Dimensional Changes In The Supporting Tssues Following Immediate Placement And Restoration Of Dental Implants In The Aesthetic Zone: A Retrospective Study

Dimensional changes in the supporting tissues following immediate placement and restoration of dental implants in the aesthetic zone: a retrospective study Nabil Omar Khzam BDSc Schoo

Dimensional changes in the supporting tissues following immediate placement and restoration of dental implants in the

aesthetic zone: a retrospective study

Nabil Omar Khzam

BDSc

School of Dentistry and Oral Health

Griffith Health Griffith University

Submitted in fulfilment of the requirements of the degree of

Master of Philosophy

March, 2010

ABSTRACT

Aim: The objective of this retrospective study was to assess the survival rate and the hard and

soft tissue response following immediate placement and provisional restoration of tooth implants in the aesthetic zone

single-Materials and Methods: Thirty-four patients (13 male and 21 female) with 37 immediately

placed and restored implants (Astra-Tech® AB, Mölndal, Sweden) were identified as eligible

to participate in this retrospective study Thirteen of these patients returned for the follow-up examination All participating patients underwent the same treatment strategy which was removal of the failed tooth, flapless surgery, immediate implant placement and the connection of a screw-retained temporary restoration Reasons for tooth loss included failed root canal treatment, trauma and tooth resorption Three months following implant placement, the temporary crowns were replaced by the definitive restorations Implant survival rates and hard and soft tissue changes were measured using photographs and peri-apical x-rays The range of observation period was between 12 to 27 months with a mean period of 16 ± 5 months

Results: At 16 ± 5 months, all implants were present at the time of follow-up with no

complications, resulting in an implant survival rate of 100% Radiographic evaluation revealed that there was no statistical difference in bone loss mesially and distally between baseline and follow-up Clinical evaluation of the soft tissue revealed no statistically significant changes in mesial papilla, distal papilla and mid-facial tissue stability throughout the observation period

Conclusions: Within the limitation of this retrospective study, immediate implant placement

and provisional restoration in the aesthetic zone of the maxilla can result in acceptable treatment outcomes as well as stable peri-implant tissues after a follow up period of 16 ± 5 months using the Astra Tech implant system

This work has not previously been submitted for a degree or diploma in any university To the best of my knowledge and belief, the thesis contains no material previously published

or written by another person except where due reference is made in the thesis itself

