Guidelines for Optimizing Outcomes with Immediate Molar Implant Placement

Special Article - Dental Implants

Austin J Dent. 2017; 4(4): 1079.

Guidelines for Optimizing Outcomes with Immediate Molar Implant Placement

Ketabi M¹ and Deporter D²*

¹Department of Periodontology, Islamic Azad University, Iran

²Department of Periodontology, Oral Reconstructive Center, University of Toronto, Canada

*Corresponding author: Douglas Deporter, Department of Periodontology, Oral Reconstructive Center, University of Toronto, 124 Edward Street, Toronto, Ontario, Canada

Received: March 21, 2017; Accepted: May 08, 2017; Published: May 24, 2017


This paper is a follow-up to a recent systematic literature review with metaanalysis of outcomes when using immediate molar implants (IMIs). An attempt has been made to offer guidelines to assist clinicians in their successful use of this treatment approach. The surgeon’s ability, proper case selection, socket anatomy, and specific modifications in osteotomy preparation all are crucial in avoiding errors, complications and implant failure. While long-term data are sparse, IMIs appear to be a viable treatment option if the offered guidelines are strictly followed.

Keywords: Tooth extraction; Dental implantation; Endosseous; Guided tissue regeneration


We have recently published a systematic review and metaanalysis of literature published from November 2008 to May 2015 reporting outcomes following immediate molar dental implant (IMI) placement [1]. The search format was that recommended by the Academy of Osseointegration Workshop on the State of Science on Implant Dentistry (SSID) [2,3]. The search language used was similar to that employed in a previous review conducted by others on IMI data up to October 2008 [4]. Criteria for qualification of studies to be included in the analysis were: i) at least 10 IMIs; ii) minimum followup 1 year in function; iii) clearly reported/interpretable survival and/or success (based on crestal bone loss) data; and iv) use of rootform, solid, titanium or titanium alloy implants. Fifteen publications fulfilling these criteria were identified, none of which were doubleblind, randomized, controlled prospective clinical trials. Recognizing this limitation, our analysis supported Atieh’s earlier conclusion [4] that it is possible to obtain good outcomes with IMIs with the added proviso that those of diameters >6 mm may be at greater risk of failure.

There are obvious advantages for patients and clinicians in providing immediate implant replacement of molar teeth. These include fewer and potentially less invasive surgical procedures, greater patient acceptance, less chair time, lower treatment fees, shorter treatment times, and potentially fewer risks. The clinician needs to be aware, however, that achieving success with IMIs is affected by many factors. In the present paper, we have attempted to formulate guidelines for the successful use of IMIs. Considerations will include case selection, reason for extraction, quality and quantity of keratinized tissue, socket anatomy and how it impacts osteotomy preparation, implant design, and initial implant stability.


Case selection

As with all technique-sensitive surgical procedures, not all clinicians will be capable of successfully employing IMI procedures because of infrequent usage of the procedure, failure to follow strict protocols, inadequately trained support staff and/or inability to manage the associated stress [5]. Likewise, not all molar sockets will be appropriate for IMI placement thereby making careful case selection crucial. Patients should be non-smokers since smokers have been shown to have 10x the risk of IMI failure as non-smokers [6]. Other patient contraindications include history of head and neck radiation in the previous 12 to 24 months [7], uncontrolled diabetes [8], use of anti-resorptive [9] or RANK ligand-inhibiting [10] drugs, and parafunctional habits such as bruxism [11].

In most situations, a pre-operative CBCT scan should be done to allow pre-treatment assessment of buccal bone thickness and proximity of vital structures [12]. In posterior mandible, Froum, et al. [13] suggested that safe placement of an IMI is likely if the distance from root apices to the nerve canal is at least 6 mm as measured on CBCT, accepting that up to 4mm of apical bone must be engaged to ensure sufficient initial IMI stability to avoid micro-movements [14]. Lin, et al. [15] used CBCT cross-sectional views and virtual IMI placements to predict the risk of nerve damage with mandibular IMIs. In a sample of 237 subjects, the mean distances between molar root apices and nerve canal (RAC) were 7.0±2.9mm for first molar and 4.3±2.7 mm for second molar sites. Nerve damage was likely to occur in 69.9% of second molar sites, but the risk was reduced to 35.4% at first molar sites. The probability of nerve damage decreased by 26% with every 1mm increase in RAC. The investigators also found that 57.5% of first molars and 62.3% of second molars had lingual mandibular ridge concavities adding the risk of lingual plate perforation and arterial damage. In another computer-based simulation study of IMI placement in posterior mandible [16] the same investigators predicted that the risk of lingual plate perforation decreased by 34% for every 1mm increase in RAC. Given all of this information, a reasonable guideline to follow is the 6 mm minimum RAC rule of Froum. With an RAC less than 6mm, it becomes safer to undertake socket preservation grafting with delayed implant placement, and clearly this is more likely to be the case for mandibular second molars.

IMI sites with a thick buccal gingival biotype (i.e., a periodontal probe cannot be seen through the tissue when inserted into the gingival sulcus) and a keratinized gingiva vertical width of =2 mm are preferred since thin and/or narrow keratinized tissue will predispose to crestal bone resorption and peri-implant gingival recession [17- 20]. Should textured implant surfaces become exposed as a result of crestal bone loss, there is the risk of peri-implantitis and progressive bone loss [21]. As well, once restored, implants with thin, narrow keratinized tissue are more likely to be associated with bleeding on probing and brushing discomfort [22]. If adequate keratinized gingiva is lacking, a graft of palatal connective tissue can be harvested and inserted under the buccal and lingual/palatal flap margins and over the implant as one would place a membrane [23]. Alternatively, a dense PTFE membrane can be placed in a similar fashion over the implant and left exposed so as to promote healing by secondary intention with generation of new keratinized tissue [24].

Citation: Ketabi M and Deporter D. Guidelines for Optimizing Outcomes with Immediate Molar Implant Placement. Austin J Dent. 2017; 4(4): 1079. ISSN:2381-9189