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

Alveolar bone regeneration around immediate implants using an injectable nHAC/CSH loaded with autogenic blood-acquired mesenchymal progenitor cells: an experimental study in the dog mandible

BACKGROUND

Lack of osseointegration between a dental implant and the walls of the alveolar bone is a common problem in immediate implantation. Injectable tissue-engineered bone (ITB) may be an effective and minimally invasive solution to the problem. In this study, an injectable bone cement, nHAC/CSH, which consists of nano-hydroxyapatite/collagen (nHAC) and calcium sulfate hemihydrate (CaSO4 .½H2 O; CSH) was investigated as a tissue-engineered scaffold material with blood-acquired mesenchymal progenitor cells (BMPC) as seeding cells.

PURPOSE

The aim of the study was to assess the new bone formation around immediate dental implants using nHAC/CSH loaded with dog blood-acquired mesenchymal progenitor cells (dBMPC) in a canine model.

MATERIALS AND METHODS

dBMPC were first isolated from peripheral blood of healthy adult dogs. Alizarin red and oil red O staining were then used to evaluate the potential of dBMPC to differentiate into bi-lineage mesenchymal tissues in vitro. Four healthy mongrel dogs were used in this study. The alveolar bone defects around immediate implants of dogs were created. Each defect was randomly assigned to one of the following three groups: (1) the ITB group (dBMPC+nHAC/CSH); (2) injectable bone cement nHAC/CSH; or (3) no materials (controls). Methylene blue staining was used to examine the bone formation after 3 months.

RESULTS

Studies in vitro revealed that dBMPC could be induced to osteoblasts and adipocytes. The ITB group (dBMPC+nHAC/CSH) showed significantly more bone-implant contact and bone density than either nHAC/CSH or control groups in the areas with peri-implant defects 3 months after implantation.

CONCLUSION

The results indicate that the ITB composed of nHAC/CSH and dBMPC may represent a useful strategy for the clinical reconstruction of bone defects around immediate implantation. However, further investigation is needed involving the use of human BMPC as well as possible use of stem cells.

An interdisciplinary treatment approach combining orthodontic forced eruption with immediate implant placement to achieve a satisfactory treatment outcome: a case report

BACKGROUND

Periodontal disease often results in severely bony defects around the teeth and leads to eventual extraction. Remaining bone morphology often compromises ideally restoration-driven positions and deteriorates the success rates for dental implants.

PURPOSE

The present investigation illustrates the clinical outcome of immediately installing an implant following orthodontic forced eruption and atraumatic extraction.

MATERIAL AND METHODS

The subject of this study is a 40-year-old Asian female with a right mandibular first molar that had a deep probing depth on the mesial side and mobility. Via the aid of radiographic examination, the tooth that had an angular bony defect and apical lesion was diagnosed as having deep caries and chronic periodontitis with a poor prognosis. After consultation with the patient, we developed a treatment plan incorporating a forced eruption with immediate implantation, intended to augment the alveolar bone volume and increase the width of keratinized gingivae, in a nonsurgical manner.

RESULTS

Following 12 months of orthodontic treatment, the tooth was successfully moved occlusally in conjunction with an 8 mm vertical interdental bone augmentation. Because of sufficient volume of bone and satisfactory gingival dimensions, the implant showed adequate initial stability in the correct position to facilitate physiological and aesthetic prerequisites. After 6 months of osteointegration, a customized impression coping was utilized to transfer the established emergence profile to a definitive cast for the fabrication of a customized abutment. The final prosthesis was made using a customized metal abutment and ceramometal crown.

CONCLUSION

In the face of difficult clinical challenges, meticulous inspection and a comprehensive treatment plan were crucial. Interdisciplinary treatment through the careful integration of multiple specialists suggests the possibility of optimal results with high predictability.

Labial and lingual/palatal bone thickness of maxillary and mandibular anteriors in human cadavers in Koreans

PURPOSE

The aim of this study is to evaluate the buccal and lingual bone thickness in the anterior teeth and the relationship between bone thickness and the tissue biotype.

