Temperature changes of one-piece implants during the setting of acrylic resin temporary crown. The effect of implant diameter. An in vitro study

The purpose of this work is to evaluate changes in temperature of one-piece titanium implant surface during the setting of acrylic resin temporary crowns and to correlate thermal changes to implant diameter. Thirty-three one-piece implants (ARRP, Alpha-Biotec) were divided into 3 groups according to diameter size (G1=3 mm, G2=3.3 mm, G3=3.6 mm). Implants were mounted on an acrylic glass apparatus. Thermocouples were positioned at the most coronal thread. Lower incisor temporary polycarbonate crowns were filled with 80 μL of self-curing acrylic resin and positioned immediately on the implant abutment. Thermal changes of the implant surface were recorded continuously for 10 min. Data were statistically analyzed using one-way analysis of variance. The mean initial temperature (C0) of groups G1, G2 and G3 was similar (24.79±0.78ºC, 25.26±0.63ºC, 24.97±1.06ºC, respectively). The setting of the acrylic resin temporary crown resulted in a significant increase in the implant surface temperature of all groups. The mean thermal amplitude (ΔC) for groups G1, G2 and G3 were 6.79±1.02ºC, 6.61±0.94ºC, 6.65±1.26ºC, respectively. The mean time to maximum temperature (Tmax) for groups G1, G2 and G3 were 337.38±42.91 sec, 324.69±41.46 sec and 317.98±37.91 sec respectively (P>0.05). Direct application of auto-polymerizing resin to the titanium abutment of one-piece implants significantly increased the cervical implant surface temperature. Implant diameter did not influence the temperature changes.

[Establishing adequate periimplant zone of keratinized mucosa to enhance periimplant health]

The presence of an adequate zone of keratinized mucosa (KM) for maintaining gingival health associated with natural teeth is usually described as the presence of 1-2 mm of attached gingiva (AG). Dental implants without KM measuring 2 mm or more, exposed to high levels of bacterial plaque, have shown higher scores of plaque accumulation, peri-implant 'mucosal inflammation', bleeding on probing, peri-implantitis, alveolar bone loss and recession. In a recent study the effects of KM width on peri-implant tissue health was assessed. Significant improvements in clinical and immunological parameters were noted after increasing KM width by the use of free gingival graft (FGG) surgery. A recent systematic review evaluated the efficacy of various techniques and biomaterials adopted in periimplant KM augmentation. Free gingival graft, connective tissue graft, acellular dermal matrix and collagen matrix were used for KM augmentation. Improvements in KM width were reported in all studies. A definitive conclusion could not be achieved owing to the lack of well-designed studies and appropriate methods of studying soft tissue. The establishment of universal surgical guidelines and measurement systems is imperative in the future. The present manuscript will describe the clinical use of FGG for establishing adequate periimplant zone of KM to enhance periimplant health.

[Animal experimentation, animal welfare and scientific research]

Hundreds of thousands of laboratory animals are being used every year for scientific experiments held in Israel, mostly mice, rats, rabbits, guinea pigs, and a few sheep, cattle, pigs, cats, dogs, and even a few dozen monkeys. In addition to the animals sacrificed to promote scientific research, millions of animals slain every year for other purposes such as meat and fine leather fashion industries. While opening a front against all is an impossible and perhaps an unjustified task, the state of Israel enacted the Animal Welfare (Animal Experimentation) Law (1994). The law aims to regulate scientific animal experiments and to find the appropriate balance between the need to continue to perform animal experiments for the advancement of research and medicine, and at the same time to avoid unnecessary trials and minimize animal suffering. Among other issues the law deals with the phylogenetic scale according to which experimental animals should be selected, experiments for teaching and practicing, and experiments for the cosmetic industry. This article discusses bioethics considerations in animal experiments as well as the criticism on the scientific validity of such experiments. It further deals with the vitality of animal studies and the moral and legal obligation to prevent suffering from laboratory animals.

[Soft tissue grafts for the treatment of mucogingival deformities and conditions on edentulous ridges]

Soft tissue grafts are commonly used to restore and/or improve mucogingival deformities and conditions around teeth or on edentulous ridges. This include vertical and/or horizontal ridge deficiency, lack of gingiva/keratinized tissue, decreased vestibular depth and abnormal color. The present article describes and illustrates different procedures using autologous soft tissue grafts including masticatory mucosal free graft, masticatory mucosal pedicle graft, subepithelial free connective tissue graft, and subepithelial dermal graft. The functional and esthetic advantages and limitations of each graft for each condition are discussed.

