Immediate implantation in fresh extraction sockets. A controlled clinical and histological study in man

Optical phenomenon of peri-implant soft tissue. Part II. preferred implant neck color to improve soft tissue esthetics

OBJECTIVES

The purpose of this study was to investigate an optical solution to eliminate the undesirable shine-through effect of implants on peri-implant mucosa by selecting an optimized implant neck color based on an objective and quantifiable method.

MATERIAL AND METHODS

The optical effect of color strips on 15 peri-implant mucosal sites of 14 patients with Straumann single-tooth implant replacements in the maxillary anterior region was analyzed. The color differences between the peri-implant mucosa with insertion of each of eight different color strips (white, black, light pink, pink, light orange, orange, gold, violet) and the gingiva of an adjacent or contralateral tooth without any color strips were compared for the selection of optimal color of implant neck. Spectrophotometric color measurements were performed to compare the color difference index (DeltaE) and color coordinates (DeltaL*, Deltaa*, Deltab* and DeltaC*).

RESULTS

The colors of the peri-implant mucosa with color strips and the gingiva of natural tooth demonstrated that the test site soft tissue with color strips of light pink, pink, light orange and orange showed a significantly smaller DeltaE value (P<0.05). Moreover, light pink exhibited the lowest mean DeltaE value of 2.6+/-0.6, indicating a clinically indistinguishable color difference.

CONCLUSIONS

The results suggest that it is possible to improve gingival esthetics by coloring the implant neck, most effectively with light pink, to mask the impact of the underlying titanium implant. The use of implants with optimized neck colors to correct an esthetic deficiency may be a feasible approach to establish improved peri-implant soft tissue esthetics.

A prospective clinical study of non-submerged immediate implants: clinical outcomes and esthetic results

OBJECTIVES

To evaluate healing of marginal defects in immediate transmucosal implants grafted with anorganic bovine bone, and to assess mucosal and radiographic outcomes 3-4 years following restoration.

MATERIAL AND METHODS

Thirty immediate transmucosal implants in maxillary anterior extraction sites of 30 patients randomly received BioOss (N=10; BG), BioOss and resorbable collagen membrane (N=10; BG+M) or no graft (N=10; control).

RESULTS

Vertical defect height (VDH) reductions of 81.2+/-5%, 70.5+/-17.4% and 68.2+/-16.6%, and horizontal defect depth (HDD) reductions of 71.7+/-34.3%, 81.7+/-33.7% and 55+/-28.4% were observed for BG, BG+M and control groups, respectively, with no significant inter-group differences. Horizontal resorption was significantly greater in control group (48.3+/-9.5%) when compared with BG (15.8+/-16.9%) and BG+M (20+/-21.9%) groups (P=0.000). Ten sites (33.3%) exhibited recession of the mucosa after 6 months; eight (26.7%) had an unsatisfactory esthetic result post-restoration due to recession. Mucosal recession was significantly associated (P=0.032) with buccally positioned implants (HDD 1.1+/-0.3 mm) when compared with lingually positioned implants (HDD 2.3+/-0.6 mm). In 19 patients followed for a mean of 4.0+/-0.7 years, marginal mucosa and bone levels remained stable following restoration.

CONCLUSION

BioOss significantly reduced horizontal resorption of buccal bone. There is a risk of mucosal recession and adverse soft tissue esthetics with immediate implant placement. However, this risk may be reduced by avoiding a buccal position of the implant in the extraction socket.

Immediate bone augmentation after infected tooth extraction using titanium membranes

Infectious process frequently results in extensive bone resorption and defect, periradicular or periapical lesions, or vertical fracture with infected sinus tract. When tooth extraction is mandated it typically results in additional bone loss in the buccal or lingual cortical plate. Immediate guided bone regeneration (GBR) and implant fixation at an infected site is frequently complicated by soft-tissue dehiscence, membrane exposure, and implant failure. The objective of this research is to assess the feasibility of immediate bone augmentation (IBA) after purulent tooth extraction, employing a dedicated titanium membrane. An intrasulcular incision was made around the tooth to be extracted and extended to 2 adjacent teeth while maintaining the papillae. Vertical releasing incisions were made to mobilize the mucoperiosteal flap. Cautious tooth extraction was executed utilizing conventional measures and was followed by meticulous curettage of the infected and granulated tissue in the socket. Titanium membranes were applied to the socket walls followed by socket filling with autologous platelet-rich fibrin and primary closure. Eight or more weeks later membrane removal and implant placement were performed. Of the 15 patients who underwent this procedure, 7 patients (47%) had early membrane exposure (between weeks 2 and 6), which was treated conservatively. No infection or early membrane removal was reported. All patients achieved sufficient bone augmentation, and 8 patients received implants without any additional GBR. IBA after infected tooth extraction, using titanium membrane application was feasible and safe and yielded adequate bone filling to support implant fixation at > or =8 weeks. Further studies need to evaluate if the titanium membrane helped in any way to inhibit plaque accumulation or resist infection in cases of early membrane exposure.

