Endoscopic evaluation of the bone-added osteotome sinus floor elevation procedure.

Sinus floor augmentation using the bone-added osteotome technique (BAOSFE) has been advocated as a predictable procedure when initial residual bone height is 4-6mm. In this report, 16 Osseotite implants were placed using the BAOSFE procedure in eight patients under endoscopic control. Intraoperative graft positioning, potential displacement of the graft material, Schneiderian membrane integrity and distension pattern were evaluated. A small-sized perforation of the sinus membrane was visualized during sinuscopic monitoring in two implant sites without significant loss of graft material confinement. Membrane vertical distension was restricted to the area surrounding the implant apices in four implant sites while a larger detachment of the membrane enfolding the implant tips, the in-between and circumferantial areas was observed in the remaining 12 sites. The two perforated sites demonstrated a localized vertical pattern of membrane distension limited to implant apices. None of the cases complicated by perforation showed clinical signs of ongoing sinus pathology throughout the follow-up period. This limited report suggests that: (1) the BAOSFE procedure in combination with implant placement yields various patterns of sinus membrane elevation; (2) potential membrane perforation may be expected when distension follows a localized vertical augmentation pattern; and (3) small membrane perforations during the BAOSFE procedure are compatible with clinically healthy postoperative sinus conditions.

Maxillary sinus floor augmentation using bioactive glass granules and autogenous bone with simultaneous implant placement. Clinical and histological findings.

This clinical study was undertaken to: 1) evaluate the use of bioactive glass Biogran combined with autogenous bone as grafting material for maxillary sinus augmentation with simultaneous implant placement using radiography and histology; and 2) document the short-term post-loading success of implants inserted in sinus cavities augmented with this material. Unilateral or bilateral sinus augmentation was performed in 12 patients with 3-5 mm of alveolar crestal bone height in the posterior maxilla prior to grafting. The sinuses were grafted with bioactive glass mixed in a 4:1 ratio with autogenous bone. Simultaneously, 2-3 threaded titanium implants were inserted into the augmented sinuses. Second stage surgery was carried out 9 to 12 months post implantation. At abutment connection, 10 core biopsy specimens were taken from different grafted sites and evaluated histologically. All 27 implants were clinically stable at second stage surgery. A mean increase in mineralized tissue height of 7.1 +/- 1.6 mm was evident when comparing the pre-surgical CT scans with those performed 9-12 months following the sinus augmentation procedure. Evaluation of the cores yielded a mean of 30.6 +/- 5.7% of bone tissue in the grafted sites. One implant failed during the prosthetic phase while the remaining 26 implants were stable 12 months post loading. This study suggests that Biogran/autogenous bone graft combination used in one-stage sinus augmentation yields sufficient quality and volume of mineralized tissue for predictable simultaneous implant placement in patients with 3-5 mm of bone height prior to grafting.

Comparison of 2 techniques of subepithelial connective tissue graft in the treatment of gingival recessions.

BACKGROUND: The clinical outcome of connective tissue grafts in the treatment of gingival recessions has been documented in numerous studies. However, no attempt has been made to correlate the postoperative mucogingival changes with the surgical parameters. The present retrospective clinical study was undertaken to 1) evaluate root coverage and mucogingival changes 1 to 1.5 years following treatment of Miller's Class I and II recession defects using 2 variants of the subepithelial connective tissue graft (SCTG) procedure, and 2) assess the effect of the surgical parameters on the postoperative gingival width. METHODS: Thirty-one recessions in 10 patients treated with the envelope technique (E) and 31 recessions in 11 patients treated with coronally positioned flap combined with connective tissue graft (CP) were retrospectively analyzed to evaluate: 1) percentage of root coverage obtained with the 2 procedures and variations in width of keratinized tissue (KT) 1 to 1.5 years postsurgery, and 2) the effect of the surgical parameters on the postoperative gingival width. RESULTS: Results showed a mean root coverage percentage of 89.6 +/- 15% for the E group and 94.7 +/- 11.4% for the CP group; the difference between groups was statistically insignificant (P = 0.1388). Mean KT increased significantly from 1.4 +/- 1.1 mm presurgery to 4.5 +/- 1.1 mm postsurgery for the E group while a minor increase in KT was observed in the CP group (2 +/- 1.5 mm presurgery versus 2.7 +/- 1.6 mm postsurgery). For both treatment groups, the mean postsurgical width of keratinized tissue (POSTKT) was found to be mathematically correlated with the mean presurgical width of keratinized tissue (PREKT) and the corono-apical height of the graft that remained exposed (GE) coronal to the flap margin in the recipient site. CONCLUSIONS: Treatment of human gingival recession defects by the 2 variants of SCTG resulted in significant recession reduction. When SCTG is grafted beneath alveolar mucosa using the combined technique (CP), transformation of the mucosa into keratinized tissue does not seem to occur, at least within 1 to 1.5 years postsurgery. The treatment outcome in terms of keratinized tissue width seems to be correlated with the presurgical gingival dimensions and the height of the graft that remains exposed at the end of the surgical procedure.

