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 μm microgrooved surface and collagen fibers perpendicular to the long axis of the implants over the 8 μm 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. To cite this article:
Shin S‐Y., Han D‐H. Influence of microgrooved collar design on soft and hard tissue healing of immediate implantation in fresh extraction sites in dogs.
Clin. Oral Impl. Res. 21 , 2010; 804–814.
doi: 10.1111/j.1600‐0501.2010.01917.x     

Peri-implant bone reactions to immediate implants placed at different levels in relation to crestal bone. Part I: a pilot study in dogs

Purpose: The aim of the present study was to evaluate bone remodeling and bone‐to‐implant contact (BIC) after immediate placement at different levels in relation to the crestal bone of Beagle dogs. Materials and methods: The mandibular bilateral second, third and fourth premolars of six Beagle dogs were extracted and six implants were immediately placed in the hemi‐arches of each dog. Randomly, three cylindrical and three tapered implants were inserted crestally (control group) and 2 mm subcrestally (experimental group). Both groups were treated with a minimal mucoperiosteal flap elevation approach. A gap from the buccal cortical wall to the implant was always left. Three dogs were allowed a 4‐week submerged healing period and the other three an 8‐week submerged healing period. The animals were sacrificed and biopsies were obtained. Biopsies were processed for ground sectioning. Histomorphometric analysis was carried out in order to compare buccal and lingual bone height loss, and BIC between the two groups. Results: All implants osseointegrated clinically and histologically. Healing patterns examined microscopically at 4 and 8 weeks for both groups (crestal and subcrestal) yielded similar qualitative bone findings. The distance from the top of the implant collar to the first BIC in the lingual crest (A–Lc) showed a significant difference (P=0.0313): 1.91 ± 0.2 mm in the control group and 1.08 ± 0.2 mm in the experimental group. There was less bone resorption in subcrestal implants than crestal implants. The mean percentage of newly formed BIC was greater with the cylindrical implant design (46.06 ± 4.09%) than with the tapered design (32.64 ± 3.72%). Conclusion: These findings suggest that apical positioning of the top of the implant does not jeopardize bone crest and peri‐implant tissue remodeling. However, less resorption of the Lc may be expected when implants are placed 2 mm subcrestally. To cite this article:
Negri B, Calvo‐Guirado JL, Pardo‐Zamora G, Ramírez‐Fernández MP, Delgado‐Ruíz RA, Muñoz‐Guzón F. Peri‐implant bone reactions to immediate implants placed at different levels in relation to crestal bone. Part I: a pilot study in dogs.
Clin. Oral Impl. Res. 23 , 2012; 228–235.
doi: 10.1111/j.1600‐0501.2011.02158.x     

CBCT fractal dimension changes at the apex of immediate implants placed using undersized drilling

Objectives: To evaluate, on the base of cone beam computed tomography (CBCT) fractal dimension, bone quality changes surrounding the apical portion of immediate implants placed under higher insertion torque utilizing an undersized drilling technique. Materials and methods: Three patients were enrolled in this study. Single implants were placed into fresh extraction sockets in the anterior maxilla and provisionalized immediately. Adequate stability was ensured on all the implants by a 28.5% undersizing of the apical portion of the osteotomy. Bone quality at the most apical 1.15 mm peri‐implant bone portion were measured by CBCT at placement and after 6 months. This analysis was carried out by evaluating the box counting fractal dimension of 15 consecutive CBCT slices related to the most apical part of each implant. Results: All the three implants were successful after an 18‐month follow‐up period. The mean fractal dimension at the implant apex exhibited a 3% increase 6 months following placement. Conclusions: Within the limitations of an explorative study, an undersized drilling resulting in high insertion torque would seem to induce no adverse changes in radiographic bone quality after 6 months of follow‐up. The most favorable entity of drilling undersizing and its effect on peri‐implant bone remodeling, should be evaluated on a larger patient population. To cite this article :
González‐Martín O, Lee EA, Veltri M. CBCT fractal dimension changes at the apex of immediate implants placed using undersized drilling
Clin. Oral Impl. Res. 23 , 2012; 954–957
doi: 10.1111/j.1600‐0501.2011.02246.x     

