Soft tissue conditions and marginal bone levels of implants with a laser-microtextured collar: a 5-year, retrospective, controlled study

AIM

To compare clinical and radiographic outcomes of implants with a Laser-Lok®-microtextured collar to implants with a resorbable blast textured (RBT) collar after a 5-year follow-up period.

MATERIALS AND METHODS

Thirty-four implants with a Laser-Lok®-microtextured collar (test group [TG]) and 31 implants with an RBT collar (control group [CG]) were placed in 45 non-smoking, periodontally healthy patients. The full-mouth plaque score, full-mouth bleeding score, number of sites with plaque, and the number of sites with bleeding on probing (BOP) were recorded at baseline, and at 1-, 2-, 3-, 4-, and 5-year follow-up. Probing depth (PD) and mucosal recession were assessed at baseline and after the 5-year follow-up period. The radiographic marginal bone loss (MBL) was calculated by subtracting the bone level at the time of crown insertion from the bone level at the 5-year follow-up.

RESULTS

An implant survival rate of 94% and of 90% was reported for the TG and the CG, respectively. No statistical differences were found between the study groups for presence of plaque (10.1% vs. 25%) or for number of sites with BOP (10.3% vs. 23%). The differences between both study groups were statistically significant for mean MBL (0.81 ± 0.24 vs. 2.02 ± 0.32 mm), mean PD (2.32 ± 0.44 vs. 4.25 ± 0.87 mm), and mean mucosal recession (0.16 ± 0.3 vs. 0.22 ± 0.3 mm).

CONCLUSIONS

Within the limitations of this study, results suggest that the laser-microtextured implant collar surface may provide more favorable conditions for the attachment of hard and soft tissues, and reduce the level of MBL.

Bone regeneration using Bioglass: an experimental study in rabbit tibia

Bioglass (BG) has been shown recently to be osteoconductive and osteopromotive in different experimental and clinical conditions. The aim of the present study was to evaluate BG particles in bone defects in rabbit tibia. In control sites, bone was observed only in the peripheral areas of the defects, while in test sites, newly formed bone was found around all BG particles, even those located in the central portion of the defect. Osteoblasts were actively secreting osteoid matrix directly on the granules' surface. BG seems to be a highly osteoconductive material.

A microscopical evaluation of 24 retrieved failed hollow implants

Twenty-four hollow ITI implants (four screws, and 20 cylinders) were retrieved because of failure, and evaluated in our laboratory, in a eight-year period (1989-1996), to see if a common cause could be observed in this implant design. No selection of these implants was carried out, and they represented the total number of implants of this type received in the above-mentioned time frame. The implants had been inserted by several different clinicians and were received from four universities and a private practice. The implants had been removed for mobility, pain, and presence of a vertical bone loss. About two-thirds of the implants were unstable in the jaw at the time of retrieval. Twenty implants had been used as single implants restoration and four in bridge reconstructions. Most of our specimens showed that the inflammatory process had reached the hollow portion of the implants. The following microscopical features were present in almost all our specimens: calculus and plaque on the coronal portion of the implant surface, presence of proliferating epithelium and of bone sequestra, and presence of bone apically to the inflammatory process. Perhaps, when the inflammatory process reaches the implant hollow portion, the infection runs a more rapid course due to the scarce vascularity of the bone inside this part.

Guided tissue regeneration versus coronally repositioned flap in the treatment of recession with double papillae

Twenty buccogingival recessions (3 mm deep) in twenty patients were selected and divided into two groups. Periodontal parameters were recorded (recession reduction, probing depth, clinical attachment level, and keratinized tissue width), and both groups were treated with regenerative therapy using a resorbable polylactic acid membrane. The test group was treated using the double papilla flap procedure, and the control group was treated using the coronally repositioned flap procedure. The results obtained at a 1-year follow-up were comparable between the test and control groups for recession reduction, probing depth, and clinical attachment level, although the test group obtained a very large amount of keratinized gingiva (+74.7%) compared to the control group.

