DENTAL XP My Notes
Filipe Lopes
  1. A systematic review on survival and
    success rates of implants placed
    immediately into fresh extraction
    sockets after at least 1 year

    2011

     

    Niklaus P. Lang
    Lui Pun
    Ka Yee Lau
    Ka Yan Li
    May CM Wong

    A systematic review on survival and success rates of implants placed immediately into fresh extraction sockets after at least 1 year


     

    Type I immediate implant placement has gained popularity because it may reduce treatment time, number of surgeries and post-extraction bone loss. However, this is potentially challenged by inadequate keratinized mucosa for flap adaptation and difficulties in achieving primary stability. Moreover, it has been proven that post-extraction bone loss is an inevitable biological process, which affects treatment outcomes.


     


     

    A total of 46 prospective studies, with a mean follow-up time of 2.08 years, were included. The annual failure rate of immediate implants was 0.82% (95% CI: 0.48–1.39%), translating into the 2-year survival rate of 98.4% (97.3–99%). Among the five factors analysed (reasons for extraction, antibiotic use, position of implant [anterior vs. posterior, maxilla vs. mandible), type of loading], only the regimen of antibiotic use affected the survival rate significantly. Lower failure rates were found in groups that were provided with a course of postoperative antibiotics.


     


     


     

    TYPES OF IMPLANT PLACEMENT

    As the debate in timing of implant placement increased, the following new classification based on morphologic, dimensional and histologic changes that follow tooth extraction was proposed at the Third ITI Consensus Conference (Ha¨mmerle et al. 2004): • Type 1: Immediate placement: an implant is placed immediately in an extraction socket as part of the same procedure with no healing of bone or soft tissues. • Type 2: Early placement (typically 4– 8 weeks of healing) with some soft tissue healing: the post-extraction site has healed soft tissue coverage of the alveolus but without significant bone healing. • Type 3: Early placement with partial bone healing (typically 12–16 weeks of healing): The post-extraction site has both healed soft tissues and a significant degree of bone healing. • Type 4: Late placement (more than 6 months after extraction): implant placement in a fully healed edentulous site.


     


     


     

    In 1978, the first report of a situation, in which the extraction followed by the placement of an implant into the fresh socket at the same appointment, was described as the “Tu¨rbingen immediate implant” (Schulte et al. 1978). This method reduced the number of dental appointments, the time of treatment and the number of surgeries required


     


     

    DISADVANTAGES

    The potential lack of keratinized mucosa for flap adaptation makes primary closure more difficult to be achieved in Type 1 than other types of implant placement.

    Moreover, the incongruity of size and shape between implants and extraction sockets presents challenges to primary implant stability


     

    Consequently, primary stability is only achieved by anchoring the implant in the apical bony region (3 –4 mm), where cancellous bone predominates. Moreover, although both animal (Araujo et al. 2005) and human studies (Covani et al. 2004a) show that spontaneous bone fill occurs in the peri-implant marginal defects after 3–4 months when the defect size is 2 mm or less, immediate implant placement cannot prevent intra- and extra-alveolar modelling and remodelling leading to the inevitable vertical and horizontal reduction in both buccal and lingual alveolar bony walls, conspicuously in the buccal aspect. Such biological changes imply higher risk of marginal mucosal recession after immediate implant placement, and hence, non-aesthetic restorations in areas of aesthetic priority may result, especially when the facial socket wall and tissue biotype are thin (De Rouck et al. 2008b).


     

    In the posterior region, immediate implants may also be exposed to the dilemma between the difficulty in achieving primary stability if placed in the centre of the socket or a substantial defect if positioned leaning towards either wall of the socket.


     

    Consequently, more questions are invited such as the minimum dimension of defects in need of grafting (Botticelli et al. 2003), subsequently the choice of grafting material as well as the risk in graft exposure and management. All these aspects related to immediate implants could possibly lower the survival rate of the implant.


     


     


     


     

    In a recent Cochrane systematic review, success, complications, aesthetics and patient satisfaction among different timing of implant placement (immediate, immediate–delayed and delayed) after tooth extraction were evaluated (Esposito et al. 2010). Two studies of parallel group design, comparing immediate and delayed implant placement were included in this review.


