Immediate Maxillary Implant Placement with Simultaneous Crestal Approach Graft and Flapless Extraction Jone Kim, DDS, MS

INTRODUCTION extraction, crestal sinus lift, immediate implant placement and ridge preservation P.I. Bränemark introduced the idea of can be combined into one surgical visit for when he noticed the the reconstruction of posterior maxillary incorporation of titanium with bone molars with appropriate preoperative tissue.1 The concept of osseointegration evaluation and meticulous surgical revolutionized the replacement of missing technique. teeth with dental implants. Greater understanding in bone and EXTRACTION physiology, accelerated by technological There is a theoretical advantage to flapless advances, has resulted in significant extractions in decreasing bone resorption. improvements in surgery; Canine studies comparing flapped versus enabling a reduction in the number of flapless extractions of second, third and surgeries with less invasive surgical fourth without bone grafting or techniques, optimized esthetics, and implant placement demonstrate no decrease in the length of total treatment significant difference in horizontal and time from extraction to final restoration. vertical bone loss. 2-4, 5 However, canine Contemporary implant surgeons employ studies comparing flapped versus flapless less traumatic surgical techniques, place extraction of more anterior first and implants immediately, and combine second premolars demonstrates a multiple surgical techniques with fewer significant difference with less bone surgeries. resorption with the flapless technique. 6 A The posterior maxillary molar site is plausible explanation for this difference particularly challenging due to reduced between the two studies may be that the alveolar bone and the presence of the stripping of the periosteum in areas of maxillary sinus. A ridge preservation bone thinner buccal bone in the more anterior graft and/or a maxillary sinus bone graft is portion of the maxilla causes greater bone often required prior to implant placement, resorption. Studies have shown that thin complicating immediate implant buccal bone (< 1 mm) has more bone placement. Simultaneous flapless resorption compared to thicker bone (> 1 mm).7-12 In addition to alveolar bone RIDGE PRESERVATION BONE resorption, full thickness flap may lead to marginal recession at the adjacent teeth, GRAFT (RPBG) defective papillae and loss of keratinized After extraction, the surrounding alveolar mucosa.13 bone goes through stages of remodeling Flapless surgery makes it simpler to bone resulting in alveolar dimensional 16-18 17 graft the socket than flapped surgery. The changes. Cardaropoli et al. and 18 flapless extraction socket is basically an Araujo and Lindhe, demonstrate empty cavity where bone grafting particles horizontal and vertical bone resorption is can be placed with ease and with less from loss of bundle bone within two weeks mobility. In addition, since no incisions are after extraction. The crestal part of the made, a flapless extraction results in less buccal bone is solely made up of bundle surgical trauma, shorter surgical time, no bone, whereas lingual bone is comprised of need of suturing and decreased swelling lamellar and bundle bone. After extraction, and pain. Because of these advantages, since the crestal part of the buccal bone is the flapless extraction technique should be made primarily up of bundle bone, considered for all teeth that require an increased bone resorption is observed in 17-24 extraction, even if the extraction site is not buccal bone compared to lingual bone. for socket management or immediate Immediate bone grafting is performed implant placement. after the extraction to preserve the However, the most important aspect of the alveolar ridge, to minimize future bone extraction, in the author’s view, is not grafting, and increase the success of the whether the flap is made or not but rather implant surgery. There is horizontal bone minimizing removal of bone. Therefore, the reduction of 32% at three months, and 29- extraction technique should focus on 63% at six to 12 months after 18,19,25-30 preserving the alveolar bone, especially extraction. There is 11-22% the buccal and interradicular bone. Among vertical bone resorption observed at six the socket bony walls, buccal bone is the months post-extraction and increasing thinnest and will, therefore, resorb more vertical resorption with multiple 19,22,31,32 than other bony walls, and the extractions. Ridge preservation preservation of interradicular bone is bone grafting (RPBG) is a predictable critical for immediate molar implant surgical modality to preserve the alveolar placement after the extraction.7,9,14,15 If the bone after the extraction and allow for 19,33-37 flapless extraction is too difficult, it is wider and longer implant placement. better to make a minimal flap and remove In a recent randomized controlled clinical less bone than to do a flapless extraction trial, 48 implants were placed into either with more bone removal. If the flapless RPBG sites or spontaneously healed extraction can be achieved with no bone extraction sites four months after tooth removal, then this should give the best extraction. All implants survived at the one clinical outcome. year follow up, but during surgery, 14/24 (58%) spontaneously healed extraction sites required additional bone grafting, whereas only 1/24 (7%) needed additional one bone graft material being superior to bone grafting in RPBG sites.38 the others. 29,33,37,40-47 No matter which bone grafting material or surgical There is an inverse correlation, resulting in technique is utilized, the ultimate goal of thinner buccal bone showing a two-fold RPBG is to preserve the alveolar bone for increase in horizontal bone loss compared future implant placement reducing the to thicker buccal bone in spontaneous need for additional bone augmentation at healed sites. Whether there is thick or thin the time of implant placement. 6,48-50 buccal bone, without bone grafting there is an average of 4.04 mm horizontal IMMEDIATE IMPLANT reduction.39 There is no correlation between the thickness of the buccal bone PLACEMENT and alveolar bone loss in RPBG sites. In an In the beginning stages of implant surgery, RPBG site there is an average of 0.71 mm implants were primarily placed in a horizontal bone reduction. RPBG is able to delayed manner. Extraction sockets healed compensate for alveolar bone contraction for several months prior to implant for both thin and thick buccal bone plates. placement. Implants placed in a delayed Therefore, what is important is not the approach have a high success rate.51- thickness of the buccal plate, but rather 55 The first clinical study of immediate whether or not RPBG was performed after implant placement was published in the extraction. 1978.56 Surgical techniques have evolved RPBG ideally should be performed in a along with increased knowledge of bone flapless manner to prevent horizontal bone healing in the extraction site to improve loss and maintain keratinized gingiva. In a the immediate placement of dental 7,26,57- prospective randomized clinical trial that implants with predictable results 65 compared flapped and flapless RPBG, Short term survival rates and clinical horizontal bone loss was 3.5 + 0.9 mm outcomes are similar in both immediate 63 and 1.7 + 0.6 mm for the flapped and and delayed approaches. Advantages of flapless approach, respectively.13 In immediate implant placement include the addition, the flapless technique showed an reduction in the number of surgeries and increased width of keratinized gingiva treatment time, preservation of alveolar compared to pre-operative measurement, height and width, optimal gingival esthetic, whereas the flapped approach showed ideal implant placement and patient’s 47,59,66-72 decreased width. However, the flapped convenience. There is more group had a slightly less vertical buccal favorable bone healing and improvement bone reduction compared to flapless (-0.6 in soft tissue contour with immediate 26 + 0.7 vs. -1.1 + 0.9 mm), which was placement. statistically significant. One of the major concerns with immediate Even though autogenous bone is the gold implant placement is the presence of standard for bone grafting, many bone at the extraction 73 graft alternatives such as xenograft, site. Successful outcomes have been allograft, alloplast , and bone demonstrated with placement of implants morphogenetic protein have been used in placed into extraction sites with periapical 5,74-76 RPBG. Currently, there is no consensus on lesions. A retrospective study of 418 immediate implants placed into extraction stability of the implant can be attained. For sites with periapical lesions demonstrated immediate molar implant placement after a 97.8% survival rate with mean follow up extraction, besides vital structures such as of 67 months. 77 Immediate implant the maxillary sinus, adequate dimensions survival rates are similar for extraction of the alveolar bone, particularly of sites with or without perapical lesions. interradicular bone, are crucial for achieving primary stability of the There are several factors that are implant.15,86 Primary stability of the implant important to ridge alteration and survival is achieved by placing the implant in the after immediate implant placement: interradicular bone. Anatomical dimensions thickness of buccal wall, horizontal bone of the interradicular bone will depend upon gap and initial primary implant tooth and trunk length and root stability.7,57,63,78Thicker bone in the buccal morphology;80 the more divergent the wall resulted in less resorption of the roots are the wider the interradicular bone. buccal wall, which will decrease the chance Vertical length of the interradicular bone of dehiscence and other implant can be limited by pneumatization of complications.7,9,39,78,79 In the posterior maxillary sinus. The location of maxilla there will frequently be a horizontal interradicular bone is usually the ideal site gap after immediate implant placement for implant placement. When there is an due to the fact that the dimension of the absence or inadequacy of interradicular socket is larger than the diameter of the bone for immediate molar implant implant. placement, the surgeon may attempt to For , the average place the implant in one of the root mesio-distal and bucco-lingual sockets. However, placing the implant at measurement is 10.4 and 11.5 mm, an off-angle will increase the magnitude of respectively. 80 If the gap is within 2 mm, force to the implant and surrounding 87 after implant placement, spontaneous bone. In addition, an implant that is healing without bone grafting can occur.57, placed in a compromised position may lead 81 If the gap is wider than 2 mm, bone to difficulties with abutment and crown grafting is recommended for immediate placement and hygiene. Therefore, good implant placement after extraction in order extraction technique to preserve the to minimize bone resorption.63 Adequate socket wall and interradicular bone is vital primary stability is another critical factor to the successful outcome of immediate for a successful clinical outcome in an implant placement after an extraction. immediate implant placement and loading of the implant.82, 83 Currently, studies demonstrating that primary stability is not crucial with implants with special types of surface treatment have only been done on delayed implant placement not on immediate implant placement. 84,85

