A pattern of peri-implantitis affecting middle implants in 3-implant splinted prostheses.

BACKGROUND: Previous investigators have noted an increased risk of crestal bone loss and failure of the middle implant of 3-implant-splinted (3-IS) fixed dental prostheses (FDPs). Possible causes have included ill-fitting prostheses, unhygienic prosthetic contours, and discrepancies in prosthetic platform heights. METHODS & RESULTS: We identified four cases in which the middle implant of a 3-IS multiunit FDP suffered advanced bone loss, ultimately leading to implant removal. While more than one possible risk for implant failure existed in each case, a common thread was that the prosthetic platform of the middle implant for all patients was coronally positioned relative to the corresponding mesial and/or distal implants. CONCLUSIONS: Splinting three adjacent implants into one prosthesis may add risk for a variety of reasons possibly including small differences in the heights of the three prosthetic tables. KEY POINTS: Why are these cases new information? Our observations suggest that discrepancies between implant prosthetic platforms supporting 3-implant splinted, multiunit FDPs may be an added risk factor for middle implant failure. What are the keys to successful management of these cases? It is possible that small differences in apico-coronal implant positioning with 3-implant splinted multiunit FDPs may affect the success of the middle implants. What are the primary limitations to success in these cases? There is limited literature involving precise protocols and long-term outcomes of 3-implant splinted implant restorations. Studies comparing 3-implant splinted FDPs to other configurations are needed.

Management of cervical external root resorption following connective tissue grafting.

BACKGROUND: Cervical external root resorption (CERR) is not a common occurrence, but can result in a hopeless tooth prognosis. Its etiology is poorly understood and its management can be challenging. The present case report describes the late presentation and management of CERR at both maxillary first premolar teeth following connective tissue grafting (CTG) procedures including use of citric acid as a chemical root surface conditioner. METHODS AND RESULTS: A 55-year-old female was diagnosed with bilateral external cervical root resorption of both maxillary first premolar teeth 28 years after CTG procedures that had included the use of citric acid root conditioning. As both teeth were asymptomatic, the patient opted for repair of the lesions via full-thickness flap elevation, meticulous removal of all granulation tissue, and restoration of the lesions with a resin-modified glass ionomer. A 2-year follow-up has been completed with no significant complications to report. CONCLUSIONS: CERR usually develops asymptomatically and is found by chance in radiographs. Its etiology is unclear, but may appear some years after soft tissue grafting to manage gingival recession. Early detection is key to be able to repair the lesions with minimal intervention.

Anatomically Driven Immediate Implant Placement in the Esthetic Zone: Two Case Reports as Proof of Principle.

Achieving favorable and stable esthetic outcomes with immediate implants used to replace maxillary anterior teeth can be challenging. Osteotomies need to be initiated along the palatal socket wall, and it is often difficult to stabilize initial drilling. An immediate implant was planned for a hopeless maxillary incisor. Using a flapless surgery technique, the tooth was removed and decoronated, and an entry point was made in the root to guide the osteotomy drills. The root was reinserted and stabilized while a precision drill and 2-mm twist drill were used in sequence to drill through the tooth root, establishing the osteotomy location but stopping 3-4 mm short of final depth. The root was then removed, and the final implant bur for a 3.5 × 11.5-mm implant was drilled to depth, engaging the necessary native bone apically. The original tooth crown was then used to prepare and insert a transitional crown. Reinserting the extracted root of a maxillary anterior tooth and using it as a guide for osteotomy preparation is an excellent method to optimally position an immediate implant palatally in the socket wall.

Long-term results of immediate implantation in mandibular posterior teeth with early loading: A retrospective case series.