METHODS

Three male and two female human cadaver heads (mean age, 55.4 years) were used in this study. First, the biotype of periodontium was evaluated and categorized into a thick or a thin group. Next, full thickness reflections of the mandible and the maxilla to expose the underlying bone for accurate measurements in the anterior regions were performed. After the removal of the half of the alveolar bone, the probe with a stopper was used to measure the thickness of bone plate at the alveolar crest (AC), 3 mm apical to the alveolar crest (AC-3), 6 mm apical to the alveolar crest (AC-6), and 9 mm apical to the alveolar crest (AC-9).

RESULTS

Four of them had a thick biotype. There was no penetration or dehiscence. The thickness of the buccal plates at the alveolar crest were 0.97±0.18 mm, 0.78±0.21 mm, and 0.95±0.35 mm in the maxillary central incisors, lateral incisors, and canines, respectively. The thickness of the labial plates at the alveolar crest were 0.86±0.59 mm, 0.88±0.70 mm, and 1.17±0.70 mm in the mandibular central incisors, lateral incisors and canines, respectively.

CONCLUSIONS

The thickness of the labial plate in the maxillary anteriors is very thin that great caution is needed for placing an implant. The present study showed the bone thickness of maxillary and mandibular anteriors at different positions. Therefore, these data can be useful for the understanding of the bone thickness of the anteriors and a successful implant placement.

Influence of a microgrooved collar design on soft and hard tissue healing of immediate implantation in fresh extraction sites in dogs

OBJECTIVE

This study compared the alveolar bone reduction after immediate implantation using microgrooved and smooth collar implants in fresh extracted sockets.

MATERIAL AND METHODS

Four mongrel dogs were used in this study. The full buccal and lingual mucoperiosteal flaps were elevated and the third and fourth premolars of the mandible were removed. The implants were installed in the fresh extracted sockets. The animals were sacrificed after a 3-month healing period. The mandibles were dissected and each implant site was removed and processed for a histological examination.

RESULTS

During healing, the marginal gaps in both groups, which were present between the implant and the socket walls at implantation, disappeared as a result of bone filling and resorption of the bone crest. The buccal bone crests were located apical of its lingual counterparts. At the 12-week interval, the mean bone-implant contact in the microgrooved group was significantly higher than that of the turned surface group. From the observations in some of the microgrooved groups, we have found bone attachment to the 12 mum microgrooved surface and collagen fibers perpendicular to the long axis of the implants over the 8 mum microgrooved surface.

CONCLUSION

Within the limitations of this study, microgrooved implants may provide more favorable conditions for the attachment of hard and soft tissues and reduce the level of marginal bone resorption and soft tissue recession.

Socket grafting with the use of autologous bone: an experimental study in the dog

BACKGROUND

studies in humans and animals have shown that following tooth removal (loss), the alveolar ridge becomes markedly reduced. Attempts made to counteract such ridge diminution by installing implants in the fresh extraction sockets were not successful, while socket grafting with anorganic bovine bone mineral prevented ridge contraction.

AIM

to examine whether grafting of the alveolar socket with the use of chips of autologous bone may allow ridge preservation following tooth extraction.

METHODS

in five beagle dogs, the distal roots of the third and fourth mandibular premolars were removed. The sockets in the right or the left jaw quadrant were grafted with either anorganic bovine bone or with chips of autologous bone harvested from the buccal bone plate. After 3 months of healing, biopsies of the experimental sites were sampled, prepared for buccal-lingual ground sections and examined with respect to size and composition.

RESULTS

it was observed that the majority of the autologous bone chips during healing had been resorbed and that the graft apparently did not interfere with socket healing or processes that resulted in ridge resorption.

CONCLUSION

autologous bone chips placed in the fresh extraction socket will (i) neither stimulate nor retard new bone formation and (ii) not prevent ridge resorption that occurs during healing following tooth extraction.