Immediately restored single implants in the aesthetic zone of the maxilla using a novel design: 1-year report

Objectives: To evaluate immediate placement and immediate restoration of a novel implant with a 12°‐angled prosthodontic platform, in fresh extraction sockets of the aesthetic zone of the maxilla. Materials and methods: Tapered, roughened surface implants of 4 mm (n=15) or 5 mm (n=13) diameter were placed in 27 participants (mean age: 47.1 years; range: 21–71 years) requiring an immediate replacement of single anterior maxillary teeth. Provisional screw‐retained all‐ceramic crowns were placed within 4 h following optical impressions. At 8 weeks (baseline), definitive screw‐retained all‐ceramic crowns were placed in occlusion. Results: Twenty‐six of the 28 implants met the inclusion criteria at surgery. Marginal bone levels revealed bone gain between surgery and baseline, and between baseline and 1 year of 0.2 mm (SD 0.75) and 0.78 mm (SD 2.45). Mean mid‐buccal mucosal margins showed gains of 0.2 mm (SD 0.44). Prosthodontic maintenance and the aesthetics of the screw‐retained implant crowns were facilitated by the external hex 12°‐angled prosthodontic platform on the novel implant design, re‐orientating the access cavity to the palatal or occlusal surfaces. All‐ceramic implant crowns showed a high success rate with low maintenance issues over 1 year. Conclusion: Tapered, roughened‐surfaced implants with a novel 12°‐angled prosthodontic platform immediately placed in fresh extraction sockets, immediately restored with provisional crowns and subsequent definitive crowns at 8 weeks were successful for 1 year. To cite this article:
Brown SDK, Payne AGT. Immediately restored single implants in the aesthetic zone of the maxilla using a novel design: 1‐year report.
Clin. Oral Impl. Res. 22 , 2011; 445–454.     

A prospective,controlled clinical trial evaluating the clinical and radiological outcome after 3 years of immediately placed implants in sockets exhibiting periapical pathology

Objectives: The aim of the present study was to compare the clinical and radiological outcome of immediately placed implants in sockets with or without periapical pathology 3 years after implant placement. Materials and methods: Twenty‐nine patients with immediate implant placement were clinically and radiologically followed 3 years after implant placement (test group: 16 patients without periapical pathology, control group: 13 patients with periapical pathologies). Clinical (full‐mouth bleeding score, full‐mouth plaque score, clinical attachment level measurements and width of keratinized mucosa buccaly of the implant) and radiological parameters (vertical distance from the implant shoulder to the first bone‐to‐implant contact [IS‐BIC]) were assessed. Both 95% confidence intervals, as well as results of statistical tests (one‐sample, two‐sample and paired t‐test) were provided. Results: The implant survival rate was 100% for all 29 implants after 3 years. The clinical and radiological parameters showed no statistically significant difference between the test and the control group at 3 years (two‐sample t‐test). The IS‐BIC was between 1.54 ± 0.88 mm (mesial, test) and 1.69 ± 0.92 mm (distal, test). Between the 1‐ and 3‐year visit the IS‐BIC increased in both groups significantly on one side of the implant: 0.30 ± 0.37 mm (mesial, test) and 0.33 ± 0.43 mm (distal, control) (one‐sample t‐test). None of the 13 examined radiographs of implants immediately placed in sockets with periapical pathologies revealed retrograde peri‐implantitis after 3 years. Conclusion: It is concluded within the limitations of this study, that after careful debridement of the extraction socket, immediate placement of implants into sites with periapical pathologies can be a successful treatment modality for at least 3 years with no disadvantages in clinical and radiological parameters to immediately placed implants into healthy sockets. To cite this article:
Truninger TC, Philipp AOH, Siegenthaler DW, Roos M, Hämmerle CHF, Jung RE. A prospective, controlled clinical trial evaluating the clinical and radiological outcome after 3 years of immediately placed implants in sockets exhibiting periapical pathology.