     

    The meta-analysis of the two trials did not show any statistically significant difference between the two groups regarding prosthesis and implant failures. Concerning immediate vs. immediate–delayed implant placement only one trial was included in the review.


     

    There were eight patients in each group. Two years after implant placement, no implant failure and complications occurred, and no statistically significant difference was found with respect to the level of periimplant marginal mucosa and marginal bone level changes. Based on the few under-powered trials, it was concluded that there was insufficient evidence to determine possible advantages or disadvantages of immediate, immediate–delayed or delayed implants (Esposito et al. 2010).


     


     


     


     


     


     


     

    Fig. 1 describes the process of identifying the 46 studies selected from an initial yield of 5887 titles. In the included studies, two had publications repeated on the same patient cohorts. In this situation, only the one with a longer observation period was chosen. Reasons for exclusion of articles not considered were noted as well.


     


     

    NOT ACCEPTABLE

    Of the 46 studies included, information on the survival of the implants was retrieved. Survival was defined as implants remaining in situ at the follow-up examinations, irrespective of their conditions. Failure was defined as implants that were lost after implant placement immediately into the extraction socket.

    NOT ACCEPTABLE

    SPECIALLY ON ANTERIOR


     


     

    Biological complications included periimplant mucositis and peri-implantitis. Peri-implant mucositis was defined as the presence of inflammation in the mucosa at the implant with no signs of supporting bone loss. Peri-implantitis was defined as the presence of inflammation in the mucosa and loss of supporting bone at the implant (Zitzmann & Berglundh 2008).


     


     

    Aesthetic outcomes were assessed by the Pink Esthetic Score (PES) introduced by Furhauser et al. (2005), and/or the papilla index described by Jemt (1997)


     

    MUITO IMPORTANTE

    The PES was based on seven parameters: mesial papilla, distal papilla, soft tissue level, soft tissue contour, alveolar process deficiency, soft tissue colour, and texture. Each parameter was assessed with a 2-1-0 score, with 2 being the best and 0 being the worst result. A maximum score of 14 can be achieved. The aesthetic outcome was optimal if the PES was 10.


     

    The papilla index (Jemt 1997) described the fullness of papillary fill: • Index 0 = no papilla present • Index 1 = less than one half the papilla height is present and a convex nature of the adjacent tissue nature is noted. • Index 2 = greater than half the height of the papilla is present but not to the full extent of the contact point. Papilla is not in complete harmony. • Index 3 = the papilla fills the entire proximal space and is in good harmony. • Index 4 = the papilla is hyperplastic.

    MUITO IMPORTANTE


     


     


     


     

    RESULTS

    A total of 46 prospective studies on implants inserted immediately into extrac- tion sockets were included in this system- atic review.

    With the exception of three studies (Becker et al. 1994; Lang et al. 1994; Becker et al. 1998), all the other 43 studies were published after the year 2000.

    Most studies had the mean follow-up time less than 3 years. Only nine studies reported implant survival rates with the mean observation period of 3 years or more.

    Five studies were multicenter studies.

    There were 16 compara- tive studies.


     


     


     

    The test and control groups were recruited to compare

    (i) implants placed in extraction sockets vs. implants inserted at healed sites (Kan et al. 2007a; Ribeiro et al. 2008; Siciliano et al. 2009; Gokcen-Rohlig et al. 2010);

    (ii) immediate implants at sites with chronic periapical lesion vs. implants at healed sites (Lindeboom et al. 2006a);

    (iii) immediate implant placement at sites with chronic periapical lesion vs. at sites without periapical lesion (Crespi et al. 2010);

    (iv) implants in acutely infected sockets vs. implants in sockets without pathology (Sie- genthaler et al. 2007);

    (v) immediate implant insertion and simultaneous connective tissue graft vs. coronally advanced flap (Cornelini et al. 2008);

    (vi) treatment of immediate implant and connective tissue graft vs. immediate implant only (Bianchi & Sanfi- lippo 2004);

    (vii) immediate implantation with GBR vs. without GBR (Bragger et al. 1996);

    (viii) submerged vs. non-submerged healing following implant placement in extraction sockets (Cordaro et al. 2009);

    (ix) immediate vs. delayed provisional restoration after immediate implant placement (Crespi et al. 2008; De Rouck et al. 2009; Prosper et al. 2010);

    (x) immediate implants restored with a platform-switching vs. a platform matching protocol (Crespi et al. 2009a; Canullo et al. 2009a,b).