Table of contents

LIST OF ILLUSTRATIONS ………1

LIST OF TABLES……… 2

ACKNOWLEDGEMENTS 4

1.0 INTRODUCTION………5

1.1 OVERVIEW……… 5

1.2 RESEARCH QUE STION………6

1.3 SIGNIFICANCE OF THE CURRENT STUDY.… ……….6

1.4 OBJECTIVES OF THE CURRENT STUDY……… …… 7

2.0 L ITERATURE REVIEW……… 8

2.1 TERMINOLOGY……….………8

2.2 HISTORICAL BACKGROUND OF IMMEDIATE IMPLANT PLACEMENT AND RESTORATION…… 10

2.3 IMMEDIATELY PLACED AND RESTORED IMPLANT

COMPARED WITH DELAYED IMPLANT PLACEMENT… 11

PLACEMENT AND R ESTORATION STRATEGY…… 12

2.5 REVIEW OF THE LITERATURE AND SEARCH STRATEGY ……… 14

2.5-1 SURVIVAL RATE OF IMMEDIATELY PLACED AND RESTORED IMPLANTS IN THE AESTHETIC ZONE………18

2.5-2 SOFT TISSUE CHANGES FOLLOWING IMMEDIATE IMPLANT PLACEMENT AND RESTORATION 29

2.5-3 HARD TISSUE CHANGES FOLLOWING IMMEDIATE IMPLANT PLACEMENT AND RESTORATION…… 39

3.0 MATERIALS AND METH ODS ……… 46

3.1 PATIENT SELECTION (THE INCLUSION CRITERIA………46

3.2 SURGICAL PROTOCOL AND TECHNIQUES………… 47

3.3 TEMPOR ARY CROWN PLACEMENT……….… 51

3.4 PERMANENT CROWN PLACEMENT ……… 53

3.5 HARD TISSUE MEASUREMENTS……….….54

3.6 SOFT T ISSUE MEASUREMENTS……… 56

3.7 OT HER MEASUREMENTS……… 59

3.7-1 I MPLANT SURVIVAL RATE……… 59

3.7- 2 ASSESSMENT OF INTERDENTAL PAPILLA………… 60

3.7-3 PLAQUE LEVELS ……… 60

3.7-4 GINGIVA L TISSUE BIOTYPE………60

3.8 STATISTICS USED IN THE STUDY……… 60

4.0 RESULTS……….62

4.1 PARTICIPANTS ENROLMENT AND DEMOGRPHICS 62

4.2 HARD TISSUE PARAMETERS……… 65

4.3 SOFT TISSUE PARAMETERS……….70

4.4 JEMT S’ INDEX……… 75

4.5 PRESENCE OF PLAQUE 75

5.0 DISCU SSION………76

5.1 PATIENT ENROLMENT……… …76

5.2 IMPLANT SURVIVAL RATE……… ….77

5.3 HARD TISSUE MEASUREMENTS……… 79

5.4 SOFT TISSUE MEASUREMENTS……… 82

5.5 PLAQUE LEVELS……… 91

5.6 GINGIVAL TISSUE BIOTYPE……….92

5.7 FUTURE CONSIDERATIONS……… 92

6.0 CONCLUSIONS……… 94

7.0 LIST OF REFERENCES……….95

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LIST OF ILLUSTRATIONS

Figure 1 Surgical techniques- failed tooth before extraction………49

Figure 2 Surgical techniques- tooth extraction……….50

Figure 3 Surgical techniques- implant secured in place……… 50

Figure 4 Temporary crown placement………51

Figure 5 Temporary crown placement………52

Figure 6 Temporary crown adjustment……….52

Figure 7 Permanent crown placement- 3 months postoperatively ……53

Figure 8 Permanent crown placement- 6 months postoperatively …….………… 53

Figure 9 Illustration of hard tissue measurements on periapical x-ray……….55

Figure 10 Illustration of the measurements of the soft tissue on photographs…… 58

Figure 11 Level of mid-buccal gingiva at placement of temporary restoration……85

Figure 12 Level of mid-buccal gingival at the follow-up……….86

Figure 13 Level of mesial papilla at the placement of the temporary restoration….89 Figure 14 Level of mesial papilla at the follow-up……….……… 89

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LIST OF TABLES

Table 1 Selected studies reporting on immediately placed and provisionally restored single

maxillary implants in the aesthetic zone……….17

Table 2 Implant survival rates for immediately placed and restored implants in the aesthetic zone……… 28

Table 3 Reported soft tissue dimensional changes following immediate implant placement and restoration in the aesthetic zone……….… 38

Table 4 Reported hard tissue dimensional changes following immediate implant placement and restoration in the aesthetic zone……… … 45

Table 5 Tooth types and reason for tooth extraction……… 64

Table 6 Overview of clinical data……… 64

Table 7 Bone level changes (presented as percentage change)……… 65

Table 8 Frequency analysis of hard tissue changes (mesial measurement in millimetrs) 66

Table 9 Frequency analysis of hard tissue changes (mesial measurement in percentage) 67

Table 10 Frequency analysis of hard tissue changes (distal measurement in millimetrs) 68

Table 11 Frequency analysis of hard tissue changes (distal measurement in percentage……… 69

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Table 12 Soft tissue level changes (presented as percentage

change) 70

Table 13 Frequency analysis for mesial papilla change in percentage 71

Table 14 Frequency analysis for distal papilla change in percentage 72

Table 15 Frequency analysis for mid-facial change in percentage 73

Table 16 Changes in soft tissue levels in millimetres 74

Table 17 Changes in the interdental papilla 75

Table 18 Implant survival rates, as reported in studies using similar treatment protocol 78

Table 19 Changes in hard tissue (mesially and distally) as reported in published studies 81

Table 20 Changes in soft tissue levels (mid-buccal aspect) as reported in published studies……… 87

Table 21 Changes in soft tissue (mesial and distal papillae) as reported in published studies ……….…………90

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ACKNOWLEDGEMENTS

I wish to express my warm appreciation and thanks to:

Prof Saso Ivanovski, for his continued guidance and commitment toward this research project

A/P Nikos Mattheos, for his kind assistance and professionalism in allowing

me to move forward with my research project

A sincere acknowledgment goes to my wife, Dr Sondus Abuoun for her

extraordinary understanding, selfless efforts and genuine friendship

My sponsor, the Libyan embassy in Canberra, with special thanks to Dr Omran Zoud and his staff for the enormous support

Sir Geoffrey Cresser for his help in the proof reading and editing of this thesis

Mrs Joy Robertson and Ms Leanne Pockley, for their daily help and assistance

Finally, I would like to dedicate this thesis to my parents

Osseointegration was first described by Brånemark [1], who defined it as a direct connection between living bone and a load-carrying endosseous implant, as observed at the light microscopic level Subsequently, osseointegration was defined as a direct structural and functional connection between living bone and the surface of a load-bearing implant [2]

The original implant placement protocol involved a load free period after implant placement of 3 and 6 months in the mandible and maxilla respectively [3] It was postulated that a load free period would assist in minimizing micromotion, thus reducing the possibility

of fibrous tissue formation or encapsulation and providing an environment conducive to osseointegration [4]