When immediate molar implants first were proposed, submerged initial healing and delayed loading were the norm. It is now recognized that some early loading of a nonocclusal nature can stimulate faster osseointegration, although full occlusal loading is still delayed for 3 or more months. Here, we test the hypothesis that earlier occlusal loading of mandibular premolar and molar immediate implants may be possible. In this retrospective case series study, 18 mandibular molar and nine mandibular premolar teeth were atraumatically extracted and immediate implants placed 1-2 mm apical to buccal and lingual crestal bone. Periimplant gaps received particular allograft covered with acellular dermal matrix barrier. Healing abutments were placed through puncture points in the membranes to help in stabilizing the latter and to permit nonsubmerged site healing. At 6-8 weeks, each implant was evaluated for stability using the Periotest® device and restored if the Periotest® (PTV) value seen was negative. Data were analyzed by t test and MannWhitney U at a significance level of P < 0.05. Retrospective assessment of all 27 implants after 5 years' period of follow up showed all implants to have survived. Overall mean crestal bone loss was determined to be-0.25 ± 0.54 mm. Individual mean bone levels for mesial and distal surfaces were-0.24 ± 0.77 mm and-0.26 ± 0.72 mm, respectively (P = 0.78). A statistically significant difference in bone loss between genders was detected. Overall mean probing depth was 2.09 ± 0.57 mm. Based on the widely used Albrektsson criteria, the overall survival and success rate was 100%. Immediate implants placed into mandibular premolar and molar extraction sockets and allowed nonsubmerged healing may be ready for restoration at earlier times than previously thought possible.

Effect of Different Implant-Abutment Mismatches on Stress Distribution: A 3-Dimensional Finite Element Study.

Platform-switching reduces peri-implant marginal bone loss (MBL). The aim of this study was to compare the effect of platform-switching on stress within crestal bone using different implant-abutment mismatches (0.65 and 1 mm) under 2 different vertical loads (30 N vs 200 N) for implants placed in posterior jaw sites. Three-dimensional modeling software was used for an implant with a diameter of 4.5 mm and length of 13 mm. Molars were modeled using computerized tomography images of bone density in human maxilla (D3 bone) and mandible (D2 bone). Collected data were analyzed using CATIA software. In posterior mandible, stress of 30 N force with platform mismatches of 0.65 or 1 mm were 2.920 and 2.440 MPa respectively. Using 200 N force, values increased to 19.44 and 16.30 MPa. In posterior maxilla and 30 N force, stresses with mismatches of 0.65 and 1 mm were 3.77 and 3.18 MPa, respectively, increasing to 25.14 and 20.17 MPa with 200 N force. The effect can be predicted to be greatest as the mismatch increases with implants placed into lower quality bone (posterior maxilla with D3 quality).

A new classification of peri implant gaps based on gap location (A case series of 210 immediate implants).

Based on our collective experiences with gap management around immediate dental implants, we have proposed a classification of gap type based on the location in relation to implant periphery. Seven types are proposed, and all but one type should heal without gap grafting provided that flap-less surgery and atraumatic extraction have been achieved. The exception is our Type II gap where the implant has been placed too far buccally leaving a gap only on the lingual/palatal. In this case, the lingual/palatal gap need not be grafted, but the buccal aspect of the implant should best to augmented to avoid the complications.

CBCT data relevant in treatment planning for immediate maxillary molar implant placement.

Background: This study used CBCT images to evaluate the suitability of maxillary first and second molar sites to receive immediate implants. Buccopalatal and mesiodistal widths of maxillary molar inter-radicular septum were evaluated at three different levels (crestal, middle, and apical), in addition to assessments of the root apex and furcation proximities to the sinus floor and comparisons of these measurements between the first and second upper molar sites before extraction. Methods: A total of 427 dental sites from 223 patients were used to measure the buccopalatal and mesiodistal widths of inter-septal/furcal (IRS) bone of maxillary first and second molars and vertical distances from the furcation and from all the root apices to the sinus floor (SF). Results: Mean coronal-most buccopalatal/mesiodistal IRS widths were 7.33/6.52 mm for the first and 6.86/5.85 mm for the second molars (P=0.008). Corresponding mean FSD (furcation-sinus floor) values were 9.69 mm (range: 2.02-24.68 mm) and 8.84 mm (range: 1.48-25.09 mm). Mean distances from all the root apices to SF were <3 mm. The palatal roots of the first molars had higher sinus intrusion rates (28.85%) than their buccal counterparts, while for the second molars, the mesiobuccal roots showed the highest sinus intrusion (37.65%). Conclusion: In the current patient sample, 61.7% of the first and 34% of the second molars had a sufficiently broad IRS to encase a 5-mm-diameter IMI (immediate molar implant) completely. The mean FSD of 9 mm for both molars indicated that some sinus floor elevation would likely be needed unless short implants were used.

