An unusual case of implant failure

A 67-year-old woman was referred with a rapidly progressing swelling in the left canine region of the edentulous mandible. Nine months earlier, 2 permucosal implants had been placed in her atrophic anterior mandible. A few weeks after implant placement, an inoperable carcinoma of the lung had been diagnosed. This tumor was treated with a combination of chemotherapy and radiotherapy. After 3 months, the implants were provided with a Dolder bar supporting an overdenture. Subsequently, progressive inflammation developed around the left implant and removal of the implant was necessary. When progressive swelling of the mucosa developed at the previous implant site, the patient was referred to an oral and maxillofacial surgeon. The swelling measured 35 mm in diameter and was biopsied. It was diagnosed as a metastasis of the lung carcinoma to the mandible. The tumor of the jaw was treated with local radiotherapy.     

Mandibular fracture caused by peri-implant bone loss: report of a case

BACKGROUND: A major complication related to excessive bone loss around implants is fracture of the mandible. This complication is most likely to occur in a very atrophic mandible. A 57-year-old woman presented with progressive pain and swelling that had been present for 5 days in the right frontal region of the mandible. An intraoral radiograph revealed a radiolucency around one of the implants in the interforaminal region. METHODS: Ten years earlier, 4 hollow-screw implants of 10 mm length had been inserted in the interforaminal region of the edentulous mandible. Throughout the 10-year postoperative period, no adverse clinical events were seen; however, during the last 7 years, no radiographic follow-up was performed. Mobility was tested after removal of the bar, on which one of the implants appeared to be mobile. The mobile implant was removed together with the fibrous tissue. RESULTS: At a recall visit 2 weeks later, a radiograph revealed a fracture of the mandible at the explantation site. Characteristic features of the hollow-screw implant are the hollow body and the transverse openings in the side walls of the implant. It has been reported that these characteristic features can enhance infection and rapid bone loss, but a case of mandibular fracture has never been described. CONCLUSION: Radiographs should be taken on a regular and perhaps more frequent basis to diagnose excessive bone loss, so that measures can be taken to prevent the risk of mandibular fracture.     

Primary stability measurements of single implants in the midline of the edentulous mandible for overdentures

Objectives: To determine the primary stability of the Southern wide diameter (8 mm) implants, Neoss regular diameter (4 mm) implants, and Southern regular diameter (3.75 mm) implants placed in the midline of edentulous mandibles for single‐implant overdentures. Variables related to host site and implant characteristics were investigated to determine their influence on the primary stability of the implants. Materials and methods: A total of 36 implants were placed in the midline symphysis of the edentulous mandibles of 36 participants. Their primary stability was then measured using the magnetic Osstell mentor device. Analysis of variance (ANOVA) was used to compare the mean implant stability quotient (ISQ) scores with one‐way ANOVA for multiple comparisons. Results: The highest measurement (ISQ) of primary stability was for the Southern 8 mm wide diameter implants (84.8, SD 9.8), followed by the Neoss 4 mm regular diameter (82.3, SD 4.8) implants and the Southern 3.75 mm regular diameter implants (75.3, SD 8.4), respectively. The Southern 3.75 mm regular diameter implants had a significantly lower mean ISQ value than the same system 8 mm wide diameter (P=0.004) and the Neoss 4 mm regular diameter implants (P=0.03). No significant differences were observed between the 8 mm and the 4 mm diameter implants (P>0.05). Conclusions: Host‐site variables such as age, gender, bone volume, and quality do not appear to influence the primary stability of the implants. No clear correlation was established between ISQ values and implant diameter. To cite this article:
Alsabeeha NHM, De Silva RK, Thomson WM, Payne AGT. Primary stability measurements of single implants in the midline of the edentulous mandible for overdentures.
Clin. Oral Impl. Res. 21 , 2010; 563–566.
doi: 10.1111/j.1600‐0501.2009.01890.x     

"All-on-Four" immediate function concept and clinical report of treatment of an edentulous mandible with a fixed complete denture and milled titanium framework.