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The original ‘Branemark protocol’ also involved placement of the implant following complete healing of the tooth extraction socket The implant was then left to heal for six months prior to prosthesis attachment in order to allow for osseointegration to occur [2] During this healing period, the implant was submerged under the oral mucosa, necessitating a second surgical procedure to expose it, which was followed by a period of soft tissue healing prior to construction of the prosthesis Although this treatment protocol demonstrated good survival rates, it was also very lengthy

With the increased popularity of dental implants, demand has grown for treatment completion in a shorter period of time compared with the original ‘Branemark protocol’ This has led to the introduction of new surgical and prosthetic protocols One such technique involves the immediate insertion of the implant at the same time as tooth extraction (immediate implant placement) and subsequent restoration of the implant with a provisional prosthesis within 24 hours (immediate restoration) This treatment protocol is most likely to

be utilised in the aesthetic zone of the patient’s dentition involving the anterior maxillary teeth [5]

1.2 Research question

The research questions are:

1) What is the survival rate associated with this clinical procedure?

2) What are the soft and hard tissues dimensional changes associated with immediately placed and restored implants in the aesthetic zone?

1.3 Significance of the current study

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The assessment of clinical outcomes associated with immediately placed and restored implants in the aesthetic zone will provide vital information to the clinical practitioner regarding this increasingly popular treatment modality

1.4 Objectives of the current study

The objectives of the current study were to retrospectively assess the survival rate, as well as soft and hard tissue dimensional changes associated with immediately placed and restored implants replacing single teeth in the aesthetic zone after a minimum follow up of 12 months

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2.1 Terminology

There has been inconsistency in the use of the key terms “immediate placement”,

“immediate loading” and “immediate restoration” in the literature Various authors have defined the terms differently leading to misinterpretation of results and miscommunication of outcomes For instance, a number of authors [4] define “immediate loading” as any restoration that is visible in the oral cavity even if it does not have any occlusal contact with the opposite dentition They argue that lip and cheek pressure, as well as tongue movement and food particles coming into contact with the implant will place a load on the implant, and hence the definition of immediate implant loading should apply Furthermore, they consider that flexure stress and strain occurring in the jaw during opening and closing movement of the mouth generates functional loads on implants even when they are not in direct occlusal function [4] Therefore, due to this discrepancy it is important to outline the terms and definitions which clearly differentiate between different clinical implant loading and placement protocols Cochran et al [6] defined the various loading protocols as follows:

 Conventional loading: Defined as the restoration of implants after a healing period of 3 and 6 months in the mandible and maxilla respectively

 Immediate restorations: Defined as any restoration placed within 48 hours of implant insertion but with no contact with the opposite dentition in both centric and eccentric occlusion The rationale behind the 48 hour window is not based on any biological consideration but is purely related to the practicality and logistics associated with the ability to perform the restorative placement at the same setting as the surgical implant placement (which is not

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always possible)

 Immediate loading: Defined as the placement of the restoration in direct contact with the occlusal plane of the opposing teeth within 48 hours of implant insertion

 Early loading: Defined as the placement of a restoration in direct contact with the opposite dentition more than 48 hours, but less than three months, after implant insertion

 Delayed loading: Defined as the delivery of the prosthesis some time after the conventional healing period of three and six months in the mandible and the maxilla respectively

Recently, a modification of the above definitions [6] has been recommended [7]:

 Conventional loading of dental implants is defined as the restoration of the implant more than 2 months after implant placement

 Early loading of dental implants is defined as loading between 1 week and 2 months following implant placement

 Immediate loading is defined as being less than 1 week following implant placement

 A separate definition for delayed loading was no longer considered necessary

In terms of implant placement protocols, the following classification can be utilised [8]:

 Type 1 or “Immediate implant placement”: The implant is placed immediately following tooth extraction

2.2 Historical background of immediate implant placement and

restoration

Several investigators have investigated the clinical outcomes resulting from immediate implant placement and/or restoration of dental implants The concept of immediate implant placement (without restoration) was introduced by Lazzara[9] in 1989, with the rationale of reducing treatment time Subsequently, Gomez et al [10] in 1997 reported a 98.84% five year success rate in eighty three implants placed immediately after tooth extraction without immediate restoration

In terms of immediate restoration of implants, Tarnow et al[11] in 1997 reported a

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97.1% success rate using a protocol that involved the placement of implants in healed sockets

in both jaws and immediately restoring them without any contact in both centric and eccentric occlusion In 1998, Wohrle[12] was the first clinician who used immediate implantation in fresh extraction sockets in the anterior area of the maxilla and placed a temporary crown immediately after surgery The outcome of this study was a 100% success rate in fourteen patients and acceptable aesthetic outcome was reported