Clin. Oral Impl. Res. 22 , 2011; 20–27.
doi: 10.1111/j.1600‐0501.2010.01973.x     

Ridge alterations following immediate implant placement and the treatment of bone defects with Bio-Oss in an animal model

Background: Conflicting data exist on the outcome of placing Bio‐Oss® (Geitslich Pharm AG, Wolhausen, Switzerland) into extraction sockets. It is therefore relevant to study whether the incorporation of Bio‐Oss into extraction sockets would influence bone healing outcome at the extraction sites. Purpose: The aim of this study was to assess peri‐implant bone changes when implants were placed in fresh extraction sockets and the remaining defects were filled with Bio‐Oss particles in a canine mandible model. Materials and Methods: Six mongrel dogs were used in the study. In one jaw quadrant of each animal, the fourth mandibular premolars were extracted with an elevation of the mucoperiosteal flap; implants were then placed in the fresh extraction sockets and the remaining defects were filled with Bio‐Oss particles. After 4 months of healing, micro‐computed tomography at the implant sites was performed. Osseointegration was calculated as the percent of implant surface in contact with bone. Additionally, bone height was measured in the peri‐implant bone. Results: Average osseointegration was 28.5% (ranged between 14.8 and 34.2%). The mean crestal bone loss was 4.7 ± 2.1 mm on the buccal aspect, 0.4 ± 0.5 mm on the mesial aspect, 0.4 ± 0.3 mm on the distal aspect, and 0.3 ± 0.4 mm on the lingual aspect. Conclusion: The findings from this study demonstrated that the placement of implants and Bio‐Oss® particles into fresh extraction sockets resulted in significant buccal bone loss with low osseointegration.     

即刻种植即刻修复的临床疗效观察

目的：观察前牙区拔牙后即刻种植即刻修复的临床效果。方法：对4例前牙种植病例，在拔牙后即刻植入6枚Friait-2或Xive种植体，同时接入Pro—Tect基台行复合树脂临时冠／桥修复，根据骨质情况，3—6个月后，行永久性修复。结果：追踪12～27个月，全部种植体成功。结论：严格掌握好适应证，拔牙后即刻种植即刻修复，临床效果良好。     

Sinus floor elevation via the maxillary premolar extraction socket with immediate implant placement: a case series

Background: When immediate implant placement is considered for teeth with close proximity to the sinus floor, apical extension of the osteotomy is significantly limited, and often a staged approach is used. Implant placement into fresh extraction sockets and sinus floor manipulation using bone‐added osteotome sinus floor elevation with implant placement are techniques most often used independently or sequentially. Very few reports have described the combined use of immediate implant placement in fresh sockets and the bone‐added osteotome sinus floor elevation technique. Methods: We present five cases in which a maxillary premolar was extracted and an implant placed into the extraction site with simultaneous abfracture of the sinus floor using osteotomes. All teeth were extracted atraumatically, and sockets carefully debrided and checked for integrity of the walls. After ideal osteotomy preparation, particulate bone graft was placed in the osteotomy and appropriately sized osteotomes were used for sinus floor elevation. After sufficient elevation, implant placement was completed and particulate bone was packed in the bone–implant gap when indicated. Results: All implants were restored after a minimum healing period of 6 months. At the time of final restoration, bone was seen surrounding the implants from the apical portion to the most coronal thread. All five implants healed without complications and were in function for periods ranging from 6 to 12 months. Conclusions: Immediate implant placement with simultaneous osteotome sinus floor elevation is an advantageous combination of two successfully used techniques. This combined approach can significantly reduce the treatment time for implant therapy in teeth with close sinus proximity and provide the operator with the ability to place implants of desired length.     