The "All-on-Four" concept-tilting the distal implants in the edentulous arches improves the prosthetic support-increases the inter-implant distance and provides better implant anchorage in the bone by using longer implants. Computer milling of a solid block of titanium also provides frameworks with improved fit and fewer technical challenges than conventional cast or noncast approaches. This clinical report describes a method of restoring an edentulous mandible with the "All-on-Four" immediate function concept and a milled titanium framework. The patient in our clinical report has reported for follow-up visits for 1 year and is satisfied with the outcome of the treatment. No discernable clinical and radiographic changes were noted around the dental implants. To date, there have been no prosthetic complications. The patient is scheduled for quarterly follow-ups to determine the effectiveness of home care.     

The management of a completely edentulous patient using simultaneous maxillary and mandibular CAD/CAM-guided immediately loaded definitive implant-supported prostheses: a clinical report

Functional rehabilitation of a completely edentulous patient with removable prostheses is a clinical challenge. A patient with an edentulous maxilla and mandible received 6 endosseous implants in the maxilla and 5 implants in the mandible using CAD/CAM surgical templates. Definitive maxillary and mandibular implant-supported fixed complete dentures were connected immediately after implant placement using a CAD/CAM-guided implant surgical placement protocol.     

Early functional loading in the fully edentulous mandible after mandibular resection and reconstruction due to an ameloblastoma: case report

Background: Immediate or early functional loading of implants in fully edentulous mandibles can enhance patient comfort and the ability to masticate within a few days after implant placement. Recently there has been evidence that this method of restoring edentulous mandibles is predictable. Purpose: The goal of this case report is to present the treatment of a patient diagnosed with a large ameloblastoma in the mandible. After removal of the tumor and mandibular reconstruction, the patient had complete anesthesia in the right mandible, with an alveolar ridge deformity. Methods: Two years after removal of an ameloblastoma in the right mandibluar sextant, five implants were installed between the mental foramina. One implant was installed for safety reasons in the event one of the others was lost. This implant remains buried. A denture was used as a drilling guide. Abutments were attached to the implants, and impression copings were fixed to the abutments. The denture was used for the “pickup” impression. Flaps were sutured, maintaining exposure of the abutments. In the laboratory, gold cylinders were heat cured to the tissue side of the denture. The cylinders were attached to the cast with laboratory screws. The gold cylinders were heat cured to the intaglio side of the denture. Five days after implant placement, the nonmetal reinforced acrylic denture was fixed to the implants with laboratory screws. The bridge is removed annually, and the implants are examined for mobility and periapical radiographs are taken. Results: The patient has worn the prosthesis for 2.5 years without loss of implants and without breakage of the nonmetal reinforced denture. At 2.5 years the implants are stable, implant sites demonstrate stable crestal bone, and the patient is eating comfortably and without limitations. Conclusion: Early functional loading of implants in the edentulous mandible may offer patients the option of wearing implant‐supported prosthesis immediately or shortly after implant insertion.     

Full-arch restoration of the jaw with fixed ceramo-metal prosthesis: late implant placement

BACKGROUND: The completely edentulous patient has few treatment options in conventional dentistry. When implants are considered, treatment plans range from a 2-implant overdenture to a completely implant-supported prosthesis. Fixed prosthesis is often the preferred selection of the edentulous patient. This study assesses the 5-year cumulative survival rate of implants placed to support full-arch fixed restoration. METHODS: During 1990 to 1995, 171 implants were placed in 22 completely edentulous jaws of 20 patients. All patients were discharged wearing immediate dentures. The implants were analyzed as to the number of implants per jaw, implant location, length, and diameter. RESULTS: The 5-year cumulative survival rate was 89.9%. The mean number of implants per jaw was 7.7 for the maxilla and 8 for the mandible. In the maxilla, the preferred implant locations were the canines, centrals, laterals, and first premolars; in the mandible, they were the canines, laterals, and first molars. The mean implant length was 14.2 mm for the mandible and 13.2 mm for the maxilla. The mean implant diameter was 3.6 mm for the maxilla and 3.8 for the mandible. CONCLUSIONS: The results of the present study indicate that fixed full-arch ceramo-metal restorations can be a predictable implant treatment modality for the edentulous patient.     