Early tissue reactions to polylactic acid resorbable membranes: a histological and histochemical study in rabbit

The aim of this study, in rabbit tibia, was an evaluation of the early reactions of the tissues to the insertion of polylactic membranes, used in connection with titanium implants. The specimens were retrieved after 1-4 weeks, and a histological analysis was performed. It was possible to see that, in the early implantation phases, no degradation of the macrostructure of the membrane was present. On the outer portion of the membrane many multinucleated giant cells (MGC) were present and membrane fragments were present inside the cytoplasm of these cells. These cells could explain the inflammatory processes reported, in some reports, with the use of materials made by polylactic and polyglycolic acid. We did not observe detrimental effects in the bone tissue around the membrane, and the membrane appeared to have a mechanical stability for the time necessary for bone regeneration.

Hollow implants retrieved for fracture: a light and scanning electron microscope analysis of 4 cases

One of the possible complications of implant treatment is the occurrence of an implant fracture. Metal fatigue and biomechanical overload seem to be the most common causes of fractured implants. This study evaluated 4 implants (3 hollow cylinders and 1 hollow screw) which fractured after a mean loading period of 2.8 years. All implants had a 4 mm diameter and had been inserted in a posterior location. In 3 cases parafunctional habits were present. In all cases a vertical resorption of the peri-implant bone was present. The endosseous portion of the implant presented always a very high bone-implant contact percentage. Scanning electron microscopic examination showed that at least one of the implant holes was involved in the fracture line; no porosities or material defects were observed on the fractured surface of the implant. In hollow implants the holes could represent a site of less resistance.

Histological evaluation of the peri-implant bone around plasma-sprayed non-submerged titanium implants retrieved from man: a report of two cases

Two cases of non-submerged implants are reported: one was removed, unloaded, after 1 year, for psychiatric reasons, and the other, after a loading period of 4 years, for a fracture of the implant. The implants and surrounding tissues were processed to obtain thin ground sections. In the first case compact lamellar bone was observed in close contact with the titanium all around the implant perimeter. No connective tissue or empty spaces were found at the bone-implant interface. Histochemical staining with von Kossa demonstrated that all the bone around the implant was highly mineralized. No areas of osteoid tissue were found at the bone-implant interface. In the implant retrieved due to fracture it was possible to observe a very high percentage of bone-implant contact.

Cellular colonization and bone formation into expanded polytetrafluoroethylene membranes: a light microscopical and histochemical time course study in the rabbit

We report on a time course study of cellular colonization of expanded polytetrafluoroethylene (ePTFE) membranes in rabbits. Bone defects (8 mm) were prepared with low speed burs in rabbit tibial metaphyses and covered with ePTFE membranes. The membranes were retrieved after 3, 6, 9, and 12 weeks. At 3 weeks, all membranes were filled by cells and osteoid tissue: no mineralized tissue was found. Osteoblasts positive for alkaline phosphatase (ALP) were observed on the outer surface and inside the material interstices of the membrane. At 6 weeks, it was possible to observe an increase of the quantity of the osteoid material inside the membranes. At 9 weeks, bone tissue was present and it usually originated from the most external part of the membrane, and spread to the central part of the membrane. Only the central portion of this bone appeared to be completely mineralized. A sharp decrease in the number of ALP-positive osteoblasts was observed. At 12 weeks, the quantity of bone present appeared to be substantially increased. Only a small percentage of the bone inside the membrane appeared to be completely mineralized. No cells positive to acid phosphatase were observed. These histological results confirm the high biocompatibility of ePTFE membranes and the bone formation inside the ePTFE interconnected nodes could, probably, help in achieving a good biomaterial-tissue integration with predictable results in bone regeneration.

Evaluation of guided bone regeneration in rabbit tibia using bioresorbable and non-resorbable membranes

The aim of this study was an evaluation of the possibility of bone regeneration in connection with implant placement, using a new bioresorbable membrane (Guidor Matrix Barrier) used previously in periodontal tissues regeneration. The study compared the bone regeneration obtained around Bonefit-ITI implants inserted in rabbit tibia using Guidor membranes, Gore-Tex membranes and in control sites. Microscopic analysis was performed after 6, 9 and 12 weeks. It was possible to see that the amount of bone around implants covered by Guidor and Gore-Tex membranes was roughly equivalent in all experimental sites at the 6-, 9- and 12-week time intervals. Also, all control sites healed completely. It could be concluded from this study that: (1) rabbit tibia cannot be recommended in research connected with guided bone regeneration, as all control sites healed in the same way as the test sites; (2) in no case did the presence or the degradation of the resorbable membrane prevent the formation of new bone; (3) no inflammatory reaction was present around the bioresorbable and the non-resorbable membranes; (4) bone formed in all cases on the outer surface of the non-resorbable membranes; (5) large Guidor membrane fragments were present in the 6-week specimens, while in the 12-week specimens only small fragments were recognizable; (6) Guidor membranes can be used in guided bone regeneration.