     

    Ten studies were randomized clinical trials (Bianchi & Sanfilippo 2004; Lindeboom et al. 2006a; Crespi et al. 2008; Cornelini et al. 2008; Cordaro et al. 2009; De Rouck et al. 2009; Canullo et al. 2009a,b; ; Crespi et al. 2009a; Siciliano et al. 2009; Prosper et al. 2010).

    Each study was assessed according to the recommended approach suggested by the Cochrane Collaboration. Four studies were judged to be at high and the remaining six studies at unclear risk of bias. (Fig. 2 and Table 1)

    Five studies were prospective cohort stud- ies, and were assessed using the Newcastle– Ottawa Scale (Wells et al. 2009). All of them scored eight of nine stars.

    A total of 2130 patients, aged between 18 and 94 were included in the 46 studies. Totally, 3082 implants were placed in which 2934 were in fresh extraction sockets and 148 were in healed sites. Twenty-five implants in two studies were not restored (Fugazzotto 2002a); Vidal et al. 2010), and one implant in one study was lost to follow- up (Calvo-Guirado et al. 2009), leaving 2908 implants for further analysis. (Table 2)


     


     

    Antibiotic prophylaxis

    Antibiotics were prescribed in 33 studies (Table 2). Four studies involved pre-opera- tive single dose of antibiotic prophylaxis, while post-operative antibiotic use of 5– 7 days was reported in 15 studies. Fourteen studies provided both pre-operative single dose and post-surgical (5–7 days) antibiotic prescription. Data regarding antibiotic prescription were not forthcoming in the remaining studies.


     


     

    In five studies, implants were inserted in the anterior region only, namely, central incisors, lateral incisors and canines (Table 2). Implants in another five studies were solely placed in posterior areas, i.e. premolars and molars. Thirty-five studies involved implan- tation in both anterior and posterior regions. One study did not state the implant loca- tions.


     


     

    Grafting materials

    No grafting materials were utilized at all in six studies (Table 2). Eleven studies involved autogenous bone grafts. Bone substitutes were used in 16 studies, of which deminera- lised bovine bone matrix (DBBM) was most frequently applied. Other reported bone sub- stitutes were demineralised freeze-dried bone allograft (DFDBA), enamel matrix derivatives (EMD), Biogran® bone graft, and HRT syn- thetic bone allograft. The main purposes of using grafting materials were to fill the marginal gaps between implants and socket walls and to cover bony dehiscences and/or fenestrations.


     

    In 12 studies, the grafting materials were covered by barrier membranes. Resorbable membranes were more commonly used than non-resorbable membranes. In five studies, bony defects around implants were solely covered by barrier membranes.

    Besides bone substitutes and barrier mem- branes, connective tissue grafting was also performed to cover immediate implants in six studies. Three studies reported a com- bined use of subepithelial connective tissue grafts (SCTG) with other grafting materials, while the other three employed SCTG as the only grafting material. The most common donor site was the palatal vault. This tech- nique was mainly applied on subjects who were of the thin gingival biotype.


     


     


     

    MUITO IMPORTANTE

    Loading

    According to the Fourth ITI Consensus Report (Weber et al. 2009), immediate load- ing of dental implants was defined as loading being earlier than 1 week subsequent to implant placement; early loading was defined as loading being between 1 week and 2 months subsequent to implant placement; and conventional loading was loading being greater than 2 months subsequent to implant placement (Table 2).

    MUITO IMPORTANTE


     


     

    In more than half of the studies, permanent restorations were retained by cement, while screw- retained restorations were used in only four studies


     


     


     

    Five factors were investigated for their impact on the survival of immediate implant:

    use of antibiotics,

    reasons for extractions,

    locations of implants (anterior vs. posterior, maxillary vs. mandibular),

    and timing of restorations:


     


     

    ANTIBIOTICS

    The estimated annual failure rate for the pre-operative antibiotic use group was 1.87%. Both the post-operative antibiotic use group and pre- and post-operative antibi- otic use group showed lower annual failure rates than did the pre-operative antibiotic use group, with the annual failure rates of 0.51% and 0.75%, respectively. The differences reached statistical significance (P = 0.002; 0.02).


