Buccal bone dimensions and aesthetic outcome at maxillary incisors replaced by conventional dental implants. A case series with a 5-year follow-up.

In the aesthetic field, successful replacement of a tooth with a dental implant requires blend and harmony within the existing dentition. The influence of the dimension of buccal bone at implant sites on aesthetic outcomes and the relation between buccal bone horizontal and vertical dimensions are unclear. The aim of the present study is to investigate the correlation between buccal bone thickness, buccal bone level and aesthetic outcome in conventionally placed implants ­ placed five or more years previously ­ supporting single maxillary incisors. Eight subjects with 8 implants and with periapical and parallel profile X-rays were clinically examined to assess the "Pink Aesthetic Score" (PES). Buccal bone level and thickness, together with the interproximal bone level, were measured. Implant survival was 100%. The mean time of implants function was 89.3 months (standard deviation 43, range 61-145). The mean PES value was 9.4. The mean interproximal bone level was located 1.3 mm apically to the implant abutment junction, while the corresponding buccal value was 1.6 mm. Buccal bone was mostly absent at the implant abutment junction; 2 and 4 mm apically respect to the junction the thickness was on average 0.44 and 0.89 mm, respectively. The dimension of buccal bone level was correlated to the buccal bone thickness at 2mm-level, to the interproximal bone level and to the soft tissue contour score. Conventional implant placement in pristine bone might lead to satisfactory long-term aesthetic results. The level of the facial mucosa and appearance of the alveolar process might emerge as critical aspects.

Radiological evaluation of the Cresco system in combination with Osseospeed implants: a preliminary 3-year report.

AIM: In this preliminary study, the 3-year radiological outcomes of Osseospeed implant-supported fixed complete or partial prostheses made with two different laboratory protocols were compared. METHODS: A convenience sample of 34 patients, who were either partially or completely edentulous in either jaw, were randomly assigned to two groups, of 17 patients each, using either a traditional laboratory protocol (control group) or the Cresco one (test group). The study's objective was an assessment of marginal bone loss around implants, measured on intraoral radiographs at 3-year follow-up. RESULTS: None of the implants inserted was lost during the study and radiological measurements of marginal bone level changes revealed that the mean marginal bone loss was respectively 0,73±0,33mm for test group and 0,88±1,13mm for control group. The differences between test and control groups were not statistically significant. CONCLUSION: This preliminary study did not demonstrate statistically significant differences in marginal bone loss around implant-prostheses prepared with the two different laboratory protocols, over the 3-year observational period.

Cement thickness at implant-supported single-tooth Lava assemblies: a scanning electron microscopic investigation.

OBJECTIVES: The fit of implant-supported single-tooth Lava zirconia assemblies was investigated in this study. The implant-abutment interface, the interface between the metallic and the zirconia portion of the abutment and the interface between Lava abutments and copings were evaluated. The adaptation of titanium abutments to implants and Lava copings was investigated as a control. MATERIAL AND METHODS: Twenty implants were randomly assigned and connected to Lava abutments (group 1) or titanium abutments (group 2). All specimens were subjected to scanning electron microscopy (SEM) analysis of the fixture/abutment fit. Afterwards, specimens were luted to Lava copings and subjected to a SEM evaluation of the marginal external adaptation of the abutments with the copings. Finally, the samples were embedded in resin, sectioned and subjected to SEM analysis of the following interfaces; group 1: titanium/zirconia interface (between the constitutive components of the Lava abutment) and the zirconia/zirconia interface (between the Lava abutment and the coping); group 2: the titanium/zirconia interface (between the titanium abutment and the Lava coping). Non-parametric analysis of variance and a post hoc test were used for statistical analysis. RESULTS: Significant differences emerged in the cement thickness between titanium and zirconia components of the Lava abutments as compared with the thickness measured at the interface between Lava copings and the abutments investigated. No differences were found in cement thickness between Lava copings and the two different abutments. CONCLUSIONS: When Lava abutments are used, the most critical cement thickness is the internal interface between its titanium and zirconia components. Lava coping adaptation for both Lava and titanium abutments is within the clinical acceptable range.

