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5 At Extraction: Immediate Implant Placement and Alveolar Ridge Preservation

5 At Extraction: Immediate Implant Placement and Alveolar Ridge Preservation

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3  Indications for Augmentation Prior to/at Implant Placement



a



b



d



e



g



h



j



53



c



f



i



k



Fig. 3.2  Root extrusion using a hook and an elastic. (a) Frontal view of upper right lateral incisor.

(b) Labial tissue was lost due to root fracture. (c) Initial radiograph. (d, e) Fabrication of an orthodontic appliance with a hook and elastic. (f) Radiograph of extrusion in process. (g) After the root

was extruded to a certain degree, the exposed portion of the root was cut, and a new hook was

attached to the remaining root. Then, the direction of the extrusion was adjusted with a new hook

and an elastic. Upon the completion of extrusion, the position of the root was fixed and retained for

over 8 weeks. (h) A temporary prosthesis used for a second stage orthodontic extrusion. The position of the hook has been adjusted. (i) Radiograph following completion of the second stage extrusion. (j) Radiograph of the implant placement and provisionalization. (k) Clinical photograph

9 years after the final implant restoration was delivered. Bone and soft tissue around the implant

are stable and healthy



implant placement. The use of CBCT (cone-beam computed tomography) could

also facilitate clinicians’ ability to analyze the facial and palatal bone [15].

Optimal aesthetic outcome with dental implants requires proper facial bone

quantity and quality to achieve proper gingival tissue architecture. It is meaningful

to focus on the facial bone especially in aesthetic zone. A recent systematic review

described buccal horizontal and vertical bone dimensional reductions following



54



S. Suzuki et al.



immediate implant placement into extraction socket [16]. Only a few previous articles regarding immediate placement and provisionalization of single implants also

reported both horizontal and vertical facial bone resorptions around 1 mm or less

after about 1 year or less healing period [17–19]. Therefore, the long-term facial

hard tissue stability following immediate placement and provisionalization of single

implants has not been well documented, nor has short-term stability. Recent findings of facial bone importance related to tooth extraction for immediate implant

placement will be discussed in this following section.

Analysis of “Facial bone alterations on maxillary anterior single implants for

immediate placement and provisionalization following tooth extraction: a superimposed cone beam computed tomography study” (Morimoto COIR 2015) [18].

This retrospective study described the facial bone changes on single implants for

immediate placement and provisionalization procedures in the aesthetic zone via

cone-beam computed tomography (CBCT) (Figs. 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, and

3.10).

A total of 12 failing maxillary incisors were replaced with a single implant

attached to a provisional. Synthetic hydroxylapatite (HA) was used in the gap

between the immediately placed implants and surrounding alveolar bone (Figs. 3.11,

3.12, and 3.13). Approximately 1-year radiographic outcomes focusing on facial

hard tissue on the implants using superimposed CBCT scans were reported in this

study. Facio-palatal cross-sectional scans of another case were shown as a demonstration for parameter measurements (Fig.  3.14). The results using Spearman’s

analysis from this data are as follows. All horizontal components were measured at

the implant platform level (IPL) (Fig. 3.15 and Table 3.1).

1.Statistically significant correlation between postoperative bone thickness (C)

and DOBI (distance between outer surface of preoperative bone to implant surface) (E) (rs = 0.839, P = 0.001) was found. Statistically significant correlation

between postoperative bone thickness (C) and horizontal gap distance (E−A)

(rs = 0.620, P = 0.032) was also found.

2.Horizontal gap distance (E–A) did not influence the amount of facial bone

resorptions (E−C, B−D).

Fig. 3.3 Preoperative

frontal view and periapical

radiograph. Maxillary right

central tooth was failing



3  Indications for Augmentation Prior to/at Implant Placement

Fig. 3.4 Preoperative

frontal view and periapical

radiograph. Maxillary right

central tooth was failing



Fig. 3.5 Immediate

postoperative frontal view

and periapical radiograph.

Maxillary right central

tooth was replaced with

immediate implant and

provisional



55



56

Fig. 3.6 Immediate

postoperative frontal view

and periapical radiograph.

Maxillary right central

tooth was replaced with

immediate implant and

provisional



Fig. 3.7  Frontal view and

periapical radiograph at 1

year. Maxillary right

central tooth was replaced

with immediately placed

single implant and metal

ceramic crown



S. Suzuki et al.



3  Indications for Augmentation Prior to/at Implant Placement

Fig. 3.8  Frontal view and

periapical radiograph at 1

year. Maxillary right

central tooth was replaced

with immediately placed

single implant and metal

ceramic crown



Fig. 3.9  Frontal view and

periapical radiograph at 4

year



57



58



S. Suzuki et al.



Fig. 3.10  Frontal view

and periapical radiograph

at 4 year



3. Preoperative facial bone thickness (A) did not correlate with the vertical or horizontal facial bone resorptions (E−C, B−D).

The healing of peri-implant hard and soft tissue for long-term alterations has not

been thoroughly evaluated, with only a few longitudinal clinical studies [20–22].

However, the outcomes from the published data seem to be stable and satisfied aesthetic results. Another case is shown in Fig. 3.16, as an example of immediate placement and provisionalization of single-implant procedure at 12 months. It also shows

decent 4 years and 1 month passed postoperatively result of cross-sectional CBCT

image on Fig. 3.17. Stable facial bone around the implant has not been visibly lost

for about 4 years. The implant site also has not experienced significant prosthetic

complications during the follow-up period.