Pre-operative and post-extraction evaluation of the socket and bone is important for determining if primary MAXILLARY SINUS BONE maxillary sinus.101-104 One of the predictors of implant failure in the posterior maxilla is GRAFT smoking. Studies have shown that smoking is a relative risk to implant Maxillary sinus bone graft (MSBG) was first failures. 105, 106 In regards to effects of introduced by Tatum in 1976. 88 smoking in MSBG, a retrospective study by Subsequently, Boyne and James published Zinser104 evaluated 1,045 implants placed the first study of maxillary sinus bone in the grafted maxillary sinus and grafting using autogenous bone grafting in concluded that smoking doubled the 1980. 89 Ever since then, a lateral window relative risk of implant failure.104 In approach, derived from the Caldwell-Luc contrast, a review of implants placed in procedure, has been the surgical choice to maxillary sinus lift sites by Pjetursson, et treat vertically deficient bone in the al.107 did find higher failure rates for posterior maxilla. 90-93 Even though smokers compared to non-smokers (3.5% autogenous bone is the gold standard, vs. 1.9 %, respectively), but this different bone grafting materials have difference was not statistically significant. been used in the lateral approach MSBG Other predictors of implant failure in the with predictable results. 94-100 posterior maxilla that were mentioned are The obvious indication for MSBG is bone quality, time lapse from extraction to inadequate vertical alveolar bone in the implant placement, residual alveolar bone posterior maxilla for implant placement. As height, augmented compared to non- long as the bone grafting does not extend augmented sinus and membrane to block the ostium, bone grafting in the thickness. sinus is not contraindicated and is After Tatum88 first introduced lateral generally a benign approach MSBG, Summers 108 published procedure. 101 Contraindications for MSBG the first crestal approach (also known as can be categorized into two groups: transalveolar) to the sinus, using a set of patient (medical) and sinus (local) tapered osteotomes with increasing factors. 101, 102 Some of the patient or diameter. Since then, MSBG has evolved medical contraindications include over the years from lateral window chemotherapy or radiotherapy of the opening to various crestal approach maxillary region, immunocompromised techniques, including using piezoelectric status, medical conditions affecting bone surgery, trephines, osteotome, hydraulic metabolism, pregnancy, uncontrolled lift/pressure, press-fit bone block, drills diabetes and alcohol or drug abuse. Sinus specifically designed for crestal approach or local contraindications include and modifications of these techniques.109- inadequate transverse dimension of the 121 Studies comparing crestal versus lateral sinus, intranasal acute or chronic sinusitis, approaches to MSBG revealed that both unrepaired , recent nasal techniques showed similar success in or sinus surgery, or tumors of the clinical results.122-124 sinus, and ostium in the surgical site. The main advantages to the crestal In addition to these contraindications, approach MSBG is that it can be done there are factors that may predispose without a flap, with less post-operative certain patients to implant failures in the swelling and pain, minimal bone grafting “tent” like lifting of the maxillary sinus materials and with reduced surgical membrane. This “tenting” effect of the time.107,116,125 The most common crestal maxillary sinus membrane, via crestal approach MSBG technique is condensing approach, allows firmer condensing of the and tapping of the bone with various bone grafting particles within the elevated diameter osteotomes to lift the sinus membrane space than the lateral membrane, which was first described by approach, which usually has a much larger Summers.108 membrane elevated space that can allow more movement of the bone grafting The crestal approach is simpler than the particles. lateral approach MSBG in the immediately extracted molar sites. This is due to the In 2000, Cosci and Luccioli, 129 published a fact that the unevenness of the maxillary study introducing a new sinus lift sinus floor often occurs from molar roots technique with the use of lifting drills to protruding into the sinus, which can make perforate, not fracture, the sinus floor and a lateral approach MSBG more challenging. lift the membrane. This technique is In addition, the lateral approach will referred to as the Cosci’s technique. The require making a buccal bony window tip is specially designed so that it will not above the mesio-buccal and disto-buccal perforate the sinus membrane even if the roots (approximately 12 mm in length) and drill tip makes contact with the membrane. continuously elevating the membrane There is no use of osteotomes. In this six inferiorly to the sinus floor, at which the year retrospective study, 265 implants lowest point is at the trifurcation of the were placed in a one stage crestal roots.80 These factors can make the lateral approach MSBG, in healed sites, with eight approach sinus lifting more challenging implant losses, resulting in a 97% survival immediately after the extraction. rate. One study even compared Cosci’s technique to Summers’ technique.116 This In the crestal approach MSBG in study showed that both techniques immediately extracted molar sites, the displayed predictable results but Cosci’s opening into the sinus is through the technique required less surgical time, less interradicular bone, which is usually the intra- and postoperative morbidity and was most inferior part of the sinus floor in the preferred by patients. In another study, maxillary molar. Elevating the membrane 134 implants placed in a multicenter from inferiorly to superiorly, will result in retrospective study using Cosci’s uniform and “tent” like sinus technique, showed implant survival rate of elevation.102Also, the crestal approach 96.3% with average follow-up time of 48.2 sinus lift is completed after a sufficient months.130In this study, the average pre- elevation and, thereby, reducing the operative alveolar bone height was 3.46 overall sinus lifting. Whereas in the lateral mm + 0.91 mm, which further shows that approach, a much larger area of the sinus implants can be successfully placed with has to be elevated due to the inability to simultaneous crestal approach MSBG in form “tent” like membrane elevation. alveolar bone height of less than 5 mm. In addition, it is the author’s opinion that better stability of the implant can be achieved with a crestal approach due to INDICATIONS AND RATIONALE extraction with simultaneous crestal approach has a high survival rate. FOR IMMEDIATE MAXILLARY One of the drawbacks for crestal approach, MOLAR IMPLANT PLACEMENT as with the lateral approach, is achieving WITH SIMULTANEOUS adequate primary stability of the implant at the time of MSBG. Most studies indicate CRESTAL APPROACH that less residual alveolar bone results in MAXILLARY SINUS BONE increased implant failure rate. 101,126, 127Therefore, studies have shown that ideal GRAFT AND FLAPLESS residual alveolar height, for immediate EXTRACTION implant placement with simultaneous crestal approach MSBG, should be 5-6 mm Reduced vertical alveolar ridge due to to achieve primary stability of the inherent bone remodeling is one of the implant.107,125 However, Gonzalez, et challenges of an implant placement after al.,128 compared the success rate of the extraction of maxillary posterior immediate implant placement with teeth.17,18 In addition to anatomic simultaneous crestal approach MSBG, in limitations, maxillary sinus healed extraction sites, with residual pneumatization, which ends normally at alveolar bone height of < 4 mm and > 4 age 20, will continue to progress after the mm, which showed 100% and 98.51% extraction with loss of vertical alveolar success rates, respectively. Simultaneous bone.94,131,132Clinicians should consider crestal approach MSBG and implant preserving the alveolar bone height by placement can be achieved in vertical immediate implant placement and/or alveolar bone of less than 5 mm with a immediate bone grafting to decrease the high success rate. sinus pneumatization and alveolar bone loss.133 In addition, time lapse from the The requirements for maxillary molar extraction to implant placement is one of implant placement, immediately after the the predictors of implant failure in flapless extraction, with simultaneous posterior maxilla.103 crestal approach MSBG are: 1) adequate horizontal dimension for diameter of Immediately after the extraction the best planned implant; 2) no major soft tissue treatment for posterior maxillary teeth defect, such as buccal or lingual fistula; 3) may be an implant placement with no oroantral communication (OAC) greater simultaneous MSBG, if indicated. In a than 3-5 mm after the extraction; 4) no retrospective analysis, 391 implants were purulent discharge from socket and/or placed immediately after the extraction of maxillary sinus after the extraction; 5) no maxillary molar teeth and 156 out of 391 major periapical and maxillary sinus implants required simultaneous MSBG due infection and/or pathology; 6) no more to inadequate alveolar bone than one alveolar wall defect; and 7) no height.86 Overall survival rate was 99.5% symptomatic maxillary sinusitis. If any of (389/391) after 75 month follow-up, the mentioned criteria are not met, the showing that immediate maxillary molar implant should be placed in a delay implant placement at the time of approach. Comprehensive pre-operative clinical and radiographic evaluations to select an ideal surgical candidate for this technique are paramount to a successful clinical outcome.

