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ABSTRACT: To evaluate whether 6 mm-long by 4 mm-wide dental implants could be an alternative to at least 10 mm-long implants placed in bone augmented with bone substitutes in posterior atrophic jaws.
Twenty patients with bilateral atrophic mandibles and 20 patients with bilateral atrophic maxillae, having 5 to 7 mm of bone height above the mandibular canal or below the maxillary sinus, were randomised according to a split-mouth design to receive one to three 6 mm-long and 4 mm-wide implants or at least 10-mm long implants in augmented bone at two centres. Mandibles were vertically augmented with interpositional equine bone blocks and resorbable barriers, and implants were placed after 3 months. Maxillary sinuses were augmented with particulated porcine bone via a lateral window and implants were placed simultaneously. All implants were submerged and loaded, after 4 months, with provisional prostheses. Four months later, definitive screw-retained metal-ceramic prostheses were delivered. Outcome measures were prosthesis and implant failures, any complication, time needed to fully recover mental nerve function (only for mandibular implants) and patient preference.
All screened patients had sufficient bone width to support 4 mm-diameter implants. Patients were followed up to 5 months post-loading and none dropped out. There were no statistically significant differences in graft, implant or prosthesis failures, though significantly more intra- and postoperative complications occurred at grafted sites. Fourteen complications occurred in 12 patients at augmented sites versus none at short implants. All complications occurred before loading. Three complications were associated with the failure of the mandibular grafts (15%), determining the failures of 3 implants in one patient and 2 prostheses could not be delivered. One patient was re-grafted and 2 patients received short implants instead. Apart from those complications associated with graft failures, there were 4 perforations of the sinus membrane during sinus lifting and 7 temporary lower lip paraesthesiae lasting up to 4 days with no long-term consequences for the patients. All maxillary implants and prostheses were successful. All 20 patients treated with mandibular implants and 15 patients treated with maxillary implants preferred short implants, whereas 5 patients treated with maxillary implants described both procedures as equally acceptable. These differences were statistically significant.
Short-term data (5 months after loading) indicate that 6 mm-long implants with a conventional diameter of 4 mm achieved similar if not better results than longer implants placed in augmented bone. Short implants might be a preferable choice to bone augmentation, especially in posterior mandibles since the treatment is faster, cheaper and associated with less morbidity. However, 5- to 10-year post-loading data are necessary before making reliable recommendations.
European Journal of Oral Implantology 01/2012; 5(1):19-33. · 1.67 Impact Factor
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ABSTRACT: To evaluate whether 5 × 5 mm dental implants with a novel nanostructured calcium-incorporated titanium surface could be an alternative to at least 5 × 10 mm-long implants placed in bone augmented with bone substitutes in posterior atrophic jaws.
Forty patients with atrophic posterior (premolar and molar areas) mandibles having 5 to 7 mm of bone height above the mandibular canal and 40 patients with atrophic maxillae having 4 to 6 mm below the maxillary sinus, were randomised according to a parallel group design to receive one to three 5 × 5 mm implants or one to three at least 5 × 10 mm-long implants in augmented bone at two centres. Mandibles were vertically augmented with interpositional bovine bone blocks and resorbable barriers and implants were placed after 4 months. Maxillary sinuses were augmented with particulated porcine bone via a lateral window covered with resorbable barriers and implants were placed simultaneously. All implants were submerged and loaded after 4 months with provisional prostheses. Four months later, definitive screw-retained or provisionally cemented metal-ceramic or zirconia prostheses were delivered. Outcome measures were prosthesis and implant failures as well as any complication.
Patients were followed to 4 months post-loading with the exception of one patient who underwent mandibular augmentation and had multiple complications at and after grafting, and subsequent graft failure, who did not want to go ahead with the treatment. This case was considered a complete failure. There were no statistically significant differences in prosthesis and implant failures. In mandibles, apart from the complete graft failure, one 5 × 10 mm implant failed at placement of the provisional prosthesis. In maxillae, one 5 × 5 mm implant failed with its provisional crown 3 months after loading. All complications occurred before loading. Significantly more intra- and postoperative complications occurred at both mandibular and maxillary grafted sites: 16 augmented patients were affected by complications versus 8 patients treated with short implants in the mandible (P = 0.022; difference in proportion = 0.40; CI 95% 0.12 to 0.68), and 5 sinus-lifted patients versus none treated with maxillary short implants (P = 0.047; difference in proportion = 0.25; CI 95% 0.06 to 0.44).