Miniplate osteosynthesis of fractures of the edentulous mandible

This study was performed to analyze treatment of fractures of the edentulous mandible and to discuss this method in relation to the mandibular height at the fracture site. Fifteen fracture sites in 11 patients with an edentulous mandible were retrospectively examined. These fractures were located: nine fractures in the mandibular body, three in the paramedian region, and three in the mandibular angle. Fractures in a mandible measuring more than 10 mm in the vertical height were treated with one miniplate. Fractures in an extremely atrophic mandible with 10 mm or less were treated using one or two miniplates, also using a modified Champy plate with 1.3 mm in thickness. A mandibular fracture with a height of 5 mm was treated with a combination of a microplate on the buccal side and a miniplate on the inferior border of the mandible with additional direct circumferential wiring. Oblique or splitting fractures were treated with direct circumferential wiring or a Herbert screw, at one fracture site each, respectively. Complications, including infection, fibrous union, nonunion and trismus, were not seen. In one patient, hypesthesia of the lower lip was, however, persistent 1 month after surgery. Miniplate osteosynthesis is the less invasive treatment, and it is suitable for fractures of the atrophic edentulous mandible, except for comminuted or defect fractures. To obtain stable fixation in severely atrophic mandibles, we need to consider the use of two miniplates or a combination with microplates.     

Mini‐Implants,Mega Solutions: A Case Series

Dental implants have evolved as a standard of care for replacement of missing teeth. Though this treatment modality promises a high level of patient satisfaction and success, it cannot be performed in all cases. Apart from medically compromised patients, implant use is also restricted whenever there is limited available bone volume at the edentulous site. An example includes the mandibular incisor, the maxillary lateral incisor region, and other sites with reduced interdental spacing and atrophic edentulous maxillary and mandibular ridges. Bone volume at some of these sites can be increased by suitable augmentation procedure for placement of a regular diameter implant (3.75 to 4.2 mm). But many a times such procedure cannot be undertaken either due to financial constraint, risk of subjecting the patient to additional surgical procedure, added time factor, or guarded prognosis of the grafted site. In such cases, mini‐implants can be used. In this case series, mini‐implants (2.5 to 3 mm) were used to replace teeth in all mouth quadrants and to retain a mandibular overdenture in a compromised case. The implants served well at all the sites with minimal bone loss and a high level of patient satisfaction. Mini‐implants hold the potential to serve as an alternate to regular diameter implants in certain situations. Preferably they should be used in multiples to retain fixed dental prostheses and might serve as an efficient, low‐cost solution for retaining overdentures in selected cases.     

A prospective clinical study on titanium implants in the zygomatic arch for prosthetic rehabilitation of the atrophic edentulous maxilla with a follow-up of 6 months to 5 years

Background Prosthetic rehabilitation with implant‐supported prostheses in the atrophic edentulous maxilla often requires a bone augmentation procedure to enable implant placement and integration. However, a rigid anchorage can also be achieved by using so‐called zygomatic implants placed in the zygomatic arch in combination with regular implants placed in residual bone. Purpose The aim of the present study was to report on the clinical outcome of using zygomatic and regular implants for prosthetic rehabilitation of the severely atrophic edentulous maxilla. Materials and Methods Sixty‐nine consecutive patients with severe maxillary atrophy were, during a 5‐year period, treated with a total of 69 fixed full‐arch prostheses anchored on 435 implants. Of these, 131 were zygomatic implants and 304 were regular implants. Fifty‐seven bridges were screw‐retained and 12 were cemented. The screw‐retained bridges were removed at the examination appointments and each implant was tested for mobility. In addition, the zygomatic implants were subjected to Periotest^® (Siemens AG, Bensheim, Germany) measurements. The patients had at the time of this report been followed for at least 6 months up to 5 years in loading. Results Two regular implants failed during the study period giving a cumulative survival rate of 99.0%. None of the zygomatic implants was removed. All patients received and maintained a fixed full‐arch bridge during the study. Periotest measurements of zygomatic implants showed a decreased Periotest values value with time, indictating an increased stability. Three patients presented with sinusitis 14–27 months postoperatively, which could be resolved with antibiotics. Loosening of the zygomatic implant gold screws was recorded in nine patients. Fracture of one gold screw as well as the prosthesis occurred twice in one patient. Fracture of anterior prosthetic teeth was experienced in four patients. Conclusions The results from the present study show that the use of zygomatic and regular implants represents a predictable alternative to bone grafting in the rehabilitation of the atrophic edentulous maxilla.     

Mandibular fractures associated with endosteal implants

Purpose

The purpose of this study is to report four cases of mandibular fractures associated with endosteal implants and to discuss prevention and treatment of these types of fractures.