Pre-operative radiographic evaluation for maxillary molar extraction should include the following: 1) horizontal and vertical dimensions of interradicular bone; 2) evaluation of maxillary sinus, such as Figure 1B. Maxillary molar tooth with inadequate infection, thickness of membrane and interradicular bone for an immediate implant placement due pathology; 3) presence of periapical to convergent roots. Notice the roots are protruding into the radiolucency, such as bone loss, infection sinus. Sinus is WNL. and lesion; 4) presence of OAC; and 5) evaluation of alveolar wall, such as wall This technique is a preferred implant defect, thickness of buccal bone and treatment plan for many, if not all, of the vertical and horizontal dimensions of the patients that desire an implant after the socket wall. It is possible to perform the extraction when they are given delayed vs. surgery with a panoramic radiograph but a immediate surgical options. cone beam CT (CBCT) is highly recommended for pre-operative If the extraction, RPBG, MSBG, and radiographic evaluation. implant placement are done in 2 or more (Figure 1A, B) Clinical evaluation for surgeries, the patient may select a non- maxillary molar should include the implant treatment option, due to increased following: 1) status of adjacent teeth; 2) treatment time, cost, and number of soft tissue evaluation (such as keratinized surgeries, even though an implant may be tissue, gingival recession, swelling and the best treatment option and the patient’s fistula); 3) inter-occlusal and mesio-distal preferred plan. The added benefit for the space; 4) clinical signs of parafunctional surgeon is less operative procedures with habits; and 5) occlusion. less office visits.

