Immediate loading of implants in the edentulous maxilla

The overall aim of this thesis was to investigate different therapeutic strategies in treatment of the edentulous maxilla with dental implants and their importance for treatment outcome. The introduction of one-stage surgery, in place of two-stage surgery, was a paradigm shift in the area of implant treatment since submerged implant healing underneath the mucosa was considered a prerequisite for healing in the original concept. The advantages of a one-stage method are that a second surgery is unnecessary, costs are lower, and patients complain less about the surgical procedures. The development of implant treatment, regardless of whether it is performed in the mandible or the maxilla, strives to shorten the period from implant placement to implant loading. For the edentulous patient--due to esthetic, economical, or psychological reasons--shortening this time and thus avoiding a long period of wearing a transitional removable prosthesis is advantageous. Use of conventional one-stage surgery makes possible and is a prerequisite for immediate loading of implants. Successful treatment outcome has been demonstrated for immediate loading of implants in the mandible, but documentation of the method in the maxilla is still sparse. Two prospective clinical studies compared (i) one- and two-stage surgery and (ii) immediate and conventional loading in patients consecutively treated in the edentulous maxilla with implant-supported fixed prostheses. The first study found that the cumulative survival rate (CSR) after one-stage surgery performed according to a conventional protocol was consistent with two-stage protocol CSRs reported in previous studies. The second study evaluated an immediate loading protocol that provided patients with interim fixed prostheses within 24 hours after implant placement. A comparison of the studies found no significant difference in CSRs. But it was found that when a conventional protocol was used, transitional removable prostheses could traumatize the bone-implant interface during healing by adverse loading on the implants, which pierced the mucosa. Moreover, splinting the implants immediately after surgery with an interim fixed prosthesis might protect them from adverse loading. In a finite element analysis comparing uncoupled and splinted implants--imitations of the clinical situations in the two studies--splinted implants drastically reduced stresses in the bone tissue surrounding the implant, which might facilitate bone healing. Two factors considered important for a successful treatment outcome, especially when loading implants immediately, are (i) jawbone quality and (ii) primary implant stability at placement. In implant literature, bone quality is generally equivalent to bone density. Results of the third clinical study in this thesis indicate that use of computed tomography with calculations of bone mineral density can be a useful tool in bone tissue evaluation before implant placement. After 1 year of loading, changes in marginal bone level, compared to baseline, did not differ between implants that were stable and implants that were not stable at placement. The results of this thesis do not strengthen earlier recommendations that immediate and early loading is a treatment alternative that can be considered only in jaws with good bone quality. In conclusion, immediate loading with interim fixed prostheses in the edentulous maxilla is a viable treatment alternative. Splinting of implants seems to be important in immediate loading, especially when bone density is low.     

Finite element analysis of narrow dental implants

Narrow-diameter implants (NDIs) traditionally have been associated to higher rates of failure in comparison with regular-diameter implants (RDIs) and wide-diameter implants (WDIs), since they generate a more unfavorable stress distribution in peri-implant bone. However, it is well known that the load sharing effect associated with prostheses supported by multiple implants (also called splinted prostheses) affords mechanical benefits. The present study involves finite element analysis (FEA) to determine whether the risks linked to NDIs could be mitigated by the mechanical advantages afforded by the splinting concept. For this purpose, a three-dimensional (3D) model of a real maxilla was reconstructed from computed tomography (CT) images, and different implants (NDIs, RDIs and WDIs) and prostheses were created using computer-aided design (CAD) tools. Biting forces were simulated on the prostheses corresponding to three different rehabilitation solutions: single-implant restoration, three-unit bridge and all-on-four treatment. Stress distribution around the implants was calculated, and overloading in bone was quantified within peri-implant volumes enclosed by cylinders with a diameter 0.1 mm greater than that of each implant. The mechanical benefits of the splinting concept were confirmed: the peri-implant overloaded volume around NDIs splinted by means of the three-unit bridge was significantly reduced in comparison with the nonsplinted condition and, most importantly, proved even smaller than that around nonsplinted implants with a larger diameter (RDIs). However, splinted NDIs supporting the all-on-four prosthesis led to the highest risk of overloading found in the study, due to the increase in compressive stress generated around the tilted implant when loading the cantilevered molar.     