Early functional loading of sand-blasted and acid-etched (SLA) Straumann implants following immediate placement in maxillary extraction sockets. Clinical and radiographic result

OBJECTIVES

To present the clinical and radiographic outcome of early loading of implants inserted into fresh extraction sockets and to present a treatment protocol for early loading of the implants by 'passively fitting' abutment-free permanent fixed complete dentures (implant FCDs).

MATERIAL AND METHODS

The study included 19 dentate patients treatment planned for extraction of all remaining maxillary teeth. In all, 116 Straumann-implants with sandblasted, large grit and acid etched (SLA) surface were placed: 77 (66%) inserted in fresh extraction sockets and 39 (34%) in healed bone. At least six implants were placed in each maxilla. One hundred and ten implants were loaded by permanent FCDs within 10 days after placements and six after 14 days. The patients were reexamined clinically and radiographically after 2-3 years of clinical function. All FCDs were removed for control of implant stability and evaluation of the peri-implant status.

RESULTS

Owing to framework fracture, two implants were lost, corresponding to a failure rate of 2%. The radiographic measurements after 2-3 years did not reveal any difference in bone height mesial and distal of the implants placed in extraction sockets vs. in healed bone. This was interpreted as a bone gain around the implants placed in extraction sockets and a slight bone loss around the implants placed in healed bone.

CONCLUSION

Early functional loading of SLA-surfaced implants following immediate placement in maxillary extraction sockets by rigid and passively fitting permanent implant FCDs is a reliable treatment alternative.

Bone Regeneration Around Implants in the Canine Mandible With Cultured Fibroblasts in Polyglactin Mesh

BACKGROUND

Human fibroblast-derived dermal substitute (HFDDS) is a tissue-engineered material that consists of polyglactin mesh seeded with cultured fibroblasts. Cultured fibroblasts are not as differentiated as tissue fibroblasts and retain the ability to differentiate into other cells types. HFDDS also is capable of stimulating angiogenesis and wound healing. The purpose of this study was to attempt to evaluate the effects of HFDDS on guided bone regeneration at sites with 1.5-mm peri-implant defects in the canine mandible.

METHODS

Fifty sand-blasted acid-etched test implants were placed into the edentulous areas of mandibular ridges of five American foxhounds. Each site had a standardized 1.5-mm circumferential peri-implant defect in the coronal half of the implant, created by a specialized drill at the time of osteotomy. In each canine two implants received no treatment of the defects, four implants were treated with polyglactin mesh (carrier only) wrapped around the circumference of the defect wall, and four implants were treated with HFDDS placed in a similar fashion to the mesh. Implant sites healed submerged for 10 weeks, at which time sacrifice took place and sections were prepared, processed, and analyzed histomorphometrically.

RESULTS

The mean distance from the top of the fixture to the first point of bone-implant contact was 2.20 mm, 2.25 mm, and 2.60 mm for the HFDDS, carrier, and control sites, respectively (P = 0.202). Overall mean percentage of bone-to-implant contact (BIC) in the defects was 32.8%, 31.0%, and 22.8% for the HFDDS, carrier, and control groups, respectively. These differences were not statistically significant, but approached statistical significance for the control group compared to HFDDS and carrier (P = 0.057). Overall mean bone fill in the defects calculated histometrically was 36.0%, 35.8%, and 33.9% for the HFDDS, carrier, and control groups, respectively. These differences were not statistically significant. Sites with dehiscence at the time of implant placement had significantly greater distance to first bone-implant contact (P = 0.002), a smaller percentage of BIC (P = 0.006), and significantly less bone fill (P = 0.006) in the defects. It was consistently found that when dehiscence occurred on the buccal side of the implant, the outcomes for all parameters measured were significantly inferior on the lingual side as well. Factorial analysis, which grouped outcomes by dehiscence categories (none, partial, or full dehiscence), revealed that with intact defects without dehiscence, HFDDS had less bone fill compared to the carrier. However, in defects with partial or full dehiscence, HFDDS had more bone fill compared to carrier sites. These differences were statistically significant (P = 0.034).

CONCLUSIONS

In intact sites without dehiscence, the presence of cultured fibroblasts in 1.5-mm-wide peri-implant defects did not significantly enhance bone regeneration compared to the carrier, polyglactin mesh. However, sites with partial or full dehiscence treated with HFDDS had significantly greater bone fill compared to the carrier (P = 0.034). When dehiscence occurs during immediate implant placement on narrow ridges without the use of membranes, bone regeneration tends to be inferior on the side of the dehiscence as well as the opposite side of the implant.

Immediate and early function of implants placed in extraction sockets of maxillary infected teeth: A pilot study

STATEMENT OF PROBLEM

Infection in tooth extraction sites has traditionally been considered an indication to postpone implant placement until the infection has been resolved.

PURPOSE

The aim of this study was to evaluate the survival rate of immediate and early-loaded implants placed immediately after extraction of teeth with endodontic and periodontal lesions or root fracture in the maxilla.

MATERIAL AND METHODS

Thirty-three patients with teeth judged to be unrestorable because of endodontic or periodontal lesions or root fracture were included in the study. After tooth extraction, 1 to 6 implants (n=76) were placed in each patient using flap or flapless surgery in fresh extraction sockets, and a fixed provisional prosthesis was placed immediately or within 36 hours. Definitive prostheses were inserted after 6 to 12 months. The treatment protocol considered initial implant and prosthesis stability and control of the inflammatory response. Clinical and radiographic analyses were performed to evaluate the treatment outcome. Data were reported using descriptive statistics.