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.     

Collagen membranes at immediate implants: a histomorphometric study in dogs

Aim: To evaluate the influence of resorbable membranes on hard tissue alterations and osseointegration at implants placed into extraction sockets in a dog model. Material and methods: In the mandibular premolar region, implants were installed immediately into the extraction sockets of six Labrador dogs. Collagen‐resorbable membranes were placed at the test sites, while the control sites were left uncovered. Implants were intended to heal in a submerged mode. After 4 months of healing, the animals were sacrificed, and ground sections were obtained for histomorphometric evaluation. Results: After 4 months of healing, a control implant was not integrated (n=5). Both at the test and at the control sites, bone resorption occurred. While the most coronal bone‐to‐implant contact was similar between the test and the control sites, the alveolar bone crest outline was maintained to a higher degree at the buccal aspect of the test sites (loss: 1.7 mm) compared with the control sites (loss: 2.2 mm). Conclusions: The use of collagen‐resorbable membranes at implants immediately placed into extraction sockets contributed to a partial (23%) preservation of the buccal outline of the alveolar process. To cite this article:
Caneva M, Botticelli D, Salata LA, Souza SLS, Carvalho Cardoso L, Lang NP. Collagen membranes at immediate implants: a histomorphometric study in dogs.
Clin. Oral Impl. Res. 21 , 2010; 891–897.
doi: 10.1111/j.1600‐0501.2010.01946.x     

Replacement of severely traumatized teeth with immediate implants and immediate loading: literature review and case reports

One of the options for management of severely traumatized dentitions is to provide immediate implant placement with immediate loading. Three representative cases out of 15 patients with 23 traumatized teeth treated to date in our clinic are presented. None had labial bone fractures. The teeth were replaced with NobelReplace Groovy implants (Nobel Biocare, Gothenburg, Sweden) in the fresh sockets immediately after extraction. They were placed toward the palatal areas in the sockets and 3 mm below the gingival margins. If there were gaps between implants and sockets wider than 1 mm, particulate deproteinized bovine bone was grafted in the gaps. Immediately after placement, the implants were loaded with provisional prostheses. The final restorations were installed 3–4 months later. The patients were reevaluated clinically and radiographically 1–3 years after the final restorations had been placed. In all 15 patients, excellent functional and esthetic results were achieved. No implants showed radiolucency, peri‐implant suppuration, or mobility. The patients were satisfied with the results. Immediate implant placement with immediate loading is an option that provides good treatment outcomes and allows good functional and esthetic results, as well as addressing the social/psychological aspects of dental trauma.     

Magnesium-enriched hydroxyapatite at immediate implants: a histomorphometric study in dogs

Aim: To evaluate the influence of magnesium‐enriched hydroxyapatite (MHA) (SintLife^®) on bone contour preservation and osseointegration at implants placed immediately into extraction sockets. Material and methods: In the mandibular pre‐molar region, implants were installed immediately into extraction sockets of six Labrador dogs. MHA was placed at test sites, while the control sites did not receive augmentation materials. Implants were intended to heal in a submerged mode. After 4 months of healing, the animals were sacrificed, and ground sections were obtained for histomorphometric evaluation. Results: After 4 months of healing, one control implant was not integrated leaving n=5 test and control implants for evaluation. Both at the test and the control sites, bone resorption occurred. While the most coronal bone‐to‐implant contact was similar between test and control sites, the alveolar bony crest outline was maintained to a higher degree at the buccal aspect of the test sites (loss: 0.7 mm) compared with the control sites (loss: 1.2 mm), even though this difference did not reach statistical significance. Conclusions: The use of MHA to fill the defect around implants placed into the alveolus immediately after tooth extraction did not contribute significantly to the maintenance of the contours of the buccal alveolar bone crest. To cite this article:
Caneva M, Botticelli D, Stellini E, Souza SLS, Salata LA, Lang NP. Magnesium‐enriched hydroxyapatite at immediate implants: a histomorphometric study in dogs.
Clin. Oral Impl. Res. 22 , 2011; 512–517
doi: 10.1111/j.1600‐0501.2010.02040.x     