Temporary Implants for Patients with Low Bone Density of the Upper Maxilla: An Alternative Rehabilitation Strategy

Background: The use of removable provisional prosthesis after implant placement is undesirable for many patients. In addition, removable prostheses place unfavorable pressure over implants during the healing period. Purpose: The use of temporary implants enable greater stability and functionality of the prostheses. Materials and Methods: This clinical report shows the use of temporary implants in a low density maxilla in conjunction with a fixed provisional prosthesis. Results: The temporary implants contributed to the support of the provisional fixed upper arch prosthesis and to patient comfort with a fixed prosthesis during the healing period. Conclusions: Fixed provisional prostheses are a potentially desirable alternative treatment strategy.     

Immediately loaded implants supporting fixed prostheses in the edentulous maxilla: a preliminary clinical and radiologic report

PURPOSE: To evaluate the survival rate of immediately loaded ITI sand-blasted, large-grit, acid-etched (SLA) solid-screw dental implants in the edentulous maxilla after 8 months of loading. MATERIALS AND METHODS: Twenty-eight patients (mean age 63 years) with edentulous maxillae each received 6 implants and 1 implant-supported fixed provisional prosthesis within 24 hours after surgery. After a mean healing time of 15 weeks, the patient received a definitive, screw-retained, implant-supported fixed prosthesis. A total of 168 implants were placed. Clinical parameters were registered after 1 month of loading with the implant-supported fixed prostheses as well as 8 months after implant placement. Radiologic examinations and assessments were made at implant placement and after 8 months. RESULTS: The mean marginal bone level at implant placement was 1.6 mm (range 0 to 5.1; SD 1.1) apical of the reference point (the implant shoulder). The mean marginal bone level at the 8-month follow-up was 3.2 mm (range 0.4 to 5.9; SD 1.1) apical of the reference point. Three implants failed during the healing period. DISCUSSION: The improved results in the present study might be a result of the positive effect of splinting the implants immediately after placement. CONCLUSION: ITI SLA solid-screw implants immediately loaded (ie, loaded within 24 hours of placement) and supporting fixed prostheses had successful survival rates after 8 months. The present results constitute a solid baseline for future follow-up studies.     

Syncrystallization: a technique for temporization of immediately loaded implants with metal-reinforced acrylic resin restorations

Background Rigid temporization has been recognized to have a significant impact on the peri‐implant tissue response in immediate implant loading since it reduces the mechanical stress exerted on each implant. Purpose A successful protocol for immediate loading of multiple implants depends on an adequate fixation and immobility of the implants to prevent the risk of micromovements in relation to the surrounding bone. The objective of this article was to evaluate a prosthetic concept for an accelerated rigid splinting of multiple implants for same‐day immediate loading with metal‐reinforced provisional restorations using a technique of welding temporary implant abutments with a prefabricated titanium bar directly in the oral cavity (syncrystallization). Materials and Methods Between June 2004 and January 2005, immediate loading of threaded implants with a metal‐ reinforced acrylic resin provisional restoration at stage 1 surgery was evaluated in 40 consecutive patients. A total of 192 implants were placed in selected edentulous or partially edentulous patients using the syncrystallization technique. Once the titanium bar was welded intraorally to the abutments, opaque was applied and the provisional restoration was relined and screw‐retained the same day. In addition, a comparison of deformations and stress distributions in implant‐supported, metal‐reinforced and nonmetal‐reinforced resin provisional restorations was analyzed in the edentulous mandible by a three‐dimensional finite element model (FEM). Results All of the 192 rigidly temporized immediately loaded implants osseointegrated. An implant success rate of 100% was achieved over a period of 6 months postplacement. No fracture or luting cement failure of the provisional restoration occurred during the observation time. Compared to mere acrylic superstructures, a significant reduction of deformation and strain within metal‐reinforced provisional restorations was detected by FEM analysis. Conclusion The results of this study indicate that the syncrystallization technique allows an expedite and adequate rigid splinting of multiple immediately loaded implants. The advantages of the technique are: (1) reduction of treatment time for immediate temporization at stage 1 surgery; (2) predictable fixation and immobility of implants in the early stages of bone healing; and (3) less time for repairing provisional restorations as a result of no or rare fracture.     

