The impact of subcrestal placement on short locking-taper implants placed in posterior maxilla and mandible: a retrospective evaluation on hard and soft tissues stability after 2 years of loading.

AIM: Objective of this study was to assess the influence of the subcrestal placement level of short implants with a locking-taper connection design on crestal bone levels and soft tissues health. METHODS: A clinical retrospective case-control study was conducted between May 2013 and September 2013. The sample was composed of patients who had received at least one 5-to-8-mm-long, plateau-design implant with a locking-taper connection system (Bicon LLC, Boston, MA, USA) in posterior areas of maxilla and mandible, in the period between January 2009 and Dicember 2011. A radiographic evaluation of the degree of subcrestal positioning(t0) was conducted to identify two implant groups: Group 1 was composed of implants placed less than 2 mm under the crestal bone; Group 2 was composed of implants placed 2 mm or more under the crest. The primary outcome variables were the crestal bone levels and the peri-implant bone loss between prosthetic loading and last control visit (t1àt2). Clinical parameters including the keratinized gingival (KG) width, modified bleeding index (mBI), modified plaque index (mPI), and probing depth (PD) were assessed at the follow-up visit. T tests were conducted to identify statistically significant differences between implants groups. Linear regression models were developed to test the dependence of the study variables by the degree of subcrestal surgical implant placement. Significance level was set at P<0.05. RESULTS: One hundred and thirty-seven implants were followed for an average period of 31 months. At the surgery, the implants were placed, on average, 2.04 mm (mesial) and 1.86 mm (distal) subcrestally. Eighty implants were placed less than 2 mm under the crest (average 1.28 mm), while fifty-seven implants were placed more than 2 mm under the crestal bone (average 2.97 mm). At the prosthetic loading (t1), the average crestal bone level was 1.11 mm, 0.79 mm in Shallow group and 1.86 mm in Deep group, with statistically significant differences between implant groups (P<0.05). At the follow-up visit (t2) the mean crestal bone levels were respectively 0.51 mm and 1.35 mm, with statistically significant differences between implant groups (P<0.05). The average peri-implant bone loss between prosthetic loading and control visit (t1àt2) was 0.04 mm in the Group 1 and 0.33 mm in Group 2. The average keratinized mucosa width was 2.16 mm, the average mBI was 0.24 , the average mPI was 0.17 and the average PD was 2.34 mm. Significant difference between groups was observed regarding to keratinized gingival width (Group 1: 1.97 mm; Group 2: 2.41 mm; P<0.05) but not for the other clinical parameters. Linear regression models confirmed the dependence of crestal bone levels by the degree of subcrestal placement (P<0.05). CONCLUSION: After two years of observation, the implant of this study have shown minimal peri-implant bone resorption. The greater subcrestal implant placement has resulted in a higher level of the peri-implant bone crest, both after the osseointegration period and after the loading period. Both the study implants groups have shown good health of peri-implant soft tissues.

Early bone formation around immediately loaded FBR-coated implants after 8, 10 and 12 weeks: a human histologic evaluation of three retrieved implants.

The surface characteristics of dental implants play an important role in the osseointegration process. Over the years implant surfaces have been subjected to different treatments, including turning, plasma spraying, coating, sand blasting, acid etching, and anodization. FBR coating is a fully resorbable calcium phosphate (CaP) coating made of brushite, obtained by electrochemical deposition on titanium plasma-sprayed (TPS) implants; this bioactive layer may be totally resorbable in 6-12 weeks and once the FBR coating has been resorbed, the newly formed bone is in contact with the roughness of the TPS surface. Human biopsy of immediately-loaded implants is certainly the most definitive means of determining the occurrence of osseointegration. In this case series the histologic and histomorphometric features of the bone-implant interface are analyzed and discussed in 3 immediately restored implants, retrieved from human subjects at 8, 10 and 12 weeks, respectively. All 3 implants were osseointegrated, with a bone to implant contact (BIC) ranging from 54.4% to 70.1%. The FBR coating was resorbed and replaced by new bone. Osteoconduction was especially noticeable between the implant threads, where the pristine bone was removed during implant bed preparation. The results suggest that the resorption window of 6-12 weeks for the CaP coating seems to be confirmed at least in the human mandible, and that immediately loaded FBR-coated implants placed in the posterior mandible can achieve osseointegration within 6-12 weeks of loading.

