Orthodontic Management of a Migrated Maxillary Central Incisor With a Secondary Occlusal Trauma.

INTRODUCTION: Normal or excessive occlusal forces exerted on teeth with a reduced periodontal support might result in a secondary occlusal trauma. This type of injury is diagnosed based on histological changes in the periodontium. Multiple clinical and radiographic indicators are, therefore, required as surrogates to assist the presumptive diagnosis of a (secondary) occlusal trauma. CASE PRESENTATION: In this case report, the diagnosis, management, and the 1-year follow-up of a secondary occlusal trauma of a maxillary central incisor are described. The occlusal relationship was rehabilitated with fixed orthodontic appliances and was further stabilized with both fixed and removable retainers. CONCLUSIONS: A combined periodontal-orthodontic approach for a secondary occlusal trauma allows the rehabilitation of periodontal, occlusal, and esthetic parameters. Twelve months after the end of the active orthodontic treatment, a combination of fixed and removable retainers showed to be effective in retaining the treatment outcome.

A retrospective analysis of early and immediately loaded osseotite implants in cross-arch rehabilitations in edentulous maxillas and mandibles up to 7 years.

BACKGROUND: Immediate loading of full-arch restorations yields good results in selected cases, but long-term follow-up and the outcome in compromised bone are scarcely evaluated. PURPOSE: To evaluate immediately loaded Osseotite implants (Biomet 3i, Palm Beach, FL, USA) installed in healed or grafted bone, with regard to implant survival and peri-implant bone loss up to 7 years in function. MATERIALS AND METHODS: Information was retrospectively retrieved from 83 patients' records with 749 Osseotite implants supporting immediately loaded semipermanent full-arch acrylic restorations. Five hundred sixty-eight (75.8%) implants were placed in healed bone and 181 (24.2%) in augmented bone, regenerated with sinus lifting and/or onlay/inlay grafts with/without biomaterials and membranes. Implant survival and success based on radiological peri-implant bone loss were registered. Wilcoxon rank sum tests evaluated peri-implant bone loss in compromised versus healed bone or between jaws or time intervals with p<.05 as statistically significant. RESULTS: Sixteen of 749 implants failed (2.1%), 11/343 in maxilla (3.2%) and 5/406 (1.2%) in mandible. After 7 years, the cumulative failure rate was 9%. Mean peri-implant bone loss increased to 1.2 mm (SD 1.0) during the first 2 years but remained unchanged thereafter. Around implants in grafted bone, on average, 0.3 mm more bone loss was found. CONCLUSION: The Osseotite implants offer a predictable long-term outcome in terms of implant survival and stable peri-implant bone under immediate loading even in grafted bone. However, the high incidence of technical repair because of fractures of the semipermanent provisionals requires attention because it may be negative from a cost-benefit perspective. Implants in grafted bone show a tendency to a more pronounced initial bone remodeling without clinical consequence in the long term.

Accuracy and complications using computer-designed stereolithographic surgical guides for oral rehabilitation by means of dental implants: a review of the literature.

BACKGROUND: In the last decade several stereolithographic guided surgery systems were introduced to the market. In this context, scientific information regarding accuracy of implant placement and surgical and prosthodontical complications is highly relevant as it provides evidence to implement this surgical technique in a clinical setting. PURPOSE: To review data on accuracy and surgical and prosthodontical complications using stereolithographical surgical guides for implant rehabilitation. MATERIAL AND METHODS: PubMed database was searched using the following keywords: "three dimensional imaging,""image based surgery,""flapless guided surgery,""customized drill guides,""computer assisted surgery,""surgical template," and "stereolithography." Only papers in English were selected. Additional references found through reading of selected papers completed the list. RESULTS: In total 31 papers were selected. Ten reported deviations between the preoperative implant planning and the postoperative implant locations. One in vitro study reported a mean apical deviation of 1.0 mm, three ex vivo studies a mean apical deviation ranging between 0.6 and 1.2 mm. In six in vivo studies an apical deviation between 0.95 and 4.5 mm was found. Six papers reported on complications mounting to 42% of the cases when stereolithographic guided surgery was combined with immediate loading. CONCLUSION: Substantial deviations in three-dimensional directions are found between virtual planning and actually obtained implant position. This finding and additionally reported postsurgical complications leads to the conclusion that care should be taken whenever applying this technique on a routine basis.