2.3 Immediately placed and restored implant compared with

delayed implant placement

The traditional implant placement protocol, where the implants are inserted into the completely healed socket, has shown a high clinical survival rate However, efforts have now focused on improving the aesthetic outcome of implant therapy, especially in more demanding aesthetic circumstances The immediate implant placement and immediate restoration treatment protocol has been developed based on the rationale that it preserves both soft and hard tissue architecture around the immediately installed implant Hui at el [13] compared implants placed according to the conventional placement protocol with those placed into extraction sockets and immediately restored His study concluded that both groups showed promising initial results in terms of patient satisfaction and aesthetic outcome Another study carried out by Guirado at el [14] revealed that immediate implant placement in fresh single tooth extraction sites followed by immediate restoration with provisional crowns had high survival rates comparable to the conventional placement protocol Conversely, Chaushu et al [15] showed that immediate placement and restoration of single tooth implants carried a 20% risk of failure This outcome may be interpreted as being a result of using press-fit rather than conventional screw type implants Most recently, Paolantonio et al [16]

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showed that immediate implant placement minimized post extraction bone resorption, this maintaining the hard tissue topography close to its original contour before extraction and had

a positive influence on the soft tissue architecture around the restored implant

In summary, there are several possible benefits of immediate placement compared with conventional placement Firstly, there are fewer surgical procedures resulting in less patient morbidity Secondly, soft tissue stability around the implant supported restoration is improved Thirdly, time is saved as both post-extraction healing and osseointegration events take place at the same time

restoration strategy

Immediate placement and restoration of implants in the aesthetic regions appears to offer a success rate that is equal to that associated with conventional treatment However, case selection is essential and there are several criteria which need to be considered These criteria include:

 Morphology and configuration of the tooth socket, soft tissue contour is determined

by the underlying bone Therefore any bone defects will potentially compromise the aesthetic outcome of the treatment [17], [18], [19], [20], [21] and [22]

 Gingival tissue configuration, the gingiva should be of healthy and symmetrical harmony to allow an aesthetic outcome Any gingival disease or defect would compromise the final outcome

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 Gingival tissue biotype, in general, a thick gingival tissue biotype is preferable in the aesthetic zone as it can mask the metallic hue of the implant neck, as well as being more resistant to recession In contrast, the thin gingival tissue biotype is more prone to recessionand tissue discoloration In these situations, surgical and prosthetic planning before implant placement is very critical, and the implant may be placed more palatally in order to have a thicker buccal volume of hard and soft tissue in order to reduce the problem of metal showing through the tissues[23], [24], [25] and [26]

 Smile line, patients with a high smile line who routinely show their gingival margin are a greater aesthetic risk than patients who don’t show their smile line during speech and laughter

 Presence of pathology/infection, poor oral hygiene and microbial plaque are causative factors that result in the occurrence of peri-implant infection and implant loss Therefore, evaluation of the oral hygiene of the patient is a mandatory step before commencing immediate implant placement and restoration [27] and [28]

 Smoking, studies show that smoking has a deleterious effect on implant integration in the short term and on the peri-implant tissue health in the long term These effects may be exacerbated in an immediate implant placement and restoration treatment protocol [29], [30], [31], [32], [33] and [34]

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2.5 Review of the literature and search strategy

The following criteria were considered in the process of selecting studies of immediate implant placement and restoration for this review:

1 Types of studies: all longitudinal studies were eligible for inclusion – randomized controlled trials, controlled clinical trials, cohort studies, case control studies and consecutive case report series Only those studies that included 6 patients or more were selected A minimum follow up time of 1 year was set as an inclusion criterion Only studies published in English were included

2 Type of treatment modality (intervention): immediate implantation into the fresh extraction socket followed an immediate placement of a provisional restoration in the aesthetic zone

3 Outcomes that were measured:

Implant survival rate

Patient satisfaction

Peri implant soft tissue changes

Peri implant hard tissue changes

Gingival biotype and its relation to recession

For this review, a detailed search strategy was used for each selected database in order to identify all of the articles published in relation to the stated aims of this review The search strategy used was a combination of free text terms and MeSH* terms The searched data bases were:

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# PUB MED, EBSCOhost and Ovid arms of MEDLINE

# CENTRAL (The Cochrane Central Registar of Controlled Trials)

# Science Direct

The terms used in this search were:

Dental Implants, Oral Implants, immediate placement, immediate restoration, Immediate Provisionalization, aesthetic, single tooth replacement, single tooth in the maxilla and extraction socket

The search strategy was as follows:

(Single Tooth* OR teeth*) AND Maxilla* AND (Immediate OR Immediate placement, OR Immediate Implantation, OR immediate restoration, OR extraction socket)

Single Tooth* AND Maxilla* AND

Single Tooth* AND maxilla * AND

Single Tooth* AND Maxilla* AND (OR provisionalization)

Single Tooth* AND Maxilla* AND

Furthermore, the search was complemented by checking the references of the selected articles for additional useful publications Also a manual search was carried out of the following major journals in dental implantology: International Journal of Oral and Maxillofacial Implants, Clinical Oral Implants Research, Clinical Implant Dentistry and Related Research

