, Prasanth T , Satisha TS , Nitin Gupta , Sumita Manandhar Immediate implant placement is the current modality to provide implant placement following tooth extraction. Post-extraction resorption of the alveolar ridge is inevitable which has been demonstrated in various histological studies, placement of immediate implants helps in preservation of alveolar ridge dimensions. Implant placement in fresh extraction sockets was initially described by Schulte and Heimke1) in 1976 and later termed it as “immediate implant placement” by Schulte et al2).
Immediate implants offer the advantages in terms of minimizing the surgical appointments, reduction in treatment time and cost thus improves patient comfort and satisfaction. Also, regarding survival rates of immediate implants, they are comparable to those of delayed implants3). Originally immediate implants were reserved for single rooted anterior teeth or premolars but placement in multirooted molars is not contraindicated though it bears surgical challenges in terms of proper angulation and parallelism and achieving primary stability.
Rebele, Zuhr, Hürzeler4) in year 2013 proposed the “pre-extractive approach” in immediate implant placement in multirooted molar teeth. In this technique implant bed preparation is done through the interradicular septal bone keeping the root apices intact which serves as anatomical guide for osteotomy. Engaging interradicular septal bone allow primary stability from apical bone, whereas keeping the roots intact prevent the deflection of osteotomy drill and help in achieving proper angulation and parallelism.
Incorporating the principles of immediate implants and residual roots as anatomic guide, three cases of grossly decayed mandibular molars are managed by placement of implants are showcased in this case series.
A 31-year-old female reported to department of periodontology with a chief complaint of one grossly carious and one missing teeth in left side of her lower jaw and want their replacement. Upon eliciting history, tooth was subjected to multiple failed attempts of root canal treatment. Radiographic examination of tooth 36 revealed wide pulp chamber communicating through mesial canal into furcation with slight furcal radiolucency suggestive of perforated canal with furcation involvement. Endodontic consultation confirmed poor prognosis and advised for extraction.
After initial clinical examination and pre-operative cone beam computed tomography (CBCT) assessment it’s been found sufficient interradicular bone width of 6 mm present in apical region of 36 and bone with normal trabecular pattern in region of 35 was present. Routine blood & urine investigations carried out and found within normal limits. Surgical phase was planned involving placement of immediate implant (4.5×12 mm) with root guided approach in 36 & conventional delayed implant (4.0×10 mm) in 35.
Following adequate local anesthesia, decoronation of 36 was done till crestal level, following which splitting of roots using long shank Lindemann bur was done and confirmed radiographically. Sequential osteotomies were performed through center of the splitted roots into the inter-radicular septum taking care of long axis of teeth and verified radiographically. Osteotomy extended 2 mm beyond root apex to gain sound apical bone and primary stability. Following completion of osteotomy, roots were extracted atraumatically using periotomes and socket was thoroughly debrided and completed osteotomy site with preserved socket walls achieved. Dental implant of 4.5×12 mm (Bredent blueSky implants, Bredent GmbH, Senden, Germany) was placed. Optimal insertion torque (25 N-cm) and sufficient primary stability, confirmed with radio frequency analysis (RFA) value of 70, was obtained. Since the jumping distance was more than 2 mm, alloplastic bone graft (Novabone dental putty, Bangalore, India) was used to fill the gap and autologous platelet rich fibrin (PRF) was used as a membrane. Missing 35 was replaced by placement of 4×10 mm implant (Bredent blueSky implants, Bredent GmbH, Senden, Germany) using conventional technique. Both implants reviewed radiographically and proper angulation and parallelism was appreciated (Fig. 1). Post-operative instructions given and chlorhexidine mouthwash 0.2% along with antibiotic and analgesics prescribed for one week.
Figure 1. Case 1 surgical steps. (A) Edentulous 35 and grossly carious 36. (B) Pre-Op CBCT 36 with 6 mm of inter radicular bone. (C) Decoronation and root splitting. (D) IOPA showing splitting of roots. (E) Osteotomy done through sectioned roots. (F) Atraumatic extraction of roots using periotomes. (G) Completed osteotomy with preserved socket walls. (H) Implant placed. (I) Jumping distance covered using bone graft and autologous PRF membrane. (J) Immediate post-op IOPA showing implants placed with optimal parallelism.