[Buccal bony exostoses induced by free gingival grafts]

Buccal Bony Exostoses (BBE) is a local benign osseous overgrowth continuous with the facial aspect of the jaw. Post operative BBE may be the result of dermal grafts used to restore the buccal vestibulum, of connective tissue graft placement, and of Free Gingival Grafts (FGG) procedures. In 46 patients in whom 72 FGG procedures were performed by the senior author (HT) over the past 12 years, BBE was clinically and radiographically diagnosed. In one case the tumor was surgically removed. The etiology, pathogenesis and frequency of BBE following FGG procedures was reviewed and discussed. We suggest that the BBE may develop owing to periosteal surgical trauma during FGG procedures, and suggest that this phenomenon receives further attention.

[Implants placement using a novel computerized tactile imaging navigation system]

An implant locating system has been developed. The system contains a stent that maps the jaw bone at the implantation site through the tissue, sends a signal to a computer with a CT scan of the jaw on it, and superimposes the position of the stent on the jaw so that a dental surgeon could angle the implant for placement without requiring to raise a flap to expose the bone. Using a novel tactile technology the system allows safe, accurate, and simple implant placement and design. The ILS software allows: 1. Importing of CT data. 2. Marking a dental arc on the computerized jaw image. 3. Planning of implant location and position on a 3-D view. 4. Affixation of the ILS to the jaw, followed by registration of the stent. 5. Navigated osteotomy and implant placement.

[Healing of osseous defects by guided bone regeneration using ribose cross linked collagen membranes]

The ultimate goal of periodontal therapy has long been the complete regeneration of the periodontal attachment apparatus. Guided Tissue Regeneration (GTR) and Guided Bone Regeneration (GBR) are two regenerative procedures which converted this goal from a dream to reality. In search of a biocompatible resorbable tissue barrier, collagen, being a natural protein and a weak antigen, has attracted much interest and became the focus of much intention during the 80's and the 90's. The understanding that cross linking of collagen with aldehyde sugars, especially ribose, produces collagen which is highly resistant to resorption in vivo led to the development of a "natural" Crossed-Linked Collagen Barrier (CB-SX). Animal and Human studies have shown that the newly developed membrane is biocompatible, remains intact in the tissues 6 months and more, and results in impressive guided tissue/bone regeneration. Spontaneous early exposure of the membrane is common but the healing potential of the resulted tissue dehiscence is favorable with no tendency for bacterial infection. The commercial version of the CB-SX is especially suitable for GBR procedures; it is highly recommended that the gingival flaps involved will properly be released, will lack tension, and be thoroughly sutured.

[Gingival depigmentation for aesthetic purposes using erbium:YAG laser: rationale and technique]

Melanin, carotene and hemoglobin are the most common natural pigments contributing to the normal color of the gums. Although physiologic and ethnic melanin pigmentation is not a medical problem, complains about "black gums" are common. Gingival depigmentation has been carried out using surgical, chemical, electrosurgical and cryosurgical procedures. Recently, Laser Ablation has been recognized as one of the most effective, pleasant and reliable techniques. Effective depigmentation of the gingival requires removal of all or most of the melanocytes from the basal layer of the gingival epithelium. Using non-specific radiation means ablation of all the epithelial cell layers, as well as connective tissue rete pegs, leaving behind only remnants of the epithelial rete ridges. CO2, Nd:YAG and Erbium:YAG lasers, meeting most of these requirements and being available in the dental office, seems to be the lasers of choice for this procedure. Five patients (3 F; 2 M) who were referred to the TAUSDM for cosmetic therapy of "black gums" were treated using Erbium-YAG laser. The laser beam was set up at 850 mj/10 pulses per second producing peak power of 2.13 kwand peak power density of 30.43 kw/sq/cm. The beam was defocused to produce a 3 mm diameter circle, thus reducing the beam penetration while increasing the treated surface. Using the "brush" technique, 800-2,000 pulses were required per patient, with an average of 500-1,100 pulses per 1 sq.cm, depending on the thickness of the epithelium and the intensity of the pigmentation. Treatment required only topical anesthesia. Healing was uneventful and required no supportive therapy. Three months follow up has shown no repigmentation in any of the patients. Patients' evaluation analysis showed that the results were pleasing; no pain was experienced during lasing as well as during healing. Two patients were interupted by the lasing burning smell, which may be reduced or eliminated by operating a power suction during the procedure.