Juvenile hyaline fibromatosis of gingiva: a case report

Juvenile hyaline fibromatosis is an extremely rare inherited condition, probably resulting from an inborn error of metabolism. It is characterized by cutaneous nodules, gingival hypertrophy and joint contractions. It affects children but usually it is not present at birth, and is microscopically characterized by a conspicuous hyalinization of the connective tissue.

Maintenance of implants: an in vitro study of titanium implant surface modifications subsequent to the application of different prophylaxis procedures

The aim of the present study was to evaluate surface alterations on titanium implant necks subsequent to different prophylaxis procedures. Fifty ITI implants were utilized. Forty implants were treated with 10 different prophylaxis procedures (ultrasonic scaler, plastic tip ultrasonic scaler, stainless steel curette, titanium curette, teflon curette, air powered system, abrasive rubber cups, polishing rubber cup and brush), and 10 implants were left as untreated controls. Surface alterations were studied on an area of 1 mm x 0.9 mm and quantified using optical microscopic, SEM and laser prophylometer analysis. The use of laser prophylometer provided an objective criterion for evaluation, expressing implant neck surface alterations in numeric values in terms of two roughness indexes, Ra and Rz. The results showed that, in comparison with the controls (Ra = 0.50; Rz = 3.98) the procedures investigated could be divided into 3 main groups: 1) Methods which altered the implant neck surface producing increased roughness (Ra = 0.68-2.08; Rz = 4.68-11.92); 2) Methods which left the implant neck surface unaltered (Ra = 0.44-0.57; Rz = 0.42-3.46); 3) Methods resulting in a smoothening of the implant neck surface (Ra = 0.36; Rz = 2.15). Group 1 included procedures that should be avoided. However, it appeared safe to apply the procedures of groups 2 and 3. To confirm these results, it will be necessary to evaluate the plaque- and calculus-removing efficacy from titanium neck implant surfaces in vivo.

Blood in saliva of HIV seropositive drug abusers: possible implication in AIDS transmission

We have studied hemoglobin concentration in saliva of anti-HIV positive and anti-HIV negative intravenous drug abusers (IVDA) and normal controls and the relationship between hemoglobin concentration in saliva and number of CD4+ cells and clinical status of AIDS in anti-HIV positive IVDA. 120 anti-HIV positive IVDA, 112 anti-HIV negative IVDA and 116 normal healthy subjects not belonging to any risk group for HIV infection completed the study. Saliva was collected at awakening before brushing teeth and the concentration of hemoglobin was determined. Hemoglobin concentration in saliva in basal conditions is higher in anti-HIV positive IVDA with respect to anti-HIV negative IVDA (p less than 0.05) and controls (p less than 0.01). In anti-HIV positive IVDA hemoglobin concentration in saliva is higher in subjects with CD4+ cells less than 200/10(6) l with respect to subjects with CD4+ greater than 200/10(6) l (p less than 0.05) and in subjects with ARC/AIDS with respect to subjects with PGL or who are asymptomatic (p less than 0.01). Subjects with ARC/AIDS have a mean concentration of hemoglobin of 19 micrograms/0.1 ml saliva (range 0-153) which corresponds to 1.3 microliters of blood/ml saliva. If 10 ml of saliva are exchanged during kissing an average of 13 microliters of blood are transferred (110 microliters of whole blood at extreme range). Blood of symptomatic patients has an HIV titer of 7 TCID/microliters which for 10 ml saliva containing an average of 1.3 microliters blood/ml saliva corresponds to an average of 90 TCID (770 TCID at the extreme range).(ABSTRACT TRUNCATED AT 250 WORDS)

[The role of Langerhans cells in periodontal disease]

Following a morphological description of Langerhans cells, the paper analyses their functional activity both as phagocytic cells and as antigen-presenting cells. The role of this cell population in periodontal disease is the examined in the light of recently reported findings.