Two-year prospective clinical comparison of immediate replacement vs. immediate restoration of single tooth in the esthetic zone

Aim: To compare the immediate restoration of single implants in the esthetic zones performed on implants placed immediately after tooth extraction or 8 weeks later (immediate replacement vs. immediate restoration). Methods: Sixteen patients (10 women and 6 men) with a mean age of 35 years (ranging from 21 to 49 years old) were treated from 2004 to 2005 for single‐tooth replacement in the upper arch. The patients were randomly divided into two groups: in the test group patients received implants placed and restored (non‐occlusal loading) at the time of tooth extraction; in the control group implants were placed 8 weeks after tooth extraction and immediately restored. All the patients received tapered effect (TE) implants from the Straumann Dental Implant System. The following parameters were evaluated at the moment of provisional restoration (within 48 h after implant placement) and at the 2 years follow‐up visit: marginal bone resorption, papilla index, position of the mucosal margin. The implant stability quotient was measured at the moment of implant placement and at the moment of the delivery of the definitive restoration. Results: No statistically significant differences were found in any of the studied parameters between the test and the control groups (P>0.05). The implant stability quotient values between the test and control groups were significant (P<0.05) at the moment of implant placement but were no more significant at the loading of the definitive restoration (P>0.05). Conclusion: The results of the present study suggest that immediate replacement without functional loading may be considered a valuable therapeutic option for selected cases of single‐tooth replacement in the esthetic area when TE implants are used. Implant stability at the moment of implant placement is slightly inferior in the immediate replacement group, but it does not affect the treatment result.     

Bio-Oss collagen in the buccal gap at immediate implants: a 6-month study in the dog

Background: Following tooth extraction and immediate implant installation, the edentulous site of the alveolar process undergoes substantial bone modeling and the ridge dimensions are reduced. Objective: The objective of the present experiment was to determine whether the process of bone modeling following tooth extraction and immediate implant placement was influenced by the placement of a xenogenic graft in the void that occurred between the implant and the walls of the fresh extraction socket. Material and methods: Five beagle dogs about 1 year old were used. The 4th premolar in both quadrants of the mandible (₄P₄) were selected and used as experimental sites. The premolars were hemi‐sected and the distal roots removed and, subsequently, implants were inserted in the distal sockets. In one side of the jaw, the marginal buccal‐approximal void that consistently occurred between the implant and the socket walls was grafted with Bio‐Oss^® Collagen while no grafting was performed in the contra‐lateral sites. After 6 months of healing, biopsies from each experimental site were obtained and prepared for histological analyses. Results: The outline of the marginal hard tissue of the control sites was markedly different from that of the grafted sites. Thus, while the buccal bone crest in the grafted sites was comparatively thick and located at or close to the SLA border, the corresponding crest at the control sites was thinner and located a varying distance below SLA border. Conclusions: It was demonstrated that the placement of Bio‐Oss^® Collagen in the void between the implant and the buccal‐approximal bone walls of fresh extraction sockets modified the process of hard tissue healing, provided additional amounts of hard tissue at the entrance of the previous socket and improved the level of marginal bone‐to‐implant contact. To cite this article:
Araújo MG, Linder E, Lindhe J. Bio‐Oss^® Collagen in the buccal gap at immediate implants: a 6‐month study in the dog.
Clin. Oral Impl. Res. 22 , 2011; 1–8.
doi: 10.1111/j.1600‐0501.2010.01920.x     

Peri-implant bone changes following tooth extraction, immediate placement and loading of implants in the edentulous maxilla