Experimental study of a new surgical technique for anatomic remodeling of atrophic socket in maxillary postextraction single implant.

Replacement therapy with immediate postextraction single dental implants has gained wider acceptance in clinical practice. However, because bone tissue volume may be insufficient for primary stability and subsequent osteointegration, many dentists prefer delaying implantation 2 or 3 months later, which may lead to greater loss of vestibular bone tissue and worsen postextraction atrophy. To avert these problems, a new surgical technique has been developed that allows immediate loading on postextraction single implants and atrophic socket remodeling. Socket remodeling is known to occur when the extraction site is completely ossified, but, depending on the length of time since tooth extraction, surgical complications may still arise, resulting in suboptimal wound healing of the socket, with unacceptable esthetic and functional outcome.

Mandibular ameloblastic fibroma in 6-years-old girl: a case report.

Ameloblastic fibroma (AF) is defined in WHO classification as a ''neoplasm composed of proliferating odontogenic epithelium embedded in a cellular ectomesenchymal tissue that resembles dental papilla, and with varying degrees of inductive change and dental hard tissue formation''. AF is a rather uncommon tumor, accounting for only 2.5% of all odontogenic tumors. AF is a true mixed tumor, in which the epithelial and ectomesenchymal elements are neoplastic. AF raises at any age, ranging from 6 months to 42 years (mean 14.6 to 15.5 years); it does not show sex predilection. The lesion occurs in nearly 70% of cases in posterior areas of the mandible. Patients exhibit swelling of the jaw; pain is not usually described. Authors present a clinical and surgical management of an early onset of a large mandibular ameloblastic fibroma in a 6-year-old girsl.

Results of double-blind placebo-controlled challenge with nickel salts in patients affected by recurrent aphthous stomatitis.

BACKGROUND: The aetiology of recurrent aphthous stomatitis (RAS) has so far not been completely clarified. Recently, several studies reported that patients affected by cutaneous diseases (i.e. dermatitis, eczema and urticaria) with positive patch test to nickel have a positive oral nickel challenge. OBJECTIVE: A retrospective data analysis of patch test and oral nickel challenge in 380 patients (204 women and 176 men) affected by RAS was performed. PATIENTS AND METHODS: We examined 380 consecutive patients affected by RAS during the period 1990-1999. In 28/380 patients the appearance of their oral symptoms coincided with the fitting of orthodontic appliance, while 352/380 reported that their oral symptoms worsened after the fitting of orthodontic appliance. All patients were studied with the series (European standard series and series for dental materials) for patch tests. RESULTS: Seventy out of 380 patients (18.4%) presented a contact sensitization to nickel sulphate (positive patch test). In all of these, the orthodontic appliance was replaced with one made of nickel-free materials. All patients were re-examined by the dentist 6 months after the removal of the orthodontic appliance. The symptoms had completely remitted in 28/70 patients, partially had improved in 31/70 patients and had remained unchanged in 11/70 patients. In all patients (n = 70) with a positive patch test to nickel we performed an oral double-blind placebo-controlled challenge (DBPC) test with nickel sulphate. The DBPC was positive in 32/70 patients, 21 of whom had partially improved and 11 had not, even after the replacement of the orthodontic appliance with material not containing nickel. None of the 28 patients in complete remission showed an adverse reaction to oral nickel challenge. CONCLUSION: The results of this study demonstrate that, in some patients with a positive patch test to nickel sulphate, the perpetuation of RAS can be related to a hypersensitivity to ingested nickel salts, independently of local contact to nickel.