RESULTS

After 1 year, 2 implants were lost, resulting in a 97.4% survival rate. A mean (SD) marginal bone loss of -0.91 (1.50) mm was recorded during the observation period. No signs of infection around the implants were detected at any follow-up visit. There was a tendency towards less bone loss with the flapless protocol, -0.74 (1.34) mm, versus flap, -1.02 (1.60) mm, and less bone loss for single, -0.55 (1.52) mm, versus multiple restorations, -0.86 (1.24) mm, with the flapless approach.

CONCLUSIONS

A high 1-year survival rate was achieved for immediately placed and immediately/early-loaded implants in the maxilla, despite the presence of infection in the location of the extracted teeth.

Vertical Crestal Bone Changes Around Implants Placed Into Fresh Extraction Sockets

BACKGROUND

The aim of this study was to analyze bone healing and vertical bone remodeling for implants placed immediately after tooth removal without guided bone regeneration techniques.

METHODS

Twenty patients received 20 implants immediately after the removal of 20 teeth. All implants were placed within the undamaged alveoli confines, and the cervical portion of each implant was positioned at coronal bone level. The distance from implant shoulder and bone crest was measured for each implant at four sites (mesial, buccal, distal, and palatal/lingual). No membranes or filling materials were used. Primary flap closure was performed in all clinical cases.

RESULTS

All peri-implant bone defects had healed completely 6 months after implant placement. The pattern of bone healing around the neck of the implants showed an absence of peri-implant defects. The vertical distance between the implant shoulder and bone crest ranged from 0 to 2 mm.

CONCLUSIONS

The bone remodeling of implants placed in fresh extraction sockets showed a healing pattern with new bone apposition around the implant's neck and horizontal and vertical bone reabsorption. The vertical bone reabsorption, which has been observed at buccal sites, was not associated with any negative esthetic implications.

Electronic Percussive Testing of the Stability of an Immediately Provisionalized Implant Placed Into a Fresh Extraction Socket: A Pilot Evaluation

It is important to achieve primary stabilization of dental implants that will be immediately loaded. Noninvasive devices that test the stability of immediately provisionalized implants placed into fresh extraction sockets are discussed. A titanium threaded implant was placed into a fresh extraction socket of a patient's nonrestorable mandibular right canine. The implant received an interim restoration immediately following its placement. The stability of the bone-implant complex was evaluated from the day of implant insertion through day 246 using an electronic percussive testing instrument. During the first month the bone-implant complex became progressively less stable reaching a peak measured level of instability at 30 days postimplantation. This was followed by progressive stabilization first measured on day 46 as the implant continued to osseointegrate. These findings suggest that the bone-implant complex became less stable during the first month after implant placement and was followed by a period of progressive stabilization reflecting bone maturation around the implant. A search of the literature found similar results in a study of single-stage implants (not immediately provisionalized) using resonance frequency analysis. The known sequence of wound healing around dental implants is reviewed to explain the findings of this pilot evaluation. Studies that use noninvasive testing devices to assess implant stability at placement and during healing may provide information that can help to optimize implant treatment outcomes.

Bone Augmentation Techniques

BACKGROUND

The advent of osseointegration and advances in biomaterials and techniques have contributed to increased application of dental implants in the restoration of partial and completely edentulous patients. Often, in these patients, soft and hard tissue defects result from a variety of causes, such as infection, trauma, and tooth loss. These create an anatomically less favorable foundation for ideal implant placement. For prosthetic-driven dental implant therapy, reconstruction of the alveolar bone through a variety of regenerative surgical procedures has become predictable; it may be necessary prior to implant placement or simultaneously at the time of implant surgery to provide a restoration with a good long-term prognosis. Regenerative procedures are used for socket preservation, sinus augmentation, and horizontal and vertical ridge augmentation.

METHODS

A broad overview of the published findings in the English literature related to various bone augmentation techniques is outlined. A comprehensive computer-based search was performed using various databases that include Medline and PubMed. A total of 267 papers were considered, with non-peer-reviewed articles eliminated as much as possible.

RESULTS

The techniques for reconstruction of bony defects that are reviewed in this paper include the use of particulate bone grafts and bone graft substitutes, barrier membranes for guided bone regeneration, autogenous and allogenic block grafts, and the application of distraction osteogenesis.

CONCLUSIONS

Many different techniques exist for effective bone augmentation. The approach is largely dependent on the extent of the defect and specific procedures to be performed for the implant reconstruction. It is most appropriate to use an evidenced-based approach when a treatment plan is being developed for bone augmentation cases.

Aesthetics in Oral Implantology: Biological, Clinical, Surgical, and Prosthetic Aspects

OBJECTIVES

The aim of this study was to identify a correct clinical, surgical, and prosthetic management of endosseous implants replacing missing teeth in the anterior maxilla, achieving predictable aesthetic outcomes. Placement of immediate post-extraction implants without incisions or flap elevation is one of the surgical treatment options able to improve the healing and regenerative potentials of the fresh socket.