Figure 1A. Cone beam CT of maxillary molar tooth. A. Maxillary molar tooth with divergent roots with adequate interradicular bone for an immediate implant placement. Sinus is within-normal-limit (WNL). SURGICAL TECHNIQUE FOR tissue is then gently pushed away from the tooth. Freeing up the crestal gingival tissue IMMEDIATE MAXILLARY slightly allows for reduced trauma to the soft tissue from any instruments that will MOLAR IMPLANT PLACEMENT be in close contact during the extraction. A WITH SIMULTANEOUS periosteal elevator can also be used to free up the crestal gingival tissue. No incision is MAXILLARY SINUS BONE made and interdental papilla is not GRAFT AND FLAPLESS detached from the bone during the EXTRACTION extraction. Pre-operative Regimen Next, a periotome (Dowell, Rancho Cucamonga, Calif.) is used to separate The patient is given the following pre- buccal bone from mesiobuccal to operative regimen: 1) If the mesiodistal and palatal bone from the patient has no allergic reaction to trunk and root of the tooth. Use of a penicillin, the patient takes 2 grams of periotome will reduce the incidence of amoxicillin 1 hour prior to surgery and alveolar bone fracture and, more then 1 gram bid for 5 days; 2) If allergic to importantly, can be used to preserve the penicillin, the patient takes 600 mg buccal bone in the socket, instead of clindamycin 1 hour prior to surgery and having the buccal bone attached to the then 150 mg qid for 5 days. Just prior to root during the extraction. Then a straight surgery, the patient’s mouth is rinsed with elevator or slightly curved elevator is chlorohexidine gluconate for approximately placed into the sulcus to gently subluxate 15-20 seconds. the tooth. After adequate subluxation, if there is enough tooth structure, an attempt is made to extract the tooth by Flapless Extraction using a modified upper forcep (Karl