Tetracycline modulates collagen membrane degradation in vitro

BACKGROUND

Structural integrity of implanted bioabsorbable barrier membranes should be preserved for a sufficient time to ensure expected results. Collagen membranes are degraded by metalloproteinases (MMP). Their degradation rate can be altered either by enhancing structural integrity or by delaying the degradation process using MMP inhibitors. Tetracyclines (TTC) present inhibitory effects on matrix MMP. Immersing membranes in TTC solution before implantation can delay their degradation. The purpose of the present study was to evaluate the effect of collagen membranes immersed in varying TTC concentration solutions on the rate of their degradation in vitro.

METHODS

Collagen bioabsorbable membranes were prepared as 5 mm diameter membrane discs. Membranes were then incubated at 4 degrees C for 24 hours, in either phosphate buffered saline (PBS, Ca2+ and Mg2+ free) or with TTC-HCl dissolved in PBS concentrations of 5 mg/ml, 50 mg/ml or 100 mg/ml. After rinsing, membranes were incubated with either bacterial collagenase or cultures of human bone lineage cells. Membrane degradation was studied on days 2, 4, 7, and 14. Two- and 3-way analysis of variance was used to analyze results.

RESULTS

Samples supplemented with bacterial collagenase exhibited a statistically significant interaction between changes of free protein in the medium, antibiotic concentration used for the immersion, presence of collagenase in the medium, and incubation time (P<0.0001). Membranes incubated with bone cells exhibited similar degradation trends.

CONCLUSIONS

Collagen membranes immersed in 50 mg/ml TTC solution exhibited the longest degradation time, both in the clostridial collagenase and the human bone cell lineage assays. Immersion in a 50 mg/ml TTC solution before implantation will delay their degradation.

Efficacy of porous bovine bone mineral in various types of osseous deficiencies: clinical observations and literature review

Recent developments in osseous regenerative techniques have increased the demand for bone-substitute grafting materials. Porous deproteinized bovine bone mineral (PBBM), a biocompatible xenograft, has been used in different osseous deficiencies prior to or in conjunction with the placement of titanium implants. The different PBBM applications in fresh extraction sites, anatomic defects, and subantral floor elevation techniques are described. The use of an occlusive barrier membrane to regenerate bone via guided tissue regeneration principles was determined for each patient by clinical parameters. PBBM was well amalgamated and incorporated with the augmented hard tissue, but the transition between preexisting bone and the newly regenerated bone-like tissue was distinguishable by clinical examination even after 12 months. Grafted material was also identified using follow-up radiographs. In the presented cases, PBBM showed clinically satisfactory results as a biocompatible filler in bone augmentation procedures.

Spontaneous early exposure of submerged endosseous implants resulting in crestal bone loss: a clinical evaluation between stage I and stage II surgery

Spontaneous early exposure of submerged implants during the osseointegration healing phase may be a harmful factor that results in early crestal bone loss around the implants. The objective of this study was to assess the effect of spontaneous early exposure on crestal bone loss around submerged implants, with special attention given to the relationship between the degree of exposure and the amount of peri-implant bone loss. Crestal bone level relative to the shoulder of the implant was measured at the time of placement and at the time of exposure 4 to 5 months later. During the period between stage I and stage II surgery, implant sites were observed, and each implant site in which spontaneous early exposure was detected was recorded. Perforations were classified according to the degree of implant exposure from Class 0 (no perforation) to Class IV (complete exposure). Measurements from 206 implants in 64 patients produced 85 groups valid for statistical comparison; each of these contained at least 2 lesions of different types. There was a statistically significant difference between bone loss associated with intact mucosa (Class 0) and Class I, Class II, and Class III lesions, and between Class I and II lesions. There were no significant differences between Class I and III and between Class II and III. In Class II and III lesions, there was more bone loss associated with the buccal aspect of the implants. Of the 115 perforated sites, 10 were associated with bone loss exceeding 2 mm, 2 presented 3 to 4 mm bone loss, 1 showed more than 4 mm, and 1 displayed more than 5 mm. In view of the clinical implications that spontaneous early exposure may have on the success of osseointegration, prematurely partially exposed implants should be exposed as soon as possible after the perforation is observed.

Histopathological morphometric evaluation of 2 different hydroxyapatite-bone derivatives in sinus augmentation procedures: a comparative study in humans

BACKGROUND

Xenografts to augment the maxillary sinus have been used extensively. The aim of the present study was to evaluate, qualitatively and quantitatively, two different HA derivatives of natural and synthetic sources on newly formed bone in the augmented sinus.