After 6 months following the procedure, radiograph was taken to ensure complete healing of the extraction socket and healthy peri implant tissue. RFA value found to be 82 suggestive of osseointegrated implants in-situ so further prosthetic rehabilitation carried out by placing screw retained porcelain fused to metal (PFM) crown over both implants (Fig. 2). One year post rehabilitation shown stable results.
Figure 2. Case 1 prosthetic rehabilitation after 6 months. (A) Harmonious occlusal relation of crowns of 35, 36. (B) 6 months post-op radiograph showing implant in-situ. (C) Occlusal view showing the position of screw hole after prosthetic treatment.
A 28-year-old female reported with chief complaint of root pieces in right lower back tooth. Intraoral clinical presentation showed root stumps in 46. Clinical evaluation by measuring buccolingual and mesiodistal dimensions of future implant site over root stumps following which CBCT assessment for implant selection was done. Placement of immediate implant (4×13 mm) using root guided approach was planned.
Osteotomy done using residual roots of 46 a surgical guide. Following osteotomy atraumatic removal of root stumps, implant placement (4.5×13 mm Bredent blueSky implants, Bredent GmbH, Senden, Germany) was done at the root guided site and RFA value was checked and found to be as 80 suggestive good initial stability. Jumping distance managed with alloplastic bone graft and PRF membrane (Fig. 3).
Figure 3. Case 2 surgical steps. (A) Root stumps in 46. (B) Osteotomy through roots of 46. (C) Implant placed and jumping distance managed with bone graft and PRF membrane. (D) Radiograph immediate after implant placement.
After 6 months, implants re-evaluated radiographically and secondary stability checked using RFA and value of 89 suggested osseointegrated implant. Subsequently prosthetically rehabilitated using screw retained porcelain fused to metal (PFM) crown over 46 (Fig. 4).
Figure 4. Case 2 after six months. (A) Screw retained prosthetic restoration crown placed on 36 months. (B) Radiograph showing implant in-situ. (C) Occlusal view of the crown.
33-year-old male reported with broken tooth in his left lower back jaw. Clinical history revealed root canal treatment in the same tooth 3 years ago. Clinical examination showed fractured crown of root canal treated 36 with poor prognosis in terms of obtaining adequate ferrule for prosthetic management. Periapical radiograph showed sufficient interradicular bone with no periapical lesion. Hence immediate implant using similar protocol of root guided approach was planned. Following similar protocol utilizing roots as anatomical guide osteotomy performed and implant bed prepared within well preserved interseptal bony walls (Fig. 5). Implant placed by gaining primary stability from apical interradicular bone. After 6 months implant successfully rehabilitated with PFM crown (Fig. 6).
Figure 5. Case 3. (A) Root canal treated with fractured crown 36. (B) Implant bed preparation with well-preserved interseptal bone. (C) Immediate radiograph after implant placement.
Figure 6. Case 3 after six months post-op prosthetic rehabilitation. (A) Porcelain fused metal (PFM) crown placed on 36. (B) 6 months post-op radiograph showing implant in-situ. (C) Occlusal view after prosthetic treatment.
Healing was uneventful in all three cases. All patients tolerated the surgical procedures well. ISQ values above 70 in cases suggestive of attaining primary stability (Table 1). Desired angulation and parallelism in implant placement were obtained. Six-month post operatively no peri-implant defect suggestive of successful osseointegration which was again confirmed radiographically and with optimal ISQ values (Table 1).