     


     

    REASONS FOR EXTRACTION

    Perio or No Perio was not significant.


     


     


     

    Most of the soft tissue changes occurred in the first 3 months. Mesial and dis- tal papillae shrank by 0.41 ± 0.32 mm (Q = 0.15, P = 0.93) and 0.34 ± 0.36 mm (Q = 0.08, P = 0.96), respectively, while the buccal mucosal level was displaced apically by 0.43 ± 0.38 mm (Q = 0.01, P = 0.995), when compared to the pre-surgical level. Soft tissues became stable after 6 months


     


     

    As no statistically significant differences were found at any sites between the sub- merged and non-submerged implant groups, weighted means at each examination visit were calculated for the three sites. When compared to the pre-surgical soft tissue lev- els, the greatest loss was recorded at the time of provisional restoration (mesial papilla: 0.95 mm, distal papilla: 0.87 mm, buccal: 0.79 mm), after which, little changes had taken place (Fig. 4).


     


     

    When soft tissue alterations upon immedi- ate restoration were compared to those after delayed restoration, mean papilla shrinkage was about twice as high in the delayed resto- ration group (DRG) as the immediate restora-

    tion group
    provisional
    2009). However, in the following 9 months, papillae in the DRG showed tendency to fill the proximal spaces, and the differences between the groups became smaller. On the other hand, mid-facial soft tissue loss showed little or no variation over time in both groups. The apical displacement of the buccal mucosal level was always about 2–3 times the magnitude in the DRG compared to the IRG during the 1-year observation period. It was concluded that this difference favoured immediate restoration (De Rouck et al. 2009) (Fig. 5a–c).


     


     


     

    Discussion

    This systematic review showed that implants placed immediately in fresh extraction sock- ets yielded a low annual failure rate of 0.82% (95% CI: 0.48–1.39%) translating to a 2-year survival rate of 98.4%.


     

    studies with a mean follow-up period of 3 years or longer were analysed separately, reaching the 4-year implant survival rate of 97.5%. This percentage is comparable to the 96.8% 5-year survival rate of implants sup- porting single crowns reported in a previous systematic review (Jung et al. 2008).


     


     

    Third ITI Consensus Conference (Ha ̈ mmerle et al. 2004), place- ment of implants is categorized by the heal- ing timing following extraction as Type 1 immediate (within 24 h of extraction), Type 2 early (4–8 weeks after extraction), Type 3 early-delayed (12–16 weeks after extraction) and Type 4 late (more than 6 months). This classification is based on the time that elapsed after tooth extraction approximating the soft and hard tissue characteristics of healing sockets according to the morpho- logic, dimensional and histologic changes. In this systematic review, the survival rate of Type 1 placements was subject to evaluation.


     


     


     

    ANTIBIOTICS

    When comparing subjects who had received a single dose pre-operatively, 5–7 days post-opera- tively, and a single dose pre-plus 5–7 days post-operative course of antibiotics, the esti- mated annual failure rates were 1.87%, 0.51% and 0.75% respectively. The annual implant failure rate in patients who were only given the single-dose of antibiotics pre-operatively was statistically significantly greater. This demonstrated that secondary to the prescrip- tion of an effective antibiotic, the duration of usage might be of importance.

    However, these findings should be interpreted with caution, as the number of implants included in the sin- gle-dose pre-operative antibiotics group was substantially fewer.


     


     


     


     

    TEETH EXTRACTED BY PERIO REASONS OR NOT

    Unfortunately, not a single prospective study reported on a group of subjects with teeth extracted solely due to periodontal disease. MUITO INTERESSANTE PARA UM ESTUDO FUTURO


     


     


     

    SITE

    Site (maxilla/mandible)

    Primary stability is of paramount importance for implant survival. Secondary to the dimen- sions of the extraction socket, the relative proportion of the load-bearing lamellar bone vs. cancellous bone also determines primary stability. As the mandible is comprised of a larger proportion of lamellar bone than in the maxilla, it is speculated that implant survival rates are correspondingly more favourable in the mandible. Accordingly, the 933 implants placed in the maxilla had an estimated annual failure rate of 0.73% compared to the 731 implants housed in the mandible, where the annual failure rate was 0.50%. This dif- ference, however, was not statistically signif- icant.