Discussion

To evaluate whether the patient's anatomy allows insertion of implants, radiological exams that demonstrate the height and the labial–lingual width are needed. To reduce the potential fracture problem, the mandible can be restrengthened with bone grafting techniques. The treatment of a fracture in an atrophic mandible is always a challenge because of the diminished central blood supply, the depressed vitality of the bone, and the dependence on the periosteal blood supply. The basic principles in fracture treatment are reduction and immobilization of the fractured site for restoration of form and function.

Conclusions

If implants are placed in severe atrophic mandible, iatrogenic fracture of the mandible may occur during or after implant surgery because implant placement weakens the already-compromised mandible. A few millimeters of cortical bone should remain on both the labial and the lingual sites after the hole for insertion of an implant has been drilled. A 3-D surgical planning should be recommended at least in severe atrophic mandibles in order to prevent a severe reduction of bone tissue.     

Analysis of incidence and associated factors with fractured implants: a retrospective study

Osseointegrated threaded titanium screw-type implants rarely lose integration after the first year of clinical function. Implant failure can occur for other reasons, with implant fracture being one of the major reasons for late failure. The purpose of the present study was to determine the incidence of implant fracture in completely edentulous and partially edentulous arches and to determine what factors may predispose an implant to a higher fracture risk. A retrospective evaluation of 4,937 implants was performed to determine the incidence of and factors common to fractured implants from a sample of implants placed and restored in one institutional setting. Based on the results of this study, the following observations were made: implants fracture at similar rates in the maxilla as in the mandible (0.6%), implant fractures occur more frequently in partially edentulous restorations (1.5%) than in restorations of completely edentulous arches (0.2%), all observed fractures occurred with commercially pure 3.75-mm-diameter threaded implants, and prosthetic or abutment screw loosening preceded implant fracture for the majority of the implants. More studies would be helpful to further explore the relationship and progression of factors associated with implant fracture.     

Syncrystallization: a technique for temporization of immediately loaded implants with metal-reinforced acrylic resin restorations

Background Rigid temporization has been recognized to have a significant impact on the peri‐implant tissue response in immediate implant loading since it reduces the mechanical stress exerted on each implant. Purpose A successful protocol for immediate loading of multiple implants depends on an adequate fixation and immobility of the implants to prevent the risk of micromovements in relation to the surrounding bone. The objective of this article was to evaluate a prosthetic concept for an accelerated rigid splinting of multiple implants for same‐day immediate loading with metal‐reinforced provisional restorations using a technique of welding temporary implant abutments with a prefabricated titanium bar directly in the oral cavity (syncrystallization). Materials and Methods Between June 2004 and January 2005, immediate loading of threaded implants with a metal‐ reinforced acrylic resin provisional restoration at stage 1 surgery was evaluated in 40 consecutive patients. A total of 192 implants were placed in selected edentulous or partially edentulous patients using the syncrystallization technique. Once the titanium bar was welded intraorally to the abutments, opaque was applied and the provisional restoration was relined and screw‐retained the same day. In addition, a comparison of deformations and stress distributions in implant‐supported, metal‐reinforced and nonmetal‐reinforced resin provisional restorations was analyzed in the edentulous mandible by a three‐dimensional finite element model (FEM). Results All of the 192 rigidly temporized immediately loaded implants osseointegrated. An implant success rate of 100% was achieved over a period of 6 months postplacement. No fracture or luting cement failure of the provisional restoration occurred during the observation time. Compared to mere acrylic superstructures, a significant reduction of deformation and strain within metal‐reinforced provisional restorations was detected by FEM analysis. Conclusion The results of this study indicate that the syncrystallization technique allows an expedite and adequate rigid splinting of multiple immediately loaded implants. The advantages of the technique are: (1) reduction of treatment time for immediate temporization at stage 1 surgery; (2) predictable fixation and immobility of implants in the early stages of bone healing; and (3) less time for repairing provisional restorations as a result of no or rare fracture.     