A prospective human clinical trial of Endopore dental implants in restoring the partially edentulous maxilla using fixed prostheses

This is the first report of a group of 50 partially edentulous patients who received a total of 151 Endopore dental implants in the maxilla. A mean implant length of 8.7 mm was used, and 76.8% of implants were placed in the posterior maxilla. At re-entry, all implants appeared to be osseointegrated and were used to support fixed prostheses. Approximately half of the crowns (57%) in these prostheses were splinted to one another, while the remainder (43%) were not. At the time of this report, the mean functional time was 34.6 months and the cumulative survival rate was 97.3% (4 implants had failed). Analysis of carefully standardized sequential radiographs indicated no significant changes in mean crestal bone levels between baseline and any of the examination times (after 6 months, 1 year, and 2 years in function). There were no detectable correlations between crestal bone loss and the factors implant length (7, 9, or 12 mm); implant diameter (3.5, 4.1, or 5.0 mm); implant position anteriorly or posteriorly in the maxilla; or whether or not the implant-supported crowns were splinted.     

Immediate loading of implants in the edentulous maxilla: use of an interim fixed prosthesis followed by a permanent fixed prosthesis: a 32-month prospective radiological and clinical study

Purpose: The aim of this study was to prospectively evaluate the survival rate of splinted and immediately loaded Straumann sandblasted, large-grit, acid-etched, solid-screw dental implants in the edentulous maxilla after 32 months of loading.
Materials and Methods: Twenty-eight patients (mean age 63 years) with edentulous maxillae received 168 implants (six each) and an implant-supported fixed interim prosthesis within 24 hours after surgery. After a mean healing time of 15 weeks, the patients received permanent screw-retained prostheses. Clinical and radiological examinations were made at implant placement and after 8, 20, and 32 months of loading. All permanent prostheses were removed at the 32-month follow-up; implant stability was checked with a torque device, and the implant stability quotient was determined with resonance frequency analysis.
Results: Mean marginal bone loss from baseline to 8 months after loading was 1.6 mm (SD 1.16; p  = .094), from 8 to 20 months 0.41 mm (SD 0.63; p  = .094), and from 20 to 32 months 0.08 mm (SD 0.49; p  = .039). The 32-month cumulative survival rate was 98.2%.
Conclusions: The 32-month survival of solid-screw implants – immediately loaded within 24 hours after placement – was similar to survival rates reported for solid-screw implants with conventional loading. Immediate loading and splinting of implants in the edentulous maxilla is a viable treatment alternative.     

Immediate function with fixed implant-supported maxillary dentures: a 12-month pilot study

STATEMENT OF PROBLEM: Immediate occlusal loading of dental implants in the edentulous mandible has proven to be an effective, reliable, and predictable procedure. There is little long-term data available on similar treatments in the edentulous maxilla. PURPOSE: The purpose of this study was to evaluate the 12-month implant survival after immediate loading of 4 to 6 implants with fixed screw-retained prostheses in edentulous maxillae. MATERIAL AND METHODS: Twenty-one patients, edentulous or with remaining teeth to be extracted in the maxilla, received 4 to 6 implants (n=111). The patients were restored with screw-retained fixed provisional prostheses supported by palladium-alloy frameworks within 24 hours after surgery. Insertion torques for implants were at least 40 Ncm. Implants, grouped as tapered or cylindrical screws, were placed in healed bone or extraction sockets. Implants were also classified as either vertical or off-angle. Definitive prostheses were placed after a mean healing time of 18 weeks. Radiographic examinations were made at the time of placement of provisional prostheses and 12 months later. Between-groups bone resorption was compared using 2-way ANOVA (alpha=.05). RESULTS: The mean follow-up time for all of the patients was 20 months (range, 13 to 28 months). The cumulative implant survival rate at the 12-month follow-up visits (after surgery) was 92.8%; the prostheses survival rate was 100%. No significant differences were found between the survival of tapered or cylindrical screw-type implants placed in postextraction sockets versus those in healed edentulous sites or between vertical and off-angle placed implants. Eight implants failed during the first 3 months, 5 of which were the most distal implants. The mean reduction in marginal bone height over the 12-month observation period was 0.84 mm (CI 95%; 0.68-0.99 mm). CONCLUSIONS: In this study with 12-month follow-up, 4 to 6 implants were sufficient to successfully support fixed implant screw-retained prostheses in the edentulous maxillae of 21 patients.     