Schumacher, Linden N.J.). Using a As mentioned previously, the most modified forcep that has smaller and important aspect of the extraction is not narrower beaks will reduce trauma to the whether the flap is made, but rather that it alveolar bone and soft tissue, compared to is focused on minimizing the removal of a conventional upper forcep. bone. Therefore, the extraction technique should concentrate on preserving the During the extraction, with a forceps or alveolar bone, especially the buccal and even with an elevator during subluxation, interradicular bone. the crown of the tooth can fracture, leaving part of the crown, trunk or roots in After is administered, the the socket. If part of the crown or trunk is first step is to gently free up the crestal in the socket, it is sectioned to separate gingival tissue away from the tooth the multi-rooted maxillary molar tooth into without stripping off any of the periosteum multiple single roots.134The goal is to from the alveolar bone. To do this, a 2/4 section the multi-rooted maxillary molar molt curette (Hu-Friedy, Chicago, Ill.) is tooth and remove the roots individually. placed into the gingival sulcus, including However, during sectioning, be cognizant the interdental gingival tissue. The soft to avoid removal of the buccal and and difficult to extract, a ½ round bur can interradicular bone, which is located just be used to section the roots, mesio-distally below the root trunk. Trunk length is or bucco-lingually, and then remove the approximately 4 mm.15 sectioned roots using appropriate instruments. All 3 roots can be removed in Since maxillary molar teeth have 3 roots, this manner. section the remaining crown or trunk into 3 parts: mesiobuccal, distobuccal and After extraction of the three roots, the palatal root. socket needs to be carefully examined for any potential complications. The following (Figure 2) To accomplish this, a ½ or #2 should be evaluated: sinus floor and round bur (SS White, Lakewood, N.J.) is membrane, socket wall, interradicular used with a surgical handpiece. During bone and presence of infection. If the sinus trisecting of the roots, it is not necessary floor is difficult to visualize, the Valsalva to touch the bone with the round bur. maneuver can be gently performed to Preserving the interradicular bone is crucial check for oroantral communication. After a for an immediate implant placement thorough examination, the socket is gently because this may be the only source of curetted to remove any granulation tissue bone for the primary stability of the and periapical lesion. However, this step implant. should be done with caution if the sinus membrane is exposed or perforated.

After careful curetting, thoroughly re- evaluate the socket. Depending on the clinical findings, the surgeon will decide at this time whether or not to continue with the next step, modify the treatment plan or abort the surgery. Whether to continue, modify, or abort the surgery will depend upon several factors: 1) sinus membrane perforation and size of perforation; 2) vertical and horizontal dimensions of interradicular bone; 3) size and location of bony wall defect; and 4) presence and Figure 2. Multi-rooted maxillary molar tooth is sectioned extent of periapical and sinus infection. into 3 separate roots, mesio-buccal (MB), disto-buccal (DB) Based on these factors and clinical and palatal (P) roots. findings, the final decision will depend on After trisecting the roots, a small elevator whether the alveolar ridge can be or 2/4 molt curette can be used to preserved, the implant can attain primary complete the separation of the roots and stability, and a sinus bone lift can be then, using the same instrument, predictably performed. If the decision is subluxate and extract the roots. A thin made to continue with the surgery, the periotome or root tip pick can also be used next step is the crestal approach MSBG. to loosen and remove the roots. If the roots are firmly embedded in the socket Crestal Approach to the MSBG (Figure 3A, B) at 600-800 RPM will be used to approach the sinus floor and enter From the pre-operative CBCT and socket the maxillary sinus without perforating the evaluation, approximate vertical and sinus membrane. These CAS drills come in horizontal dimensions of the interradicular various diameters (2.8, 3.1, 3.3, 3.6, 3.8, bone are estimated. Ideal bucco-lingual 4.1 mm) and the drill tip is specially and mesio-distal position of the implant is designed to minimize sinus perforation usually the mid-crest of the interradicular even if the tip of the drill touches the sinus bone. The author’s crestal approach membrane. maxillary sinus bone grafting technique is similar to the technique that was described by Cosci and Luccioli,129 where “lifting” drills are used to perforate the sinus floor without perforating the sinus membrane.

The first drill used in the crestal approach MSBG is a 1.3 mm pilot drill (Salvin, Charlotte, N.C.) at 800 RPM, with copious normal or sterile water irrigation. The depth of the drilling is approximately 1-2 mm short of the estimated vertical dimension of the interradicular bone. During drilling with a pilot drill, the sudden feel of denser bone may indicate that the Figure 3A. Crestal approach sinus drill (CAS drill). A. 4.1 mm drilling depth is at or close to the sinus CAS drill. floor, which is composed of cortical bone. Cortical bone will feel denser compared to medullary bone and the surgeon’s tactile sensations should be able to differentiate between cortical and medullary bone during drilling. The next drill used is a 2.0 mm twist drill, again 1-2 mm shy of estimated vertical length of the interradicular bone. After each drilling sequence, measure the depth of the drill site with a depth gauge or probe. It is important not to drill through the sinus floor with the twist drill, as this will Figure 3B. 4.1 mm CAS drill with a stopper. increase the likelihood of sinus membrane perforation. After using the 2.0 mm twist To further reduce the chance of sinus drill, specially-designed crestal approach membrane perforation, drill stoppers are sinus (CAS) drills (Hi-Ossen, Fairless Hills, used during the drilling sequence to better Pa.) visualize the depth of the drill, and to prevent entering the sinus too quickly. Drill stoppers come in various lengths and they can be “snapped” into place at the junction of the drill and shank. Stoppers come in different lengths, in increments of 1 mm, which will indicate the length of CAS drill that will be entered into the drill site. A stopper will hit the ridge and prevent the drill from entering deeper once the appropriate length is reached.