A prospective study on the accuracy of mucosally supported stereolithographic surgical guides in fully edentulous maxillae.

BACKGROUND: Flapless implant placement using guided surgery is widespread, although clinical publications on the precision are lacking. PURPOSE: The purpose of this study was to evaluate the accuracy of mucosal-supported stereolithographic guides in the edentulous maxillae. MATERIALS AND METHODS: Seventy-eight OsseoSpeed™ implants (Astra Tech AB, Mölndal, Sweden) of 3.5 to 5 mm width and 8 to 15 mm length were installed consecutively in 13 patients. Implants were functionally loaded on the day of surgery, and implant location was assessed with a computed tomography scan. Mimics 9.0 software (Materialise N.V., Leuven, Belgium) was used to fuse the images of the virtually planned and actually placed implants, and the locations, axes, and interimplant distances were compared. RESULTS: One implant was lost shortly after insertion because of abscess formation caused by remnants of impression material. Seventy-seven implant locations were analyzed. The deviation at the entrance point ranged between 0.29 mm and 2.45 mm (SD: 0.44 mm), with a mean of 0.91 mm. Average angle deviation was 2.60° (range 0.16-8.86°; SD: 1.61°). At the apical point, the deviation ranged between 0.32 mm and 3.01 mm, with a mean of 1.13 mm (SD: 0.52 mm). The mean deviation of the coronal and apical interimplant distance was respectively 0.18 mm (range 0.07-0.32 mm; SD: 0.15) and 0.33 mm (range 0.12-0.69 mm; SD: 0.28). These deviations are lower than the global coronal and apical deviations. CONCLUSION: The present study is the first to investigate the accuracy of stereolithographic, full, mucosally supported surgical guides in the treatment of fully edentulous maxillae. Clinicians should be warned that angular and linear deviations are to be expected. Short implants show significantly lower apical deviations compared with longer ones. Reasons for implant deviations are multifactorial; however, it is unlikely that the production process of the guide has a major impact on the total accuracy of a mucosal-supported stereolithographic guide.

Clinical outcome and bone preservation of single TiUnite™ implants installed with flapless or flap surgery.

BACKGROUND: Flapless, free-handed implant surgery offers advantages for patient comfort, but studies on long-term clinical success based on marginal bone loss are scarce. AIM: The aim of this study was to compare single implants installed with a flap (F) or flapless (FL) surgery with respect to survival and marginal bone preservation after at least 3 years. MATERIALS AND METHODS: Fifty-three TiUnite™ Brånemark implants, installed in 49 patients (27 females; 22 males; mean age 53 years) were examined. Then, 25 F and 28 FL were delayed loaded; bone level from the abutment-implant level was measured on intraoral radiographs. From 44 (21 F, 23 FL), 31 (18F, 13 FL), and 36 (18 F, 18 FL) implants, radiographs were available at baseline and after 1 and 3 years of function. RESULTS: The overall survival rate was 100% and the overall mean bone loss after an average of 38 months was 1.35 mm (SD 0.91; range 0-3.7). Both F and FL showed increasing bone loss during the first year with a higher bone loss for FL than for F sites (p < .01). Afterward, no further bone loss occurred and both groups were statistically equal (p > .7). On individual implant level, nearly 80% in both F and FL were considered a success showing bone loss between 1.5 and 1.9 mm. CONCLUSIONS: Single implants yield an excellent prognosis with stable bone levels irrespective of the surgical technique, and free-handed flapless surgery is a viable alternative to more extensively planned guided surgery. Proper case selection and clinical experience are considered prerequisites for a predictable treatment outcome.