Immediate loading in partially and completely edentulous jaws: a review of the literature with clinical guidelines

The introduction of immediate loading was a paradigm shift in implant dentistry as it was previously believed that an unloaded period was essential for bone healing in order to promote osseointegration. However, this belief could not be confirmed by clinical studies or by human histology. Hitherto, numerous reports have been published on immediate loading in various indications. An important factor for success is primary implant stability. The latter can be improved by adapting drilling protocols to enhance lateral compression of the bone and by using tapered implant designs with apical thread fixation. To some extent, the use of implants with a microrough surface and rigid splinting may compensate for suboptimal stability. It is important to avoid fracture of the provisional restoration at all times as this may result in local overloading and implant failure. Also, unevenly distributed occlusal contacts may contribute to failure and therefore occlusion ought to be evaluated at every occasion, especially during the early phase of healing. Taking these aspects into account, immediate loading in the fully edentulous mandible by means of an overdenture has been shown to be predictable in terms of implant survival (94.4–100%). However, the procedure may result in additional costs as a result of the need for repeated relining. In addition, the scientific basis for this treatment concept in the maxilla is very scarce. Immediate loading in the fully edentulous jaw by means of a fixed prosthesis is a well‐documented treatment concept. In the mandible, three implants have been shown to be insufficient, given the failure rate of up to 10%. With at least four implants a failure rate of 0–3.3% may be expected. In the maxilla, four to six implants could be too limited, given the failure rate up to 7.2%. Increasing the number of implants may reduce implant failure to 3.3%. Provisional fixed prostheses are particularly prone to fracture in the maxilla and hence reinforcement is warranted. Immediately loaded single implants have lower survival rates, of 85.7–100%, with no clear impact of occlusal contact. In fact, a meta‐analysis demonstrated a five times higher risk of failure for immediately loaded single implants when compared with delayed loading. No study showed superior soft‐tissue preservation or esthetics following immediate loading of single implants compared with other loading protocols. However, this finding may not imply that a provisional implant crown becomes redundant when soft‐tissue conditioning is deemed necessary. Taking into account earlier factors for success, immediate loading in the partially edentulous jaw by means of a fixed prosthesis seems predictable in terms of implant survival (95.5–100%). However, there are no studies with data on soft‐tissue parameters, esthetic aspects or patient‐centered outcomes, and the available studies mainly relate to the load‐carrying part of the dentition. Clinical studies focusing on these aspects of treatment outcome are clearly needed. High patient satisfaction is the most important advantage of immediate loading, especially during the early healing phase. In this context, one should also realize that studies have revealed comparable patient satisfaction in patients following delayed loading once their prosthesis is in place. In the decision‐making process, this aspect should be properly discussed with the patient along with other advantages and disadvantages of immediate loading.     

An assessment of crown-to-root ratios with short sintered porous-surfaced implants supporting prostheses in partially edentulous patients

PURPOSE: Implant length, implant surface area, and crown-to-root (c/r) ratio and their relationship to crestal bone levels were analyzed in 2 groups of partially edentulous patients treated with sintered porous-surfaced dental implants. MATERIALS AND METHODS: One hundred ninety-nine implants were used to restore 74 partially edentulous patients with fixed prostheses. Implants were categorized according to their length ("short" versus "long") and estimated surface area ("small" versus "large"). "Short" implants had lengths of 5 or 7 mm, while "long" implants were either 9 or 12 mm in length. "Small" implants had estimated surface areas of < or = 600 mm2, while "large" implants had estimated surface areas > 600 mm2. Other data collected included c/r ratio (measured on articulated diagnostic casts), whether or not the implants were splinted, and standardized sequential radiographs. RESULTS: The mean c/r ratio was 1.5 (SD = 0.4; range 0.8 to 3.0), with 78.9% of the implants having a c/r ratio between 1.1 and 2.0. Neither c/r ratio nor estimated implant surface area (small or large) affected steady-state crestal bone levels. However, implant length and whether the implants were splinted did appear to affect bone levels. Long implants had greater crestal bone loss (0.2 mm more) than short implants; splinted implants showed greater crestal bone loss (0.2 mm more) than nonsplinted ones. These differences were statistically significant. DISCUSSION AND CONCLUSIONS: Sintered porous-surfaced implants performed well in short lengths (7 mm or less) in this series of partially edentulous patients. The data suggested that long implants and/or splinting can result in greater crestal bone loss; longer implants and splinted implants appeared to favor greater crestal bone loss in this investigation. These conclusions are, of course, specific to the implants used and would not be relevant to other implant types.     