Strategic considerations in treatment planning: deciding when to treat, extract, or replace a questionable tooth

Prosthodontists face the difficult task of judging the influence and significance of multiple risk factors of periodontal, endodontic, or prosthetic origin that can affect the prognosis of an abutment tooth. The purpose of this review is to summarize the critical factors involved in deciding whether a questionable tooth should be treated and maintained, or extracted and possibly replaced by dental implants. A MEDLINE (PubMed) search of the English, peer-reviewed literature published from 1966 to August 2009 was conducted using different keyword combinations including treatment planning, in addition to decision making, periodontics, endodontics, dental implants, or prosthodontics. Further, bibliographies of all relevant papers and previous review articles were hand searched. Tooth maintenance and the acceptance of risks are suitable when: the tooth is not extensively diseased; the tooth has a high strategic value, particularly in patients with implant contraindications; the tooth is located in an intact arch; and the preservation of gingival structures is paramount. When complete-mouth restorations are planned, the strategic use of dental implants and smaller units (short-span fixed dental prostheses), either tooth- or implant-supported, as well as natural tooth abutments with good prognoses for long-span FDPs, is recommended to minimize the risk of failure of the entire restoration.

Peri-implant defect augmentation with autogenous bone: a study in beagle dogs

This study evaluates the success of immediate endosseous implants placed along with autogenous bone graft to fill the peri-implant gap. Thirty-two implants were inserted in 8 beagle dogs. The right and left lateral incisors in the maxilla and the mandible of all animals were extracted, and immediate postextraction implants were placed. In the control sites, no bone grafts or barrier membranes were used. In the contralateral experimental site, autogenous bone graft was used. The implants were retrieved with the jawbone for histomorphometric studies. The histomorphometric measurements were carried out using a computerized image analysis system. All implants were covered by compact, mature bone under examination in light microscopy. A high bone-implant contact percentage and bone density was observed at both grafted and nongrafted implant sites. The sites filled with autogenous bone graft showed a significantly higher crestal bone level and bone density compared to the nonfilled sites. The observations of the study emphasize that the filling of the peri-implant bone defects with autogenous bone grafts showed a better outcome compared to unfilled defects.

Transmucosal healing around peri-implant defects: crestal and subcrestal implant placement in dogs

OBJECTIVE

This study was designed to evaluate the transmucosal healing response of implants placed with the junction of the smooth surfaces, either crestal or subcrestal, into simulated extraction defects after healing periods of 1 and 3 months.

MATERIALS AND METHODS

A total of 23 Straumann SP v3.3 mm NN, SLA 10 mm implants were placed in the mandibular premolar regions of three greyhound dogs 3 months after the teeth were removed. Five control implants were placed at the crestal bone level, and test implants with surgically created peri-implant defects of 1.25 mm wide x 5 mm depth were placed either at the crestal (nine implants) or at the 2 mm subcrestal (nine implants) bone level. Implants on the right side were placed 1 month before the dogs were sacrificed, and implants on the left side were placed 3 months before sacrifice. All dogs had daily plaque control following surgery and were sacrificed 3 months after implant placement for histological and histometric analyses.

RESULTS

Mesial-distal ground sections of the control and test implant specimens showed a greater %BIC in the coronal defect region after 3 months of healing. This healing response was incomplete for the test implants compared with the control implants after a 1-month healing period. The histometric measurements for test implants placed at the crestal bone level or 2 mm subcrestal with surgically created peri-implant defects were more coronal or closer to the implant margin compared with the control implants. Additionally, the degree of osseointegration between the newly formed bone and the implant surface was similar between the test implants.

CONCLUSION

Peri-implant defects of 1.25 mm width healed with spontaneous bone regeneration around implants placed transmucosally at crestal or 2 mm subcrestal with a high degree of osseointegration after a 3-month healing period.

Analysis of the socket bone wall dimensions in the upper maxilla in relation to immediate implant placement

BACKGROUND

Animal and human researches have shown that immediate implant placement into extraction sockets failed to prevent socket dimensional changes following tooth extraction. It has been suggested that a minimal width of 1-2 mm of buccal bone is necessary to maintain a stable vertical dimension of the alveolar crest.

AIM

To determine the dimensions of the bony wall at extraction sites in the esthetic zone (anterior teeth and premolars in the maxilla) and relate it to immediate implant placement.