[The role of LGL cells (NK and K) in periodontal disease]

The paper reports the morphological and functional aspects of NK and K cells in the light of the most recent advances in the field, and pays particular attention to their cytotoxic and suppressor capacities. The role of NK and K cells in periodontal disease is then described and it is observed how this cell population is absent in healthy gums, whereas it is found with increasing frequency at disease reaches the chronic stage. The presence of LGL cells is therefore thought to be associated with the development of plaque-induced inflammation.

[An epidemiological study on dental-periodontal pathology in a sample of the school-age population of the city of Naples. I. Periodontal pathology]

The paper reports the results of a study of the prevalence of periodontal diseases found in a sample group, aged between 6 and 18, resident in Naples. The structure of the survey, the clinical methods of collecting data and the statistical processing of data were carried out according to WHO directives regarding the study of oral pathologies.

[An epidemiological study on dental-periodontal pathology in a sample of the school-age population of the city of Naples. II. Prevention and periodontal therapy]

The need for periodontal prevention and therapy was quantified according to the prevention of pathologies within the framework of an epidemiological study carried out on a sample population aged between 6 and 18 years. Data were collected using the CPITN method (WHO).

[The role of phagocytic cells in periodontal disease]

Having described the morphological and functional characteristics of phagocytic cells, the paper underlines that, in addition to the etiological responsibility of bacterial plaque, the main role in the onset and evolution of periodontitis is played by the host's response. Phagocytic response plays a fundamental role in the host's defence reaction and represents the first barrier to the penetration of bacteria into periodontal tissue. In addition to their defensive role, phagocytic cells may also be responsible for damage to periodontal tissue as a collateral effect of their phagocytic function, thus worsening the periodontal lesion.

[The direct and indirect tissue-damaging action of periodontally pathogenic bacteria]

The paper describes the aggregation mechanism of bacterial plaque to the acquired film and analyses the method with which bacteria adheres to periodontal tissues, before examining the direct and indirect histolesive capacity of periodontopathogenic bacteria.

[Radiologic risk and INAIL insurance]

The Authors examine in this scientific work the radiological risk to which the dentist is exposed during his daily professional activity. They underline, moreover, the partial interpretation of the regulation in force by INAIL and ANPEQ that bind the dentist to a series of accomplishments that seem unjustified as regards the laws in force.

[Environmental pathology and dentistry. II. Occupational diseases and stomatomucositis due to allergic factors]

Professional diseases and stomatomucositis due to allergic factors represent two important aspects of odontostomatology in which there is a clear relationship with environmental factors. The paper analyses the etiopathogenetic and clinical aspects of the most common forms of disease which lead to alterations of the oral mucous.

[The relationship between lichen ruber planus orale, hepatopathies and hypersensitivity to the components of dental restorations]

A group of patients with lichen planus, a pathology affecting the cutis and mucosa which may affect the oral cavity, were studied. All patients underwent laboratory tests to assess hepatic function. Prick tests, using a series of haptens found in materials used in dental reconstruction work, were also performed in 53 patients who possessed dental prostheses. The statistically significant correlation between lichen planus, especially in its erosive form, and hepatic damage is underlined. However, the correlation between sensitivity to the haptens contained in materials for dental reconstruction work and lichen planus was not significant.

[The free subepithelial connective tissue graft]

After a description of advantages and disadvantages of traditional surgical techniques for the correction of gingival retractions, a new surgical techniques is indicated: the subepithelial connective tissue graft. The latter technique is assessed and described in detail and its relative efficacy in comparison with the traditional techniques is emphasized.

[Oral lichen planus and chronic hepatopathy. Clinico-statistical study]

Recent researches on the aetiopathogenesis of lichen planus have revealed a significant physiopathological and clinical association of this disease with the chronic hepatopathies. A clinico-statistical investigation has been carried out for the purpose of ascertaining the real importance of oral LP in the economy of this association. The results substantially demonstrated that oral LP, particularly the erosive variety, rather than cutaneous or cutaneous-mucosa clinical forms, occupies a central role in relation to association with the chronic hepatopathies (an important factor for diagnosis and predictive purposes). It has also been found that the erosive variety presents a significantly higher frequency in forms of LP with an exclusively oral involvement. Hence the need to propose an interdisciplinary type clinico-diagnostic approach to LP patients, particularly those with erosive type oral LP.