Relevant Anatomic and Biomechanical Studies for Implant Possibilities on the Atrophic Maxilla: Critical Appraisal and Literature Review

Purpose: The purpose of this review was to highlight anatomic and biomechanical aspects of atrophic maxillae for implant possibilities. Materials and Methods: A MEDLINE electronic search of the years 1966 to 2009 was conducted with the keywords “atrophic,”“resorbed,”“edentulous,” and “maxilla.” Results: Twenty papers presented the following findings: (1) previous use of a removable prosthesis is a risk factor for resorption, with flabby tissues related to the severity of resorption; (2) implants in the reconstructed maxilla (≤5 mm) and supporting overdentures had a higher risk for bone loss based on the worse periimplant soft‐tissue health observed; (3) bleeding on probing was found with pocket depths ≥5 mm in half of the zygomatic implants; (4) prevalence of bone septa is higher in atrophic maxillae, and changes on nasopalatine canal can reduce up to 44.4% of the full length of buccal bone plates; (5) female patients have less medullar bone quantity and connectivity than male patients; (6) transectioning of nutrient vessels is easier and accelerates resorption; (7) stress does not concentrate on maxillary sinus base cortical bone contiguous to trabecular bone; (8) splinted implants receive nine times less load than nonsplinted implants even under oblique loading; (9) implant stability quotient (ISQ) values for implants ranged between 60 and 65; (10) in vivo force transfer to implants is similar between fixed prostheses and overdentures; (11) inclined implants generate better biomechanical responses; (12) masticatory efficiency and bite forces improve in maxillectomized patients who receive obturators with milled bar attachments. Conclusion: Sound implant‐supported choices for an atrophic maxilla must be made with a thorough understanding of its anatomic and biomechanical factors.     

Human ex vivo bone tissue strains around natural teeth vs. immediate oral implants

Purpose: To compare ex vivo bone tissue strains around natural teeth with immediate implants supporting unsplinted and splinted fixed prostheses. Material and methods: Six linear strain gauges were bonded on the labial marginal bone of bilateral maxillary anterior teeth in two fresh‐frozen human cadavers. The natural teeth were loaded in centric occlusion via an occlusal splint with integrated miniature load cells. Strain measurements were performed at a sample rate of 10 kHz and under a maximum load of 100 N, simultaneously monitored from a computer connected to data acquisition system. Upon extraction of the anterior teeth, Ø 4.1 mm and Ø 4.8 mm ITI^® dental implants were placed into sockets of incisors and canines, respectively. Installation torque value (ITV) of each implant was measured by a custom‐made torque wrench and resonance frequency analyses (RFA) were also undertaken. Strain measurements were performed for (1) single‐tooth implant restorations, (2) unilateral splinted anterior implants, and (3) bilateral splinted anterior implants. Finally, an autopolymerizing acrylic resin was injected into the implant sockets for simulation of osseointegration and strain measurements were performed. Results: Microstrains of all groups were statistically comparable (P>0.05), although lower strains were elicited for implants in sockets of incisors in comparison with natural teeth. Microstrains around canine implants were comparable or higher than those induced around natural canines. For all groups, microstrains around canines were higher than those around lateral (P<0.05) and central incisors (P<0.01), which had similar strain levels (P>0.05). The RFA values of implants were comparable. The ITVs of implants in sockets of lateral incisors and canines were similar and were higher than those of implants in central incisor regions. Conclusion: The labial marginal bone having no contact with immediate implants may experience strain gradients within physiologic levels due to deformation of bone under load. Although one prosthetic design does not seem to have clear advantages over another, splinting of implants may be considered as a safety measure for immediately loaded immediate implants, if possible.     