Histology of connective tissue graft. A case report.

BACKGROUND: Few investigations can be found in the literature on the histological nature of the attachment of connective tissue grafts to root surfaces previously exposed by recession. METHODS: In this case report, a 24-year-old patient was treated with a connective tissue graft combined with a partial-thickness coronally positioned flap for root coverage of Class I Miller recessions at the maxillary right and left canines and first premolars. The treated sites exhibited 83% and 100% root coverage on the right and left sides, respectively. Twelve months later, the case required extraction of all 4 first premolars for orthodontic reasons. Two conservative block sections including the maxillary first premolars with the buccal soft tissues were obtained and processed histologically in a bucco-palatal plane. RESULTS: Histological analysis showed that healing occurred via a long junctional epithelium throughout the major portion of the previous recession site. Only minimal signs of new cementum-like tissue formation could be seen in the apical portion of the recession area coronal to the base of the instrumented root surface. No root resorption or ankylosis could be detected in any of the serial sections. CONCLUSIONS: The findings of this case report outline the possible variations in the histological outcome of connective tissue grafts. These variations can be attributed to differences in size and shape of the recession defects and flap positioning at the end of surgery.

Measurement of the dimensions and abutment rotational freedom of gold-machined 3i UCLA-type abutments in the as-received condition, after casting with a noble metal alloy and porcelain firing.

STATEMENT OF PROBLEM: Laboratory processing of implant-supported prostheses may alter the surface of the abutment in contact with the implant head and thus the interface fit. PURPOSE: This study assessed changes at the implant interface of gold-machined UCLA abutments after casting and porcelain baking in the case of single-tooth restorations. MATERIAL AND METHODS: The depth (d) and width (w) of the hexagonal portion of the abutment, the apical diameter (D) of the abutment, and the abutment rotational freedom (R) were assessed for 30 gold-machined UCLA abutments before casting procedures (time 0), after casting with a noble metal alloy (time 1), and after the addition of porcelain (time 2) to detect any eventual fitting change in the abutments on the top of the implant hexagon. RESULTS: No significant differences relative to all study parameters (d, w, D, and R) were observed between times 0, 1, and 2 (P=.576). CONCLUSION: The results of this investigation suggest that, if all laboratory steps are observed carefully, changes at the implant interface of gold-machined UCLA abutments do not occur.

Removal torque and histomorphometric investigation of 4 different titanium surfaces: an experimental study in the rabbit tibia.

This study presents a histomorphometric and biomechanical comparison of bone response to commercially pure titanium screws with 4 different types of surface topographies placed in the tibial metaphysis of 12 rabbits. Each rabbit had 4 implants placed, 2 in each tibia. The 4 surface topographies were a machined surface, a grit-blasted surface, a plasma-sprayed surface, and an acid-etched (Osseotite) surface. After a healing period of 5 weeks, histomorphometric and removal torque data revealed a significantly higher percentage of bone-to-implant contact and removal torque for acid-etched implants compared to machined, blasted, and plasma-sprayed implants. Within the limits of this short-term experimental study, the results indicated that micro-rough titanium surfaces obtained with acid-etching procedures achieved a 33% greater bone-to-implant contact over machined titanium surfaces with an abutment-type roughness and provided enhanced mechanical interlocking.

In vitro comparison of master cast accuracy for single-tooth implant replacement.