METHODS

A bilateral sinus augmentation procedure with simultaneous (16 out of 20 sites) or subsequent implant placement was performed in 10 patients. The antrum was randomly filled with a deproteinized, bovine hydroxyapatite mineral (B-HA) on one side and a non-ceramic resorbable hydroxyapatite (NC-HA) on the other. Cylindrical specimens were harvested from the augmented core at 12 months. Decalcified specimens were sectioned at a cross-horizontal plane and stained with hematoxylin and eosin for histopathologic and histomorphometric examinations. Tissue area fractions of bone, marrow, and the grafted particles were calculated for each specimen from the lateral to the deep region, and changes in values were compared within each material and between them.

RESULTS

New bone formation was evident. B-HA and NC-HA particles were observed in all specimens surrounded by newly formed bone in direct connection or by soft tissue marrow. Morphometrically in the B-HA sites, from the lateral to deeper area, bone area fraction increased from 29.8% to 54.2% (average 42.1%) and marrow area fraction decreased from 37.9% to 26.7% (average 33.3%). The mineral area fraction decreased from 32.3% to 19.1% (average 24.7%). All increasing/decreasing patterns were statistically significant (P < 0.001). In the NC-HA sites, from the lateral to deeper area, bone area fraction increased from 25% to 36.5% (average 32.3%) and marrow area fraction decreased from 51.6% to 41.9% (average 43.2%) (P <0.001). The mineral area fraction decreased from 29% to 21.7% (average 24.6%) (P = 0.038). Comparison between the two HA derivative groups showed a significant difference between the bone area fraction averages (P = 0.0053) and between the increasing patterns along the core depth (P = 0.0006). There was also a significant difference between the decreasing marrow patterns (P = 0.003), but not between their averages. Comparison between the mineral area fractions showed no differences.

CONCLUSIONS

B-HA and NC-HA were proven to be biocompatible materials. Although the B-HA-augmented sites showed a higher percentage of bone formation at 12 months, both are suitable bone derivatives in sinus augmentation procedures and can accommodate osseointegrated implants.

Porous bovine bone mineral in healing of human extraction sockets: 2. Histochemical observations at 9 months

BACKGROUND

Porous bovine bone mineral (PBBM) has been used in ridge preservation procedures following tooth extractions. The aim of this study was to investigate histochemically tissue sockets grafted with PBBM at 9 months post-extraction. By using different histochemical stainings, characteristics of the newly formed bone; i.e., lamellar/woven ratio at different socket depths, were investigated and the arrangement of bone around the grafted material, as well as the nature of the amorphous organic material found in all specimens, were examined.

METHODS

After extraction of 15 single-rooted maxillary teeth from 15 patients, socket sites were grafted with PBBM particles (250 to 1,000 mu). Primary soft tissue closure of the grafted site was established using the rotated split palatal pedicle flap technique. At 9 months, a cylindrical tissue specimen, 2.5 mm in diameter, was trephined from each previously grafted site followed by placement of a screw-shaped implant. Horizontal tissue section cuts, 5 mu wide, were prepared for histological examination. Histochemical staining included alcian blue, periodic-acid Schiff, Mallory trichrome, reticulin, Van Gieson, and picrosirius red (PSR). PSR stained slides were further evaluated morphometrically, using polarized microscopy to determine the amount of lamellar versus woven bone in superficial, mid and deep specimen section cut areas.

RESULTS

All staining methods revealed that newly formed bone encircled and adhered to the grafted material in most specimens. Mallory trichrome staining showed osteoblasts present within an osteoid layer, lining the interface zone of PBBM particles and the new osseous tissue. Morphometric evaluation of the PSR stained slides disclosed a constant pattern of increased osseous tissue in a coronal-apical direction. An average of 17.1% osseous tissue with 1:12.9 lamellar/woven bone ratio was calculated in the superficial area. The average bone tissue fraction was 48.3% with a lamellar/woven ratio of 1:3.8 in the mid section area and in the deep area, it increased to 63.9%, with a lamellar/woven ratio average of 1:1.7. Differences between ratios at these sites were statistically significant (P<0.001). An amorphous organic substance was noted in most grafted particles. This material usually attached cell striae and harbored glycoproteins as revealed by periodic-acid Schiff and alcian blue stainings. Mallory trichrome staining showed denatured protein within the decalcified mineral particles; reticulin, Van Gieson stainings, and polarization of PSR stained sections refuted the existence of collagen in the grafted particles.