The aim of this study was to clinically and radiographically evaluate peri-implant bone level changes after rehabilitation of a fully edentulous maxilla by placement of six implants in either fresh extraction sites or healed edentulous ridges up till 18 months after implant placement. Twenty patients with a terminal dentition in the maxillae (11 men, 9 women) received a total of 120 OsseoSpeed implants; 118 implants could be loaded immediately of which 59 were placed in extraction sockets and 59 were placed in healed sites. Within 24 h after surgery, all patients received a chairside-assembled, fibre-reinforced temporary fixed prosthetic reconstruction in occlusion. Six months post-surgery, final screw-retained CoCr (15) or Ti (5) computer numerical control-milled and acrylic-veneered frameworks were placed directly at implant level without interposing abutments. Intraoral radiographs were taken 6 and 18 months after implant placement. Implant survival rate was 100%. Mean marginal bone level was located on average -0.35 mm below the reference point (standard deviation 0.29, range -1.20 to +0.02 mm) 18 months after loading. Whether implants were placed in healed bone sites or fresh extraction sockets did not significantly affect the bone level changes. Furthermore, the use of either CoCr or Ti at the implant level did not significantly affect marginal bone loss. Within the limits of this prospective clinical trial, results seem to indicate that immediate placement and occlusal loading of five to six implants in the edentulous maxilla can be carried out successfully. Whether or not those implants are placed in fresh extraction sockets does not seem to alter the outcome. The present data show a successful 1-year outcome of a treatment protocol involving tooth extraction immediately combined with implant placement and loading.     

Soft tissue dimensions in flapless immediate implants with and without immediate loading: an experimental study in the beagle dog

Objective: The aim of the present study was to evaluate the peri‐implant soft tissue dimensions in flapless immediate implants with and without immediate loading. Material and methods: This study was carried out on six beagle dogs. Four implants were placed (two per side) immediately after tooth extraction (third and fourth premolars). Flapless immediate implant placement was performed in one hemimandible (control). The same procedure was performed in the contralateral side and immediate prosthesis was connected (test). After 3 months of healing, the dogs were sacrificed. Results: None of the implants and prosthesis were lost. Barrier epithelium in the loaded group was 2.51 mm at the buccal and 2.34 mm at the lingual aspect. In the no loaded group, the results were similar, 2.54 and 2.2 mm at the buccal and lingual side, respectively. Connective tissue in the loaded group was 1.38 mm at the buccal and 0.65 mm at the lingual aspect, and in the no loaded group 1.48 mm at the buccal and 0.53 mm at the lingual side. Biological width dimensions were 3.9 mm at the buccal and 2.95 mm at the lingual aspect for the loaded group, and 4.01 and 2.64 mm at the buccal and lingual aspect for the no loaded group. Conclusions: The results of the present study suggested that soft tissues dimensions around immediate implants with immediate loading were similar to immediate implants without loading. To cite this article:
Blanco J, Carral C, Liñares, A, Pérez J, Muñoz F. Soft tissue dimensions in flapless immediate implants with and without immediate loading: an experimental study in the beagle dog.
Clin. Oral Impl. Res. 23 , 2012; 70–75.
doi: 10.1111/j.1600‐0501.2011.02183.x     

Factors influencing ridge alterations following immediate implant placement into extraction sockets