Effectiveness of buccal pouch grafting in minimizing loss of alveolar dimension: A canine investigation.

BACKGROUND: The study's purpose was to study buccal pouch grafting (BPG) with xenograft, freeze-dried bone allograft (FDBA), or FDBA + decalcified FDBA (DFDBA) on alveolar ridge width preservation and overlying soft tissue thickness at dog premolar extraction sites. MATERIALS AND METHODS: In this animal study, 4 dogs had their mandibular first premolar (P1) and distal roots of P2, P3, and P4 extracted (after endodontic treatment of the mesial roots) bilaterally. A small buccal pouch was created at each extraction socket and four treatments tested: nothing, xenograft, FDBA, or FDBA + DFDBA. Casts made pretreatment and at 1 and 3 months after treatment allowed measurements of buccolingual alveolar ridge width (BLRW), while overlying buccal soft tissue thicknesses were measured clinically. Data were assessed using analysis of variance to compare changes in soft tissue thickness and BLRW between times and treatments. Tukey-Kramer adjustment for multiple comparisons was applied for doing post hoc, pairwise comparisons. Results were considered significant if P < 0.05. RESULTS: Control sites showed significant (P = 0.0067) decreases in soft tissue thickness over time while there was a trend for increased soft tissue thickness at all grafted sites. There were significant losses in BLRW over time for control (P = 0.0032) and FDBA groups (P = 0.015) with a trend for loss with FDBA + DFDBA. Pairwise comparison using Tukey-Kramer adjustment revealed significant increases in BLRW from T1 to T3 for the xenograft group relative to all the others. CONCLUSION: BPG using xenograft is effective in maintaining hard and soft tissue stability following tooth extraction.

A Systematic Review of Outcomes Following Immediate Molar Implant Placement Based on Recently Published Studies.

BACKGROUND: Immediate implant placement in molar extraction sites has become a treatment option for experienced clinicians. PURPOSE: The aim of this study was to provide a systematic review and meta-analysis of outcomes from recent clinical studies with immediate molar implants. MATERIALS AND METHODS: A systematic review was undertaken of relevant literature published from November 2008 to May 2015. Data collected included implant survival rates after at least 1 year in function, cumulative crestal bone loss, and implant location (maxilla vs mandible) and diameter. Implant diameters were grouped as "wide" (4-6 mm) or "ultra-wide" (>6-9 mm). Survival and bone loss with 95% CIs were calculated using a random effects model. Meta-analysis techniques were used to compare survival rates and cumulative mean bone loss between immediate and delayed placement implants. Survival rates also were computed and compared between wide and ultra-wide implants using chi-square testing. The quality of each study was assessed using established criteria. RESULTS: The literature search provided 15 papers published between November 2008 and May 2015 that satisfied the inclusion criteria. Data on survival were found for a total of 768 immediate molar implants inserted in 757 patients. Meta-analysis of these data showed an implant survival rate of 98% with no difference between maxilla and mandible. Five studies included delayed molar implants as controls, and no significant differences were detected. A significant difference (p = .048) was found in relation to implant diameter with implant failures being higher (3.67 vs 1.45%) for ultra-wide (>6-9 mm) versus wide (4-6 mm) implants. The majority of the 15 studies were determined to be either "average" (prospective case series) or "fair" (retrospective) in quality. CONCLUSION: While there are still no published reports from double-blind, randomized, controlled (best quality) clinical trials of immediate molar implant placement, high survival rates have been reported. The present data, however, suggests that there may be an optimal diameter for this implant application. Meta-analysis of the limited bone loss data reported estimated the overall mean cumulative bone loss after at least 1 year to be 0.57 mm.