A Double-Blind Randomized Controlled Trial (RCT) of Titanium-13Zirconium versus Titanium Grade IV Small-Diameter Bone Level Implants in Edentulous Mandibles - Results from a 1-Year Observation Period

Background: The use of endosseous dental implants has become common practice for the rehabilitation of edentulous patients, and a two‐implant overdenture has been recommended as the standard of care. The use of small‐diameter implants may extend treatment options and reduce the necessity for bone augmentation. However, the mechanical strength of titanium is limited, so titanium alloys with greater tensile and fatigue strength may be preferable. Purpose: This randomized, controlled, double‐blind, multicenter study investigated in a split‐mouth model whether small‐diameter implants made from Titanium‐13Zirconium alloy (TiZr, Roxolid?) perform at least as well as Titanium Grade IV implants. Methods and Materials: Patients with an edentulous mandible received one TiZr and one Ti Grade IV small‐diameter bone level implant (3.3 mm, SLActive®) in the interforaminal region. The site distribution was randomized and double‐blinded. Outcome measures included change in radiological peri‐implant bone level from surgery to 12 months post‐insertion (primary), implant survival, success, soft tissue conditions, and safety (secondary). Results: Of 91 treated patients, 87 were available for the 12‐month follow‐up. Peri‐implant bone level change (?0.3 ± 0.5 mm vs ?0.3 ± 0.6 mm), plaque, and sulcus bleeding indices were not significantly different between TiZr and Ti Grade IV implants. Implant survival rates were 98.9 percent and 97.8 percent, success rates were 96.6 percent and 94.4 percent, respectively. Nineteen minor and no serious adverse events were related to the study devices. Conclusion: This study confirms that TiZr small‐diameter bone level implants provide at least the same outcomes after 12 months as Ti Grade IV bone level implants. The improved mechanical properties of TiZr implants may extend implant therapy to more challenging clinical situations.     

Implant osseointegration in the absence of primary bone anchorage: a clinical report

The authors identified no report describing implant primary stability obtained by external fixation as a means to achieve osseointegration in craniofacial settings. This article describes a situation in which an implant was placed without direct contact with the resident bone; primary stability was provided by an external device. An edentulous patient was restored with 5 endosseous titanium implants to support a mandibular fixed prosthesis. An implant placed in the right central incisor position was removed after 48 hours and replaced with a shorter and narrower implant without contact with resident bone. Thus, primary stability for the implant was provided by rigid fixation to the prosthesis rather than by bone anchorage. At recall examinations after 6 and 27 months, all implants, including the implant in the right central incisor position, showed clinical and radiographic signs of osseointegration. Resonance frequency analysis indicated acceptable stability and osseointegration for all implants. Observations of this patient suggest that implant osseointegration can be achieved by providing primary stability using a fixed complete denture. Primary bone anchorage/contact does not appear to be critical to the osseointegration process.     

Immediate loading in partially and completely edentulous jaws: a review of the literature with clinical guidelines

The introduction of immediate loading was a paradigm shift in implant dentistry as it was previously believed that an unloaded period was essential for bone healing in order to promote osseointegration. However, this belief could not be confirmed by clinical studies or by human histology. Hitherto, numerous reports have been published on immediate loading in various indications. An important factor for success is primary implant stability. The latter can be improved by adapting drilling protocols to enhance lateral compression of the bone and by using tapered implant designs with apical thread fixation. To some extent, the use of implants with a microrough surface and rigid splinting may compensate for suboptimal stability. It is important to avoid fracture of the provisional restoration at all times as this may result in local overloading and implant failure. Also, unevenly distributed occlusal contacts may contribute to failure and therefore occlusion ought to be evaluated at every occasion, especially during the early phase of healing. Taking these aspects into account, immediate loading in the fully edentulous mandible by means of an overdenture has been shown to be predictable in terms of implant survival (94.4–100%). However, the procedure may result in additional costs as a result of the need for repeated relining. In addition, the scientific basis for this treatment concept in the maxilla is very scarce. Immediate loading in the fully edentulous jaw by means of a fixed prosthesis is a well‐documented treatment concept. In the mandible, three implants have been shown to be insufficient, given the failure rate of up to 10%. With at least four implants a failure rate of 0–3.3% may be expected. In the maxilla, four to six implants could be too limited, given the failure rate up to 7.2%. Increasing the number of implants may reduce implant failure to 3.3%. Provisional fixed prostheses are particularly prone to fracture in the maxilla and hence reinforcement is warranted. Immediately loaded single implants have lower survival rates, of 85.7–100%, with no clear impact of occlusal contact. In fact, a meta‐analysis demonstrated a five times higher risk of failure for immediately loaded single implants when compared with delayed loading. No study showed superior soft‐tissue preservation or esthetics following immediate loading of single implants compared with other loading protocols. However, this finding may not imply that a provisional implant crown becomes redundant when soft‐tissue conditioning is deemed necessary. Taking into account earlier factors for success, immediate loading in the partially edentulous jaw by means of a fixed prosthesis seems predictable in terms of implant survival (95.5–100%). However, there are no studies with data on soft‐tissue parameters, esthetic aspects or patient‐centered outcomes, and the available studies mainly relate to the load‐carrying part of the dentition. Clinical studies focusing on these aspects of treatment outcome are clearly needed. High patient satisfaction is the most important advantage of immediate loading, especially during the early healing phase. In this context, one should also realize that studies have revealed comparable patient satisfaction in patients following delayed loading once their prosthesis is in place. In the decision‐making process, this aspect should be properly discussed with the patient along with other advantages and disadvantages of immediate loading.     