MATERIALS

Fifty-five patients (33 men, 22 women), ranging in age from 19 to 57 years (mean 29), were selected for this study. All the patients were not smokers, no bruxers, presented stable soft tissue conditions, an acceptable occlusion, and the absence of pathologies that would contraindicate bone healing. Patients were treated with implants made by 2 manufacturers: Institute Straumann, Walderburg, Switzerland and Friadent, Mannheim, Germany. A total of 87 implants were placed immediately after each failing tooth had been removed. The temporary restoration was placed 3 months after implant placement, and the final restoration was placed 4 months from the surgical procedure. The patients were evaluated clinically and radiographically at implant placement, and 2, 4, 18, and 24 months post-insertion.

RESULTS

At 24 months, only 3 implants were lost (2 in male patients;1 in female patient). All of these failed implants did not achieve osseointegration. The overall success rate was 96.6%, with an implant failure rate of 3.4%, all prior to restoration.

CONCLUSIONS

The immediate placement in the anterior maxilla fresh extraction sockets without incisions or flaps elevation is a surgical option that can ensure ideal peri-implant tissues healing, preserving the presurgical gingival and bone aspects. For a predictable aesthetic result, the most important aspect seems to be the height and thickness of the buccal bone wall, which remain after immediate placement of the fixture.

Tissue modeling following implant placement in fresh extraction sockets

OBJECTIVE

To study whether osseointegration once established following implant placement in a fresh extraction socket may be lost as a result of tissue modeling.

MATERIAL AND METHODS

Seven beagle dogs were used. The third and fourth premolars in both quadrants of the mandible were used as experimental teeth. Buccal and lingual full-thickness flaps were elevated and distal roots were removed. Implants were installed in the fresh extraction socket. Semi-submerged healing of the implant sites was allowed. In five dogs, the experimental procedure was first performed in the right side of the mandible and 2 months later in the left mandible. These five animals were sacrificed 1 month after the final implant installation. In two dogs, the premolar sites on both sides of the mandible were treated in one surgical session and biopsies were obtained immediately after implant placement. All biopsies were processed for ground sectioning and stained.

RESULTS

The void that existed between the implant and the socket walls at surgery was filled at 4 weeks with woven bone that made contact with the SLA surface. In this interval, (i) the buccal and lingual bone walls underwent marked surface resorption and (ii) the height of the thin buccal hard tissue wall was reduced. The process of healing continued, and the buccal bone crest shifted further in the apical direction. After 12 weeks, the buccal crest was located>2 mm apical of the marginal border of the SLA surface.

CONCLUSION

The bone-to-implant contact that was established during the early phase of socket healing following implant installation was in part lost when the buccal bone wall underwent continued resorption.

Modeling of the buccal and lingual bone walls of fresh extraction sites following implant installation

OBJECTIVE

To determine whether the reduction of the alveolar ridge that occurs following tooth extraction and implant placement is influenced by the size of the hard tissue walls of the socket.

MATERIAL AND METHODS

Six beagle dogs were used. The third premolar and first molar in both quadrants of the mandible were used. Mucoperiostal flaps were elevated and the distal roots were removed. Implants were installed in the fresh extraction socket in one side of the mandible. The flaps were replaced to allow a semi-submerged healing. The procedure was repeated in the contra later side of the mandible after 2 months. The animals were sacrificed 1 month after the final implant installation. The mandibles were dissected, and each implant site was removed and processed for ground sectioning.

RESULTS

Marked hard tissue alterations occurred during healing following tooth extraction and implant installation in the socket. The marginal gap that was present between the implant and the walls of the socket at implantation disappeared as a result of bone fill and resorption of the bone crest. The modeling in the marginal defect region was accompanied by marked attenuation of the dimensions of both the delicate buccal and the wider lingual bone wall. Bone loss at molar sites was more pronounced than at the premolar locations.

CONCLUSION

Implant placement failed to preserve the hard tissue dimension of the ridge following tooth extraction. The buccal as well as the lingual bone walls were resorbed. At the buccal aspect, this resulted in some marginal loss of osseointegration.

Immediate Restoration of Single Implants Placed Immediately After Tooth Extraction

BACKGROUND

Some of the original surgical protocols for implant surgery have been reassessed to satisfy the patient's continuously increasing expectation for shorter rehabilitation time, improved esthetics, and increased comfort. The aim of this study was to evaluate the 12-month clinical success of 18 single-tooth implants inserted immediately after tooth extraction and restored the same day with non-functional loading.

METHODS

A total of 18 patients (12 women and six men), 22 to 60 years old, were enrolled in this study. Eighteen single implants were inserted in fresh extraction sockets and immediately restored with temporary abutments and crowns. All experimental sites showed an absence of fenestrations or dehiscences of the bone walls and a residual gap between implant surfaces and surrounding bone walls < or =2 mm. All temporary prostheses were positioned the same day of surgery and were not in occlusal contact with opposing arches. The comparison between the baseline and 12-month visits was performed with the Student t test for paired data (statistically significant at a level of alpha = 0.05).