     


     


     

    SITE (anterior/posterior)

    However, as evidenced in this review, the difference in survival rates between implants placed in anterior single-rooted and posterior multi- rooted sockets was negligible.


     


     


     

    LOADING

    Immediately loaded and conventionally loaded implants had reported implant survival rates of 98.2% and 98.5%, respectively after a 2-year observation period.


     


     


     

    Success

    A successful treatment should be the treat- ment with absence of any biological, techni- cal and aesthetic complications. Since all these complications take time to develop, this systematic review assessed a total of nine studies with the mean follow-up time of 3 years or more for the estimation of the suc- cess rates of implant-related therapy.


     


     


     


     

    Biological complications

    Peri-implant mucositis and peri-implantitis have been shown to be prevalent. A system- atic review (Zitzmann & Berglundh 2008) concluded that peri-implant mucositis occurred in approximately 80% of the sub- jects and in 50% of the implants; while peri- implantitis was found in 28% and !56% of subjects and in up to 43% of implant sites.

    Diagnosis of peri-implant diseases required assessment of the presence or absence of bleeding on probing (BOP) in the peri-implant soft tissues, and changes in the level of cres- tal bone (Lang & Berglundh 2011). Three of the nine studies reported on BOP. In one study (Bianchi & Sanfilippo 2004), 31% of the implants showed signs of peri-implant mucositis.


     


     

    Technical complications

    Three studies assessed technical complica- tions, among which two were free from this type of complication and one study (Covani et al. 2004b) had loosening of abutment screws occurring in 9.8% of implants sup- porting single crowns during the 4 years of function. This finding is comparable to that reported in the systematic review on implant-supported single crowns (Jung et al. 2008), which demonstrated a cumulative incidence of screw or abutment loosening of 12.7% in 5 years.


     


     

    Aesthetic complications

    Although not included in previous descrip- tions of implant success criteria (Albrekts- son et al. 1986), the aesthetic aspect of implant-supported restorations has attracted more attention in recent years. Despite the high survival rate of immediate implants, which has been addressed in this system- atic review, soft tissue alterations, espe- cially the buccal marginal mucosal recession, appeared to be inevitable. About 20% of patients in the two included studies with follow-up time ! 3 years (Bianchi & Sanfilippo 2004; Botticelli et al. 2008) suf- fered from restorations with limited aes- thetic outcomes due to buccal soft tissue recession. It was in accordance with a recent follow-up study by Kan et al. (2011), which stated that while the mean aesthetic satisfaction rating by patients was almost perfect (9.9 of 10) at the 1-year recall, 4 of 35 patients (11%) complained of unsatisfac- tory restorations caused by facial gingival recession after a longer period of observa- tion (mean 4 years, range: 2–8.2 years).


     


     

    In recent years, several indices have been developed to provide guidance on objective and comprehensive assessment of aesthetic outcomes of an implant restoration. They include the Pink Esthetic Score (Fu ̈ rhauser et al. 2005), the Implant Crown Aesthetic Index (Meijer et al. 2005) and the modified PES/White Esthetic Score (WES) (Belser et al. 2009). However, none of the long-term stud- ies in this systematic review evaluated the aesthetic outcomes using any of these indi- ces. In the future, more routine utilization of these indices is recommended for aesthetic monitoring.


     


     

    In a recent publication, Kan et al. (2011) followed up the same patient population as the study published in 2003 for 2–8.2 years (mean 4 years) and reported the soft tissue changes beyond the first year evaluation. When compared to the pre-surgical status, mesial and distal papillae lost height of 0.53 mm and 0.39 mm at first year follow- up; and lost 0.22 mm and 0.21 mm at the last examination appointment. The signifi- cantly smaller loss in papilla height over time demonstrated that papillae might have the capacity of continuous regrowing follow- ing implant restoration. It is also important to note that gingival biotype did not signifi- cantly influence the papilla level changes.