[Relations of gingival hypertrophy and blood levels of cyclosporin A in patients with renal transplants]

Gingival overgrowth is defined as hyperplasia of gingival tissue due to local, systemic or drug-related causes. To see if the incidence and severity of this side-effect are related to cyclosporine A (CyA) dosage and/or blood levels BCyA), we analysed data from 24 renal transplanted outpatients, grouped as follows: controls (C, n = 3): patients on immunosuppressive therapy other than CyA; group 1 (G1, n = 10): patients with BCyA steadily 300 ng/mL (RIA); group 2 (G2, n = 11): patients with BCyA steadily between 301 and 650 ng/mL. BCyA averaged 290 +/- 21 in G1 and 481 +/- 100 in G2 (p less than 0.001): mean cyclosporine A dosage (mg/kg/die) was not significantly different: 4.1 +/- 1.4 in G1 and 4.97 +/- 2.4 in G2. However, six patients in G2 also received calcium antagonists known to increase CyA blood levels (diltiazem and nicardipine) for clinical purposes or deliberately to increase CyA bioavailability. Mean time from transplant was (in months) 19 +/- 11 in G1, 16 +/- 15 in G2 and 62 +/- 24 in C (G1 vs G2: NS; C vs G1 and 2: p less than 0.001). Mean GFR (mL/min) was 75 +/- 22 in C, 65 +/- 18 in G1 and 53 +/- 19 in G2 (NS). Dental hygiene, as assessed by scoring (0-3: absent, mild, moderate and severe) the bacterial plaque, was similar in all groups. Gingival overgrowth, was similarly scored (0-3) and was absent in C and in 20% of G1, mild in 40% of G1 and 33% of G2, moderate in 40% of G1 and 33% of G2 and severe in 0% of G1 and 33% of G2 (G1 vs G2: p less than 0.05). Our data suggest that the severity of gingival overgrowth in transplanted patients with similar oral hygiene is mainly related to CyA blood levels.

[Alloplastic grafts in the treatment of infrabone lesions]

The possible treatment of periodontal infrabone defects is examined in the light of current developments. The possibility of using alloplastic grafts to create new periodontal structures is discussed in particular detail.

[Periodontal diagnosis. Review of the literature]

The possible ways of diagnosis periodontal disease are examined in the light of what is reported in the literature. Particular stress is laid on the importance of the diagnosis of diseases "activity", a condition that is indispensable for the implementation of correct periodontal therapy.

[Desquamative gingivitis: etiopathogenetic and clinical assessment]

The aetiopathogenetic, diagnostic, clinical and therapeutic aspects of a particular form of gingival condition given various names in the past but presently defined as "chronic desquamative gingivitis" have been examined. Desquamative gingivitis is an uncommon clinical condition whose aetiology remains uncertain. It has therefore not yet been definitely established wether it is a specific entity or whether, as is confirmed by much clinical evidence and laboratory data, it is merely an oral clinical sign of dermatological type pathologies (pemphigus vulgaris, benign mucosal pemphigoid, bullous pemphigoid, erosive lichen ruber planus, psoriasis).

Treatment of pediculosis pubis. Clinical comparison of efficacy and tolerance of 1% lindane shampoo vs 1% permethrin creme rinse

Pediculosis pubis (PP) is a common sexually transmitted disease. Current therapy with 1% lindane or various synergized pyrethrins as a single dose has been accepted as adequate by the medical community. We treated 53 men with the diagnosis of PP with either 1% lindane (Kwell) shampoo for four minutes or 1% permethrin (Nix) creme rinse for ten minutes, according to random assignment. All patients combed with fine-toothed combs immediately after therapy. They were examined for tolerance and efficacy at 24 to 48 hours and again at ten days (eight- to 12-day range). In the lindane group, ten (40%) of 25 subjects were infested at the final assessment. In the permethrin group, 12 (43%) of 28 subjects were infested at the final assessment. The difference was not statistically significant. Both treatments were well tolerated, with one mild adverse reaction in each group. We concluded that both agents were equivalent in the treatment of PP. On the basis of the high failure rate, we propose that the therapy of PP with any agent should include a second treatment at ten days.