A retrospective report on three implant devices used to restore posterior partial edentulism: overall performance and changes in crestal bone levels.

Three implant designs were used to treat posterior partial edentulism. A total of 799 implants (563 Osseotite, 65 Straumann SLA,171 Endopore SPS) were placed in 345 patients. SPS implants were used in sites with less bone, had shorter lengths, and functioned longer than the threaded implant designs. Comparing implant losses, SPS implants had a higher failure rate (9.3%) compared with Osseotite (4.0%) or SLA (0%) implants. SPS implant losses generally occurred as late failures, while Osseotite losses were early failures. However, among surviving implants, SPS implants had less crestal bone loss at all time intervals compared with both of the threaded implant designs.

Performance of titanium alloy sintered porous-surfaced (SPS) implants supporting mandibular overdentures during a 20-year prospective study.

OBJECTIVE: This study was undertaken to assess short, sintered porous-surfaced (SPS), press-fit implants with mandibular overdentures to restore edentulous patients with severe mandibular resorption. MATERIALS AND METHODS: Implant lengths of 7, 8, 9, and 10 mm were used, all with 2-mm polished collars, making the designed intrabony lengths 5, 6, 7, and 8 mm. Each patient received three non-splinted implants placed using a two-stage protocol. RESULTS: Only 22 (with 53 implants) of the original 52 patients were available after 20 years. All but one of these patients was functioning with their implant-retained overdentures. Life table analysis accounted for all patients and implants, and showed a 20-year survival of 73.4%. Analysis of carefully standardized radiographs revealed mean cumulative bone loss after 20 years of 0.67 mm relative to the polished collar-SPS junction. CONCLUSIONS: Short SPS implants with mandibular overdentures can provide an acceptable treatment over a 20-year period for fully edentulous patients with severe alveolar resorption.

The effects of laser microgrooves on hard and soft tissue attachment to implant collar surfaces: a literature review and interpretation.

This paper summarizes current knowledge on the benefits of laserablated microgrooves in neck regions of endosseous dental implants. Like machine-tooled coronal microthreads with particle-blasted surfaces, laser-ablated microgrooves help to preserve crestal bone. However, they also appear to uniquely favor a true gingival connective tissue attachment comparable to that of natural teeth.

Short dental implants: what works and what doesn't? A literature interpretation.

Dental implants with lengths ≤ 8 mm have been used with success in posterior arch regions where significant alveolar ridge resorption has occurred. Nevertheless, many clinicians are reluctant to use them regularly, if at all. Key factors for success include implant surface roughness, surgical placement methods, and, possibly, implant diameter, all of which are discussed here.

Performance of sintered, porous-surfaced, press-fit implants after 10 years of function in the partially edentulous posterior mandible.

This article updates the results of a prospective clinical trial of press-fit, sintered, porous-surfaced dental implants placed in the posterior mandible of partially edentulous patients. Implants used had overall lengths (including transgingival collar regions) of 7 or 9 mm with designed intrabony lengths (lengths of sintered surface in contact with bone) of 6 or 8 mm. Forty-eight implants were placed in 24 patients, the majority of which replaced molar teeth, and the mean crown-to-root ratio was 1.4. Over 10 years of implant function, 2 patients with 3 implants died and 3 patients with 4 implants were lost to follow-up because of infirmity or relocation. The survival and success rates were both 95.5%. Two implants failed; the mean cumulative crestal bone loss (measured from the implant-abutment interface) for the remaining implants was 1.2 mm. Crestal bone loss was not affected by the crown-to-root ratio, prosthesis design, or whether an implant was the most distal unit in a sextant. However, there was a trend for greater crestal bone loss when implants were opposed by implants rather than by natural teeth.

Use of sintered porous-surfaced dental implants to restore single teeth in the maxilla: a 7- to 9-year follow-up.