STATEMENT OF PROBLEM: The inaccuracy in transferring the position of the hexagonal head of a single implant to the working cast can result in a final single tooth crown, which clinically may present occlusal and/or interproximal contacts that are different from those contacts on the master cast obtained by the technician. PURPOSE: This in vitro study evaluated the accuracy of the master casts obtained using square pick-up impression copings for single-tooth replacement. Copings used were (1) copings as sold by the manufacturer, and (2) copings modified by sandblasting and coating with impression adhesive their roughened surfaces before final impression procedures. MATERIAL AND METHODS: A polymeric resin model with a standard single implant was used to simulate a clinical situation. A group of 20 impressions were made using nonmodified impression copings; a second group of 20 impressions were fabricated with modified copings. Master casts fabricated for both groups were analyzed to detect rotational position change of the hexagon on the implant replicas in the master casts in reference to the resin model. RESULTS: The rotational position changes of the hexagon on implant replicas were significantly less variable in the master casts obtained with the modified impression copings than in the master casts achieved with the nonprepared copings. CONCLUSION: Improved precision of the impression was achieved when the adhesive-coated copings were used.

[Odontostomatologic symptomatology in eating disorders. A controlled study]. / Semeiotica odontostomatologica dei disturbi del comportamento alimentare. Uno studio controllato.

BACKGROUND: This study investigated odontostomatologic signs and symptoms associated with Anorexia Nervosa and Bulimia Nervosa (Eating Disorders, ED). METHODS: The authors have examined the following conditions in a group of 14 female subjects (average age: 23.5 +/-4.8) suffering for ED, compared to a control group of 12 female subjects (average age: 22.58 +/-1.83) negative for ED diagnostic criteria: temporo-mandibular joint status, salivary pH, periodontal indexes (plaque index, bleeding index, pockets presence, gingival recession presence), dental indexes (DMF-T, DMF-S; dental erosion or perymolisis), salivary glands swelling, oral hygiene habits (related to vomiting behavior). RESULTS: The results obtained revealed a greater prevalence of gingival recession, diffuse marginal gingivitis, perymolysis, salivary glands involvement, lower salivary pH in the Eating Disorders (ED) group when compared with a non-ED control group. The results, obtained for the first time from a group of Italian subjects resident in a mediterranean country, agree with those obtained by authors working in an anglo-saxon area. CONCLUSIONS: Since odontostomatologic pathologies may be the only detectable sign of Anorexia Nervosa and/or Bulimia Nervosa,the data presented in this study could facilitate the early identification of these patients and provide guidelines for the evaluation of oral pathologies in anorexic and bulimic patients.

Guided bone regeneration using demineralized laminar bone sheets versus GTAM membranes in the treatment of implant-associated defects. A clinical and histological study.

This study was designed to compare the regenerative potential at dehisced implant sites of the resorbable demineralized laminar bone sheets and non resorbable GTAM membranes. Twenty-six standard screw-type fixtures showing buccal dehiscences in 7 patients were treated using the GBR principles and received either laminar bone sheets (experimental) or GTAM (control) membranes. Twelve experimental and 10 control sites were available for evaluation at second stage surgery carried out 8 months following implant placement. Height and maximum width of the dehiscence defects were measured at the time of implant insertion and at second-stage procedure. Mean percentage of defect fill was 75.17% in the experimental dehiscences versus 86.70% in the control defects. A statistically significant difference in the percentage of defect fill could not be evidenced between the two treatment modalities. Complete fill was observed in 25% of the experimental versus 70% of the control sites. A significant difference was found in the median Density Index with the GTAM group showing a consistency similar to bone in a larger number of sites. Histologically, material with the same staining features of bone was evidenced inside the GTAM membranes in 3 cases while newly-formed bone was present in all instances under the control GTAM barriers. In the laminar bone-treated sites, the membrane maintained its integrity in almost all cases. Newly formed bone was found underlying the membrane in cases with a Density Index of 5 with no evidence of bony tissue adhering to the laminar sheets.

Electrically charged GTAM membranes stimulate osteogenesis in rabbit calvarial defects.