Surgical and prosthetic concepts for predictable immediate loading of oral implants

Immediate loading of oral implants is an established concept for lower jaw restoration using four intraforaminal implants splinted together with a bar. There is a lot of misunderstanding in the literature and not exact definition of the term "immediate loading." Moreover, the number of implants to restore edentulous jaws is relatively high to compensate for the loading forces and dependent on the bone quality and quantity. This report presents the different surgical and prosthetic concepts for immediate loading to get long-term success in the upper and lower jaw. When the primary stability is adequate, only six implants may be loaded immediately after surgery, if the implants are splinted using a provisional fixed restoration. Using a number of six primary stable implants, it is possible to restore edentulous jaws independent on the clinical situation. This concept may be used successfully in the posterior part of the mandible when three implants are splinted with provisional crowns and loaded immediately. The biomechanical aspects, the implant design and surface seem to be of great importance for the long-term success in compromised and advanced surgical cases. In conclusion, immediate loading of oral implants may be successful if a primary stability as well as immobilization (splinting) immediately after surgery are taken care.     

Immediate non-occlusal vs. early loading of dental implants in partially edentulous patients: a multicentre randomized clinical trial. Peri-implant bone and soft-tissue levels

Objectives: To compare peri‐implant bone and soft‐tissue levels of immediately non‐occlusally loaded vs. non‐submerged early loaded implants in partially edentulous patients up to 14 months after placement. Material and methods: Fifty‐two patients were randomized in five Italian private practices: 25 in the immediately loaded group and 27 in the early loaded group. To be immediately loaded, single implants had to be inserted with a torque of ≥30 N cm, and splinted implants with a torque of ≥20 N cm. Immediately loaded implants were provided with non‐occluding temporary restorations within 48 h. After 2 months, the provisional restorations were placed in full occlusion. Implants were early loaded after 2 months. Final restorations were provided 8 months after placement. Blinded assessors evaluated peri‐implant bone and soft‐tissue levels. Results: Fifty‐two implants were immediately loaded and 52 were early loaded. No drop‐out occurred. One single immediately loaded implant failed 2 months after placement. Both groups gradually lost peri‐implant bone in a highly statistically significant manner at 2, 8, and 14 months. After 14 months, patients of both groups lost an average of 1.1 mm of peri‐implant bone. There were no statistically significant differences between the two loading strategies for peri‐implant bone and soft‐tissue level changes (P>0.05). After 14 months, the position of the soft tissues did not change significantly from baseline (delivery of the final restorations 8 months after placement). Conclusions: There were no statistically or clinically significant differences between immediate and early loading of dental implants with regard to peri‐implant bone and soft‐tissue levels as evaluated in the present study.     

A multicenter prospective evaluation of 2-months loaded Osseotite implants placed in the posterior jaws: 3-year follow-up results

Abstract: In this prospective study, the clinical outcome of 2‐months loaded implants placed in the posterior jaws was evaluated after up to 3 years of functional loading. 405 Osseotite^® implants with microtextured acid‐etched surface were consecutively placed in 11 fully and 164 partially edentulous patients (mean age 53.5± 15.3 (S.D.) years) using a one‐stage technique. 282 implants, supporting 154 restorations, were placed in the mandible, while 123 implants, supporting 75 restorations, were placed in the maxilla. A total of 99 single‐tooth restorations, 119 short‐span fixed bridges and 11 full‐arch prostheses were applied. The mean time interval from surgery to connection of provisional restoration was 2.0±0.7 months. 9 failures were reported up to 3 years of follow‐up; of these, 4 mandibular and 2 maxillary implants failed during the initial healing period (before prosthesis connection), while 3 mandibular implants failed after loading. No other complications occurred throughout the study. Life table analysis showed a cumulative survival rate of 97.5% for the mandible and 98.4% for the maxilla. Post‐loading implant survival rate was 98.9% for the mandible and 100% for the maxilla. The excellent outcome of this interim report suggests that microtextured Osseotite^® implants in the posterior jaws may safely bear a functional load applied 2 months after insertion. The results of the present study are particularly encouraging for implants placed in the maxilla, since both a significant reduction of the healing period compared to the 6 months suggested by the classical Brånemark protocol, and an excellent post‐loading function may be achieved also in low quality bone.     