This report from a prospective study discusses the status of a group of 20 single maxillary sintered porous-surfaced (SPS) dental implants after 7 to 9 years in function restored with screw-retained crowns. Twenty patients each received a single SPS implant placed in a two-stage surgical approach; 65% replaced premolar or molar teeth, while the remainder replaced anterior teeth. Patients were examined annually. Standardized radiographs were used to assess peri-implant crestal bone levels and to determine an implant success rate. Jemt Papilla Index scores were used to assess the extent of papilla reformation between each implant and its two contiguous teeth. After 7 to 9 years, 17 implants were available for assessment (one patient had died, and two patients had moved away). One implant was removed after the 9-year visit because of progressive bone loss, giving a survival rate of 92.9%. The failure of this implant was related to deficiency in initial alveolar ridge width with loss of the remaining thin buccal cortical plate. With the exception of the failed implant, no significant changes in mean annual crestal bone loss were noted from years 1 to 9, giving a similar success rate (92.9%). Jemt Papilla Index scores of 2 or 3 were assigned for the majority of papillae. SPS implants can be used effectively to replace single missing maxillary teeth.

Dental implant design and optimal treatment outcomes.

Whereas the majority of endosseous dental implants have threaded screw geometries, press-fit implants with a sintered porous surface (SPS) geometry integrate via three-dimensional bone ingrowth. These two classes of implants are suited for different site conditions and, when used appropriately, will provide optimal and minimally invasive treatment protocols. The present report argues that generally, threaded screw implants perform best in long lengths (with a "defined intrabony length" above 8 mm) and denser bone, while press-fit SPS implants perform optimally at short lengths ("defined intrabony length" of 5 mm or less) and in primarily cancellous bone. Threaded implants are more appropriate for immediate placement and immediate loading, while press-fit SPS implants perform well in resorbed posterior sites, including maxillary sites with as little as 3 mm of subantral bone. Understanding the benefits and limitations of these two implant concepts is key to successful and minimally invasive implant treatment.

"Biologic width"and crestal bone remodeling with sintered porous-surfaced dental implants: a study in dogs.

PURPOSE: The aim of this study was to obtain histometric measurements of bone and peri-implant mucosal tissue contact with implants of 2 sintered porous-surfaced designs. The "short-collar" design had a collar height (smooth coronal region) of 0.75 mm, while the "long-collar" model had a smooth coronal region of 1.8 mm. MATERIALS AND METHODS: Implants (2 per side) were placed in healed mandibular extraction sites of 4 beagle dogs using a submerged technique. After 4 weeks of healing, they were uncovered and used to support fixed partial dentures for a 9-month period. After sacrifice, specimens were retrieved and nondemineralized sections were examined histometrically to determine the most coronal bone-to-implant contact (first BIC) using the microgap as a reference and standard mucosal parameters of "biologic width." RESULTS: Significant (P = .001) differences in first BIC were found between designs (1.97 mm for long-collar versus 1.16 mm for short-collar implants) for posteriorly located implants but not for anteriorly located ones (1.21 mm versus 1.38 mm; P = .40). If crestal bone loss involved sintered surface, fibrous connective tissue ingrowth was observed to replace lost bone. No significant differences in peri-implant mucosal measurements (total peri-implant mucosal thickness; length of the epithelial component of this mucosa, and thickness of the connective tissue component) were detected between implant designs. CONCLUSIONS: Results suggest that "biologic width" accommodation drives initial crestal bone loss with sintered porous-surfaced implants. Histometric data obtained for bone contact showed no significant differences between the long- and short-collar implant designs.

Ultrashort sintered porous-surfaced dental implants used to replace posterior teeth.

BACKGROUND: This retrospective multicenter report provides data from a case series of partially edentulous subjects treated with an ultrashort (5-mm-long) sintered porous-surfaced (SPS) dental implant. METHODS: The implant used had a tapered truncated cone shape, was 5-mm long, and had a maximal coronal diameter of 5 mm. Twenty-six implants were placed in 20 subjects to replace primarily maxillary and mandibular molar teeth. Submerged primary healing was used. Nine implants were restored with single crowns, one carried a single cantilever, and the remaining 16 implants were part of fixed implant-supported bridges, generally as the most distal abutment. RESULTS: After functional periods of 1 to 8 years, two maxillary implants failed, giving maxillary and mandibular failure rates of 14.3% and 0%, respectively. CONCLUSION: The results of this case series suggest that an SPS, press-fit, tapered dental implant with a length of 5 mm and a maximal coronal diameter of 5 mm should be investigated further as a solution for the management of highly resorbed posterior sites in partial edentulism, particularly in the mandible.

