Minimally Invasive Single Implant Treatment (M.I.S.I.T.) based on ridge

preservation and contour augmentation in patients with a high aesthetic risk

profile: one-year resultsCosyn J et al, JCP 2015; 42: 398–405.

Shilpa Shivanand

II MDS

INTRODUCTION• Immediate implant placement is a popular treatment concept

in contemporary practice. • Predictable results can be achieved in patients with an intact

buccal bone wall and thick gingival biotypeCosyn et al 2012

• However, clinical reality shows that a buccal bone dehiscence or fenestration is common following tooth extraction.

• In addition, a thin scalloped gingival biotype can be found in about one-third of the population.

De Rouck et al 2009

• Given their risk profile, these patients are usually treated in a more conservative way.

• This includes flap surgery for implant placement after a post-extraction healing period of at least 6 weeks, often combined with GBR in case of bone deficiency.

Buser et al 2008, Cosyn 2012, De Rouck 2009• Although these procedures have been shown to be

predictable from a clinical and radiographic point of view, multiple studies have shown poor aesthetic results, especially after bone augmentation

Cosyn et al 2012, den Hartog et al 2013

Minimally Invasive Single Implant Treatment (M.I.S.I.T.) ?

AIM

• The goal of this prospective study was to explore the outcome of Minimally Invasive Single Implant Treatment (M.I.S.I.T.) based on ridge preservation and contour augmentation in patients with a buccal bone dehiscence and/or thin-scalloped gingival biotype.

• Mid-facial recession at the failing tooth has been considered another aesthetic risk factor

Martin et al 2007• Hence, another goal was to explore the outcome of M.I.S.I.T.

in patients with mid-facial recession at the failing tooth.

MATERIALS AND METHODS

• Patients with a failing tooth were enrolled in a private practice in Belgium between April 2011 and December 2012 to participate in a prospective case series.

• All patients were in need of a single implant.

INCLUSION CRITERIA

• At least 18 years old.• Good oral hygiene defined as full-mouth plaque score ≤25%

(O’Leary et al. 1972).• Presence of a single failing tooth in the anterior maxilla

(upper right to upper left second premolar) with both neighbouring teeth present.

INCLUSION CRITERIA …• High aesthetic risk profile characterized by at least one of the

following:1. mid-facial recession at the failing tooth in reference to the

contra-lateral tooth2. buccal bone dehiscence (regardless of depth) at the time of

tooth extraction3. thin-scalloped gingival biotype as determined by the

transparency of a periodontal probe in the buccal sulcus of the contra-lateral tooth

De Rouck et al 2009

EXCLUSION CRITERIA

• Systemic diseases.• Smoking.• Periodontal disease or history of periodontal treatment.

STUDY GROUPS

• As the presence of mid-facial recession at the failing tooth was decisive for the treatment trajectory, patients were included in the so called “non-recession group” (NRG) or ‘recession group’ (RG).

• The study protocol was approved by the ethics committee of the University Hospital in Brussels (ID: 143201111007).

TOOTH EXTRACTION AND RIDGE PRESERVATION IN THE NON-RECESSION GROUP

(NRG)• Antibiotic therapy (Amoxicillin 1 g, twice daily for 4 days) was

started 1 h pre-operatively. • Prior to tooth extraction, patients rinsed with a 0.2%

chlorhexidine solution.• Teeth were extracted without flap elevation.• Following meticulous bone curettage a collagen-enriched

bovine derived xenograft (Bio-Oss) was inserted and condensed, with the purpose of maintaining the ridge profile.

• The wound was protected with single monofilament sutures that were removed after 2 weeks.

• Patients continued local disinfection twice a day during 2 weeks and used ibuprofen 600 mg when deemed necessary.

• A removable partial denture was used as provisional tooth replacement in all patients.

IMPLANT PLACEMENT IN THE NON-RECESSIONGROUP (NRG)

• 4 to 6 months following ridge preservation NobelActive implants were installed.

• Based on CBCT analysis and bone sounding, a freehanded flapless approach was chosen using a 3.5 mm tissue punch in a palatal position.

• In borderline cases (<6 mm buccopalatal width as measured on CBCT) a standard flap was raised and single sutures were applied.

CONTOUR AUGMENTATION IN THE NONRECESSION GROUP (NRG)

• 3 months following implant placement a provisional screw retained crown was connected onto the implant.

