Giovanni Battista Grossi

Histomorphometric Evaluation of Anorganic Bovine Bone Coverage to Reduce Autogenous Grafts Resorption: Preliminary Results

Physiologic resorption due to remodeling processes affects autogenous corticocancellous grafts in the treatment of atrophic jawbone alveolar ridges. Such a situation in the past made overgrafting of the recipient site mandatory to get enough bone support to dental implants in order to perform a prosthetic rehabilitation. Anorganic bovine bone, conventionally used to treat alveolar bone deficiencies in implant surgery, showed a high osteoconductive property thanks to its micro and macrostructure very similar to that of human hydroxyapatite. An original technique provides for the application of a thin layer of anorganic bovine bone granules and a collagen membrane on the top of the corticocancellous onlay bone grafts to reduce in a remarkable way the graft resorption due to remodeling. The results of a clinical prospective study and a histomorphometric analysis done on autogenous grafts harvested from the iliac crest showed that the proposed technique is able to maintain the original bone volume of the corticocancellous blocks.

In vitro evaluation of the frictional forces between brackets and archwire with three passive self-ligating brackets.

The aim of this in vitro study was to evaluate the frictional forces between bracket and archwire that included three passive self-ligating brackets (Damon SL2 SDS). The brackets were individually bonded to a brass mount using a preformed 0.021 x 0.025 inch stainless steel wire jig in order to exclude adverse tipping or torsion. The central bracket was positioned 1 mm higher than the others, in order that the three brackets were vertically unaligned. Thirty-six similar set-ups including in total 108 brackets were investigated using the same wire: copper (nickel-titanium) 0.014 inches. A testing machine was designed and constructed to measure the frictional forces between the wire and the three-bracket set-up. Twelve set-ups were tested to measure kinetic frictional forces between the wire and unaligned passive self-ligating brackets used in the closed position. The frictional properties of two sets of 12 three-bracket set-ups (control) were tested and measured with an open slide and conventional ligation. A stainless steel ligature wire was used in the former, while elastomeric modules were employed in the latter. One-way analysis of variance showed a significant effect of ligation mode on the frictional properties of the three-bracket set-ups (P < 0.001). Post hoc pairwise comparison showed that the frictional forces arising from passive self-ligation were significantly lower (P < 0.01) than those resulting from elastic ligation. The same result was achieved when comparing self-ligation and metallic ligation (P < 0.01). No significant difference was found when comparing elastic and metallic ligation.

Could local anesthesia while breast-feeding be harmful to infants?

Background Few studies have been carried out on the levels and possible toxicity of local anesthetics in breast milk after parenteral administration. The purpose of this study is to determine the amount of lidocaine and its metabolite monoethylglycinexylidide (MEGX) in breast milk after local anesthesia during dental procedures. Methods The study population consisted of seven nursing mothers (age, 23–39 years) who received 3.6 to 7.2 mL 2% lidocaine without adrenaline. Blood and milk concentrations of lidocaine and its metabolite MEGX were assayed using high-performance liquid chromatography. The milk-to-plasma ratio and the possible daily doses in infants for both lidocaine and MEGX were calculated. Results The lidocaine concentration in maternal plasma 2 hours after injection was 347.6 ± 221.8 &mgr;g/L, the lidocaine concentration in maternal milk ranged from 120.5 ± 54.1 &mgr;g/L (3 hours after injection) to 58.3 ± 22.8 &mgr;g/L (6 hours after injection), the MEGX concentration in maternal plasma 2 hours after injection was 58.9 ± 30.3 &mgr;g/L, and the MEGX concentration in maternal milk ranged from 97.5 ± 39.6 &mgr;g/L (3 hours after injection) to 52.7 ± 23.8 &mgr;g/L (6 hours after injection). According to these data and considering an intake of 90 mL breast milk every 3 hours, the daily infant dosages of lidocaine and MEGX were 73.41± 38.94 &mgr;g/L/day and 66.1 ± 28.5 &mgr;g/L/day respectively. Conclusions This study suggests that even if a nursing mother undergoes dental treatment with local anesthesia using lidocaine without adrenaline, she can safely continue breast-feeding.