METHODS

As part of an ongoing prospective randomized-controlled multicenter clinical study on immediate implant placement, the width of the buccal and palatal bony walls was recorded at 93 extraction sites.

RESULTS

The mean width of the buccal and palatal bony walls was 1 and 1.2 mm, respectively (P<0.05). For the anterior sites (canine to canine), the mean width of the buccal bony wall was 0.8 mm. For the posterior (premolar) sites, it was 1.1 mm (P<0.05). In the anterior sites, 87% of the buccal bony walls had a width < or = 1 mm and 3% of the walls were 2 mm wide. In the posterior sites, the corresponding values were 59% and 9%, respectively.

CONCLUSIONS

If the criterion of a minimal buccal bone width of 2 mm to maintain a stable buccal bony wall is valid, only a limited number of sites in the anterior maxilla display such a clinical situation. The data suggested that in the majority of extraction sites in the anterior maxilla, thin (< or = 1 mm) buccal walls were present. This, in turn, means that in most clinical situations encountered, augmentation procedures are needed to achieve adequate bony contours around the implant.

A prospective, randomized-controlled clinical trial to evaluate bone preservation using implants with different geometry placed into extraction sockets in the maxilla

AIM

The primary objective of this study was to determine the association between the size of the void established by using two different implant configurations and the amount of buccal/palatal bone loss that occurred during 16 weeks of healing following their installation into extraction sockets.

MATERIAL AND METHODS

The clinical trial was designed as a prospective, randomized-controlled parallel-group multicenter study. Adults in need of one or more implants replacing teeth to be removed in the maxilla within the region 15-25 were recruited. Following tooth extraction, the site was randomly allocated to receive either a cylindrical (group A) or a tapered implant (group B). After implant installation, a series of measurements were made to determine the dimension of the ridge and the void between the implant and the extraction socket. These measurements were repeated at the re-entry procedure after 16 weeks.

RESULTS

The study demonstrated that the removal of single teeth and the immediate placement of an implant resulted in marked alterations of the dimension of the buccal ridge (43% and 30%) and the horizontal (80-63%) as well as the vertical (69-65%) gap between the implant and the bone walls. Although the dimensional changes were not significantly different between the two-implant configurations, both the horizontal and the vertical gap changes were greater in group A than in group B.

CONCLUSIONS

Implant placement into extraction sockets will result in significant bone reduction of the alveolar ridge.

Immediate loading of modified acid etched dental implants in postextraction sockets: a histological and histomorphometrical comparative study in nonhuman primate Papio ursinus

PURPOSE

Immediate loading of dental implants inserted into fresh postextraction sites has recently been proposed as a novel but challenging surgical approach. However, histological evidence and comparative data are still missing. The aim of this study was an histological and histomorphometrical comparison of submerged and immediately loaded dental implants with a new modified acid etched surface inserted into postextraction sites of nonhuman primates.

MATERIALS AND METHOD

Thirty-two implants were placed in postextraction sockets of 4 adult Chacma Baboons (papio ursinus). Each baboon received 8 implants: 4 submerged and 4 immediately loaded. The implants were retrieved after 90 days of healing with a 4-mm trephine bur and processed for histology and histomorphometry.

RESULTS

The bone-to-implant contact percentage in the submerged and immediate loaded implants was 86.02% and 86.85%, respectively, with no statistically significant differences. In the immediately loaded implants a greater amount of ongoing remodeling was observed.

CONCLUSIONS

Immediate loading seemed to be a valid alternative to conventional technique when a implant is inserted into postextraction sockets. Further comparative studies on a greater number of samples are necessary to confirm our findings.