The search strategy initially yielded 80 articles From these, 17 articles were considered

3) Implantation in the mandible or maxilla without any differentiation (7 articles): [45], [46], [52], [56], [59], [74] and [75]

4) Case reports of immediately placed and loaded implants (16 articles): [45], [47], [50], [52], [53], [59], [76], [77], [78], [79], [80], [81], [82], [83], [84], and [85]

5) The 17 included articles, alongside a description of the study type, implant system used and the numbers of included patients/implants are outlined in Table 1

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*Delayed implant placement

RCT, randomized controlled trial; CS, case series

Table 1 Selected studies reporting on immediately placed and provisionally restored single maxillary implants in the aesthetic zone

Patient/implant

Implant systems

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2.5-1 Survival rate of immediately placed and restored implants

in the aesthetic zone

The term ‘implant survival rate’ is defined as the percentage of implants that present

at follow up [99], although it is important to note that the status of the implant not specified [100] Conversely, implant success is defined as the presence of the implant at the end of an observation period, along with the absence of progressive bone loss, radiolucency, mobility (clinically), pain, discomfort and/or neuro-sensory changes [101]

All studies selected for this review reported on the survival rates of immediate implant placement and restoration in the aesthetic zone A review of these studies in relation

to the implant survival outcome is presented in this part of the review

The primary goal of Wohrle‘s (1988) investigation was to predictably maintain soft tissue morphology in the aesthetic zone of the maxilla and avoid postextraction complications related to hard tissue resorption and soft tissue recession Fourteen implants were placed in fourteen consecutive patients (14/14) Five of the implants were placed in the lateral incisor position and the other nine were placed in the central incisor position The implant system used was Replace (Steri-Oss, Yorba Linda, CA, USA) and both screw-type cylindrical and screw-type tapered implants were used All surgical and prosthetic procedures were carried out by the same clinician None of the implants were lost with an overall survival rate of 100% in a follow-up period ranging from six to 36 months [12] In 2001, Hui et al [13] proposed immediate placement and restoration as a treatment modality aimed at provide an immediate and cost effective solution for restoring a single missing tooth in the maxillary aesthetic region This prospective clinical investigation included twenty-four participants,

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thirteen of which had immediate implant placement and restoration while eleven received implants in healed sites All of the implants were placed in the maxillary aesthetic region The overall follow-up period ranged from one to 15 months According to the authors, the desirable goals of patient satisfaction, good aesthetic outcome and reduced treatment cost were achieved in this treatment protocol The implant system used was Brånemark (Nobel Biocare AB, Göteborg, Sweden), and the implant types were both screw-type tapered and cylindrical The implant survival rate of this study was 100% within the reported one to 15 months period of follow-up for both groups

Guirado et al [14] conducted a prospective study involving eighteen implants in thirteen patients using the Osseotite system (3i, Implant Innovation, USA) All of the implants were placed in the maxillary aesthetic zone with nine placed into fresh extraction sockets and nine into healed sites The observation period was one year and a 100% implant survival rate was reported Advantages associated with the one stage protocol included immediate aesthetics, comfort and no need for surgical re-entry Furthermore, the interdental papilla adjacent to the implants were preserved leading to optimal aesthetic results The author concluded that the placement of implants immediately into fresh extraction sockets was a viable and predictable treatment alternative associated with a high survival rate

Chaushu et al [15] hypothesised that the immediate restoration of implants replacing single missing teeth could be successfully achieved following immediate implant placement into fresh extraction sockets, as well as healed sockets This study included twenty-six consecutive patients who received twenty-eight implants Nineteen implants were placed into fresh extraction sites, and nine were placed into healed sites The two implant systems used

in this study were Steri-Oss, (Yorba Linda, CA, USA), (21 implants) and Alpha Bio

hydroxy-20

apatite coated cylindrical implants, (7 implants) The follow-up period ranged from six to 18 months, with a mean of 13 months for the immediately placed implants and 16.4 months for implants placed into healed sites There were three failures among the immediately placed and restored implants, all occurring during the first month following implantation, resulting

in an overall survival rate of 82.4% for this group The patients who lost their implants were over 50 years of age In each of these patients there was initial discomfort, followed by moderate pain and implant mobility Another two patients experienced swelling with a purulent exudate On the other hand, all of the non-immediate implants survived the healing period without any loss leading to a 100% short term survival rate for this group All surviving implants of both groups were free from any complications The results of this study revealed a 100% success rate in the healed sites but about a 20% failure rate associated with immediate placement into extraction sites The use of a press fit cylindrical implant type may explain in part the low success rate in the immediate group