Long-term survival rate of implants placed in conjunction with 246 sinus floor elevation procedures: Results of a 15-year retrospective study

OBJECTIVES The aim of the present long-term study was to retrospectively evaluate the survival rate of implants placed in regenerated maxillary sinuses and to assess the influence of hypothetical predictors of implant failure. METHODS A database including 218 patients who received dental implants after sinus lift procedures was analyzed. The following variables were systematically included and evaluated: type of graft material used, number of surgeries performed, and use of membranes to cover the lateral antrostomy and/or to repair accidental Schneiderian membrane perforations. The Kaplan-Meier estimator was used for comparisons among the groups. RESULTS A total of 589 dental implants were positioned in 246 grafted sinuses and were in function for 3-186 months. The Kaplan-Meier cumulative survival rate was 98.3% after 15.5 years of follow-up. All implant losses occurred within 52 months (4.3 years) after augmentation. According to the log-rank test, no statistically significant difference was shown between each patient/implant variable (p>0.05). CONCLUSIONS Despite the limitations inherent in this type of study, no statistically significant differences between the groups could be found. Intraoperative Schneiderian membrane perforations did not affect the outcome of the implants positioned. CLINICAL SIGNIFICANCE The present long-term study is intended as a reference for clinicians approaching sinus floor elevation surgery in order to provide them with relevant operative findings. Since all the drawbacks occurred within the first 5 years, medium-term follow-up studies could be suitable for further retrospective evaluations.

Do ultrasonic dental scalers interfere with implantable cardioverter defibrillators? An in vivo investigation

OBJECTIVES To test the in vivo effects of an ultrasonic dental scaler on various implanted cardioverter defibrillator (ICD) models. METHODS 12 consecutive patients with ICDs had continuous both electrocardiogram monitoring and device interrogation to detect interferences during the use of an ultrasonic dental scaler. RESULTS No interferences were detected by any ICD. Evaluation of the electrocardiograms for each patient failed to show any abnormalities in pacing during testing. CONCLUSION The results of this study suggest that the routinary clinic use of piezoelectric dental scalers do not interfere with the functioning of any of the tested ICDs. CLINICAL SIGNIFICANCE Ultrasonic dental scalers have been suspected of electromagnetic interference (EMI) with the normal functioning of ICDs and the use of this type of equipment for patients with these devices has been controversial. This is the first in vivo study to investigate EMI of ICD activity during the operation with ultrasonic dental scaler.

Two-stage treatment protocol of keratocystic odontogenic tumour in young patients with Gorlin–Goltz syndrome: Marsupialization and later enucleation with peripheral ostectomy. A 5-year-follow-up experience

OBJECTIVE Keratocystic odontogenic tumour (KCOT) is a benign uni- or multicystic intraosseous odontogenic tumour with potential for local destruction and tendency for multiplicity, especially when associated with Gorlin-Goltz syndrome. We suggest a conservative surgical treatment based on marsupialization and later enucleation with peripheral ostectomy in order to preserve jaws integrity in young patients. METHODS Three young patients affected of nevoid basal cell carcinoma syndrome (NBCCS or Gorlin-Goltz syndrome) presented large and multiple KCOTs, which have been treated following a two-stage surgical strategy. Initially marsupialization was performed and after a mean period of 10 months, contextually to evident reduction in radiological size image, enucleation with peripheral ostectomy was carried out. RESULTS All the patients showed high collaboration in daily self-irrigation of the stomia with chlorhexidine 0.2% during the period of marsupialization. Definitive surgical intervention led to complete healing and no signs of recurrence have been observed during a 5-year-follow-up. CONCLUSIONS The main advantage of this modality is the preservation of important anatomical structures involved in the lesion and jaws continuity. Therefore in a selected group of cooperative patients, especially those affected of Gorlin-Goltz syndrome, the surgical protocol exposed allows for a less invasive approach with excellent results avoiding extensive disfiguring procedures.

Twelve-Year Retrospective Follow-Up of Machined Implants in the Posterior Maxilla: Radiographic and Peri-Implant Outcome.

PURPOSE To retrospectively evaluate the survival rate of machined implants in sinus-lifted posterior maxilla after 12 years, with special reference to radiographic outcome and peri-implantitis. MATERIALS AND METHODS From 37 possible candidates, 29 patients with 59 implants were evaluated. Implants were placed in the posterior maxilla in combination with a sinus elevation procedure (27 patients) or 6 months after sinus elevation (2 patients). Marginal bone level changes were radiographically evaluated at baseline and 1, 7, and 12 years post-loading. Probing depth was measured; presence/absence of plaque and bleeding on probing were recorded. RESULTS Four out of 59 implants failed in 4 out of 29 patients (cumulative survival rate = 93.2%). The mean bone loss was 0.78 mm (± 0.88) after 12 years. Changes in the mean bone level were statistically significant between baseline and all the other follow-up intervals (p < .001). Statistically significant differences could be demonstrated for the first- to 12th-year interval (p < .05) and for the seventh- to 12th-year interval (p < 0.001). No statistically significant differences could be demonstrated at the first- to seventh-year interval (p = .32). The mean overall probing depth was 2.9 ± 0.66 mm. Probing depth was moderately correlated with the marginal bone changes at 7 year and after 12 year follow up (p = .05). No signs of peri-implantitis were reported during the 12-year follow-up period. CONCLUSIONS This follow-up demonstrates a very good prognosis when implants with machined surfaces are used. The frequencies of implant failures were very small. Within the limits of the results from this study, the risk of peri-implantitis in the posterior maxilla might be considered a minor problem when implants with machined surfaces are used.

