for implant overdenture outcomes, the bar-clip IOD was a significantly more successful prosthesis, requiring less maintenance than the titanium alloy matrix and spring ball attachment IOD employed in this study. The null hypothesis was therefore defeated.     

Survival and stability of strategic mini-implants with immediate or delayed loading under removable partial dentures: a 3-year randomized controlled clinical trial

Clinical Oral Investigations - Stability values of mini-implants (MIs) are ambiguous. Survival data for MIs as supplementary abutments in reduced dentitions are not available. The aim of this...     

A relaxed implant bed: implants placed after two weeks of osteotomy with immediate loading: a one year clinical trial

A waiting period of 2?weeks after osteotomy increases the surrounding tissue activity to its maximum level as collagen formation and neoangiogenesis represent a relaxed and acceptable implant bed configuration. The aim of the present study was a clinical and radiologic evaluation of early osteotomy with implant placement delayed for 2?weeks with immediate loading in the anterior and premolar region with minimally invasive approach. Seven GS II implants (Osstem) were placed in 6 patients. Osteotomy was done followed by flap closure without placement of the implant. After waiting for approximately 2?weeks, implant placement was done, which was loaded immediately with provisional crown in implant protected occlusion. It was replaced by definitive restoration after 6-8?weeks, which was considered baseline. Implant stability and marginal bone levels were assessed with clinical and radiologic parameters at baseline, 6- and 12-month intervals. None of the implants were found mobile during the 1-year period. The average mean marginal bone loss was 0.4?mm over the 1-year follow-up period. In the present study, early osteotomy with delayed implant placement showed negligible crestal bone loss with no mobility.     

A randomized controlled clinical trial comparing guided with nonguided implant placement: A 3-year follow-up of implant-centered outcomes

Statement of problemImplant-based prosthetic solutions can be time consuming. If implants can be placed successfully with a guide, surgery time can be reduced.PurposeThe purpose of this randomized controlled clinical trial was to assess implant outcomes, both clinical and radiological, comparing guided with nonguided implant placement after 3 years of follow-up.Material and methodsA total of 314 implants were placed in 72 jaws (60 participants). The jaws were randomly assigned to 1 of the 6 treatment groups: Materialise Universal/mucosa (Mat Mu), Materialise Universal/bone (Mat Bo), Facilitate/mucosa (Fac Mu), Facilitate/bone (Fac Bo), freehand navigation (Freehand), and a pilot-drill template (Templ). Radiographic and clinical parameters (bone loss, pocket probing depth, bleeding on probing, and plaque scores) were recorded at the time of implant placement, prosthesis installment (baseline), and 1-year, 2-year, and 3-year follow-up. Analysis was performed using a linear mixed model, and correction for simultaneous hypothesis was made according to Sidak (α=.05).ResultsThree participants left the study before the 3-year follow-up; hence, 302 implants in 69 jaws were included in this study. None of the implants failed. The mean marginal bone loss after the third year of loading was 0.7 ±1.3 mm for the guided surgery group and 0.5 ±0.6 mm for the control group. No significant intergroup or follow-up period differences were observed (P>.05). In the guided surgery groups, the mean number of surfaces with bleeding on probing and plaque at 3-year follow-up was 1.7 ±1.5 and 1.7 ±1.7, respectively; for the control groups, this was 1.6 ±1.4 and 1.6 ±1.6, respectively. The mean pocket probing depth was 3.0 ±1.3 mm for the guided group and 2.6 ±1.0 mm for the control group. No significant differences were found (P>.1).ConclusionsWithin the limitation of this study, no statistically significant differences could be found between the guided group and the control group at the 3-year follow-up.     

Caries prevalence four years after the end of a randomised controlled trial

This study measured dental caries in children after cessation of a 30-month randomised clinical trial in which the intervention group received supervised toothbrushing once a day at school with 1,000 ppm fluoride toothpaste and a home support package encouraging twice-daily toothbrushing. The non-intervention group did not brush at school or receive the home support package. Children were aged 5 years at baseline and were examined every 6 months during the trial, then at 6, 18, 30 and 54 months after the end of the trial. Significantly less caries developed in first permanent molars of intervention children at the end of the trial. Of the 428 children who were examined at the end of the trial 329 (77%) were examined 54 months later when the children were aged 12 years on average. The intervention group still had less caries (D3FS caries increment 1.62) than the non-intervention children (D3FS caries increment 2.65, p < 0.05). Prolonged benefits have been found for intervention children principally in less caries in first permanent molars. Further follow-up at an age when the second molars and premolars have all erupted will help determine whether this benefit is due to a long-term behavioural change or a prolonged biological effect.     

Retrospective analysis of the influence of abutment structure design on the success of implant unit. A 3-year controlled follow-up study

A comparative study of 96 Spline and Threadloc implants is presented. The authors examined the possibility of the failure of the retaining screws of two different antirotational systems (the Threadloc system with hexagonal polyhedral extension and the Spline system), and the possible incorrect link between the abutment and the transfer. After an observation period of 36 months starting from the day of prosthesis insertion, three single Threadloc fixtures (20%) and five pairs of joint Threadloc fixtures (5.7%) presented problems and a partial prosthetic screw loosening. For the Spline series fixtures, no screw loosening was encountered. Regarding the safety of the link between abutment and implant, the best results were obtained from the Spline system, which did not hinder the dentist in positioning the link with the abutment. This is the result of the different geometries of the two antirotational mechanisms which are present on the two fixtures. It is believed that the precise contact between the abutment and the fixture avoids the triggering of a phlogistic process, which can develop into periimplantitis. Therefore, when hex systems are used, an x-ray, which verifies this correct situation, is always recommended during the follow-up.