In another prospective clinical study carried out by Kan et al [87] the implant survival rate, peri-implant tissue response, aesthetic outcomes and patient satisfaction were evaluated This study included thirty-five patients with a mean age of 36.5 years, and each patient received a single flat platform, screw type tapered implant (Replace, Nobel Biocare, Yorba Linda, CA, USA) All of the implants were placed into fresh extraction sockets The implant survival rate was 100% after a follow-up period of one year All of the patients were satisfied with the aesthetic outcome of their restorations The author concluded that a favourable implant success rate, peri-implant tissue response and aesthetic outcome can be achieved with immediately restored single implants placed in the maxillary aesthetic zone In a more recent investigation with similar aims, the same author conducted another study, but instead of using flat platform implants, a scalloped implant platform design was used [93] The introduction

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of this new platform design aimed to replicate the irregular bony topography which results after tooth extraction, thus preventing future bone loss The implant system used was (Nobel perfect; Nobel Biocare, USA) Thirty-eight implants were placed in twenty-nine patients with

a mean age of 45.1 years Fifteen implants were placed into healed sites while the other twenty-three were placed into fresh extraction sites At the one year follow-up all implants remained in function with an overall survival rate of 100%

The stated purpose of Groisman‘s study [86] was to evaluate the survival rate of two tapered implants which were immediately placed and restored in the maxillary aesthetic region The diameter of the inserted implants was selected based upon the size of the tooth sockets (Nobel Biocare, Yorba Linda, CA, USA) The observation period was two years, but only ten implants were followed up for the full 24 months At the conclusion of the follow up period, 6 implants had been lost resulting in an overall implant survival rate of 93.5% According to the author, one implant was lost due to trauma and two others due to overload

ninety-in patients with a deep overbite The cause of failure for the other three implants was not described The study concluded that immediately placed and restored tapered implants did not show any adverse effects with regards to osseointegration Favourable aesthetic outcome was achieved in eighty-two of 92 cases, representing 89% of the total number

Lorenzoni et al [88] evaluated the clinical outcomes of immediately placed and restored stepped-screw type grit-blasted, acid etched FRIALIT-2 Synchro implants one year after placement in the maxillary anterior region In the course of this study, nine patients received

12 implants; eight of which were placed into fresh extraction sites and four were placed into healed sites All implants were immediately restored with acrylic resin provisional crowns,

up period ranged from twelve to thirty months All patients received friction-fit temporary crowns instead of cemented crowns After a mean duration of four and half months following the surgical procedure, the permanent crowns were placed Implant survival, along with hard and soft tissue changes, was recorded at follow up with an overall survival rate of 96.4% One patient, a heavy smoker, lost one implant within one month of surgical placement Furthermore, unfavourable soft tissue recession was associated with one implant However, most of the restorations maintained an aesthetic gingival contour and architecture Eleven of the 28 provisional restorations needed further treatment; six required replacement during the temporization period and five required re-cementation after becoming loose The study concluded that immediate temporization of maxillary single-tooth implants could be both safe and predictable and the procedure appeared to yield favourable soft tissue aesthetic outcomes The authors concluded that this treatment protocol utilizing the Astra Tech ST implant system resulted in predictable outcomes following immediate implant placement and restoration with provisional acrylic resin crowns

In a study using two different implant systems, NT Osseotite (3i Implant Innovations Inc) implants and Frialit-2 (Friatec AG, Mannheim- Germany), forty-three single implants were inserted in thirty-eight patients A survival rate of 100% was reported following an

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observation period of 24 months The patients were divided into two groups, immediate and delayed implant installation The first group received twenty-eight immediately placed implants while the rest of the patients received delayed implant placement [90]

In another study using the Straumann TE implant system (Institute Straumann AG, Waldenburg, Switzerland), twenty-two single implants were immediately restored and followed up for one year Three of these implants were placed into healed sockets while the rest were placed immediately into fresh extraction sockets [91] The temporary crowns were completely out of occlusion in both centric and eccentric positions Screw-retained temporary crowns were constructed to avoid the use of adhesive cements which may interfere with the healing process during osseointegration [16] Nineteen of the implants were placed in the maxilla and three in the mandible Premolars were the most common teeth to be replaced (13 teeth), followed by central incisors (6 teeth) and lateral incisors (3 teeth) The study reported

a survival rate of 100% All the implants were successful according to the criteria of Smith and Zarb[101] Within the limits of this investigation, immediate restoration of single-tooth implants placed in fresh extraction sockets was considered to be an acceptable option

In a study conducted by Ferrara et al [92], thirty-three consecutive patients with a mean age of 41 years received a single implant supported crown to replace a missing maxillary tooth at the time of tooth extraction The implant system used was Frialit-2 (Friatec AG, Mannheim- Germany) Thirteen central incisors, nine lateral incisors, four canines and seven first premolars were included The follow-up period ranged from one to four years There were two implant failures resulting in an overall success rate of 93.9% One implant did not integrate while another one became unstable as a result of trauma