The first CAS drill used is a 2.8 mm with a stopper that will give a slightly longer drill length than the last measured drilled Figure 4A. Hydraulic lifter. depth. Then, sequential CAS drills with A. A hydraulic lifter is used to elevate the sinus membrane. increasing diameter and shorter stoppers, to increase the length of the drill by increments of 1 mm, are used until the sinus floor is perforated. Drilling should be done gently and slowly to minimize sinus membrane perforation. In addition, all CAS drills do not need to be utilized for every case. During the drilling sequence, CAS drills that are close in diameter can be skipped, depending upon the “softness” and amount of the bone present. As soon as the sinus floor is felt, there should be a Figure 4B. Using the hydraulic lifter, normal saline (NS) or sudden “soft” feel with no resistance. sterile water is injected into the sinus to elevate the After the sinus floor is felt, carefully membrane. examine the site for any perforation of the The hydraulic lifting is done using a NS membrane. If a visual evaluation of the filled 3 cc syringe that is connected to a sinus membrane cannot be achieved, the rubber hose, which also has a broader can be performed rubber tip connected at the other end. The gently to check for OAC. If the sinus broader rubber tip will be placed right up membrane is not perforated, the next step against the crestal drill site and is the hydraulic lifting of the membrane. approximately 0.5 – 1.0 cc of NS will be slowly injected into the sinus cavity to

elevate the membrane. After injecting NS (Figure 4A, B) The purpose of this step is into the sinus cavity, draw NS back into to gently elevate the membrane using the same syringe and then inject more NS sterile liquid, such as normal saline (NS), into the sinus cavity again, like a which will reduce the risk of sinus “pumping” action. This step is done membrane perforation while elevating the multiple times to elevate the membrane membrane. slowly. One of the drawbacks with this step is that a significant amount of NS may leak out because the rubber tip may not fit tightly in the drilled implant site. This can of the interradicular bone. If much of the make it more challenging to hydraulically interradicular bone is missing or removed lift the membrane. A best effort should be during the extraction, the implant is placed made to lift the membrane up to or close 3-4 mm below the buccal gingival margin, to the desired vertical length with assuming primary stability of the implant hydraulic lifting. can be achieved and there is no significant gingival recession and buccal bone loss. After hydraulic lifting, the bone carrier is used to carry the bone grafting particles Ridge Preservation Bone Graft into the crestal drill site. Then, push gently into the sinus cavity with a bone Due to dimensional changes after the condenser. Adequate sinus bone grafting extraction, Ridge Preservation Bone Graft can be verified with CBCT or a blunt-ended (RPBG) is a routine procedure for all depth gauge. After adequate MSBG, the immediate implant surgeries. After the next step is implant placement. implant is placed into a final position, the implant is covered with a cover screw, Immediate Implant Placement cotton ball or sterilized

polytetrafluoroethylene (PTFE) tape (also Horizontal and vertical dimensions of known as plumber’s tape) prior to bone interradicular bone will determine the grafting in order to prevent bone grafting diameter and length of the last CAS drill to particles falling inside of the implant. If all be used, and thus, that of the implant that the socket walls are intact, freeze-dried will be placed. As mentioned previously, a cortico-cancellous mineralized allograft CBCT can give approximate dimensions of (Osteokor, Surgikor, Calif.) is loosely the interradicular bone, which will packed into the socket, even if the gap is determine the approximate diameter of the less than 2 mm. For any socket wall implant. However, the exact diameter of defect, which is usually the buccal wall, the implant will be determined during xenograft (Bio-Oss, Geistlich, N.J.) is surgery. The last CAS drill will be placed in the bony defect area and then determined by dimensions of the allograft is placed in the remaining socket interradicular bone and should be at least space. Bone grafting particles are placed 2-3 mm away from the buccal bone. This is up to the fixture level and, after removing usually not a problem for molar sites since the cover screw or material that is the average bucco-lingual and mesio-distal covering the inside of the implant, the measurement is 10 mm.80 Generally, the healing abutment is then placed. The top diameter of the implant that is placed in a of the healing abutment should be at or molar site is 4-5 mm, with 5 mm being the slightly above the gingival margin. One of most common, and the length is 10 -12 the main advantages of placing the healing mm. abutment is faster soft tissue healing After bone grafting and attaining the compared to primary closure. desired sinus elevation, the implant is After the healing abutment is placed, placed in a routine manner, just like it is additional bone grafting particles are done in any other immediate implant placed approximately 1-2 mm above the surgery. The final vertical position of the implant fixature level. Resorbable collagen implant is usually at or just below the crest membrane (Cytoplast, Osteogenic Biomedical, Texas) is placed above any exposed bone grafting particles. There is no undermining of the soft tissue or periosteum during placement of the resorbable collagen membrane. Even though an incision or flap was not made, non-resorbable sutures (Cytoplast, Osteogenic Biomedical, Texas) are placed bucco-lingually to provide some gingival tautness and to prevent the resorbable membrane from coming out too early during normal oral function and hygiene. SURGICAL CASES Figure 5A. Pre-operative periapical radiograph of tooth #14. Surgical Case 1