Effect of implant design on preservation of marginal bone in the mandible.

BACKGROUND: Implant design and surface may have an influence on the marginal bone response during immediate functional loading. AIM: The purpose of this study was to radiographically study the effect of implant design on marginal bone preservation at immediately loaded implants used for prosthetic rehabilitation of the completely edentulous mandible. MATERIALS AND METHODS: A total of 39 patients, previously treated with five implants for support of a full-arch fixed bridge in the mandible, were included in the study. Either machined Brånemark implants (Ma) (Nobel Biocare AB, Gothenburg, Sweden) or surface modified Astra Tech implants with (Mi) or without a microthreaded neck (Ti) (TiOblast, AstraTech AB, Mölndal, Sweden) were used. All fixtures were loaded with a provisional glass fiber or metal-reinforced screw-retained restoration within 24 hours. The provisional restorations were replaced by a 12-unit screw-retained metal-ceramic or metal-resin cantilever bridge after 3 months. Bone loss from baseline to 1 year of loading was measured by means of intraoral radiographs. Only patients with baseline and 1-year radiographs of all implants were selected for comparison. Statistical analysis was carried out on both patient and implant levels. RESULTS: The survival rates after 1 year in function were 98.6, 100, and 100% for the Ma, Ti, and Mi implants, respectively. The overall mean bone loss after 1 year was 1.03 mm (SD 0.87; range -0.77 to 2.5). The mean bone loss was calculated to 1.52 (SD 0.66) for the Ma group, 0.79 (SD 0.79) for the Ti group, and 0.70 (SD 1.01) for the Mi group. There was a significant difference between Ma and Ti (p = .023) and between Ma and Mi (p = .046) groups but not within Ti and Mi implants (p = .70). These conclusions were also valid when the statistical analysis was performed on implant level. CONCLUSIONS: There is no impact of design and surface on implant survival in the completely edentulous mandible. Bone preservation in immediately loaded implants in the mandible is influenced by implant design and significantly better on surface-modified AstraTech implants compared with machined Brånemark implants. In the mandible, a microthread design of the implant collar does not seem to improve bone preservation.

Two-year outcome with Nobel Direct implants: a retrospective radiographic and microbiologic study in 10 patients.

INTRODUCTION: The Nobel Direct implant (Nobel Biocare AB, Göteborg, Sweden) was developed to minimize marginal bone resorption and to result in "soft tissue integration" for an optimized aesthetic outcome. However, conflicting results have been presented in the literature. The aim of this present study was to evaluate the clinical and microbiologic outcomes of Nobel Direct implants. MATERIALS AND METHODS: Ten partially edentulous subjects without evidence of active periodontitis (mean age 55 years) received 12 Nobel Direct implants. Implants were loaded with single crowns after a healing period of 3 to 6 months. Treatment outcomes were assessed at month 24. Routine clinical assessments, intraoral radiographs, and microbiologic samplings were made. Histologic analysis of one failing implant and chemical spectroscopy around three unused implants was performed. Paired Wilcoxon signed-rank test was used for the evaluation of bone loss; otherwise, descriptive analysis was performed. RESULTS: Implants were functionally loaded after 3 to 6 months. At 2 years, the mean bone loss of remaining implants was 2.0 mm (SD +/- 1.1 mm; range: 0.0-3.4 mm). Three out of 12 implants with an early mean bone loss >3 mm were lost. The surviving implants showed increasing bone loss between 6 and 24 months (p = .028). Only 3 out of the 12 implants were considered successful and showed bone loss of <1.7 mm after 2 years. High rates of pathogens, including Aggregatibacter actinomycetemcomitans, Fusobacterium spp., Porphyromonas gingivalis, Pseudomonas aeruginosa, and Tanerella forsythia, were found. Chemical spectroscopy revealed, despite the normal signals from Ti, O, and C, also peaks of P, F, S, N, and Ca. A normal histologic image of osseointegration was observed in the apical part of the retrieved implant. CONCLUSION: Radiographic evidence and 25% implant failures are indications of a low success rate. High counts and prevalence of significant pathogens were found at surviving implants. Although extensive bone loss had occurred in the coronal part, the apical portion of the implant showed some bone to implant integration.