RESULTS

During the 12-month follow-up period, one fixture was removed 4 weeks after implant placement following an abscess. All remaining implants healed uneventfully with no complications and were assessed as stable and successful at the 12-month checkup. No technical complications such as screw loosening, resin fracture, or pain during chewing were registered during the 12-month period.

CONCLUSIONS

Within the limits of the data from this study, it can be suggested that immediate placement and restoration of a single implant can be a valid and successful option of treatment in the case of single compromised teeth. Moreover, this treatment protocol eliminates the need for removable provisional restoration and seems to maintain the preexisting architecture of soft and hard tissues in most cases. Nonetheless, further prospective and long-term studies are required to obtain a better insight into the limitations of this protocol.

Implants in the esthetic zone

To achieve a successful esthetic result and good patient satisfaction,implant placement in the esthetic zone demands a thorough under-standing of anatomic, biologic, surgical, and prosthetic principles. The ability to achieve harmonious, indistinguishable prosthesis from adjacent natural teeth in the esthetic zone is sometimes challenging. Placement of dental implants in the esthetic zone is a technique-sensitive procedure with little room for error. Guidelines are presented for ideal implant positioning and for a variety of therapeutic modalities that can be implemented for addressing different clinical situations involving replacement of missing teeth in the esthetic zone.

The Immediate Placement of Endosseous Dental Implants in Fresh Extraction Sites

The use of endosseous dental implants to rehabilitate both fully and partially edentulous patients has been peer-reviewed in the literature for more than 25 years. Cumulative success rates for the treatment of partial edentulism with dental implants has been reported as 96% in delayed or late-placement sites. Recently, significant attention has been given to the placement of implants in fresh extraction sites to avoid such potential concerns as bone resorption, multiple surgical procedures, increased treatment time, and unsatisfactory esthetics. This article discusses the salient aspects of immediate dental implant placement from a historical, histologic, and clinical-perspective, and describes the surgical methods for this procedure.

"PASS" principles for predictable bone regeneration

Guided bone regeneration is a well-established technique used for augmentation of deficient alveolar ridges. Predictable regeneration requires both a high level of technical skill and a thorough understanding of underlying principles of wound healing. This article describes the 4 major biologic principles (i.e., PASS) necessary for predictable bone regeneration: primary wound closure to ensure undisturbed and uninterrupted wound healing, angiogenesis to provide necessary blood supply and undifferentiated mesenchymal cells, space maintenance/creation to facilitate adequate space for bone ingrowth, and stability of wound and implant to induce blood clot formation and uneventful healing events. In addition, a novel flap design and clinical cases using this principle are presented.

Clinical Outcome of Implants Placed Immediately After Implant Removal

BACKGROUND

The purpose of this study was to evaluate the clinical success of implants placed immediately after the explantation of failed implants due to fracture at 12 months.

METHODS

Nine immediate implants were placed in nine patients following explantation of nine fractured implants. Five experimental implants did not require any regenerative procedures; the remaining four immediate implants were grafted with deproteinized porcine bone particles and covered with bioabsorbable membranes. All implants were restored with fixed prostheses. The follow-up period was 12 months.

RESULTS

No residual bone defects were observed or probed around any implant at the second-stage surgery, and all implants were asymptomatic and stable. All the implants were successful after prosthetic rehabilitation showing no mobility, pain, suppuration, or absence of peri-implant radiolucency. The radiographic measurements showed no significant bone loss pattern at the 12-month follow-up visit.

CONCLUSION

The findings of this study suggested that implants placed immediately after implant explantation due to biomechanical fracture could be performed with results that are similar to results obtained with implants placed immediately after tooth extraction.

Early Clinical Experience With a New One-Piece Implant System in Single Tooth Sites

PURPOSE

To evaluate the clinical efficacy of a new 1-piece implant in single tooth sites.

MATERIALS AND METHODS

Early clinical results were evaluated through observation and collection of survival data for 45 1-piece Direct implants (Nobel Biocare, Yorba Linda, CA). Patients ranged in age from 19 to 54 years, of which 23 were women and 12 were men. Both anterior and posterior single tooth defects were treated, with the majority being in the maxillary anterior zone. Five of the 45 implants placed were in immediate extraction sites. Observation periods ranged from 2.5 to 32 months.

RESULTS

One implant failure was detected over the observation period. It occurred in a maxillary lateral incisor site, and was placed and immediately loaded after tooth extraction. The overall success rate was 97.8%.

CONCLUSION

Within the limited parameters of this study, it can be concluded that the 1-piece implant design can be used effectively as a basis for restoring single tooth defects. Longer observation periods, more detailed soft tissue analysis, and larger numbers of implants in varied arch sites will be required to establish definitive protocols for the use of this implant.

Ridge alterations following implant placement in fresh extraction sockets: an experimental study in the dog

OBJECTIVE

To study dimensional alterations of the alveolar ridge that occurred following implant placement in fresh extraction sockets.