CONCLUSIONS

Cancellous PBBM is a biocompatible filler agent in extraction socket sites and an acceptable graft for edentulous ridge preservation at sites prepared to receive endosseous implants. The osteoconductivity of PBBM was determined based on promoting osseous ingrowth and close integration with the newly generated bone. Grafted particles were not significantly resorbed at 9 months. Further studies are needed to determine the resorbable capability, as well as the nature and significance of the amorphous organic substance of PBBM observed in the grafted particles.

Spontaneous early exposure of submerged implants: II. Histopathology and histomorphometry of non-perforated mucosa covering submerged implants

BACKGROUND

Spontaneous early exposure is a complication that could account for significant interference during the early healing phase of dental implants. Spontaneous perforations of the mucosa covering implants have been classified according to the degree of implant exposure from 0 (no perforation) to IV (complete exposure). In this study, the characteristics of the epithelium and connective tissue of clinically non-perforated mucosa over submerged implants are histologically and histomorphometrically evaluated.

METHODS

Ten randomly selected tissue disks of intact (Class [Cl]-0) mucosa covering submerged implants were removed using a biopsy punch. Identical mucosal punch specimens were obtained from edentulous sites treated by non-submerged (1-stage) implants for use as controls. Specimens were histopathologically examined. The epithelial width and inflammatory infiltrate adjacent to the epithelium were histomorphometrically measured and the data statistically analyzed.

RESULTS

Non-perforated mucosa covering the submerged implants (Cl-0) was characterized by an inflammatory fibro-epithelial hyperplasia. In 70% of Cl-0 hematoxylin and eosin-stained sections, there was mineralized material in the connective tissue, mostly sequestra. The epithelial width was 1.5 times higher (0.553 +/- 0.187 mm) when compared to controls (0.345 +/- 0.129 mm; P <0.0001). Concomitantly, the chronic inflammatory infiltrate was almost double in Cl-0 specimens (1,411 +/- 617 cell/mm2) when compared to controls (833 +/- 275 cells/mm2; P<0.001). A positive correlation between the linear combination of the epithelial width and the linear combination of the inflammatory cell concentration was found in both groups: Cl-0: r = 0.669, P= 0.0001; control: r = 0.541, P= 0.005.

CONCLUSIONS

Different factors may result in the formation of spontaneous early perforation, most of which are associated with mechanical trauma to the mucosa or tension in the tissue flaps covering the implants. Bone debris produced during the osteotomy could act as an additional predisposing factor; these are sequestrated and accompanied by chronic inflammatory cell infiltration as well as epithelial-covering reaction. Since this study focused only on specimens from intact mucosa, until further investigation of this phenomenon in spontaneously perforated sites is conducted, no conclusions on the role of these histopathological findings can be made.

Spontaneous early exposure of submerged implants: III. Histopathology of perforated mucosa covering submerged implants

BACKGROUND

Spontaneous early exposure of dental implants could interfere with the early healing phase of dental implants. These exposures have been clinically classified according to degree of implant exposure from 0 (intact mucosa) to IV (complete exposure). The characteristics of perforated mucosa (Class I and II) covering submerged dental implants were examined histologically in this study.

METHODS

Biopsy specimens of 34 Class I and II perforated mucosa covering submerged dental implants were examined histologically. Serial sections were evaluated from the periphery of the specimen to the center of each perforation lesion.

RESULTS

Class I specimens presented hyperplastic epithelium characterized by hyperparakeratosis and acanthosis. Chronic inflammatory cells diffusely infiltrated the connective tissue. Sections closer to the perforation revealed gradual epithelial invagination; in the deepest aspect, there was a cyst-like structure in all Class I specimens examined. A thin layer of connective tissue containing necrotic material and debris formed the "cystic" wall proximal to the implant cover screw. Class II specimens presented the same epithelial patterns; however, the cystic structures were replaced by direct contact between the cover screw and the oral cavity via the perforation.

CONCLUSIONS

Spontaneous early perforations are the sequela of either traumatic irritation or failure of the tissue flaps to produce primary healing. Most Class I perforations include epithelial invagination and the formation of a cyst-like structure. Necrosis of the base of the "cyst" or enlargement of the perforation results in direct communication between the oral cavity and the covering screw surface (Class II).

Porous bovine bone mineral in healing of human extraction sockets. Part 1: histomorphometric evaluations at 9 months

BACKGROUND

Extraction socket wound healing is characterized by resorption of the alveolar bone at the extraction site. This produces a decrease in ridge volume, deformations of ridge contours, and, thus, difficulties in delayed placement of root-form implants in an ideal position. Cancellous porous bovine bone mineral (PBBM) applied to fresh extraction sockets has recently been proposed to minimize the reduction in ridge volume. The aim of this study was to investigate the influence of PBBM grafted particles on the histopathologic pattern of the intrasocket regenerated bone and to evaluate histomorphometrically the healed PBBM grafted extraction socket site at 9 months' post-extraction.