Simultaneous implant placement and vertical ridge augmentation with a titanium-reinforced membrane: a case report

The present report demonstrates a clinical approach to achieve vertical ridge augmentation around endosseous implants. Two implants were placed, leaving the threads exposed, in the atrophic mandibular right posterior quadrant of a male patient. Both implants were covered with a titanium-reinforced expanded polytetrafluoroethylene (e-PTFE) membrane. Second-stage surgery was performed 12 months after implant placement. Upon membrane removal, growth of mineralized tissue was observed around both implants, covering areas previously not covered by bone. Implants were then progressively loaded and restored. Titanium-reinforced e-PTFE membranes can be satisfactorily used for vertical augmentation of atrophic ridges.     

Immediate Rehabilitation of the Extremely Atrophic Mandible with Fixed Full‐Prosthesis Supported by Four Implants

Purpose: To prospectively assess the outcome of immediate rehabilitation of extremely atrophic mandibles by a full‐arch fixed bridge anchored to four implants. Material and Methods: Twenty patients with edentulous mandibles were included in the study. Each patient received a full‐arch fixed bridge supported by two axial and two distal tilted implants. Prosthetic loading was applied within 48 hours of surgery. Patients were scheduled for follow‐up every 6 months up to 2 years and annually until 5 years. Radiographic evaluation of marginal bone level change was performed at 1 year. Results: All patients were followed for a minimum of 1 year (range 20–48 months, mean 30.1 months). No failures were recorded to date. The 1‐year implant survival rate and prosthesis success rate were 100%. Marginal bone loss around axial and tilted implants was similar at 12‐month evaluation, being, respectively, 0.6 ± 0.3 (standard deviation) mm and 0.7 ± 0.4 mm. High patient's level of satisfaction was recorded for function, phonetics, and aesthetics. Conclusion: This technique could be considered a viable treatment option for the rehabilitation of the atrophic mandible.     

Comparing bar and double-crown attachments in implant-retained prosthetic reconstruction: a follow-up investigation

Objectives: A removable implant‐retained dental prosthesis in an edentulous mandible can use telescopic crowns or a bar superstructure as anchorage elements for an overdenture. The aim of this study was to compare the clinical results for bar‐anchored and telescopic crown‐retained overdentures in implant prosthetic treatment of the toothless lower jaw with two or more implants placed in the intraforaminal region. Material and methods: A clinical and radiographical comparison was made of the telescope vs. the bar method for removable prosthetic rehabilitation treatments in patients with an edentulous mandible. For evaluation of the clinical data, the sulcus fluid flow rate, Periotest values, and the peri‐implant bone loss were recorded. Results: In the follow‐up examinations, 19 implant losses were reported between insertion and review of 328 implants. The frequency distribution of the observed loss rates showed no treatment‐specific trend. In the group with bar‐treated implants, failure led to ‘group loss’ of the whole prosthetic superstructure. Failure of one of the double‐crown‐stabilized full dental prosthesis could usually be adapted so that the overdenture remained usable even without re‐implantation. Conclusions: After comparing all the clinical parameters evaluated, no significant difference between the stabilization of full dentures via conus and telescopic crowns and bar‐anchored dentures could be found. The choice of one particular method remains the decision of the professional treating the patient.