MATERIAL AND METHODS

Five beagle dogs were included in the study. In both quadrants of the mandible, incisions were made in the crevice region of the third and fourth pre-molars. Buccal and minute lingual full-thickness flaps were elevated. The mesial root of the four pre-molars root was filled and the teeth were hemi-sected. Following flap elevation in (3)P(3) and (4)P(4) regions, the distal roots were removed. In the right jaw quadrants, implants with a sand blasted and acid etched (SLA) surface were placed in the fresh extraction sockets, while in the left jaws the corresponding sockets were left for spontaneous healing. The mesial roots were retained as surgical control teeth. After 3 months, the animals were examined clinically, sacrificed and tissue blocks containing the implant sites, the adjacent tooth sites (mesial root) and the edentulous socket sites were dissected, prepared for ground sectioning and examined in the microscope.

RESULTS

At implant sites, the level of bone-to-implant contact (BC) was located 2.6+/-0.4 mm (buccal aspect) and 0.2+/-0.5 mm (lingual aspect) apical of the SLA level. At the edentulous sites, the mean vertical distance (V) between the marginal termination of the buccal and lingual bone walls was 2.2+/-0.9 mm. At the surgically treated tooth sites, the mean amount of attachment loss was 0.5+/-0.5 mm (buccal) and 0.2+/-0.3 mm (lingual).

CONCLUSIONS

Marked dimensional alterations had occurred in the edentulous ridge after 3 months of healing following the extraction of the distal root of mandibular pre-molars. The placement of an implant in the fresh extraction site obviously failed to prevent the re-modelling that occurred in the walls of the socket. The resulting height of the buccal and lingual walls at 3 months was similar at implants and edentulous sites and vertical bone loss was more pronounced at the buccal than at the lingual aspect of the ridge. It is suggested that the resorption of the socket walls that occurs following tooth removal must be considered in conjunction with implant placement in fresh extraction sockets.

Treatment Options Following Single-Rooted Tooth Removal: A Literature Review and Proposed Hierarchy of Treatment Selection

BACKGROUND

Alveolar bone changes following tooth extraction have been well documented and have given rise to a number of treatment approaches. Included in these approaches are placement of various grafting materials, immediate implant placement, and a combination of both.

METHODS

A review of all pertinent literature discussing regenerative therapy at the time of tooth extraction or immediate implant placement with or without concomitant regenerative therapy was carried out.

RESULTS

A clinically-based hierarchy of treatment selection following extraction of single rooted teeth is proposed, based upon the available literature and clinical experience. The role of patient phenotype is considered.

CONCLUSION

Utilization of the proposed hierarchy of treatment selection affords a logical framework within which to predictably treat a variety of patients.

A prospective clinical study of bone augmentation techniques at immediate implants

The efficacy of combinations of membranes and autogenous bone grafts at immediate implants were compared in a prospective study. Sixty-two consecutively treated patients each received an immediate implant for a single tooth replacement at a maxillary anterior or premolar site. Dimensions of the peri-implant defect at the implant collar were measured as follows: vertical defect height (VDH), horizontal defect depth (HDD) and horizontal defect width (HDW). Each implant randomly received one of five augmentation treatments and were submerged with connective tissue grafts: Group 1 (n=12)--expanded polytetrafluoroethylene membrane only, Group 2 (n=11)--resorbable polylactide/polyglycolide copolymer membrane only, Group 3 (n=13)--resorbable membrane and autogenous bone graft; Group 4 (n=14)--autogenous bone graft only, and Group 5 (n=12)--no membrane and no bone graft control. At re-entry, all groups showed significant reduction in VDH, HDD and HDW. Comparisons between groups showed no significant differences for VDH (mean 75.4%) and HDD (mean 77%) reduction. Significant differences were observed between groups for HDW reduction (range, 34.1-67.3%), with membrane-treated Groups 1, 2 and 3 showing the greatest reduction. In the presence of dehiscence defects of the labial plate, HDW reduction of 66.6% was achieved with membrane use compared with 37.7% without membranes. Over 50% more labial plate resorption occurred in the presence of a dehiscence defect irrespective of the augmentation treatment used. The results indicate that VDH and HDD reduction at defects adjacent to immediate implants may be achieved without the use of membranes and/or bone grafts.

Bucco-Lingual Crestal Bone Changes After Immediate and Delayed Implant Placement

BACKGROUND

Implants placed immediately after tooth extraction offer several advantages, but many authors have reported problems in filling the residual gap between the implant and the socket walls. Barrier and grafting techniques have been tested and yield varying results, so it has been suggested that the timing of implant placement may be important for success. The aim of this study was to analyze bone healing and coronal bone remodeling around 35 implants, 20 placed immediately after tooth removal and 15 placed 6 to 8 weeks after extraction.

METHODS

All the implants were submerged and placed within the alveoli confines, leaving circumferential defects because the implants did not contact the bone at their coronal aspects; stabilization was achieved in the bone apically. After implant placement the mean distance from buccal bone to lingual bone was 10 mm (SD 1.522) for immediate implants and 8.86 mm (SD 2.356) for delayed implants. No membrane or filling materials were used. Primary flap closure was accomplished in all cases.