An eleven-year case report of an avulsed maxillary central incisor after delayed replantation.

A 12 year-old girl presented with an avulsed maxillary central incisor for a trauma occurred two days earlier. The avulsed tooth was endodontically treated and replanted. Regardless of the ankylosis and replacement root resorption the tooth was retained for a very favourable nine-year period after trauma. In addition no severe infraposition occurred. When the extraction was necessary, despite the slight atrophy, as a result of compromised alveolar bone development due to ankylosis, an implant-supported crown was placed as definitive rehabilitation without recourse to bone augmentation procedures. In conclusion, delayed replantation in children will require long-term therapeutic commitment. In favourable cases, tooth with delayed replantation might be retained for a very long time thus avoiding the bone atrophy that would have accompanied early tooth loss and, consequently, reducing grafting requirements when a definitive implant-supported restoration will be required.

The speed of sound correlates with implant insertion torque in rabbit bone: an in vitro experiment.

OBJECTIVES: This study investigated the correlation of quantitative ultrasound with bone quality as evaluable from implant final insertion torque. MATERIAL AND METHODS: Implants were planned at diaphyses (group 1) and epiphyses (group 2) of 16 rabbit femurs where amplitude-dependent speed of sound (Ad-SOS) was measured. The insertion torque from 7-mm-long implants placed at planned sites was recorded. The correlation between cutting torque and Ad-SOS was evaluated using Spearman's coefficient. RESULTS: Statistics were based on data from 15 diaphyses and 13 epiphyses. The mean insertion torque was 8.8 N cm while the mean Ad-SOS was 1710.9 m/s. A negative correlation resulted between insertion torque and Ad-SOS. CONCLUSIONS: In the rabbit bone model investigated, quantitative ultrasound correlates inversely with implant insertion torque. Although this correlation remains to be verified in humans because rabbit femur does not convincingly represents different human bone qualities, it seems that ultrasound could convey potentially useful, pre-surgical, site-specific, non-invasive information on bone mechanical characteristics therefore deserving further research efforts.

Stability values of titanium dioxide-blasted dental implants in edentulous maxillas: a 3-year pilot study.

The purpose of this follow-up study was to measure the resonance frequency of Astra Tech TiO(2) blasted implants at second surgery, at one and 3 years of loading. Secondly, it was investigated whether resonance frequency at second surgery could discriminate between successful implants and those that will fail over a 3-year period. Fifty titanium dioxide-blasted implants in eight consecutive patients with edentulous maxillas seeking fixed rehabilitations, were included in the study at abutment connection after 6 months of healing. Resonance frequency, clinical and radiographic records were obtained at abutment connection and after one and 3 years of loading. The cumulative survival rate after 3 years was 100%. The mean resonance frequencies were 65 +/- 4.8 implant stability quotient (ISQ) at second surgery (range 50-78 ISQ), 66 +/- 3.4 ISQ after 1 year of loading (range 53-76 ISQ) and 64 +/- 3.8 ISQ after 3 years of loading (range 53-77 ISQ). No significant differences resulted between these three time points. The marginal bone level decrease of 0.6 mm between the second surgery and the 3-year follow-up was observed. One limitation of the study is that no late failures were encountered in this relatively small sample. Consequently, it was not possible to establish a cut-off ISQ for implants that, after abutment connection, would maintain their stability over a 3-year period. Nevertheless, it might be concluded that following the first year of loading the range of 53-76 ISQ describes the stability of osseointegrated Astra Tech TiO(2) blasted implants.

One-year outcome of narrow diameter blasted implants for rehabilitation of maxillas with knife-edge resorption.