METHODS

PBBM particles (250 to 1,000 microns in size) were grafted in 15 fresh human extraction sockets in 15 patients. Socket wall bone height was measured from the crestal ridge level before the mineral particles were inserted. Primary soft tissue closure was performed to protect the grafted particles via a pediculated split palatal flap. At 9 months, socket bone walls were remeasured and cylinder bone samples of the previously PBBM-grafted sites were obtained. Decalcified specimens were sectioned at a cross-horizontal plane and stained with hematoxylin and eosin for histopathologic and histomorphologic examination. Tissue area percentage of bone, PBBM, and connective tissue (CT) was calculated for each specimen from the crestal to the apical region and changes in values compared.

RESULTS

Average clinical overall bone fill of the augmented socket sites was 82.3%. Histologically, PBBM particles were observed in all specimens. Newly formed bone was characterized by abundance of cellular woven-type bone in the coronal area, while lamellar arrangements could be identified only in the more apical region. New osseous tissue adhered to the PBBM. Histomorphometric measurements showed an increase of mean bone tissue area along the histological sections from 15.9% in the coronal part to 63.9% apically (average 46.3%). CT fraction decreased from 52.4% to 9.5% (average 22.9%) from the crestal to the apical region. PBBM area fraction varied from 26.4% to 35.1% (average 30.8%). Statistical analysis of the comparison between areas of bone, CT, and PBBM was performed in different points along the coronal-apical axis. Differences were significant (P <0.01) at the most crestal, middle, and apical section cut areas, but not at the cervical section cuts. Bone area fraction increased in the apical direction as much as CT correlatively decreased. Unlike CT and bone, PBBM retained constant relative volume (approximately 30%), regardless of the depth of the specimen cores.

CONCLUSIONS

PBBM particles are an appropriate biocompatible bone derivative in fresh extraction sockets for ridge preservation. The resorbability of this xenograft could not be recognized in a 9-month period. Further investigation is needed to clarify the resorptive mechanisms of PBBM.

Subgingival acellular dermal matrix allograft for the treatment of gingival recession: a case report

Root coverage procedures using subgingival soft tissue grafts or guided tissue regeneration have attracted much interest within the past 2 decades. Recently, acellular dermal matrix allograft (ADMA) has been introduced as a substitute for palatal donor tissue in gingival augmentation procedures. This study was undertaken to examine the potential of ADMA to be used as a substitute for autogenous connective tissue graft material in a root coverage procedure in a case with moderate gingival recession combined with reduced keratinized attached gingiva. After thorough root planing and conditioning of the root surface with a saturated solution of tetracycline-HCl, a trapezoidal mucoperiosteal flap was raised and the papillae were de-epithelialized. The exposed bone surrounding the exposed root surface was perforated with a No. 2 round drill, and the exposed root and surrounding bone were covered by ADMA. The allograft was stabilized by 5-0 vicryl sutures. The flap was coronally positioned to completely cover the ADMA. Healing was uneventful. Eight-month observations and measurements showed root coverage of more than 3.5 mm (>80%), a gingival margin that was harmonious with the neighboring teeth, and an increase of the zone of keratinized attached gingiva, from 1 to 3 mm. Within the limitations of these clinical observations, it is suggested that ADMA may be a possible substitute to free autogenous connective tissue grafts and/or bioabsorbable barrier membranes. Further clinical and histological studies are necessary to understand the healing process of this surgical wound.

Autogenous masticatory mucosal grafts in extraction socket seal procedures: a comparison between sockets grafted with demineralized freeze-dried bone and deproteinized bovine bone mineral