RESULTS

At second-stage surgery all peri-implant defects were filled, and the mean distance from buccal bone to lingual bone was 8.1 mm (SD 1.334) for immediate implants and 5.8 mm (SD 1.265) for delayed implants. This pattern of coronal bone remodeling, showing a narrowing of the bucco-lingual width, was clinically similar for the two groups, although it should be noted that the delayed implants exhibited smaller bucco-lingual bone width already at the first measurement: it can be speculated that early remodeling may start immediately after tooth extraction and continue, non-uniformly, even after delayed implant placement.

CONCLUSIONS

This study suggests that circumferential defects could heal clinically without any guided bone regeneration (GBR) in both experimental groups, and that the procedure was virtually free from complications in the postoperative period, probably because of the absence of barrier membranes and/or grafting materials. Histologically, peri-implant defects of over 1.5 mm heal by connective tissue apposition, rather than by direct bone-to-implant contact, but clinically this healing may be very successful. No histological analysis was carried out in the present study, but even the largest residual gaps were filled with hard tissue that could not be probed. Thus, such outcomes can be considered clinically successful. The different rate of bone remodeling around immediate or delayed implants could have implications for the preferred timing of implant placement in sites of high esthetic concern.

Hard-tissue alterations following immediate implant placement in extraction sites

BACKGROUND

The marginal gap that may occur following implant installation in an extraction socket may be resolved by hard-tissue fill during healing.

OBJECTIVE

To study dimensional alterations of hard tissues that occur following tooth extraction and immediate placement of implants.

MATERIAL AND METHODS

Eighteen subjects with a total of 21 teeth scheduled for extraction were included. Following flap elevation and the removal of a tooth and implant installation, clinical measurements were made to characterize the dimension of the surrounding bone walls, as well as the marginal defect. No membranes or filler material was used. The flaps were subsequently replaced and secured with sutures in such a way that the healing cap of the implant was exposed to the oral environment. After 4 months of healing a re-entry procedure was performed and the clinical measurements were repeated.

RESULTS

Fifty-two marginal defects exceeding 3 mm were present at baseline: 21 at buccal, 17 at lingual/palatal, and 14 at approximal surfaces. At the re-entry eight defects exceeding 3.0 mm remained. During the 4 months of healing, the bone walls of the extraction underwent marked change. The horizontal resorption of the buccal bone dimension amounted to about 56%. The corresponding resorption of the lingual/palatal bone was 30%. The vertical bone crest resorption amounted to 0.3+/-0.6 mm (buccal), 0.6+/-1.0 mm (lingual/palatal), 0.2+/-0.7 mm (mesial), and 0.5+/-0.9 mm (distal).

CONCLUSION

The marginal gap that occurred between the metal rod and the bone tissue following implant installation in an extraction socket may predictably heal with new bone formation and defect resolution. The current results further documented that marginal gaps in buccal and palatal/lingual locations were resolved through new bone formation from the inside of the defects and substantial bone resorption from the outside of the ridge.

Alveolar bone regeneration for immediate implant placement using an injectable bone substitute: an experimental study in dogs

BACKGROUND

The aim of the present study was to assess the efficacy of a ready-to-use injectable bone substitute for bone regeneration around dental implants placed into fresh extraction sockets.

METHODS

Third and fourth mandibular premolars were extracted from three beagle dogs and the interradicular septa were surgically reduced to induce a mesial bone defect. Thereafter, titanium implants were immediately placed. On the left side of the jaw, mesial bone defects were filled with an injectable bone substitute (IBS), obtained by combining a polymer and biphasic calcium phosphate ceramic granules. The right defects were left unfilled as controls. After 3 months of healing, specimens were prepared for histological and histomorphometric evaluations.

RESULTS

No post-surgical complications were observed during the healing period. In all experimental conditions, histological observations revealed a lamellar bone formation in contact with the implant. Histomorphometric analysis showed that IBS triggers a significant (P<0.05) increase in terms of the number of threads in contact with bone, bone-to-implant contact, and peri-implant bone density of approximately 8.6%, 11.0%, and 14.7%, respectively. In addition, no significant difference was observed when number of threads, bone-to-implant contact, and bone density in the filled defects were compared to the no-defect sites.

CONCLUSION

It is concluded that an injectable bone substitute composed of a polymeric carrier and calcium phosphate significantly increases bone regeneration around immediately placed implants.

Immediate Implants Supporting Single Crown Restoration: A 4-Year Prospective Study

BACKGROUND

The placement of implants at the time of tooth extraction has several clinical advantages, such as preservation of the alveolar ridge width and height and reduction of the restorative treatment time. The aim of this study was to evaluate the cumulative success rate of dental implants placed in fresh extraction sockets with and without guided bone regeneration (GBR) used to support a single crown restoration. All of the patients were preselected as candidates for implants.

METHODS

Ninety-five patients aged 20 to 68 years with 163 implants were included. All patients were partially edentulous and participated in a personally tailored recall schedule. The follow-up period was 48 months. Patients underwent a clinical and radiographic evaluation annually.

RESULTS

The 4-year cumulative success rate was 97%. Five of the 163 implants failed, two during the initial healing time, which were considered early failures and three a year after prosthetic rehabilitation, which were considered late failures. No failure of prosthetic rehabilitation was observed.