3  Indications for Augmentation Prior to/at Implant Placement

Fig. 3.11 Immediate

implant was placed



Fig. 3.12 Synthetic

hydroxylapatite (HA) used

to fill the gap between

immediately placed

implants and surrounding

alveolar bone



59



60



S. Suzuki et al.



Fig. 3.13  HA has filled in

the space and provisional

would be delivered on the

implant



3.5.2 T

 he Role of Preoperative Facial Bone Through Extraction

for Immediate Implant Placement

It is inevitable that failing tooth sites encounter bundle bone issues after extraction.

Some animal studies have shown compromised bone postoperatively [23, 24].

Alveolar ridge models and remodels after tooth extraction [25]. Since immediate

implant placement procedures always include tooth extraction, the prime concern

emerges at aesthetic area.

It is necessary to place bone graft material in the gap between the facial bone and

implant to prevent the subsequent bone resorption even when the gap is very small.

The purpose of the grafting is to maintain the peri-implant hard and soft tissue condition, especially for the facial bone. However, the marginal bone resorption still

occurs, and the bone material does not completely prevent facial bone loss [26, 27].

It may help to retain postoperative facial bone thickness after preoperative original

bone has lost [19]. Therefore, the original facial bone may be able to act as a slow

resorbable membrane to maintain the space for bone regeneration. If the facial bone

thickness is wide enough to possess cortical bone and cancellous bone, the thickness may remain after extraction.

Unfortunately, facial bone thickness in the anterior maxilla is not as great as that

in the molar area. It is natural to develop different approaches to treat aesthetic zone

and posterior area. The average facial bone thickness in the aesthetic zone is usually

reported as less than 1.0 mm [28–30]. The so-called thick facial bone in the anterior



61



3  Indications for Augmentation Prior to/at Implant Placement



a



b



c



d



e



f



12 mm



12 mm



12 mm



10 mm



10 mm



10 mm



8 mm



8 mm



8 mm



6 mm

A



C



6 mm



4 mm



4 mm



2 mm



2 mm



0 mm

(CPL)



0 mm

(CPL)

B



6 mm

E



4 mm

2 mm

0 mm

(CPL)



D



Fig. 3.14  The first case. Facio-palatal cross-sectional scans of implant placement site. Preoperative

image of natural tooth before extraction (left image) and postoperative image of immediately placed

and provisionalized single implant (middle image) at 14 months were superimposed facio-palatally

(right image): (a) Preoperative facio-palatal. (b) Postoperative facio-palatal. (c) Superimposed faciopalatal. (d) Preoperative illustration. (e) Postoperative illustration. (f) Superimposed illustration.

Postoperative image was displayed in gray scale on the superimposed illustration. A. Facial initial

bone thickness measurements and B. facial vertical bone level measurement compared to the superimposed postoperative implant platform level (IPL). C. Facial residual bone thickness measurements and

D. facial vertical bone level measurement compared to the IPL. E. DOBI (distance between outer

surface of preoperative bone to implant surface) measurements



62



S. Suzuki et al.



Preop

4mm



Superimposed

4mm



A



2mm



2mm



0mm

(IPL)



0mm

(IPL)



E



B



A : Preoperative bone thickness 0.54mm

(1.66mm, 0.23mm)

1.46mm

B : Preoperative bone level

(2.39mm, 0mm)



Postop

4mm



C



E : DOBI



2.08mm

4mm

2mm

0mm

(IPL)



E – A : Horizontal gap distance 1.41mm

(4.00mm, 0.65mm)



2mm



4mm



0mm

(IPL)



2mm

D



C : Preoperative bone thickness 1.77mm

(4.43mm, 1.08mm)

D : Postoperative bone level

1.08mm

(2.93mm, 0mm)



(4.43mm, 1.29mm)



E



E



0mm

(IPL)



E – C : Horizontal bone distance -0.26mm

(0mm, -0.80mm)

B – D : Vertical bone level change -0.25mm

(0.56mm, -0.80mm)



Fig. 3.15  Horizontal and vertical facial bone measurements: median (max, min) (mm). Horizontal

measurements were performed at IPL. DOBI (distance between outer surface of preoperative bone

to implant surface)

Table 3.1  Spearman’s rank correlation coefficient analysis was used to evaluate relationship

between the parameters as nonparametric statistics



3  Indications for Augmentation Prior to/at Implant Placement



63



Fig. 3.16  The second case. Facio-palatal cross-sectional scans of implant placement site.

Preoperative image of natural tooth before extraction (left image) and postoperative image of

immediately placed and provisionalized single implant (middle image) at 12 months were superimposed facio-palatally (right image)



maxilla is not actually thick enough to keep the bone structure completely as it is at

preoperative status and starts resorbing after extraction no matter what we apply in

the socket only. Preoperative facial bone thickness had no significant correlation

with horizontal or vertical facial bone resorption [18]. A study showed a similar

result of no significant correlation between maxillary anterior preoperative buccal

bone width and the soft tissue and aesthetic results after immediate implant placement and restoration [31]. Overlay bone graft around the socket in combination

with the intra-socket bone graft procedure might be helpful to overcome the situation. On the other hand, a recent study found a correlation between hard tissue

changes and preoperative bone thickness and gap distance after immediate implant

placement in between maxillary premolars sites [32]. But since more than half of

the implants were placed at the premolar sites and bone width was measured at

1 mm apically from alveolar crest at the surgery, it is hard to compare the results to

our study.



3.5.3 Gap Consideration for Immediate Implant

It had been said that it is not necessary to place any bone materials in horizontal

gap when the gap size is smaller than 1.0  mm. It is currently seen to receive

bone grafting in the gap around implants no matter how small the gap size is.



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