Successful preservation of the edentulous ridge after extractions may eliminate or reduce the need for ridge augmentation procedures. It has been claimed that grafting fresh extraction sockets and sealing them with autogenous soft tissue grafts promote ridge preservation after tooth extraction. In this study, the survival of free autogenous connective tissue grafts sealing extraction sites was evaluated. In 24 healthy patients, 42 maxillary anterior teeth were extracted. After socket debridement, soft tissue margins of the socket orifice were carefully cut to remove epithelial debris, Sockets were filled with either demineralized freeze-dried bone allografts (DFDBA) or deproteinized natural bovine bone mineral xenograft (DBBMX) to the level of the alveolar bone crest. Circular connective tissue grafts, slightly larger in diameter than the soft tissue socket orifice, were obtained and placed on top of the filler graft material sealing the sockets. Grafts were stabilized and secured by sutures and inspected weekly for the first month. The grafts were classified into 3 groups according to clinical parameters: vital, partially vital and non-vital. After 1 week, 18 grafts were vital, 13 partially vital and 11 non-vital. When only 1 sample unit (1 site per patient) was compared between DFDBA and DBBMX grafted sockets, no significant difference in graft vitality was shown (P = 0.34 for vital; P = 0.67 for vital plus partially vital). After 1 month, all socket orifices were sealed with mucosa. Based on the present observations, it seems that connective tissue grafts sealing fresh extraction sites are mainly dependent on underlying tissue vascularization and that sealing grafted fresh extraction sockets filled with bone substitute allograft or xenograft materials may be beneficial but an unpredictable procedure.

Immediate loading of modular transitional implants: a histologic and histomorphometric study in dogs

Modular Transitional Implants (MTI) are made from pure titanium and are used to support fixed provisional restorations during the osseointegration of definitive implants. This study histologically examined the jaw response to loaded MTIs in the dog mandible. Three implants were inserted transmucosally into each side of the mandible in 3 dogs. Stability was examined using a Periotest. Anterior and posterior implants were splinted using a cemented acrylic resin fixed partial denture to allow immediate loading. The middle implant remained unloaded and was used as a control. Dogs were sacrificed 11 to 12 weeks after implantation, and tissue blocks containing the implants were removed. Histologic examination showed that 10 of the 18 implants had good bone-to-implant contact, with the percentage of bone contacting the threaded portion of the implant varying from 30% to 65%. There was no statistical difference (p > 0.1) in percentage of bone-to-metal contact between loaded and unloaded implants. Six implants were entirely surrounded by connective tissue with or without inflammation; two implants were lost during the study. The success rate did not differ between loaded and unloaded implants. In the successful implants trabecular bone made good contact with the implant, forming supporting struts. There was bone remodeling in some bone-to-metal contact areas. It is believed that success was mainly influenced by the initial bone density at the implant site and by the uncontrolled load that the animals applied to the implants during the early healing stage.

Spontaneous early exposure of submerged implants: I. Classification and clinical observations

BACKGROUND

It is believed that during the osseointegration phase of submerged dental implants, complete mucosal coverage and isolation of the implant from the oral cavity avoids trauma and infection and establishes favorable conditions for osseointegration. Spontaneous early exposure is one of the complications that could adversely affect osseointegration of implants.

METHODS

This study clinically classifies spontaneous early exposure and describes and analyzes this complication in a group of 148 patients treated with 372 submerged implants: 216 (58%) in the mandible and 156 (42%) in the maxilla. Edentulous sites were exposed by mid-crestal incisions and full thickness gingival flaps. Incisions were closed in an attempt to achieve complete closure and healing by primary intention. Measurements were taken to avoid mechanical trauma to the mucosa over the implants. Patients were followed up weekly and examined to identify early exposures. Perforations were classified according to the degree of exposure from 0 (no perforations) to 4 (complete exposure).

RESULTS

Of the implants 51 (13.7%) presented spontaneous early exposure, (13%) in the mandible and 23 (14.7%) in the maxilla. Class 2 perforation was the most frequent, followed by Class 3, Class 1 and Class 4. Inflammation at the mucosal orifices of the perforations was minimal, but no objective index (bleeding, probing) was taken in order to avoid morphological changes of the lesions that were biopsied for histological examination.

CONCLUSIONS

Early perforation and partial exposure of the implant's covering device are a focus for plaque accumulation which, if left untreated, may result in inflammation, damage to the peri-implant mucosa, and possible peri-implant loss.

Castration prevents calcium channel blocker-induced gingival hyperplasia in beagle dogs

1. The purpose of this study was to investigate testosterone's role on the calcium channel antagonist oxodipine-inducing gingival hyperplasia in a dog model. 2. Two experiments were conducted using castrated and intact male dogs. Oxodipine was administered orally for 90 days, at a dose of 24 mg/kg/day. In the first experiment, the occurrence of gingival hyperplasia was evaluated. In the second, the gingival index (GI) and gingival hyperplasia index (GHI) were recorded and correlated with serum levels of testosterone. 3. A significant positive correlation between GI, GHI and plasma testosterone was noted. Castrated dogs were injected with testosterone, 4 months after the start of oxodipine treatment, while in the non-castrated dogs, administration of oxodipine was stopped. Castration correlated with lack of GH, while testosterone injection to the same dogs was associated with an increase of GI and GHI. 4. Since it is known that testosterone receptors are present in the gingiva, it is proposed that oxodipine-induced gingival hyperplasia could be mediated by the calcium channel blocker on plasma testosterone levels.