A 48-year-old male presents with failing (RCT) and unrestorable tooth #14. (Figure 5A- C) Patient’s past medical history (PMH) is non-contributory. Pre-operative clinical evaluation showed a missing crown of tooth #14, minimal gingival recession, and severe buccal abrasions of adjacent teeth. Adjacent teeth that show severe abrasions will be restored with new restorations PFM at a later time. Cone beam CT showed mild thickening of the sinus membrane, periapical infection with possible sinus floor perforation and approximately 5-7 mm of vertical length of the interradicular bone.

Figures 5B & C. Pre-operative clinical intra-oral views. (Figure 5D-F) After treatment options were discussed with the patient, the chosen treatment plan was immediate implant placement after the extraction, with simultaneous MSBG.

Figure 5F. Pre-operative CBCT of palatal root (PR) of tooth #14. Slight thickening of the membrane is noted. From the CBCT, estimated vertical length of the interradicular bone is 5-7 mm.

Figure 5D. Pre-operative CBCT of MB root and (Since the detailed description of the surgical technique was outlined in one of interradicular bone of tooth #14. the previous sections, only the key points of the surgery will be mentioned for surgical cases.)

Since the crown was missing, tooth #14 was sectioned to extract the mesio-buccal, disto-buccal and palatal roots separately without making a flap.

(Figure 5G, H). Next, a pilot drill is used to make the initial drill site, drilling about 1 mm short of estimated minimum vertical dimension of the interradicular bone that was measured in the CBCT. Then, a twist drill (2.0 mm) is used to make the drill site slightly wider and to drill up to the same vertical depth as the pilot drill. Then, a 2.8 mm CAS drill, which is the narrowest CAS

drill diameter, with a 6 mm stopper will be Figure 5E. Pre-operative CBCT of DB root and interradicular used to widen the drill site and to increase bone of tooth #14 the vertical depth, gradually getting closer to the sinus floor.

Figure 5I. CAS drill with a stopper.

Figure 5G. Without a flap, tooth is sectioned into 3 separate roots, MB, DB and P roots.

Figure 5J. The CAS drill with a stopper being used to perforate the sinus floor.

After the sinus floor is met and the membrane is intact, a hydraulic lift is

performed. Approximately 0.5 – 1.0 cc of Figure 5H. Roots are extracted one at a time. Interradicular NS is pushed into the sinus cavity to elevate the membrane. During hydraulic bone is preserved. lifting, the goal is to lift the membrane (Figure 5I, J) Sequential CAS drilling is superiorly as possible but not more than followed with appropriate stoppers to the desired vertical length. After hydraulic increase the length of the drill, 1 mm lifting, bone grafting particles are gently incrementally, until the sinus floor is met. condensed into a space between the sinus After each CAS drilling sequence, using a floor and the membrane is lifted until the blunt ended instrument, the drill site is sinus membrane is adequately elevated. checked for sinus floor perforation, since the sinus floor can be partially perforated, such as in cases where the sinus floor is inclined or uneven. (Figure 5 K,L) This can be verified with (Figure 5 M) A cover screw is placed and radiograph or a blunt ended measuring allograft bone particles are placed into the instrument. remaining socket space, similar to RPBG technique. The cover screw is then removed and the healing abutment is placed. Resorbable membrane is placed over the exposed bone grafting particles and non-resorbable sutures are placed in an interrupted manner.

Figure 5K. Bone carrier being used to place the bone grafting materials into the elevated sinus membrane space.

Figure 5M. Implant (5 x 10 mm) is positioned in the interradicular bone.

(Figure 5 N) Surgery was uneventful and there was no sinus membrane perforation. The sutures were removed in 1-2 weeks and patient is to follow-up for 5-6 months or until the implant is ready for abutment and final restoration.

Figure 5L. View of the implant site after bone grafting. Notice that the implant site is within confines of the interradicular bone.

After adequate sinus elevation, an implant (5 x 10 mm) is placed in the ideal position, which is at or just below the crest of the interradicular bone, or 3-4 mm below the buccal free gingival margin.

Figure 5N. Clinical view immediately after surgery

(Figure 5O-V)

Figures 5Q & R. Five month post-operative clinical views.

Figure 5S. Five month post-operative clinical view with healing abutment removed.

Figures 5O & P. Cone beam CT taken immediately after surgery. Note the dome or tent shape of the elevated sinus.

Figure 5T. Five month post-operative periapical radiograph.

was discussed but the patient decided not to go through with the orthodontic treatment. Pre-operative CBCT showed mild thickening of the sinus membrane without any other lesions, and 3-7 mm of vertical length of the interradicular bone.

Figure 5U. Ten month post-operative periapical radiograph. (Final restoration was placed six months post-operatively).

Figure 6A. Pre-operative periapical radiograph of tooth #14.