OBJECTIVES: This study aimed at assessing the clinical outcome of narrow diameter implants in the treatment of knife-edge edentulous maxillas of adequate bone height but inadequate width (class IV of Cawood and Howell). MATERIAL AND METHODS: Twelve consecutive patients (eight women and four men, mean age 58 years) with class IV atrophic edentulous maxillas were included in the study. Seventy-three microthreaded TiO(2)-blasted implants were placed and the resonance frequency measured. All the implants had a diameter of 3.5 mm. After 6 months of submerged healing, fixed implant-supported prostheses were delivered to the patients and resonance frequency and radiographic examinations performed. After the first year of loading, the implant outcome was again evaluated clinically, radiographically and with resonance frequency analysis. RESULTS: All the implants were followed up to 1 year of loading and their survival rate was 100%. Bone loss after 1 year of loading was (mean+/-SD) 0.30+/-0.13 mm. Stability values were (mean+/-SD) 63+/-5.8 ISQ at placement, 60+/-4.7 ISQ at the abutment connection and 61+/-5 ISQ after 1 year of loading. A significant difference resulted between placement and abutment connection values (P=0.03). CONCLUSIONS: According to the present study, narrow implants may be used to restore edentulous maxillas with atrophies of class IV of Cawood and Howell. When planning the treatment of edentulous maxillas with such a resorption pattern, this possibility has to be considered as an alternative to more demanding grafting techniques.

Sinus membrane elevation in combination with placement of blasted implants: a 3-year case report of sinus augmentation without grafting material.

Owing to the increasing use of dental implants to restore edentulous conditions, clinicians often face situations where available bone volumes are reduced and need to be augmented before implant placement. This is common in the posterior maxilla, where the presence of the maxillary sinus combined with severe atrophy of the bone crest, owing to long-standing edentulism or pathological conditions, might preclude implant placement. Techniques to augment the sinus floor in combination with several grafting materials are commonly used to restore adequate volumes for implantation. Recent studies have described bone reformation and integration of oxidized implants by simple elevation of the sinus membrane without any grafting material. The aim of this case report is to document the application of the sinus membrane elevation technique in combination with the placement of 3 blasted microthreaded implants in a patient who was clinically and radiographically followed up for 3 years. During the follow-up period, the blasted implants were all stable and intraoral radiographs showed that the bone reformed in contact with the implants and remained stable.

Use of short implants for functional restoration of the mandible after giant cell tumor removal. Case report.

The giant cell tumor of the jaws is a rare benign lesion, it has a slow and progressive evolution and it is locally aggressive. Its etiopathogenesis is unknown, it is most common in the mandible and it is often asymptomatic but pain arises from palpation of the area. Diagnosis is made by radiological and histological examination and surgical treatment is necessary. The clinical case of a 28-year-old man affected by a giant cell tumor of the mandible with an aggressive clinical and radiographical behaviour is reported. The patient showed a jaw swelling covered by hyperemic fibro-mucous tissue from tooth 4.6 to 3.4, absence of cortical bone and mobility of teeth. He also reported lip anesthesia. The giant cell tumor diagnosis was made with orthopantomography (OPT), computed tomography (CT) and needle biopsy. The lesion was surgically removed and histological examination confirmed the diagnosis. In spite of the wide loss of bony substance after surgery, the patient was provided with an implant supported fixed prosthesis without previous bone graft. In this case short implants allowed the prosthetic rehabilitation of a mandible with severe ''resorption'' due to surgical removal of a tumor. Implants were placed in the residual bone volume and successfully used to support a fixed prosthesis. The final result is optimal as is the quality of life of the young patient.

A comparative study of Endoflare-Hero Shaper and Mtwo NiTi instruments in the preparation of curved root canals.