Bone neogenesis was studied in membrane-protected defects in a rabbit calvaria defect model using neutral, negatively, and positively charged titanium-reinforced GTAM membranes. Two standardized circular 8 mm wide and 1 mm deep defects were created in the calvaria of 36 rabbits leaving the inner cortex intact. The defects were subsequently covered with dome-shaped Ti-reinforced GTAM membranes stabilized with a titanium screw allowing the edges of the membranes to be closely approximated to the bone surface. The animals were divided into 6 groups of 6 rabbits each and were sacrificed at 5 days (Group 1), 10 days (Group 2), 3 weeks (Group 3), 5 weeks (Group 4), 10 weeks (Group 5), and 20 weeks (Group 6). The distribution of the 72 membranes according to charge yielded 4 positively charged, 4 negatively charged and 4 neutral domes in each group. Histomorphometric analysis showed a more rapid and increased bone neogenesis with the negatively charged domes. A mean total area of 27.95% of newly-formed bone was observed in the negatively charged membrane sites at 10 days while negligible bone formation occurred with the neutral and positively charged domes at the same evaluation interval. Over time, negatively charged membranes supported more new-bone formation than neutral membranes while positively charged membranes showed the least new bone. This work demonstrates that negative electrical stimulation accelerates and maintains bone neogenesis. These results also suggest the potential applications of negatively charged GTAM membranes in clinical settings.

Bone response to orthodontic loading of endosseous implants in the rabbit calvaria: early continuous distalizing forces.

The purpose of this experimental study was to evaluate the effect of early orthodontic loading on the stability and bone-implant interface of titanium implants in a rabbit model. Twenty-four short threaded titanium fixtures were inserted in the calvarial mid-sagittal suture of 10 rabbits. Two weeks following insertion, 20 implants (test group) were subjected to continuous distalization forces of 150 g for a period of 8 weeks. The remaining four implants (control group) were left unloaded for the same follow-up interval. Clinically, all implants except for one test fixture were stable, and exhibited no mobility or displacement throughout the experimental loading period. Histologically, all stable implants were well-integrated into bone. No differences could be found between the pressure and tension surfaces of the test implants relative to bone quality and density within a range of 1000 microns from the fixture surface. Similarly, qualitative differences were not observed between the apical and coronal portions of test fixtures. Morphometrically, a mean percentage bone-to-implant contact of 76.00 +/- 18.73 per cent was found at the test pressure sides, 75.00 +/- 11.54 per cent at the test tension sides, and 68.00 +/- 15.55 per cent at the control unloaded surfaces. No statistically significant differences in the percentage of bone-to-metal contact length fraction were found between test pressure surfaces, test tension surfaces, and unloaded control surfaces. Marginal bone resorption around the implant collar or immediately beneath it was found in roughly the same percentage of analysed sites in the test and control fixtures. In contrast, slight bone apposition was demonstrated at the implant collar of the test pressure surfaces, while no apposition or resorption were observed in the test tension zones. This study suggests that short endosseous implants can be used as anchoring units for orthodontic tooth movement early in the post-insertion healing period.

Postloading behavior of regenerated tissues in GBR-treated implant sites.

The objective of this study was to assess, using reentry procedures, the capacity of regenerated tissues in implant-associated defects to respond to occlusal loading. Two groups of patients treated with membrane-augmented osseointegrated implants were included in the study. In group A (7 patients), a total of 9 implant-associated defects, including 6 dehiscences and 3 immediate extraction sites, were prospectively followed up 6 months following prosthesis connection. In group B (3 patients), 4 dehiscence defects were retrospectively evaluated 5 years after prosthetic loading. All defects in both groups had an uneventful healing period beyond the 6 months following implant insertion and showed complete fill with bone-like hard tissues at abutment connection surgery. A second surgical reentry was carried out to evaluate the quantitative changes in the regenerated tissues at the membrane-treated sites; it was carried out 6 months following prosthesis connection in group A, and 5 years postloading in group B. At the second reentry procedure, the mean percentage of defect fill at the dehiscence sites was 82% +/- 12.8% in group A and 83% +/- 7.3% in group B. In the 3 immediate extraction sites in group A, the most apical bone-implant contact around the implant was consistently located at about 1 mm, relative to the coronal aspect of the implant shoulder, as evidenced both radiographically and during the second reentry. The trends noted in this investigation suggest that tissues regenerated in successfully treated implant-associated defects can be maintained in the short-term and long-term periods following prosthetic loading.

Role of intramarrow penetration in osseous repair: a pilot study in the rabbit calvaria.