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Canullo and Rasperini [94] investigated immediately placed and restored implants using the TSATM series 5 Defcon® Impladent (Barcelona, Spain) system A platform switching design, whereby the trans-mucosal abutment was narrower than the implant platform, was used in order to maintain the surrounding peri-implant tissue dimensions Ten 6 mm diameter implants were immediately placed into fresh extraction sockets in the aesthetic zone of the maxilla A provisional 4 mm diameter trans-mucosal abutment was subsequently connected to the implant body, and a provisional crown was adapted and adjusted for non-occlusal contact

in centric as well as eccentric positions The definitive restoration was completed three months following implant placement Nine patients with 10 sites were treated and the follow-

up period was 22 months All 10 implants were found to be clinically osseointegrated with a 100% survival rate

Hall et al [95] evaluated the use of immediately placed and temporized tapered implants (Southern Implants Ltd, Irene, South Africa) to replace single teeth in the anterior maxilla The participants’ mean ages were 43.25 years and the implants were followed up for one year The patients were randomly divided into conventional (control group = 14 patients) and immediate restoration groups (test group = 14 patients) The test implants received provisional screw-retained crowns within four hours of implant placement, while in the conventional restoration group; temporary crowns were placed after 26 weeks In the immediate placement/restoration group, one implant was lost for an overall survival rate of 93%, while in the control group two implants were lost at the one year follow-up This investigation concluded that the immediate placement and restoration protocol used in this study resulted in similar outcomes as conventionally restored implants

The main aim of Palattella‘s study [96] was to compare the immediate restoration of

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implants placed using an immediate and a delayed placement protocol Sixteen patients with

a mean age of 35 years were treated for single-tooth substitution in the anterior maxilla The patient population was randomly divided into two groups In the first group (test group), eight patients received nine implants placed and restored at the time of tooth extraction The second group (control group) of eight patients received nine implants placed eight weeks after tooth removal All implants underwent immediate restoration All patients received the same implant system in the form of tapered effect (TE) Straumann implants (Institute Straumann

AG, Waldenburg, Switzerland) Marginal bone resorption, papilla index and the position of mucosal margin were assessed at the time of provisional restoration fabrication (within 48 hours after implant placement) and at a two year follow-up visit No implants were lost, resulting in a 100% survival rate for both groups after twenty-four months The results suggest that immediate implant placement and restoration without functional loading may be considered a valuable therapeutic option for selected cases of single-tooth replacement in the aesthetic area

A recent study conducted by De Rouck [97] also evaluated implant survival rates, soft and hard tissue changes and patient satisfaction in relation to immediately placed and restored implants in the anterior maxilla Thirty consecutive patients underwent the same treatment protocol which consisted of flap elevation followed by immediate implant placement and connection of a screw-retained provisional restoration The implant system used was Nobel Replace Tapered (Nobel Biocare, Goteborg, Sweden) Clinical and radiographic assessments were carried out at 1, 3, 6 and 12 monthly intervals The results revealed that one implant failed in the first month of follow up resulting in a survival rate of 97% It was concluded that this particular protocol can be considered to be a valuable treatment modality in carefully selected patients

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Ribeiro et al [98] compared immediately placed implants with those placed into healed sockets Eighty-two implants were placed in the maxilla of forty-six patients, with forty-six implants inserted using the immediate placement protocol while the other thirty-six were inserted using the delayed placement protocol The implant system used for this investigation was Conexao Sistema (de Protese Ltda, Sao Paulo, SP, Brazil) Success of implant integration was assessed according to the criteria described by Albrektsson [102] The follow-up period ranged from 18 to 39.7 months Three of the implants from the immediate placement group failed, resulting in a survival rate of a 93.5% The delayed placement group had an overall

success rate of 100 % The differences in survival rate between the two groups were not

statistically significant [98]

Summary and conclusion:

Table 2 shows the results of studies which investigated the survival rate of immediately placed and restored implants in the aesthetic zone An implant survival rate of 100% was described in all except five studies, namely, Chaushu et al [15] achieved osseointegration in 78.6% of the cases while Groisman [86] achieved 93.5% and Ferrara et al [92] reported 93.9% In two other recent studies, the reported implant survival rates were 93% and 97% respectively [95, 97] Therefore, the majority of the studies reported that the implant survival rate following immediate placement and restoration is comparable to that achieved using conventional therapy

Based on the results of studies carried out over relatively short time periods, the replacement of single teeth in the maxillary aesthetic region can be predictably achieved using an immediate implant placement and restoration protocol However, studies with a

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longer follow up are needed to further document survival outcomes of this treatment modality

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*Delayed implant placement

RCT, randomized controlled trial; CS, case series

Table 2 Implant survival rates for immediately placed and restored implants in the aesthetic zone

Patient/implant

Follow up period (months)

lost

Implant survival rate %

(1998)

Cylindrical tapered

The gingiva consists of two functional portions, the keratinized masticatory component which faces the oral cavity and the non-keratinized area facing the tooth, which is involved in the attachment of the gingiva to the tooth