Immediate Loading: Three Cases with up to 38 Months of Clinical Follow-up

Since the first report describing the placement of dental implants into fresh extraction sockets, there has been an increasing interest in this technique. The advantages of immediate implant placement have been reported to include a reduction in the number of surgical interventions, potentially decreased alveolar bone resorption after tooth loss, and shorter treatment time. Appropriate indications, good surgical technique, eand the use of a prosthetic protocol have resulted in success for immediate loading and immediate implantation. Adverse patient-related factors, such as systemic health, a smoking habit, poor oral hygiene, presence of a thin biotype, or an infection in the region of the extraction, are contraindications for this treatment. Patient satisfaction is very high, and some difficulties related to the implantation site in late implantations may be eliminated. This article reports on three cases of immediate loading with up to 30 months of clinical follow-up.

Hard tissue alterations after socket preservation: an experimental study in the beagle dog

OBJECTIVES

The aim of the following experimental study was to assess bone changes in the horizontal and vertical dimension when using different socket preservation procedures.

MATERIAL AND METHODS

In five beagle dogs the distal roots of the 3rd and 4th premolar were extracted without elevation of a mucoperiosteal flap and the following treatments were assigned: Tx 1: The extraction socket was filled with BioOss Collagen (Geistlich Biomaterials, Wolhusen, Switzerland) and interrupted sutures were applied.: Tx 2: The extraction socket was filled with BioOss Collagen (Geistlich Biomaterials, Wolhusen, Switzerland) and a free gingival graft was sutured to cover the socket.: Tx 3: The extraction socket was left with its blood clot and interrupted sututes were applied.: Four month after surgery the dogs were sacrificed and from each extraction site two histological sections were selected for histometric analysis. The following parameters were evaluated: (1) the vertical dimension was determined by placing a horizontal line on the lingual bone wall. Then, the distance from this line to the buccal bone wall was measured. (2) The horizontal dimension was assessed at three different areas measured from the top of the lingual crest: 1 mm (Value 1), 3 mm (Value 3) and 5 mm (Value 5).

RESULTS

The mean vertical loss of the buccal bone plate for the Tx 1 group was 2.8+/-0.2 mm. The Tx 2 group showed vertical loss of 3.3+/-0.2 mm. The Tx 3 group demonstrated 3.2+/-0.2 mm of mean vertical loss. The horizontal dimension of the alveolar process was 4.4+/-0.3/6.1+/-0.2/7.2+/-0.1 mm at the three different levels for the Tx 1 group. The Tx 2 group depicted bone dimensions of 4.8+/-0.2/6.0+/-0.2/7.1+/-0.1 mm. The horizontal dimension of the Tx 3 group was 3.7+/-0.3/6.2+/-0.2/7.0+/-0.1 mm. When the results from the horizontal measurements were tested with the analysis of variance (ANOVA), a clear significance could be found in particular for Value 1 mm between the test groups Tx 1 and Tx 2 and the control group (Tx 3) (P<0.001). Furthermore the mean of treatment 1 (Tx 1) was slightly significantly lower than of treatment 2 (Tx 2) (P<0.05).

CONCLUSION

The findings from the present study disclose that incorporation of BioOss Collagen into the extraction socket has only limited impact on the subsequent biologic process with particular respect to the buccal bone plate. The horizontal measurement of the alveolar ridge depicted that the loss of the buccal bone plate was replaced to a certain amount by newly generated bone guided by the BioOss Collagen scaffold. It seems that the mechanical stability provided by BioOss Collagen and furthermore by a free gingival graft could act as a placeholder preventing the soft tissue from collapsing.

Ridge alterations following immediate implant placement in the dog: flap versus flapless surgery

OBJECTIVE

To assess the healing process after flap or flapless surgery in immediate implant placement.

MATERIAL AND METHODS

This study was carried out on five Beagle dogs. Four implants were placed in the lower jaw in each dog immediately after tooth extraction. Flap surgery was performed before the extraction on one side (control), and flapless on the contrary (test). After 3 months of healing, the dogs were sacrificed and prepared for histological analysis.

RESULTS

Ten implants were placed in each group. Two failed (one of each group). The percentage of bone-implant contact was very similar in both groups: 64.8% and 65.1% for the flap and the flapless group, respectively. The difference between the mean distance from the peri-implant mucosa margin to the first bone-implant contact at the buccal aspect was statistically significant between both groups (3.02 mm. flapless and 3.69 mm. flap group). The mean first bone-implant contact at the buccal aspect was located in relation to the sand-blasted and acid-etched level at 0.82 mm for the flapless group and 1.33 mm for the flap group. This difference was not statistically significant.