     


     


     

    On the other hand, significantly more recession was reported at the facial mucosa at the last examination visit than the first- year follow-up ( 1.13 mm vs. 0.55 mm), and significantly more apical displacement occurred in patients with thin gingival bio- type than those with thick gingival biotype ( 1.50 mm vs. 0.56 mm).


     


     

    The above results showed that although the greatest changes in soft tissues took place in the first 6 months following immediate implant placement and immediate restora- tion, soft tissue remodelling might continue over the years. While mesial and distal papil- lae had tendencies to gain height, buccal mucosal recession might get more pro- nounced over time.


     


     

    Papilla shrinkage and the apical displacement of buccal mucosa were of a lesser extent in immediate restored implant group at the 3-month follow-up. Nevertheless, at the 12-month re-examina- tion, the two groups yielded comparable results when examining the change in papilla height. However, the differences in the posi- tion of the buccal mucosa persisted through- out the 12-month observation period. The authors thus concluded that immediate resto- ration of immediate implants might help limit buccal recession, but more randomized clinical trials of longer follow-up period are required before any definitive conclusions can be drawn on this issue.


     


     


     


     


     

    Conclusion

    1. The estimated annual failure rate of implants placed in extraction sockets was 0.82% (95% CI: 0.48–1.39%) translating to a 2-year survival rate of 98.4% (97.3–99%).

     

    2. The estimated annual implant failure rate was lower after a 5–7 days post-oper- ative antibiotic course (0.51%) than a sin- gle dose of pre-operative antibiotics (1.87%) (P = 0.002).

     

    1. Scarce data concerning biological compli- cations were available in long-term (!3 years) studies. Future research should pay more attention to evaluate peri-implant tissues by periodontal probing and radiographs.


    4. Technical complications were not com-

    monly reported in studies with follow-up

    time of 3 years or more.
    5. About 20% of patients who underwent

    immediate implant placement and delayed restorations suffered from subop- timal aesthetic outcomes due to buccal soft tissue recession in studies with observation period of 3 years or more.

    6. It has been shown in a 1-year RCT that immediate restoration after immediate implant placement might help limit buc- cal mucosal recession, but more long- term RCTs are required to confirm this potential benefit. On the other hand, the influence of factors, such as gingival bio- types and bucco-lingual position of implants, on buccal soft tissue levels should not be overlooked.

    7. To date the use of platform-switching technique to reduce marginal bone resorption is controversial and needs fur- ther investigation. However, good OH is still a pre-requisite for maintaining bone levels in the long run.


     


     


     

    References

    Abrahammsson, I., Berglundh, T., Linder, E., Lang, N.P. & Lindhe, J. (2004) Early bone formation adjacent to rough and turned endosseous implant surfaces. An experimental study in the dog. Clini- cal Oral Implants Research 15: 381–392.

    Adell, R., Lekholm, U., Rockler, B. & Branemark, P.I. (1981) A 15-year study of osseointegrated implants in the treatment of the edentulous jaw. International Journal of Oral Surgery 10: 387– 416.

    Albrektsson, T., Zarb, G., Worthington, P. & Eriksson, A.R. (1986) The long-term efficacy of currently used dental implants: a review and pro- posed criteria of success. The International Journal of Oral & Maxillofacial Implants 1: 11–25.

    Hard tissue change

    As with the soft tissue changes, most of the marginal bone loss was found in the first 3 months following immediate implant placement and immediate restoration. At the end of the first year, the bone loss was gener- ally less than 1 mm. One possible means to minimize the hard tissue changes, in short- tem, could be the use of platform-switching technique, where a wider-diameter implant is restored with a narrower-diameter abutment. In one randomized clinical controlled trial, significantly less mean bone resorption occurred adjacent to platform-switched abut- ment restorations than that found at sites using platform-matched abutments (Canullo et al. 2009a). However, in another RCT, no such differences were demonstrated (Crespi et al. 2009a). Hence, more clinical trials are required to confirm the possible benefits of the platform-switching technique.

    In the long run, good oral hygiene is a pre- requisite for maintaining bone levels. With low plaque and mucositis levels, bone levels even improved (mean gain of 0.2 mm) after

    Lang et al Systematic review on Type 1 implants should pay more attention to evaluate

    peri-implant tissues by periodontal prob-

    ing and radiographs.
    4. Technical complications were not com-

    monly reported in studies with follow-up

    time of 3 years or more.
    5. About 20% of patients who underwent

    immediate implant placement and delayed restorations suffered from subop- timal aesthetic outcomes due to buccal soft tissue recession in studies with observation period of 3 years or more.