Immediate Occlusal Loading of Osseotite® Implants in Mandibular Edentulous Patients: A Prospective Observational Report with 18-Month Data

PURPOSE: To evaluate the efficacy of treatment consisting of placement and immediate occlusal loading of implants in 27 patients with edentulous mandibles. MATERIALS AND METHODS: Twenty-seven patients were treated in two private practice settings. One hundred fifty-one implants were placed and immediately occlusally loaded with fixed implant prostheses (15 cement-retained, 12 screw-retained) on the day of implant placement. The implant-retained prostheses were inserted within 5 hours of implant placement. Patients were followed for at least 18 months. The required criteria for immediate occlusal loading was primary implant stability of at least 30 Ncm of insertion torque. The implant prostheses were removed at least 12 months post-placement and the implants were evaluated for primary clinical stability and radiographic bone apposition to implants. RESULTS: At the 12-month follow-up appointments, cumulative survival rates of 98.0% and 100% were recorded for implants and prostheses, respectively. Three implants failed within 3 months. All other implants were clinically successful. CONCLUSIONS: Immediate occlusal loading of multiple, splinted mandibular implants is an effective treatment when implants are stable at insertion and are rigidly splinted with implant-retained prostheses.     

Immediate loading of 190 endosseous dental implants: a prospective observational study of 40 patient treatments with up to 2-year data

PURPOSE: The present study was undertaken to determine the feasibility of using primary stability as a predictor of implant success in patients whose implants were immediately loaded. MATERIALS AND METHODS: The study included 40 patients, in whom a total of 190 implants were placed, 102 in maxillary sites and 88 in mandibular sites. All were loaded within 72 hours of placement. Sixteen patients were completely edentulous in the mandible and/or the maxilla. The remaining 24, who were partially edentulous, received fixed partial dentures or single-implant restorations. All of the definitive implant restorations were screw retained. The criterion for loading was clinical judgment of primary stability, verified by a "screw test." Impressions were made after implant placement to facilitate the fabrication of a laboratory-made heat-processed provisional restoration from acrylic resin. Following a 4-month period for osseointegration and soft tissue healing, definitive fixed prostheses were fabricated. RESULTS: There were no surgical complications. After 1 to 2 years, all 190 implants had survived and were considered 100% successful, as determined by independent testing of mobility and radiographic evidence of osseointegration. In 4 patients, fracture of the provisional restoration occurred during the healing period. DISCUSSION: Clinical research has shown that immediate loading is a viable treatment modality. The favorable success rate reported in this study for rough-surfaced implants suggests that adherence to a protocol, an important parameter of which is primary stability above 32 Ncm, can lead to osseointegration. CONCLUSION: The results of this limited investigation suggest that patients who are partially or completely edentulous may be immediately restored with implants and fixed provisional restorations, provided that the dental implants are adequately stable immediately after their surgical placement. This alternative therapeutic approach did not appear to affect the up-to-2-year survival of the implants in this patient population.     

Effect on the amount of bone-implant contact when splinting immediate-loaded dental implants

PURPOSE: Much attention has been focused on the immediate or early loading of implants with or without splinting. The purpose of this study was to evaluate the contact rate between bones and implants, with or without splinting. MATERIALS AND METHODS: Under general anesthesia, an 8-mm-deep cavity for a dental implant was drilled in the mandibular ridge of dogs where teeth had been extracted 4 months earlier. Rough-surfaced, cylindrical screw implants (International Team for Implantology [ITI] monotype implants 4 mm diameter and 8 mm long, Straumann, Basel, Switzerland) were placed with splinting on the right side and without splinting on the left side using gold abutment. Resin plates for the maxilla were adjusted to attach to the gold abutment in each mandible. At 4, 8, or 12 weeks after the implantation, specimens were stained using toluidine blue and fuchsin. The sections were observed and morphometric analysis was performed to measure the rates of bone-implant contact and new bone-implant contact. RESULTS: The ratio of bone-implant contact on the lingual side was higher than on the buccal side in both the splinted and the unsplinted groups, and the rates in the splinted group were also higher than in the unsplinted group. The ratio of new bone-implant contact was not significantly different between the splinted and unsplinted groups, except for spongy bone at 4 weeks. CONCLUSION: Splinting of immediate-loading dental implants can be adequate for osseointegration, particularly in spongy bone.     