CONCLUSION

Flapless immediate implant surgery produces a significant reduction in the vestibular biologic width and a minor reduction in buccal bone plate resorption.

Effect of grafting materials on osseointegration of dental implants surrounded by circumferential bone defects. An experimental study in the dog

AIMS

This study was designed to evaluate the effect of gap width and graft placement on bone healing around implants placed into simulated extraction sockets in the mandibles of four beagle dogs.

MATERIALS AND METHODS

Four Ti-Unite implants (13 mm x 3.3 mm) were placed on each side of the mandible. Three implants were surrounded by a 1.35 mm circumferential and a 5 mm deep gap around the coronal portion of the implants. A fourth implant was inserted conventionally into both sides of the mandibles as a positive control. The gaps were filled with either Bio-Oss, autogenous bone or with a blood clot alone. The study design was balanced for animal, side and modality. Ground sections were prepared from biopsies taken at 3 months, and computer-aided histometric measurements of bone/implant contact and area of bone within threads were made for the coronal 5 mm. Data were analysed using analysis of variance.

RESULTS

The mean bone/implant contact was 9.8 mm for the control and ranged from 9.3 to 11.3 mm for the three test modalities. The corresponding values for area within threads were 1 mm(2) and 1-1.2 mm(2). Modality had a significant effect on both bone/implant contact (F=16.9; P<0.0001) and area within threads (F=16.7; P<0.0001).

CONCLUSION

The results of this study suggest that both autogenous bone graft and Bio-Oss played an important role in the amount of hard tissue fill and osseointegration occurring within marginal bone defects around implants.

Replacement of teeth exhibiting periapical pathology by immediate implants. A prospective, controlled clinical trial

OBJECTIVES

The aim of the present study was to test whether or not immediate implantation leads to more biological complications, when performed at extraction sockets of teeth exhibiting periapical pathology compared with teeth not exhibiting periapical pathology.

MATERIALS AND METHODS

In 17 consecutively admitted patients, immediate implant placement was planned in order to replace single teeth exhibiting periapical pathology (test group). These teeth demonstrated pain, periapical radiolucency, fistula, suppuration or a combination of these findings. Another 17 consecutively admitted patients in need of single tooth replacement in the absence of periapical pathology served as the control group. Implant placement and accompanying bone regeneration were performed according to standard clinical procedures. Implants were loaded after a healing period of 3 months. Clinical and radiographical parameters were assessed at the time of implant placement (baseline) and at 12 months thereafter.

RESULTS

Out of the 34 patients, four test and one control patient had to be withdrawn from the study due to the inability to obtain primary implant stability. The residual 29 implants revealed a survival rate of 100% 1 year after placement. Clinical and radiographical differences between 12 months and baseline comparing test and control groups showed no statistical significances for any of the parameters assessed. Within test and control groups there was a statistically significant loss of vertical bone height at the adjacent teeth (mesial test=0.4+/-0.6 mm, control=0.4+/-0.5 mm; distal test=0.3+/-0.2 mm, control=0.7+/-0.8 mm) as well as at the implant site (mesial test=1.9+/-1.4 mm, control=1.8+/-1.1 mm; distal test=1.7+/-1.4 mm, control=1.6+/-1.1 mm) and of buccal keratinized mucosa (test=-2.2+/-1.2 mm; control=-1.3+/-1.6 mm) between baseline and 12 months. During the first 13 weeks of healing, two sites of the test and one site of the control group showed signs of infection, which required intervention. Neither the incident of early exit nor of signs of infection was statistically significantly different between the test and the control group (Mann-Whitney U test).

CONCLUSION

It is concluded that for those implants where primary stability was achieved, the immediate implant placement performed at extraction sockets exhibiting periapical pathology did not lead to an increased rate of complications and rendered an equally favorable type of tissue integration of the implants in both groups. Implant placement into such sites can, therefore, be successfully performed.