Performance of threaded versus sintered porous-surfaced dental implants using open window or indirect osteotome-mediated sinus elevation: a retrospective report.

BACKGROUND: The purpose of this retrospective report was to evaluate the performance of dental implants placed in a teaching environment in patients requiring maxillary sinus elevation. METHODS: Threaded (acid-washed or sand-blasted acid-etched) and sintered porous-surfaced (SPS) press-fit implants were used. Sinuses were managed using direct (open window) or indirect (osteotome-mediated) techniques. Records were available for 97 implants in 62 patients. Preoperative subantral bone heights were determined from radiographs, primarily panoramic. Of 69 threaded implants used, 40 and 29 were placed using direct (DTH) and indirect (ITH) techniques, respectively. Twenty-eight SPS implants were placed using the indirect technique. Implant failure rates using the Kaplan-Meier method of analysis and cumulative crestal bone loss (the latter based on bone levels seen in the most recent radiographs) were determined for both types of implants. RESULTS: The mean preoperative subantral bone height for DTH implants was 5.0 mm (range, 1 to 12 mm). Preoperative bone heights for ITH implants and SPS implants placed using the indirect approach were 7.2 mm (range, 4 to 12 mm) and 4.2 mm (range, 3 to 6 mm), respectively. Significant differences in preoperative bone height were seen between DTH and ITH implants (P <0.0001) and between ITH and SPS implants (P <0.0001). Average functional times were 18.7 months and 16.3 months for DTH and ITH implants, respectively, whereas the average functional time for SPS implants was 49.9 months. Time in function was significantly greater (P <0.0001) for SPS than DTH and ITH implants. Significant differences in implant length were also seen, with SPS implants significantly shorter than DTH or ITH implants. Three implants failed to integrate, one in each of the three treatment groups, giving initial survival rates of 97.5%, 96.6%, and 96.4% for DTH, ITH, and SPS implants, respectively. Mean cumulative crestal bone loss measurements were 1.84, 1.90, and 0.57 mm for DTH, ITH, and SPS implants, respectively. Bone loss was significantly less with SPS implants than with DTH or ITH implants. A second SPS implant failed after 7 years in function, likely because of prosthetic deficiencies. This late failure reduced the Kaplan-Meier survival rate to 80.4% for the SPS group. CONCLUSION: Results from this teaching clinic suggest that the use of dental implants with sinus elevation procedures is a predictable treatment for the resorbed posterior maxilla.

A pilot study to assess the performance of a partially threaded sintered porous-surfaced dental implant in the dog mandible.

PURPOSE: The purpose of this study was to compare patterns of crestal bone remodeling with 2 sintered porous-surfaced dental implant designs during a 14-month functional period. MATERIALS AND METHODS: Two root-form press-fit dental implants were evaluated in healed extraction sites in dog mandibles. The standard (control) design was a press-fit implant with a 2-mm machined collar; the remainder of the implant had a sintered porous surface. The test or "hybrid" design had 3 coronal machined threads instead of a machined collar; the remainder of the implant had a sintered porous surface. RESULTS: Standardized radiographs indicated significantly less crestal bone loss (0.82 to 0.93 mm versus 1.45 to 1.5 mm) with the hybrid design and a slower approach toward an apparent steady state (12 to 14 months for the hybrid versus 7 months for the standard design). Morphometric assessment of back-scattered scanning electron micrographs confirmed that crestal bone loss was significantly less for the hybrid design on all but the lingual implant aspect. CONCLUSION: The addition of coronal threads to an implant relying on a sintered porous surface geometry for its long-term osseointegration reduced the extent of crestal bone loss compared to a machined collar region.