Evaluation of postoperative discomfort after impacted mandibular third molar surgery using three different types of flap.

OBJECTIVE The surgical extraction of an impacted third molar involves a wide range of consequences such as trismus, swelling, and pain, as well as more significant complications, temporary or permanent, that can manifest altered sensitivity of the tongue or lips. The purpose of this prospective study was to evaluate the effects of three different flaps on postoperative discomfort considering trismus, edema, and pain, after the extraction of impacted third molars. The data derived from the analysis of the surgical trials performed at the Oral Surgery Unit, Department of Surgical, Reconstructive and Diagnostic Sciences, IRCCS Policlinico, University of Milan, directed by Professor F. Santoro, MD. METHOD AND MATERIALS This study, developed over 2 years, involved 238 patients for a total of 238 extractions of impacted mandibular third molars. The 238 surgeries were performed on 114 men and 124 women: 54 avulsions were performed with the elevation of an envelope flap (Group 1), 48 avulsions through the elevation of a triangular flap (Group 2), and the remaining 136 avulsions were performed using a trapezoidal flap (Group 3). RESULTS Trismus was significantly reduced (P < .05) in patients treated with envelope flap, as was the swelling perceived by the patient (P < .05). Pain was closely related to the elevation of a mucoperiosteal flap and osteotomy. Our study does not reveal statistically significant differences between the three types of flap used; however, the number of analgesic tablets taken was lower in cases of elevation of a less traumatic flap (envelope and triangular flaps). CONCLUSION The data collected in this study indicate the envelope flap as the most suitable for the reduction of the expression of postoperative complications such as swelling and trismus.

Risk indicators related to peri-implant disease: an observational retrospective cohort study

Purpose The aim of the present study was to retrospectively investigate the influence of potential risk indicators on the development of peri-implant disease. Methods Overall, 103 patients referred for implant treatment from 2000 to 2012 were randomly enrolled. The study sample consisted of 421 conventional-length (>6 mm) non-turned titanium implants that were evaluated clinically and radiographically according to pre-established clinical and patient-related parameters by a single investigator. A non-parametric Mann-Whitney U test or Kruskal-Wallis rank test and a logistic regression model were used for the statistical analysis of the recorded data at the implant level. Results The diagnosis of peri-implant mucositis and peri-implantitis was made for 173 (41.1%) and 19 (4.5%) implants, respectively. Age (≥65 years), patient adherence (professional hygiene recalls <2/year) and the presence of plaque were associated with higher peri-implant probing-depth values and bleeding-on-probing scores. The logistic regression analysis indicated that age (P=0.001), patient adherence (P=0.03), the absence of keratinized tissue (P=0.03), implants placed in pristine bone (P=0.04), and the presence of peri-implant soft-tissue recession (P=0.000) were strongly associated with the event of peri-implantitis. Conclusions Within the limitations of this study, patients aged ≥65 years and non-adherent subjects were more prone to develop peri-implant disease. Therefore, early diagnosis and a systematic maintenance-care program are essential for maintaining peri-implant tissue health, especially in older patients.

Osseointegrated implants in vertical ridge augmentation with a nonresorbable membrane: a retrospective study of 75 implants with 1 to 6 years of follow-up.

The aim of this study was to retrospectively evaluate 75 implants inserted in vertically augmented bone at the time of or prior to implant placement after 1 to 6 years of prosthetic loading. The study included 21 patients (29 surgical sites). The vertical procedure was performed combining a titanium-reinforced expanded polytetrafluoroethylene membrane with autograft (7 sites), allograft (5 sites), or auto-xenograft (17 sites). Healing was uneventful in 24 surgical sites. Three sites showed premature exposure, and two sites presented an abscess. Two implants were lost, for a cumulative survival rate of 93.6%. Mean bone remodeling at 1, 2, 3, 4, 5, and 6 years was 0.34, 0.72, 1.04, 0.84, 0.56, and 0.61 mm, respectively. The implant success rate was higher with a simultaneous approach (82.5%) compared with a staged approach (66.8%). Implants surrounded by keratinized mucosa revealed a higher success rate (82.1%) than those without it (58.4%).