• To compensate for tissue loss at the buccal aspect a connective tissue graft (CTG) harvested from the palate was used.

• The provisional crown was removed and a buccal sulcular incision was made. A partial thickness pouch procedure with a depth of about 12 mm was prepared.

• A CTG with appropriate size was pulled into the envelope and sutured. Finally, the provisional crown was reinstalled.

• Sutures were removed after 1 week.

Permanent crown in the non-recessiongroup (NRG)

• Provisional crowns were adapted at the buccal aspect in case of coronal migration of the mucosal margin.

• Following roughening with a diamond bur, flowable composite was added at the buccal aspect hereby inducing soft tissue retraction in a controlled manner.

• After 3 months of function, the emergence profile was replicated for the permanent restoration.

• Screw-retained full-ceramic crowns were a priori chosen.

NRG

Clinical procedure in the recession group(RC)

• Patients with mid-facial recession at the failing tooth in reference to the contra-lateral tooth were treated in a similar way as described above, yet they received a CTG at the time of ridge preservation.

• A portion of that CTG was left uncovered at the coronal part.• To limit the risk of necrosis in this area, a much larger CTG was

needed in the RG than in the NRG.

RC

Consort

Clinical outcome

• 1 Implant success was evaluated at 3 and 12 months using the success criteria by Buser et al 1990.

Clinical outcome…

• 2 Bone loss was recorded at the mesial and distal aspect of each implant at 3 and 12 months with implant installation as a reference time point.

• The distance from the implant-abutment interface to the first bone-to-implant contact as assessed on digital peri-apical radiographs was used as a basis for bone loss calculation.

• Mesial and distal values were averaged to receive 1 value per implant and per time point.

Clinical outcome..• 3 Plaque was registered at 12 months at four sites per implant

(mesial, distal, mid-facial, palatal) using a dichotomous score (0: no visible plaque at the soft tissue margin; 1: visible plaque at the soft tissue margin).

• 4 Probing depth was recorded at 12 months and at the same sites to the nearest 0.5 mm using a periodontal probe.

• 5 Bleeding on probing was registered 15 s following pocket probing. A dichotomous score (0: no bleeding; 1: bleeding was given.

• 6 Complications from biological and technical nature were recorded at all occasions.

Aesthetic outcome

• 1 Mesial and distal papillary recession was registered at 3 and 12 months by means of an acrylic stent provided with direction grooves.

• Baseline registration was performed with the failing tooth still in situ.

• A positive value corresponded to papillary recession, a negative value to papillary gain.

Aesthetic outcome…

• 2 Mid-facial recession was recorded at 3 and 12 months in a similar way as papillary recession.

• 3 Pink Esthetic Score (PES) (F€urhauser et al 2005) was registered at baseline (failing tooth in situ) and at 12 months.

• 4 White Esthetic Score (WES) (Belser et al 2009) was registered at 12 months.

STATISTICAL ANALYSIS• Descriptive statistics included mean values and standard deviations

for age, plaque, probing depth, bleeding on probing, bone loss, papillary recession, mid-facial recession, PES, WES, gender, reason for tooth extraction, tooth location, presence of buccal bone dehiscence, gingival biotype, flapless/flap surgery, maximum implant insertion torque, implant success.

• Bone loss was evaluated over time using the paired samples t-test.

RESULTS• The vast majority of the cases (N = 42) demonstrated a buccal

bone dehiscence following tooth extraction.• Seventeen patients had a thin scalloped gingival biotype.• Flapless implant placement could be performed in 40 patients

(35 in NRG and 5 in RG).• Five patients in the NRG did not receive a CTG because of

refusal (N = 2) or because it was considered unnecessary given the limited amount of alveolar process remodelling (N = 3).

• A second CTG was performed in one patient of the NRG and in one patient of the RG.

Clinical outcome- results

• From the 50 consecutively treated patients, 47 could be evaluated at 12 months.

• All 47 implants survived and 46 of those could be considered successful.

• Significant bone loss was registered and amounted to 0.31 mm on average at 3 months and 0.48 mm on average at 12 months.

Pre-operative radiograph

flapless implant placement 4 months following tooth extraction and ridgepreservation

provisional crown 3 months later

permanent crown 3 months later

• At study termination mean bone loss was 0.40 mm for implants installed via flap surgery and 0.49 for implants installed via flapless surgery.

• Mean plaque was 17% , mean probing depth was 3.1 mm and mean BOP as 23% at 12 months.