A model study on flapless implant placement by clinicians with a different experience level in implant surgery.

INTRODUCTION: Some implant companies advocate that flapless surgery is easy to perform and beneficial for aesthetics and patients morbidity. However, studies objectively analyzing the position in the bone of implants installed with this approach are lacking. This in vitro model study was performed to analyse deviations in position and inclination of implants placed with flapless surgery compared with the ideally planned position and to examine whether the outcome is affected by experience level. METHODS: Identical radio-opaque resin models were developed with a silicon lining mimicking the soft tissues and six edentulous single tooth spaces. Eighteen clinicians (six periodontists, six general dentists and six students) drilled four implant sites each (Straumann AG, Basel, Switzerland) with a flapless approach. Corresponding CT-scan images of the models were available. A virtual implant program (Simplant, Materialise NV, Leuven, Belgium) was used to plan the ideal position and to compare this with the implant angulation and position of the test implants. RESULTS: There were no significant differences between the experience groups for all parameters except for global deviations between dentist and students, angle deviations between dentists and students and horizontal deviations between specialists and students. In incisor sites, specialists and students deviated significantly more in global deviation and depth than dentists. In premolar and molar sites, there were no significant differences except for horizontal deviations between specialists and dentists in molar sites. As a consequence of the malpositioning, perforations were seen in 59.7% (43/72) of the implant occasions when the artificial mucosa was removed from the model. CONCLUSION: The three-dimensional location of implants installed with flapless approach differs significantly from the ideal, although neighbouring teeth were present and maximal radiographical information was available. Within the limitations of this in vitro model study it seems necessary to point out that these deviations would in a clinical situation lead to complications such as loss of implant stability, aesthetical and phonetical consequences. The outcome is not influenced by the level of experience with implant surgery. This points out that more precise measurements of soft tissue in situ or additional use of guiding systems are recommendable.

Immediate loading in the completely edentulous mandible: technical procedure and clinical results up to 3 years of functional loading.

OBJECTIVES: This prospective mono-center study describes a clinical technique to provide dental implants with a temporary cross-arch cantilever bridge functionally loaded on the day of fixture insertion and discusses the 3-year follow-up of four to six machined surface Brånemark implants installed in the interforamina area. MATERIAL AND METHODS: Ninety Brånemark implants were installed in 18 edentulous mandibles. Five patients were heavy smokers and one had Down syndrome. The day of surgery, a 10 unit provisional glassfiber-reinforced cantilever bridge was installed. The final 12 unit bridge was in place after an average of 144 days (range 10-332). Bone-to-implant level was assessed radiologically from the day of surgery up to 3 years. RESULTS: Two out of five fixtures were lost within 3 months in the Down syndrome patient but the provisional bridge continued to function on the three remaining implants until the patient was successfully reoperated. Another implant was lost after 11 months due to a non-detected fracture in the metal framework, resulting in overloading of the cantilever part. As no additional losses occurred during the follow-up time (range 57-26 months), the total failure rate is 3/91 (3.3%). Seventeen of the 18 patients are loading their implants more than 3 years and nine have moved beyond the 4-year period. Average bone remodelling as measured on the apical radiographs from 12 patients at 0, 12 and 36 months revealed a statistically significant bone loss from the initial 0.1 mm [standard deviation (SD) 0.2; range 0-0.7] toward 1.8 mm (SD 0.2; range 1.6-2.2) during the first year of function. (Wilcoxon's signed rank test; P<0.002). After 3 years, no further significant bone loss occurred. CONCLUSION: This 3-year study shows that machined surface Brånemark implants can be immediately loaded with cross-arch cantilever bridges with an average bone-remodelling pattern indicative of a steady state after 1 year of loading.