BACKGROUND: The use of intramarrow penetration in combination with osseous reconstructive surgery has been recommended in various periodontal and oral surgical applications. The purpose of this pilot study was to evaluate the effect of intramarrow penetration on the rate of bone neogenesis in protected spaces created on the calvarial bone using occlusive titanium domes in 16 adult white rabbits. METHODS: In each rabbit, 2 standardized circular 1 mm deep slits were prepared in the bone, one on each side of the midline using a trephine. Within the perimeter of one of the slits, the external cortical surface of the skull bone was mechanically perforated using a carbide round bur (experimental site), while the bone surface within the other slit (control site) was left intact. Subsequently, 2 prefabricated titanium domes with an inner diameter of 4.8 mm and an inner height of 3.0 mm were anchored in the prepared slits. The animals were divided into 4 groups of 4 rabbits each and were sacrificed at 10, 21, 42, and 60 days. The specimens were assessed for the percentage bone fill and density of the newly formed bone within the boundaries of the domes. RESULTS: Histomorphometric analysis showed significantly increased bone neogenesis within the experimental domes at 10, 21, 42, and 60 days. A mean total area of 29% newly formed bone was demonstrated in the experimental sites at 21 days, while negligible bone formation (9%) occurred with the control domes at the same evaluation interval. Bone density was consistently higher in experimental domes at all healing intervals. CONCLUSIONS: Within the limits of this study, the results demonstrate that intramarrow penetration accelerates initial bone neogenesis and results in increased bone fill and density, suggesting that its use can be beneficial in bone regenerative procedures.

Mandibular overdentures anchored to single implants: a five-year prospective study.

STATEMENT OF PROBLEM: It is unknown what minimum number of implants are required to satisfactorily support and retain a mandibular overdenture. PURPOSE: The purpose of this study was to evaluate a treatment modality by using mandibular overdentures anchored to single implants in a geriatric patient population. MATERIAL AND METHODS: Twenty-one patients with a mean age of 74.2 years were treated with single implants inserted at the mandibular midline according to the standard two-stage surgical technique. O-Ring or ball attachments were connected to the implants and served as overdenture anchorage. Implant success rate, improvement of oral comfort and function, condition of the peri-implant soft tissues, Periotest values, and the interproximal marginal bone level were evaluated for up to 5 years after delivery of the overdentures. RESULTS: None of the implants were lost during the follow-up period. A mean marginal bone loss of 1.42 +/- 0.56 mm was noted at 60 months. Plaque Index was consistently high around the abutments at all reevaluation intervals but was associated with a low Gingival Index. Pocket Depth averaged 2.41 +/- 0.17 mm for the entire follow-up period. Remarkable improvement of oral comfort and function were evidenced with the overdenture treatment. CONCLUSION: Rehabilitation with mandibular overdentures anchored to a single implant can be a therapeutic alternative for elderly patients experiencing discomfort and functional difficulties with conventional mandibular dentures.

Heat generation during implant site preparation: an in vitro study.

Thermal changes elicited during drilling and tapping procedures used in site preparation for screw-shaped and cylindrical implants were measured in vitro in blocks of bovine cortical femur bone. Heat-sensitive thermocouples were placed in the bone specimens at 4- and 8-mm depths and at a constant distance from the periphery of the drilling site; this distance was preset for each type of bur used. Rotary cutting was performed with 10-mm-long twist drills (2- and 3-mm diameter) and triflute drills (3.3- and 4-mm diameter) running at 1,500 rpm with external irrigation. A special guide drill was used to ensure unidirectional continuous drilling with a load of 2,000 g. In addition, the effect of irrigation was evaluated during tapping procedures with 10-mm-long taps used at 20 rpm. The greatest temperature increase was observed with the 2-mm twist drill at both 4- and 8-mm depths. Significantly greater temperature increase was noted at the 8-mm depth versus the 4-mm depth with the twist drills. Such significant difference between temperature rise at the two different drilling depths was not observed with the triflute burs. The time interval required for the maximum temperature reached during rotary cutting to return to baseline values was two times longer for the 2-mm twist drill than for the 3.3-mm triflute bur at both drilling depths. No statistically significant differences could be found between the maximum temperatures generated when tapping was performed with and without irrigation at both 4- and 8-mm depths. It can be suggested that the geometry of triflute burs combines cutting efficacy with greater heat dissipation capabilities than twist drills at the drilling depths of 4 and 8 mm used in this study.