CONCLUSIONS

Implants placed into fresh extraction sockets with or without regenerative procedures and used to support single crown prosthesis showed a very high cumulative success rate (97%) in a 4-year prospective study. Several observations should be made: 1) all the patients were preselected as candidates for implants and were following a strict oral hygiene regimen; 2) all efforts were made to reduce the number of cases requiring GBR procedures; 3) all the implants had an acid etched/sandblasted implant surface; and 4) all the prosthetic restorations were single crowns.

The immediate rehabilitation by means of a ready-made final fixed prosthesis in the edentulous mandible: a 1-year follow-up study on 50 consecutive patients

Although a two-stage procedure with symphyseal oral implants can lead to a long-term (15 years) 99% cumulative survival rate, a one-stage approach with immediate loading via prefabricated elements seems to offer a short-term acceptable outcome with significantly lower costs. A series of 50 consecutive patients, not eliminated for any systemic or smoking condition, received at the department of periodontology three implants in the symphyseal area, connected by a very rigid horse shoe-shaped titanium bar. A final screw retained prosthetic framework was placed on top of it at the department of prosthetic dentistry within 2 days after surgery (44) or after a delay, due to purely external factors, of up to 10 days (6). Forty-five patients were followed for 1 year. In one patient, all three implants failed and another four patients were lost to follow-up. The cumulative failure rates for implants and prostheses at 1 year were, respectively, 7.3% and 5%. The mean marginal bone loss at 1 year was 1.08 mm (SD: 1.62; range -5.68 to +2.55). This study shows that stable marginal bone levels can be maintained around immediately loaded implants in the lower jaw in an average patient population for at least 1 year. The survival rate is, however, lower than for a staged approach.

Immediate implants covered with connective tissue membranes: human biopsies

BACKGROUND

Osseointegration has been shown to occur around implants placed immediately after tooth extraction in humans. To date, such osseointegration has been achieved only with titanium plasma-sprayed (TPS) implants placed in extraction sockets with a bone-to-implant distance of less than 2 mm. In a previous report, when this horizontal defect dimension (HDD) exceeded 2 mm, the resulting percentage of bone-to-implant contact was reduced, indicating that the immediate technique would be limited in most cases to non-molar teeth. In an attempt to improve the bone-to-implant contact and the initial bone-to-implant contact in a vertical dimension, the implant surface, the type of membrane, and the method of membrane placement used in a previous study by our group were modified.

METHODS

Ten large-grit sandblasted, acid-attacked (SLA) titanium implants were placed into immediate extraction sites in 5 patients. HDDs of 0.0 to 1.5 mm (controls), 1.5 to 4.0 mm, and >4.0 mm were used. Following insertion, implants were completely covered with a connective tissue membrane. This was in contrast to the use of an expanded polytetrafluoroethylene (ePTFE) membrane penetrated by the neck of the implant in our previous report. Primary closure of soft tissue flaps was achieved in each case. Six months after placement, 7 of the implants were histologically examined.

RESULTS

Osseointegration occurred across all HDDs, with the percentage of bone-to-implant contact in the 0.0 to 1.5 mm HDDs similar to that seen in the >4.0 mm HDDs. The first bone-to-implant contact measured vertically was similar in both the smaller and larger HDDs.

CONCLUSIONS

Osseointegration was successful in immediate implant placement sites with horizontal defect dimensions wider than 4 mm in humans when SLA titanium implants were completely covered with connective tissue membranes. It remains undetermined whether the different type of membrane, placement of the membrane, type of implant surface, or a combination of these 3 factors were responsible for the improved osseointegration in HDDs >4 mm. Further study is needed.

Bucco-lingual bone remodeling around implants placed into immediate extraction sockets: a case series

BACKGROUND

Implants placed immediately after tooth extraction have shown high percentages of clinical success. Few studies in the scientific literature have observed the horizontal bone remodeling in the buccal-lingual direction after immediate placement of implants. The aim of this study was to analyze bone healing and coronal bone remodeling around 15 implants placed immediately after tooth removal without the use of guided bone regeneration (GBR) techniques.

METHODS

Ten patients received a total of 15 implants placed immediately after removal of 15 single-rooted teeth. All implants were placed within the alveolar confines, limiting, in most cases, small peri-implant bone defects. After implant placement, the distance from the buccal to lingual bone plate was measured. No membranes or filling materials were used. Primary flap closure was performed in all cases.

RESULTS

At second-stage surgery, all peri-implant defects were completely filled and the distance from buccal to lingual bone was measured again. The pattern of bone healing around the neck of immediate implants showed an absence of peri-implant defects and a narrowing of bone crest width in a buccal-lingual direction. The mean distance between buccal bone and lingual bone at the time of implant placement was 10.5 mm (+/- 1.52) and, at second-stage surgery, 6.8 mm (+/- 1.33).

CONCLUSIONS

The coronal bone remodeling around immediate implants showed a healing pattern with new bone apposition around the neck of the implants and, at the same time, bone resorption with horizontal width reduction of the bone ridge. The small peri-implant bone defects were completely healed without the use of GBR procedures. An absence of complications during the healing period was also observed, probably due to the absence of barrier membranes and grafting materials.