Short-term data (4 months after loading) indicate that 5 × 5 mm implants achieved similar results compared to longer implants placed in augmented bone. Short implants might be a preferable choice to bone augmentation especially in posterior mandibles since the treatment is faster, cheaper and associated with less morbidity. However, 5 to 10 years of post-loading data are necessary before making reliable recommendations.
European Journal of Oral Implantology 01/2012; 5(2):149-61. · 1.67 Impact Factor
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ABSTRACT: To evaluate whether 6.3 mm-long implants could be a suitable alternative to longer implants placed in vertically augmented atrophic posterior mandibles.
Sixty partially edentulous patients having 7 to 8 mm of residual crestal height and at least 5.5 mm thickness measured on CT scans above the mandibular canal were randomised according to a parallel group design either to receive 1 to 3 submerged 6.3 mm-long implants or 9.3 mm or longer implants (30 patients per group) placed in vertically augmented bone. Bone was augmented with interpositional an organic bovine bone blocks covered by resorbable barriers. Grafts were left to heal for 5 months before implant placement. Four months later, provisional acrylic prostheses were delivered, and were then replaced after another 4 months by definitive metal-ceramic prostheses. Outcome measures were prosthesis and implant failures, complications, and radiographic peri-implant marginal bone level changes. All patients were followed up to 3 years after loading.
Four patients dropped out, two from each group. The augmentation procedure failed in two patients and only 6.3 mm-long implants could be inserted. There were no statistically significant differences for prosthesis and implant failures. Three prostheses could not be placed or had to be remade in the short implant group versus 4 prostheses in the augmented group. Two short implants failed versus 3 long implants, all in different patients. There were statistically significantly more complications in augmented patients (22 complications in 20 augmented patients versus 5 complications in 5 patients of the short implant group). Both groups gradually lost peri-implant bone in a statistically significant way at 4 months, and 1 and 3 years after loading. Three years after loading, patients of the short implant group lost an average of 1.24 mm of peri-implant bone compared with 1.76 mm in the long implant group. Short implants experienced statistically significantly less bone loss (0.52 mm; CI 95% 0.20 to 0.83, P = 0.002) than long implants.
When residual bone height over the mandibular canal is between 7 and 8 mm, 6.3 mm short implants could be an interesting alternative to vertical augmentation since the treatment is faster, cheaper and associated with less morbidity. Longer follow-ups are needed to confirm these results.
European Journal of Oral Implantology 01/2011; 4(4):301-11. · 1.67 Impact Factor
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ABSTRACT: To compare the effectiveness of immediate post-extractive single implants with delayed implants placed in preserved sockets after 4 months of healing. Implants that achieved an insertion torque of at least 35 Ncm were immediately non-occlusally loaded.
Just after tooth extraction and in the presence of a loss of the buccal plate bone less than 4 mm, compared to the palatal wall, 106 patients requiring a single immediate postextractive implant in the maxilla from second premolar to second premolar were randomly allocated to immediate implant placement (immediate group; 54 patients) or to socket preservation using anorganic bovine bone covered by a resorbable collagen barrier (delayed group; 52 patients) according to a parallel group design at three different centres. Bone-to-implant gaps were to be filled with anorganic bovine bone, however this was not done in 17 patients (corresponding to 40% of those who should have been grafted). Four months after socket preservation, delayed implants were placed. Implants placed with an insertion torque >35 Ncm were immediately loaded with non-occluding provisional single crowns, replaced, after 4 months, by definitive crowns. Outcome measures were implant failures, complications, aesthetics assessed using the pink esthetic score (PES), and patient satisfaction, recorded by blinded assessors. All patients were followed up to 4 months after loading.
