Sr. No.

Author (year)

Type of study

No. of expanders placed

Placement of expander

Duration

Result

Complications

1

Byun SH, et al. [31]

Prospective randomised control trial

23

Sub-periosteal

4 weeks

1) Mean tissue augmentation was 6.88 ± 1.64 mm vertically.

2) Ultrasonographic measurements of overlying gingiva revealed no thinning after tissue expansion (p > 0.05).

3) Higher vertical bone gain was shown in the experimental group (5.12 ± 1.25 mm) compared with that in the control patients (4.22 ± 1.15 mm;(p < 0.05).

1) Two patients experienced tearing of the silicone shell leading to uncontrolled over-expansion.

2) One patient showed mucosal perforation associated with previous severe scars.

2

Salah El-Abbasey, et al. [49]

Prospective clinical study

8

Sub-mucosal

60 days

1) The mean soft tissue volume after 60 days following the expansion procedure was 834.4 ± 59 mm³ on optical scanning of pre and post-operative cast analysis.

2) No underlying bone resorption was observed due to the placement of the expander sub-mucosally

No complications

3

Elbolke NN, et al. [50]

Prospective clinical study

10

Sub-periosteal

4 weeks

Primary wound closure during bone augmentation procedure

Sufficient bone volume (1.19 cm³) was clinically observed for the placement of dental implants.

Minor perforation at 02 sites close to the incision line measuring 4 × 5 mm and 4 × 7 mm respectively.

4

Bhavsar AK, et al. [51]

Prospective randomised control trial

10

Sub-periosteal

2 weeks

1) No mean gain in Keratinized tissue width: The mean difference from baseline to six months is 0.46 mm ± 0.292 mm which is statistically not significant (p = 0.061).

2) No mean increase in vestibular depth from baseline to six months post-operatively (p = 0.977).

3) No mean increase in keratinized tissue thickness from baseline to six months post-operatively (p = 0.592).

4) No improvement in gingival recession depth from baseline to six months post-operatively (p = 0.693).

5) A good color and texture achieved six month post-operative p < 0.01.

6) Statistically insignificant difference in Plaque index and Gingival Index (p = 0.732, p = 0.147) at baseline and 6 months post-operatively.

7) Osmed^® STE could generate surplus of soft tissue volume but it proved to be ineffective in achieving significant gain in the keratinized tissue. However, the gain thus obtained was not sustained.

5

Mertens C, et al. [52]

Prospective clinical study

11

Sub-periosteal

20, 40, 60 days

1) The expansion time depended on the defect size and expander dimensions.

2) The expanded soft tissue was of normal texture, color, and thickness.

3) No signs of inflammation or thinning of the mucosa were visible.

4) No increase in keratinized mucosa was documented after the expansion phase.

Perforation of the expanders through the oral mucosa, extreme preoperative scarring in the treated areas.

6

Park SH, et al. [53]

Case series

02 (0.15, 0.045 ml)

Sub-periosteal

Case 1: 6 weeks

Case 2: 3 weeks

Tension-free wound closure over the augmented bone without periosteal incision after the use of the expander.

No complications

7

Abrahamsson P, et al. [54]

Prospective clinical study

20

Sup-periosteal

2 weeks

The mean soft tissue profile change was more after placing soft tissue expander.

The mean vertical and lateral augmentation at grafting and implant placement was more after placing soft tissue expander.

2 patients had minor perforation of the soft tissue expander.

8

Kaner D, et al. [55]

Proof of principle study

24

Subperiosteal expander

60 days

1) After expander placement incidence of graft expositions was low (4%).

2) MicroCTs of bone revealed a good ratio of bone volume/tissue volume (mean BV/TV 5 0.1614 0.0582).

02 sites had perforation.

02 sites had infection.

9

Von See C, et al. [56]

Technical note

1

Subperiosteal expander

21 days

Tension-free coverage of the augmented bone without periosteal releasing incision.

No technical problems or inflammatory reactions.

10

Lew D, et al. [57]

Prospective clinical study

10

Subperiosteal expander

-

To avoid injury to mental and inferior alveolar nerves as well as perforation of sinus membrane, a bilateral crestal incisions at canine area with subperiosteal expander with a posterior filling port was used.

One patient complained of continuous pain following the procedure.

Tissue dehiscence in the horizontal ramus area.

Hypoesthesia of the inferior alveolar nerve 6 months postoperatively.

11

Quayle AA, et al. [58]

Prospective clinical study

18

Subperiosteal expander

3-6 weeks

1) The procedure is technique sensitive

2) Predictable ridge augmentation is obtained, dissemination of HA particles is eliminated and significant improvement in denture function is achieved.

1) Transient mental nerve hypoesthesia: Due to direct manipulation of the nerve during the dissection.

2) Wound dehiscence: Due to Staphylococcal infections.

Patient’s medical condition (emphysema) and serial inflations with larger volume was performed.

3) Dehiscence: Pinhead sized defect on the lingual aspect of the augmented ridge due to the over packing to the HA at second stage surgery.

12

Schwartz HC, et al. [59]

Prospective clinical study

17

Subperiosteal expander

2 weeks

1) The expander is placed under direct visualization via an extraoral approach and hydroxy-apatite was injected into this capsule from the intraoral route in class IV mandibular resorption cases.

2) An extraoral approach minimised the mental nerve injury and its complications as well as reduced the hospital time.

3) The extra-oral approach was most reliable and effective method of treatment especially for the geriatric patient population.

1) No infections, no wound dehiscence, and no vascular problems, no deflations or other mechanical failures of the STE.

2) In one case, the STE was overfilled with saline that resulted in ballooning of the STE and corresponding bulge in the HA at that spot. This led to a painful area when a denture was worn which had to be trimmed.

13

Wittkampf Albert, et al. [60]

Case series

60 U-shaped silicone 3.6 mL

Subperiosteal expander

1 month

Sufficient soft tissue augmentation with the use of soft tissue expanders.

1) Two patients had unilateral paraesthesia of the lower lip after insertion of the expander.

2) Two dehiscence occurred immediately after insertion of the STE.

14

Lew D, et al. [61]

Case report

1

Subperiosteal expander

1 month

An advantage of placing the soft tissue expander was increase in quantity and the quality of the soft tissue. The flaps are highly vascular and thick because of the fibrous capsule that forms around the tissue expander.

Two problems faced:

1) The need for an added procedure to insert the tissue expander.

2) Time necessary to incrementally inflate the tissue expander.

15

Lew D, et al [62]

Preliminary report

1

Subperiosteal expander

4-5 weeks

Advantages:

1) A major advantage of the tissue expander is that with the controlled tunnel formation a subsequent vestibuloplasty is not always necessary.

2) Scarred tissue in previously surgically involved areas can be satisfactory dissected for tunnel preparation in augmentation.

3) The morbidity associated with this procedure is less than that encountered with the complete open envelope technique of the maxilla and mandible for class IV reconstruction.

1) Two patients experienced dehiscence of the incision.

2) Pain on injection of the saline.

3) Loss of sensation in the mental region.