Anatomically, the normal mucosa surrounding the tooth is subdivided into three main components:

 The marginal gingiva or free gingiva is pink in colour and has a firm consistency It forms the unattached part of the gingiva It extends from the top of the gingival margin to the free gingival groove which is localized at the level of the cemento-enamel junction (CEJ) The free gingival groove separates the free gingiva from the attached gingiva The free gingiva is separated from the tooth via gingival sulcus or crevice [103]

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 The interdental papilla is that part of the gingiva which occupies the region between adjacent teeth or implants It has different shapes and forms on anterior compared to posterior teeth Its shape is determined mainly by the contact point of the adjacent teeth, the width of the proximal surface of the teeth and the position of the cemento-enamel junction In the anterior region of the dentition it is pyramidal in shape, while in the posterior region it is tent-shaped with wider extension in the bucco-lingual direction This is a result of the presence of contact areas rather than contact points in the premolar-molar region [103]

 The attached gingiva extends from the free gingival groove to the mucogingival line The mucogingival line separates the attached gingiva from the alveolar mucosa The attached gingiva is firmly attached to the underlying periostum of the alveolus [103] It is firm in texture, coral pink in colour and has small depressions on the surface called stippling There

is no mucogingival line present on the palate, as the entire hard palate is covered by attached masticatory mucosa

The peri-implant mucosa is the soft tissue which immediately surrounds the dental implant Following the placement of a transmucosal healing abutment, a soft tissue seal begins to form around the implant This soft tissue seal will act as a barrier which protects the underlying structures, thus supporting the establishment and maintenance of osteointegration [103]

The appearance and dimensions of the buccal soft connective tissue depends mainly

on the anatomy of the underlying bony tissue Indeed, the final architecture and form of buccal tissue is determined by the position and inclination of the fully erupted teeth [104] A study by Ochenbein et al [105] showed that the anatomy of the gingiva is related mainly to

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the shape of the alveolar bone crest It was suggested that two types of gingival biotype exist, namely a pronounced scalloped (thin) and a flat (thick) biotype Individuals with the thin biotype have delicate cervical convexity and a small interdental contact area which is located very close to the incisal edge, while the crown form of the associated teeth is slender and tapered The incisor teeth surrounded by this type of biotype have a thin free gingiva and the outline is highly scalloped [106] Furthermore, the papillae associated with a thin biotype are long and narrow In contrast, the flat gingival biotype is associated with square crowns with prominent cervical convexity The contact area of the thick biotype is boarder and located more apically resulting in short interdental papillae

A study measuring the thickness of gingiva using bone sounding technique [87] reported that the thickness of gingiva varied between subjects of different gingival biotypes This study concluded that the thick gingival biotype has more soft tissue volume than the thin biotype on the buccal and interdental aspects

The presence or absence of the interdental papilla may be assessed visually If there is

a space apical to the contact area, which is characterised by a black triangle, the papillae are considered incomplete On the other hand, if there is no space apical to the contact area, the papillae are considered complete Tarnow et al [107] measured the distance between the interdental contact point and the crest of the interdental alveolar bone in order to determine if there is a relationship between this dimension and the height of the interdental papilla The results of this study showed that the papilla was always complete when the distance from the contact area to the crest of interproximal bone was less than or equal to 5 mm However, when this distance was more than 5 mm, about half of the cases had incomplete papilla fill

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There must be gentle handling of the peri-implant soft tissues during surgical implant placement due to their delicate nature Any traumatic manipulation of these areas may compromise the aesthetic outcome The peri-implant soft tissue should be in complete harmony with that of the surrounding tissues in terms of colour, form, shape and contour, resulting in restorations that mimic the lost dentition In recent years, the success of dental implant restoration is no longer judged solely by successful osseointegration, with aesthetic outcome become of increasingly importance This is particularly the case when implants are placed in the aesthetic zone, and this represents a challenge to both surgeons and restorative dentists The peri-implant soft tissue architecture is one of the most important factors in determining the aesthetic outcome of implants placed in the aesthetic zone, especially in patients with a high lip line

This review identifies and discusses studies which measured the soft tissue outcomes of immediately placed and restored implants in the anterior maxilla The pioneering study of Wohrle [12] assessed soft tissue changes in 14 consecutive cases involving immediate implant placement and restoration during follow up period ranging from 9 to 36 months The outcome of this study revealed that only two cases showed facial recession of 2 mm or more, with the remaining cases demonstrating stable soft tissue outcomes

In the study by Cornelini et al [91] measurements of the soft tissue were taken at the time

of implant placement and after one year of follow up The soft tissue parameters measured included a mucositis score, mucosal margin level, variation of gingival level and variation of papillary position According to Jemt‘s index, no scores of 0, 1 or 4 were found [108] Twenty-seven of the papillae received a score of two which meant that at least half of the height of interdental papillae was present The other seventeen papillae presented with a score