Nineteen (35%) implants were not immediately loaded in the immediate group versus 39 (75%) implants in the delayed placement group because an insertion torque >35 Ncm could not be obtained. No patient dropped out. Two implants failed in the immediate group (4%) versus none in the delayed group. More minor complications occurred in the immediate group (8) than the in the delayed group (1) and this was statistically significant (P = 0.032). At delivery of definitive crowns, 4 months after loading, aesthetics were scored as 12.8 and 12.6 in the immediate and delayed groups, respectively. There was no statistically significant difference (P = 0.5). Patients of both groups were equally satisfied.
There were more complications at immediate post-extractive implants when compared to delayed implants. The aesthetic outcome appears to be similar for both groups and it seems more difficult to obtain a high insertion torque in sockets preserved with anorganic bovine bone.
European Journal of Oral Implantology 01/2011; 4(4):329-44. · 1.67 Impact Factor
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ABSTRACT: To evaluate whether short (5 to 8.5 mm) dental implants could be a suitable alternative to longer (>11.5 mm) implants placed in atrophic maxillae augmented with autogenous bone for supporting dental prostheses.
Twenty-eight patients with fully edentulous atrophic maxillae having 5 to 9 mm of residual crestal bone height at least 5 mm thick, as measured on computerised tomography scans, were randomised into two groups either to receive 4 to 8 short (5 to 8.5 mm) implants (15 patients) or autogenous bone from the iliac crest to allow the placement of at least 11.5 mmlong implants (13 patients). Bone blocks and the windows at maxillary sinuses were covered with rigid resorbable barriers. Grafts were left to heal for 4 months before placing implants, which were submerged. After 4 months, provisional reinforced acrylic prostheses or bar-retained overdentures were delivered. Provisional prostheses were replaced, after 4 months, by definitive screw-retained metal-resin cross-arch fixed dental prostheses. Outcome measures were: prosthesis and implant failures, any complications (including prolonged postoperative pain) and patient satisfaction. All patients were followed for 5 months after loading.
All patients could be rehabilitated with implant-supported prostheses and none dropped out. One bilateral sinus lift procedure failed due to infection, though short implants could be placed. One implant failed in the augmented group versus 2 short implants in 2 patients. All failures occurred before loading. Significantly more complications occurred in augmented patients: 8 complications occurred in 5 augmented patients (all complained of pain 1 month after bone harvesting from the iliac crest). No complications occurred in the short implant group. All patients were fully satisfied with the treatment and would do it again.
This pilot study suggests that short implants may be a suitable, cheaper and faster alternative to longer implants placed in bone augmented with autogenous bone for rehabilitating edentulous atrophic maxillae. However, these preliminary results need to be confirmed by larger trials with follow-ups of at least 5 years.
European Journal of Oral Implantology 01/2011; 4(3):191-202. · 1.67 Impact Factor
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ABSTRACT: To evaluate the clinical outcome of 2 implants versus 4 implants placed flapless in fully edentulous mandibles and immediately restored with metal-resin screw-retained cross-arch prostheses.
Sixty patients from two different centres were randomised: 30 to the allon- 2 group and 30 to the all-on-4 group. To be immediately loaded, implants had to be inserted with a minimum torque of 40 Ncm. Outcome measures were prosthesis and implant failures, and biological and biomechanical complications.
Flaps were raised in 18 patients. Two implants in 2 patients did not reach the planned insertion torque and were immediately replaced by larger diameter ones. Four months after loading, no drop-out or implant failure occurred. One biomechanical complication occurred in the all-on-2 group versus 4 in the all-on-4 group. There were no statistically significant differences between groups for complications. There were no differences between centres.
These very preliminary results, just 4 months after loading, suggest that immediately loaded mandibular cross-arch fixed dental prostheses can be supported by only 2 dental implants. Longer follow-ups (around 10 years) are needed to understand whether cross-arch mandibular prostheses can be successfully supported by only 2 dental implants.
European Journal of Oral Implantology 01/2011; 4(3):205-17. · 1.67 Impact Factor