Single-tooth implant rehabilitation: a retrospective study of 67 implants.

The use of osseointegrated implants is an accepted procedure for the treatment of total and partial edentulism and offers good predictability of long-term success. For the last several years, this procedure has also been used for single-tooth replacement following loss of teeth for traumatic, periodontal, and carious lesions. This paper reports the clinical experience of 47 patients treated for a single-tooth replacement. Sixty-seven screw-type standard, self-tapping implants and mini-implants were placed. The results were similar to those for complete and partial osseointegrated prostheses. The total implant survival rate was 94.4%. Two implants were lost as a result of suppuration caused by membrane exposure, while another was lost after loading. The results suggest that single-tooth replacement using osseointegrated implants provides predictable success.

Histochemical and confocal laser scanning microscopy study of the bone-titanium interface: an experimental study in rabbits.

The aim of our study was an analysis of the presence of an unmineralized bone matrix between mineralized bone and titanium screws in rabbit tibiae. A microscopical analysis, using a histochemical technique, was performed on the titanium-bone interface of commercially pure titanium implants placed in rabbit tibiae and harvested after 2 months. Thin ground sections of the specimens were prepared by the cutting-grinding system and stained using the von Kossa method for calcium salts and basic fuchsin for osteoid. The microscopical and morphometrical evaluation showed that bone covered about 40% (+/- 7.5%) of all implants. Mineralized bone was, however, in direct contact with the titanium surface on only about 10% of the implant, while in the remaining 30% the mineralized bone was separated from the implant by an unmineralized tissue. This basophilic, probably osteoid matrix, could represent the medium that allows the biochemical exchanges between bone and cells under the influence of the implant. A small, optically translucent gap (1-5 microns), probably an artifact, was present in some areas between titanium and bone. Confocal laser scanning microscopy (CLSM) in a fluorescent mode showed the presence at the interface of a fluorescent material. Results from our study showed that light microscopy of thin ground sections allowed a good analysis of the real nature of the titanium-bone interface. Moreover, this double staining technique showed the presence of an unmineralized bone matrix at most of the bone-titanium interface.

Urinary excretion of unmetabolized benzene as an indicator of benzene exposure.

Benzene concentrations in urine samples (Cu, ng/L) from 110 workers exposed to benzene in chemical plants and gasoline pumps were determined by injecting urine supernate into a gas chromatograph. The urine was saturated with anhydrous N2SO4 to facilitate the passage of benzene in the air over the urine. The solvent was stripped from the urine surface and concentrated on an adsorbent substrate (Carbotrap tube) by means of a suction pump (flow rate 150 ml/m). Wash-up of the head space was achieved by simultaneous intake of filtered air through charcoal. Benzene was thermically desorbed and injected in a column (thermal tube disorder, Supelco; 370 degrees C thermal flash; borosilicate capillary glass column SPB-1, 60 m length, 0.75 mm ID, 1 microns film thickness; GC Dani 8580-FID). Benzene concentrations in the urine from 40 non-exposed subjects (20 smokers > 20 cigarette/d and 20 nonsmokers) were also determined [median value of 790 ng/L (10.17 nmol/L) and 131 ng/L (1.70 nmol/L), respectively]. The 8-h time-weighted exposure intensity (Cl, micrograms/m3) of individual workers was monitored by means of charcoal tubes. The median value for exposure to benzene was 736 micrograms/m3 (9.42 mumol/m3) [geometric standard deviation (GSD) = 2.99; range 64 micrograms/m3 (0.82 mumol/m3) to 13,387 micrograms/m3) (171.30 mumol/m3)]. The following linear correlation was found between benzene concentrations in urine (Cu, ng/L) and benzene concentrations in the breathing zone (Cl, micrograms/m3): log(Cu) = 0.645 x log(Cl) + 1.399 r = .559, n = 110, p < .0001 With exclusion of workers who smoked from the study, the correlation between air benzene concentration and benzene measured in urine was: log(Cu) = 0.872 x log(Cl) + 0.6 r = .763, n = 63, p < .0001 The study results indicate that the urinary level of benzene is an indicator of occupational exposure to benzene.