Aim: To identify factors that may influence ridge alterations occurring at the buccal aspect of the extraction site following immediate implant placement.
Material and methods: In 93 subjects, single-tooth implants were placed immediately into extraction sockets in the maxilla (tooth locations 15–25). A series of measurements describing the extraction site were made immediately after implant installation and at re-entry, 16 weeks later. The implant sites were stratified according to four factors: (i) implant location (anterior/posterior), (ii) cause of tooth extraction (periodontitis/non-periodontitis), (iii) thickness of the buccal bone walls (≤1/>1 mm) and (iv) the dimension of the horizontal buccal gap (≤1/>1 mm).
Results: (i) The location where the implant was placed (anterior/posterior) as well as (ii) the thickness of the buccal bone crest and (iii) the size of the horizontal buccal gap significantly influenced the amount of hard tissue alteration that occurred during a 4-month period of healing. At implant sites in the premolar segment, the fill of the horizontal gap was more pronounced than in the incisor–canine segment, while the vertical crest reduction was significantly smaller. Furthermore, at sites where the buccal bone wall was thick (>1 mm) and where the horizontal gap was large (>1 mm), the degree of gap fill was substantial.
Conclusions: The thickness of the buccal bone wall as well as the dimension of the horizontal gap influenced the hard tissue alterations that occur following immediate implant placement into extraction sockets.
To cite this article:
Ferrus J, Cecchinato D, Pjetursson EB, Lang NP, Sanz M, Lindhe J. Factors influencing ridge alterations following immediate implant placement into extraction sockets.
Clin. Oral Impl. Res . 21 , 2009; 22–29.     

Immediate and delayed implant placement into extraction sockets: a 5-year report

Background: As a complement to the earlier reported 3‐year results from a prospective multicenter study of immediate and delayed placement of implants into fresh extraction sockets, the 5‐year results are reported. Purpose: The purpose of this 5‐year report was to evaluate the immediate and long‐term success of implants placed into fresh extraction sockets, with respect to implant size and type, bone quality and quantity, implant position, initial socket depth, and reason for tooth extraction. Materials and Methods: This paper presents the 5‐year results of the original 12 centers that participated with 143 consecutively included patients. A total of 264 implants were placed either immediately after tooth extraction or after a short soft‐tissue healing time (3–5 weeks). The patients were divided into five subgroups, depending on the type of insertion method used. Results: The outcome demonstrated that the cumulative implant survival rate after 5 years of loading has not changed and remains 92.4% in the maxilla and 94.7% in the mandible. No difference in failure rates can be seen between the groups when relating the failures to insertion method. Conclusion: This prospective study demonstrated that placing Brånemark implants into fresh extraction sites can be successful over a period of 5 years of loading. One of the outcomes of the study shows that there is a clinical correlation between implant failure and periodontitis as a reason for tooth extraction, even if it is difficult to give it a casual association. It can be hypothesized that periodontitis affected tissues might have a negative local influence because of the presence of infrabony defects that could possibly increase the gap between bone and implant or jeopardize achievement of primary stability.     

Immediate Postextractive Dental Implant Placement with Immediate Loading on Four Implants for Mandibular‐Full‐Arch Rehabilitation: A Retrospective Analysis

Background: To date, only few studies have reported on the clinical outcomes of immediate postextraction implant placement and immediate loading. Purpose: The purpose of this retrospective study was to report the results of immediately loading four implants placed in fresh extraction sockets in the mandible after a follow‐up of 24 months. Materials and Methods: Between January 2001 and January 2009, 50 patients (28 women and 22 men, average age 54 years), had 347 teeth extracted and a total of 200 dental implants placed in the mandible. The patients received a provisional fixed bridge the same day and a permanent one 3 months later. Clinical checkups were performed after 1, 2, 3, 6, 12, and 24 months. Marginal bone measurements were made in intraoral radiographs taken 1 day after surgery and after 1 year. A questionnaire was used to evaluate self‐perceived factors related to comfort, aesthetics, and function. Results: All bridges were stable and no implant failures were recorded during the follow‐up, giving a survival rate of 100%, at 2 years. The marginal bone loss amounted to 1.33 ± 0.36 mm after 1 year and 1.48 ± 0.39 mm after 2 years. Ten patients showed prosthetic complications with the provisional bridge, but all the definitive prostheses remained stable throughout the study period without any complications. The patients reported satisfaction with the treatment. Conclusions: The present retrospective study showed that immediate loading of four implants immediately placed in extraction sockets is a valid treatment modality for the totally edentulous mandible.