AIM: To analyse the shaping ability of two new NiTi rotary systems in molar curved canals. METHODOLOGY: Thirty molar root canals with curvatures from 24 degrees to 69 degrees were divided into two groups that were balanced in terms of curvature. The canals in one group were shaped using the Mtwo (Sweden & Martina, Padova, Italy) and the canals in the other group using the Endoflare-Hero Shaper (Micro-Mega, Besançon, France) in a modified sequence. Pre- and post-instrumentation X-rays were taken using a radiographic platform, with a contrast medium being used to enhance canal opacity. The dentine removed at five positions along the canals, the symmetry of canal shaping and the presence of aberrations were analysed through computer-aided measurements. The instrument failures, the working time and the changes in working length were also recorded. The Mann-Whitney U-test was used for statistical analyses. RESULTS: Both systems produced uniform dentine removal and symmetrical canal shapes; there was no significant difference between the systems (P > 0.05). In the apical region, preparations were centred in the canal. A mean loss of working length of 0.55 mm for Mtwo and 0.58 mm for Endoflare-Hero Shaper was detected, with no significant differences between the instruments (P > 0.05). No aberrations were seen and no instruments separated. The mean working time was 124.4 s for the Mtwo system and 141.3 s for the Endoflare-Hero Shaper but this difference was not statistically significant (P > 0.05). CONCLUSION: The systems tested in this study were effective in shaping curved canals in extracted teeth.

Clinical and histologic evaluation of an active "implant periapical lesion": a case report.

A new entity called "implant periapical lesion" has recently been described. This lesion could be the result of, for example, bone overheating, implant overloading, presence of a preexisting infection or residual root fragments and foreign bodies in the bone, contamination of the implant, or implant placement in an infected maxillary sinus. This case report describes a titanium implant that was placed in the maxillary premolar region. A fenestration involving the middle portion of the implant was present. After 7 months, the apical portion of the implant showed radiolucency. This lesion rapidly increased in size and a vestibular fistula appeared. A systemic course of antibiotics was not successful, and the implant was then removed. The histologic examination showed the presence of necrotic bone inside the antirotational hole of the implant. The etiology of the implant failure in this instance could possibly be related to bone overheating associated with an excessive tightening of the implant and compression of the bone chips inside the apical hole, producing subsequent necrosis.

Preliminary report of an experimental design for in vivo testing of bonded restorations applied to a new enamel-dentinal bonding agent.

Because of inconsistency often found between in vitro testing and in vivo performance, a new restorative bonding system was evaluated by the placement of restorations in vivo in teeth to be extracted. The microleakage was determined following extraction after 3 months of clinical service. In each of the sample teeth, two restorations were placed on the labial surface, one in the middle of the enamel portion and the other extending over the cementoenamel portion. The results of this pilot study indicated that bonding to conditioned enamel with the new adhesive material is effective, and bonding to conditioned dentin appears to be clinically adequate.

Hydrocolloid impressions of multirooted teeth: a clinical report.

An indirect technique for taking hydrocolloid impressions of multirooted teeth is described. Advantages of both hydrocolloid impression material and the technique are discussed.

Measurement of enamel thickness in relation to reduction for etched laminate veneers.

The etched porcelain laminate veneer is a new conservative treatment that offers a solution to fractured, discolored, and worn anterior teeth. Preparation of enamel should be 0.5 mm to give minimal porcelain thickness and to avoid an overcontoured restoration. At the same time, dentinal exposure is contraindicated, because resin bonds better with enamel than with dentin. One hundred fourteen extracted teeth were measured at the gingival, middle, and incisal thirds. The resulting data reported on labial enamel thickness of anterior teeth may offer guidance in the preparation of laminate veneers.

[Restoration of a fractured incisor with recovery of the fragment]. / Restauro di un incisivo fratturato con recuperio del frammento.

The Authors propose the functional and estetical maintenance of a maxillary incisor, which presents a third class traumatic break, as Ellis opinion. After the positive exit, offered by the partial pulpotomy intervent, effected in order to keep on saving the vitality of the element, the same one was built again, putting on the original incisor fragment, recuperated by the restaurating operation, concerning on composed materials. After twenty-four months the Authors present the clinic control.