    6. It has been shown in a 1-year RCT that immediate restoration after immediate implant placement might help limit buc- cal mucosal recession, but more long- term RCTs are required to confirm this potential benefit. On the other hand, the influence of factors, such as gingival bio- types and bucco-lingual position of implants, on buccal soft tissue levels should not be overlooked.

    7. To date the use of platform-switching technique to reduce marginal bone resorption is controversial and needs fur- ther investigation. However, good OH is still a pre-requisite for maintaining bone levels in the long run.

    Acknowledgement: Thissystematic review was supported by an educational grant of the Osteology Foundation, Luzerne, Switzerland, and the Clinical Research Foundation (CRF) for the promotion of oral health, Brienz, Switzerland. The valuable contributions of Drs M. Lulic and W. C. Tan are highly appreciated.

    Becker, W., Dahlin, C., Becker, B.E., Lekholm, U., van Steenberghe, D., Higuchi, K. & Kultje, C. (1994) The use of e-ptfe barrier membranes for bone promotion around titanium implants placed into extraction sockets: a prospective multicenter study. The International Journal of Oral & Max- illofacial Implants 9: 31–40.

    Bianchi, A.E. & Sanfilippo, F. (2004) Single-tooth replacement by immediate implant and connec- tive tissue graft: a 1-9-year clinical evaluation. Clinical Oral Implants Research 15: 269–277.

    Botticelli, D., Berglundh, T., Buser, D. & Lindhe, J. (2003) The jumping distance revisited: an experi- mental study in the dog. Clinical Oral Implants Research 14: 35–42.

    © 2011 John Wiley & Sons A/S

    59 | Clin. Oral. Impl. Res. 23(Suppl. 5), 2012/39–66

    5 years of et al. 2008).

    implant

    functioning

    (Botticelli

    Conclusion

    1. The estimated annual failure rate of implants placed in extraction sockets was 0.82% (95% CI: 0.48–1.39%) translating to a 2-year survival rate of 98.4% (97.3–99%).

     

    2. The estimated annual implant failure rate was lower after a 5–7 days post-oper- ative antibiotic course (0.51%) than a sin- gle dose of pre-operative antibiotics (1.87%) (P = 0.002).

     

    3. Scarce data concerning biological compli- cations were available in long-term (!3 years) studies. Future research

     

    Araujo, M.G., Sukekava, F., Wennstrom, J.L. & Lindhe, J. (2005) Ridge alterations following implant placement in fresh extraction sockets: an experimental study in the dog. Journal of Clinical Periodontology 32: 645–652.

    Barone, A., Rispoli, L., Vozza, I., Quaranta, A. & Covani, U. (2006) Immediate restoration of sin- gle implants placed immediately after tooth extraction. Journal of Periodontology 77: 1914– 1920.

    Becker, B.E., Becker, W., Ricci, A. & Geurs, N. (1998) A prospective clinical trial of endosseous screw-shaped implants placed at the time of tooth extraction without augmentation. Journal of Peri- odontology 69: 920–926.

    Lang et al Systematic review on Type 1 implants Botticelli, D., Renzi, A., Lindhe, J. & Berglundh, T.

    (2008) Implants in fresh extraction sockets: a pro- spective 5-year follow-up clinical study. Clinical Oral Implants Research 19: 1226–1232.

    Bra ̈ gger, U., Ha ̈ mmerle, C.H. & Lang, N.P. (1996) Immediate transmucosal implants using the prin- ciple of guided tissue regeneration (ii). A cross- sectional study comparing the clinical outcome 1 year after immediate to standard implant place- ment. Clinical Oral Implants Research 7: 268– 276.

    Branemark, P.I., Adell, R., Breine, U., Hansson, B. O., Lindstrom, J. & Ohlsson, A. (1969) Intra-osse- ous anchorag of dental prostheses I. Experimental studies. Scandinavian Journal of Plastic Recon- structive Surgery, 3: 81–100.

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