(Figure 6B-D) After treatment options were discussed, the treatment plan chosen was immediate implant placement, after the extraction, with simultaneous MSBG. (The sequence of surgical steps and follow- up will be similar to the one described for Surgical Case 1.)

Figure 5V. Twenty month post-operative periapical radiograph. Note the newly formed sinus floor above the implant.

Surgical Case 2

A 36-year-old female presents with failing RCT of tooth #14 with poor long term prognosis. (Figure 6A). Her PMH is non-contributory. Clinical examination showed multiple missing teeth, crowding of upper maxillary teeth and normal gingival soft tissue around tooth #14. Orthodontic treatment option, along with other treatment options, (Figure 6E-I) There was no sinus membrane perforation or complications during the surgery. The sutures were removed in 1-2 weeks and post-operative healing was uneventful.

Figure 6B. Pre-operative CBCT of MB root of tooth #14.

Figure 6E. Fractured crown during an attempt to extract with a forcep.

Figure 6C. Pre-operative CBCT of DB root of tooth #14. Figure 6F. Without a flap, tooth is sectioned into three separate roots, MB, DB and P roots.

Figure 6G. View of the finished implant site after bone Figure 6D. Pre-operative CBCT of PR of tooth #14. Sinus grafting. Note the implant site is within the confines of the membrane is slightly thickened. From the CBCT, estimated interradicular bone. vertical length of the interradicular bone is 3-7 mm.

Figure 6H. Photo taken immediately after surgery.

Figures 6K & L. Clinical views five month post-operative.

Figure 6I. CBCT taken immediately after surgery. Note the dome or tent shape of the elevated sinus. (Implant dimension: 4.8 x 10 mm)

(Figure 6J-Q)

Figure 6M. Clinical view eight months post-operative. Final restoration was placed six months post-operatively.

Figure 6J. Facial view one week post-operative. Note that the patient has no post-operative facial swelling.

Figure 6N. Eight month post-operative periapical radiograph.

Figure 6Q. CBCT view 18 months after surgery.

Surgical Case 3

A 51-year-old male presents with retained root tips of tooth #2. (Figure 7A) The patient’s PMH is non- contributory. Clinical examination showed missing teeth #4 and 30, normal gingival

soft tissue, and missing crown of tooth #2

with retained root tips.

Figures 6O & P. Clinical views 18 months after surgery. Figure 7A. Pre-operative panoramic radiograph.

(Figure 7B, C) Pre-operative CBCT showed a thickened sinus membrane without any other sinus lesions, periapical radiolucency extending to the sinus cavity with sinus floor perforation, and 3-5 mm vertical measurement of the interradicular bone with resorption at the furcation.

Figure 7D. Pre-operative CBCT of MB root of tooth #2. Notice the vertical bone resorption of the interradicular bone.

Figure 7E. Pre-operative CBCT of DB root of tooth #2. Notice the thickening of the sinus membrane and perforation at the apex of DB and palatal roots.

Figures 7B & C. Pre-operative clinical view of tooth #2.

(Figure 7D-F) For this case, the major concerns were periapical lesion, and ability to achieve primary stability of the implant due to vertical interradicular bone loss. After the extraction, interradicular bone, sinus floor and membrane will need to be Figure 7F. Pre-operative CBCT of palatal root of tooth #2. thoroughly evaluated. From the CBCT, estimated vertical length of the interradicualr bone is 3-5 mm. After treatment options were discussed with the patient, the treatment plan chosen was immediate implant placement, after the extraction, with simultaneous MSBG. (The sequence of surgical steps and follow-up will be similar to the one described for Surgical Case 1.)

(Figure 7G – L) After the extraction, the sinus floor was perforated but the membrane was intact. There was no sinus membrane perforation or complications during the surgery. The sutures were removed in 1-2 weeks and post-operative Figure 7H. Using the CAS drill with a stopper to perforate healing was uneventful. the sinus floor.

Figure 7I. Use of a blunt-ended bone condenser to gently lift Figure 7G. Roots extracted without a flap. the sinus membrane during bone grafting. Marking on the bone condenser indicates that the sinus elevation is just beyond 10 mm. (Figure 7M-R)

Figure 7J. Implant is positioned and the socket is filled with bone grafting particles.

Figures 7M & N. Clinical views 10 months after the surgery. Implant was ready in 5-6 months but the patient decided to wait on the final restoration.

Figures 7K & L. Immediate post-operative clinical views. Here, Gelfoam (Pfizer, New York, N.Y.) was placed over the resorbable membrane. This was one of the earlier cases and, currently, Gelfoam is no longer used. Figure 7O. Periapical radiograph with the final restoration 11 months after surgery.

Figure 7R. CBCT taken 21 months after surgery.

CONCLUSION With a thorough pre-operative clinical and radiographic evaluation, a maxillary molar implant placement, immediately after the extraction, with simultaneous maxillary sinus bone grafting is a predictable treatment modality with a successful clinical outcome in an ideal situation, even with pneumatized maxillary sinus. Combining 4 proven surgical techniques Figures 7P & Q. Clinical view 21 months after surgery. into one surgery will reduce the total treatment time, and the number of surgeries and is the treatment option preferred by the patient who wants to have an immediate implant placement after a maxillary molar extraction.

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