Table 1 . ISQ values immediately after implant placement and 6 months post-op
| Case | Implant stability quotient (ISQ) values | |
|---|---|---|
| Immediately after implant placement (Primary stability) | 6 Months post-op (Secondary stability) | |
| Clinical case 1 | 76 | 82 |
| Clinical case 2 | 68 | 73 |
| Clinical case 3 | 80 | 89 |
Immediate implants are gaining popularity in recent times as they are predictable and it achieves success rates that are comparable to those of delayed implants placed in healed sites. Compared to conventional implants, immediate implants offer many advantages like reduced number of surgical procedures, reduction in overall treatment time and thus cost effectiveness with overall better patient acceptance and satisfaction5). The systematic review and meta-analysis by Atieh et al.6) documented the survival rates of 99% in immediately placed single implants in fresh molar extraction sites over an observation period of upto 11 years. Lang et al.7) reported a mean survival & success rate of 98.4% (97.3∼99%) of implants placed immediately into fresh extraction sockets after at least 2-year post placement.
Immediate implant placement in single rooted teeth as a postextractive approach has been used conventionally since long time8). However, placement of immediate implant in multirooted tooth faces many challenges in terms of thickness of interradicular septum, remaining bone in the interradicular area, periapical pathologies and angulation of adjacent teeth. Also, in multirooted molars this approach poses surgical challenges in terms of osteotomy preparation through interseptal bone with an inherent risk of drill slippage into extraction sockets and thus compromise in achieving a proper angulation and parallelism. For ideal placement of implant use of surgical guides like made of auto polymerized resin, vacuum formed template, gutta percha guided template, metal sleeves, etc., have been suggested. These surgical difficulties can be overcome by utilizing the pre-extractive approach where osteotomy carried out through residual roots utilizing them as natural surgical guide for implant bed preparation. In year 2013, Rebele, Zuhr, Hürzeler4) brought the novel concept of improved guidance in implant bed preparation through interradicular bone septa.
The present case series demonstrated the novel approach of root guided implants that allowed precise guidance using roots as anatomical guide during implant bed preparation for immediate implants at multirooted molar sites. Keeping roots till osteotomy prevents the slippage of drills. Drilling through the dentin of retained root aspects appears to be similar to drilling through tissue slightly harder than dense cortical bone. This is in accordance with study done by Davarpanah and Szmukler-Moncler9), who reported implant placement in contact with ankylosed root fragments. Osteotomy through interseptal bone keeping roots in situ provide optimal angulation and parallelism. Natural roots acts like surgical stent and thus root guided implants approach is an economical alternative to stent guided immediate implants. Once osteotomy completed root fragments removed atraumatically using periotomes, this flapless approach provides an added advantage of minimal ridge remodeling. In this context, it is recommended to use root guided pre-extractive inter-radicular implant bed preparation where primary stability for implants provided by interradicular bone.
However, it is important to consider the condition of the tooth and remaining bone10). Root in apical area should be devoid of any active infections and favorable root forms are desirable. Similarly, sufficient remaining bone (inter radicular, apical) should be available for immediate implant placement. If the bone conditions are not favorable and it’s difficult to achieve primary stability.
Though novelity of root guided approach where osteotomy carried out through roots is providing advantage of precise implant placement but it also raises a concern of pushing of drill debris into the extraction sockets. This may act as local source of infection which may compromise implant success11). To overcome this thorough socket debridement should be carried prior to implant placement.
Once osteotomy completed an implant of suitable size is placed using either of submerged or non-submerged healing protocol. Care should be taken to cover the jumping distance between implant and interseptal bony wall by placing Bone graft and Platelet Rich Fibrin as a membrane12).
This case series has demonstrated that pre-extractive approach of using root guided immediate implant in multirooted molars which allows a simple and guided implant placement using anatomy and geometry of roots utilizing them as natural surgical guide for optimal angulation and parallelism in implant positioning. This novel approach of root guided implants is a simple, economical and useful alternative of the standard approach of immediate implant placement at multirooted molar extraction sites. Root guided implants is operator friendly technique where dual advantage of immediate implant and natural roots as surgical guide makes it a promising treatment modality in precision placement of immediate implants in molar areas.
Author ORCID Information
Pramod Kumar Prasanth T Satisha TS Nitin Gupta Sumita Manandhar |
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