Immediate rehabilitation of the edentulous jaws with full fixed prostheses supported by four implants: interim results of a single cohort prospective study

Objectives: The purpose of this study was to prospectively evaluate the clinical and radiographic outcomes of immediately loaded full‐arch fixed prostheses supported by a combination of axially and non‐axially positioned implants in a large cohort of patients with completely edentulous jaws, up to 5 years of function. Materials and methods: One hundred and seventy‐three edentulous patients (80 males and 93 females) were enrolled according to specific selection criteria. Each patient received a full‐arch fixed prosthesis supported by two distal tilted implants and two anterior axially placed implants. The provisional functional acrylic prosthesis was delivered the same day as surgery in all cases. All cases were finalized 4–6 months later. The patients were scheduled for follow‐up at 6 and 12 months of function, and annually up to 5 years. At each follow‐up plaque and bleeding score was assessed and radiographic evaluation of marginal bone level was performed. Results: The overall follow‐up range was 4–59 months. A total of 154 immediately loaded prostheses (61 in the maxilla and 93 in the mandible) were in function for at least 1 year and were considered for the analysis. Four axially placed implants failed in the maxilla and one tilted implant in the mandible, all within 6 months of loading. No further implant failure occurred to date. Implant survival at 1 year was 98.36% and 99.73% for the maxilla and the mandible, respectively. Marginal bone loss at 1 year averaged 0.9±0.7 mm in the maxilla (204 implants) and 1.2±0.9 mm in the mandible (292 implants). No difference was found in marginal bone loss between axial and tilted implants. Plaque and bleeding scores progressively improved from 6 to 12 months. Fracture of the acrylic prosthesis occurred in 14% of total cases. Conclusions: The present preliminary results from a relatively large sample size suggest that the present technique can be considered a viable treatment option for the immediate rehabilitation of both mandible and maxilla. To cite this article:
Agliardi E, Panigatti S, Clericò M, Villa C, Malò P. Immediate rehabilitation of the edentulous jaws with full fixed prostheses supported by four implants: interim results of a single cohort prospective study.
Clin. Oral Impl. Res. 21 , 2010; 459–465.
doi: 10.1111/j.1600‐0501.2009.01852.x     

Immediate versus delayed loading of dental implants in the maxillae of minipigs. Part II: histomorphometric analysis

PURPOSE: To assess histomorphometric parameters of dental implants placed in partially edentulous maxillae of minipigs. MATERIALS AND METHODS: In 9 minipigs, 6 XiVE implants were placed on each side of the maxilla, either after implant site preparation by an osteotome technique or by spiral drills. The implants were restored with fixed provisional restorations and loaded either immediately or after healing periods of up to 5 months. After a loading period of 6 months, the animals were sacrificed and the implants were retrieved together with the adjacent bone. Histologic specimens were prepared and bone-to-implant contact (BIC) ratio, interthread bone area, and peri-implant bone area were determined. RESULTS: An analysis of variance revealed that the BIC ratio on the palatal side was significantly influenced by the preparation technique of the implant site (P = .001) and by the healing period (P = .02). After implant site preparation by an osteotome technique, higher BIC values were achieved for implants that were loaded either immediately or after healing periods of 1 to 3 months. After healing periods of 4 to 5 months, implant site preparation with spiral drills showed slightly better results in regard to BIC. Interthread bone area and peri-implant bone area did not differ significantly statistically for the 2 implant placement techniques and the 3 healing periods. DISCUSSION AND CONCLUSION: After 6 months of functional loading in the maxilla, successful immediately loaded implants performed the same as implants subjected to an unloaded healing period prior to loading as far as histomorphometric data were concerned. Prospective randomized clinical studies should be carried out in humans to compare immediate loading to loading after an unloaded healing phase.