• The provisional crown fractured in 1 patient. • There were no other complications up to 12 months.

Aesthetic outcome results

• Significant papillary recession was observed in the NRG pointing to 0.2 mm on average at 12 months.

• Mid-facial recession was minimal in the NRG.• Papillary recession did not reach statistical significance in the

RG.• Mid-facial soft tissue gain amounted to 0.9 mm on average in

the RG at 12 months.

• Mean PES on the total sample was 11.4 at baseline and 10.9 at 12 months (p = 0.110).

• Soft tissue colour improved best, whereas soft tissue texture deteriorated most over time.

• Mean WES was 8.2

DISCUSSION• Risk assessment is of key importance in therapeutic decision-making

(Martin et al 2007, Cosyn et al 2012)• Recent studies have shown poor aesthetic outcome of immediate

implant treatment in patients with a buccal bone dehiscence and a thin-scalloped gingival biotype.

(Kan et al 2007, 2011, Cosyn et al 2012)• Even traditional protocols based on flap surgery, GBR and bone

augmentation may fall short in these patients, atleast when optimal aesthetics is considered a clear treatment objective

(Cosyn,De Rouck 2009, Cosyn et al 2012)

• This study showed a favourable clinical outcome of M.I.S.I.T. under challenging conditions.

• The concept is based on ridge preservation.• A traditional outcome measure of implant therapy is marginal

bone loss, which amounted to 0.48 mm on average after 1 year of function.

Kielbassa et al 2009, Arnhart et al 2012, Cosyn et al 2013• The present study showed a mean bone loss of 0.40 mm for

implants installed via flap surgery and 0.49 for implants installed via flapless surgery.

CONCLUSION

• In conclusion, this short-term prospective study offers a proof of principle of M.I.S.I.T. in patients with a high aesthetic risk profile.

• The concept based on ridge preservation and contour augmentation resulted in a favourable clinical and aesthetic outcome.

CRITICAL EVALUATION

• M.I.S.I.T not followed in all patients so biased study design• No CBCT• No surgical stents used• Only 1yr follow up

CROSS REFERENCE

I. Minimally Invasive Surgical Placements of Nonsubmerged Dental Implants: A Case Series Report, Evaluation of the Surgical Technique and Complications. Tee YL, J Oral Implantology 2011.

• Minimally invasive surgical implant placement has numerous advantages over conventional open flap technique.

• A series of cases is described here explaining the use of the tissue punch with discussion of the complications and management.

• A sharp probe guided by the surgical template was used to mark the point for implant placement through the mucosa.

• A bleeding spot thus generated indicated the location over which the tissue punch would be applied.

• The punch was applied onto the ridge and rotated to ensure a clean core of soft tissue would be subsequently removed.

• The core of soft tissue was then wrapped in saline soaked gauze and saved for possible grafting needs after implant placement.

• A surgical guide was used throughout to ensure a favorable placement of the implant in 3 dimensions.

• Immediate postoperative radiographs were done to confirm complete seating.

3 days post 3 months post Final crown

RESULTS:• All 5 cases exhibited excellent soft-tissue architecture preservation

at 1 week postsurgery with minimal edema, and there were no complaints of pain during the early postoperative healing period.

• All of the implants achieved successful osseointegration.• The soft-tissue architecture remained stable with preservation of

adequate attached gingival throughout the healing period of the implants, contributing to an esthetically pleasing and biologically sound result after final restorations.

II. Effect of Flapless Surgery on Single Tooth Implants in the Esthetic Zone: A Randomized Clinical Trial. Bashutski et al, JOP 2013.

• In this randomized, controlled study comparing the flapless and traditional flap protocol for implant placement, 24 patients received a single implant in the anterior maxillary region.

• A cone beam computed tomography–aided surgical guide was used for implant placement surgery for both groups.

• Implants were restored using a onepiece, screwretained ceramic crown at 3 months. Radiographic and clinical measurements were assessed at baseline (implant placement) and at 3 (crown placement), 6, 9, and 15 months.

RESULTS:• Implant success rate was 92% in both groups. • Crestal bone levels in the flap group were more apical in

relation to the implant platform than those in the flapless group for the duration of the study.

• No differences among groups were noted for all other measurements and both resulted in high success rates.

• A flapless protocol may provide a better shortterm esthetic result, although there appears to be no longterm advantage.