Bone regeneration for reintegration in peri-implant destruction

Complications and deterioration around functional osseointegrated implants stem from two major factors: bacterial-initiated disease and overloading. Peri-implant breakdown can occur during the postsurgical phase and before the reconstructive phase as a result of surgical trauma and/or predisposed compromised recipient bone site. Technical errors also potentially contribute to bone loss, which results in the loss of osseointegration. Two case reports associated with peri-implant destruction are presented. The possible etiologic factors are discussed, and an attempt to regenerate lost peri-implant tissue is demonstrated via guided bone regeneration principles using barrier membranes.

Effect of non-erupted third molars on roots of approximal teeth. A radiographic, clinical and histologic study

This study was undertaken to evaluate clinically and histologically root resorption in extracted human second molars in close proximity to non-erupted third molars. The control group consisted of extracted second molars that were proximal to fully erupted third molars. Eight out of the 11 teeth in the study group presented different degrees of radiographic root resorption, nine presented clinical resorption, and all 11 had histologic evidence of root resorption. In the control group, no signs of root resorption were seen radiographically or clinically. Histologically, limited sites of resorption were identified in all teeth, which were partially repaired by cellular cementum. Histologic observation of study specimens revealed root surface resorption in 10 out of the 11 teeth, one showing replacement resorption as well. Inflammatory resorption was observed in the three most advanced cases in the study group. Reparative cementum partially lining resorbed areas was evident in all teeth with surface resorption. Within the limits of this study, radiographic identification of distal root resorption of second molars in close proximity to non-erupted third molars appears reliable. The findings may support the hypothesis that the presence of a non-erupted third molar in close proximity to the distal root of the second results in root resorption.

Preimplant guided bone regeneration in the anterior maxilla

Guided bone regeneration is a clinical procedure aimed at promoting bone formation at sites where there is severe bone loss. The purpose of this article was to demonstrate reconstruction of deformations of the alveolar process resulting from traumatic injuries to maxillary incisor teeth by guided bone regeneration procedures followed by insertion of dental implants. In both cases, submembranous space-making was stabilized by human demineralized freeze-dried bone. Implant insertion at the sites of bone augmentation resulted in successful restorations. Histologic examination of biopsy samples from the submembranous hard tissue revealed particles of demineralized freeze-dried bone allografts partially surrounded by uninflamed connective tissue and by vital bone adjacent and adhered to the demineralized freeze-dried bone allograft particles.

Periodontal and peri-implant bone regeneration: clinical and histologic observations

The principle of guided tissue regeneration by barrier membranes to restore lost periodontal tissue around natural teeth has also been used around osseointegrated implants in an attempt to restore alveolar ridge defects. While most periodontal procedures in the literature describe root coverage by mucogingival surgery, which achieves healing through soft tissue attachment, regeneration of denuded root surfaces is performed by guided tissue regeneration using expanded polytetrafluoroethylene barrier membranes and demineralized freeze-dried bone allografts as inductive/conductive materials. In this study the technique is applied in two partially exposed cylindrical hydroxyapatite-coated implants in extraction sites in one patient. Surgical reentry in both sites is presented, with histologic examination revealing new bone formation on the exposed root surface and the hydroxyapatite-coated implants.

Clinical efficacy of a degradable film-forming product containing carbamide peroxide to reduce tooth discolouration

The methods used to lighten tooth discolouration while conserving the tooth structure have attracted much attention in a society which places a high value on esthetics. The purpose of this article is to present a home bleaching agent that uses a film-forming preparation containing carbamide peroxide (CP) which, while degrading, serves as a slow release delivery system of the bleaching agent. The efficacy of the preparation containing 3% CP and 10% CP on reduction of tooth discolouration is evaluated by a Chromameter in a double-blind placebo-controlled study. The effect of the tested bleaching agent on the gingival status, plaque accumulation and pulp sensitivity is also assessed.

Collagen gel and membrane in guided tissue regeneration in periodontal fenestration defects in dogs

The effect of a collagen gel matrix as a submembranous space-maintaining material was evaluated in guided tissue regeneration procedures. In 4 dogs, contralateral surgical circular fenestration defects, 5 mm in diameter, were produced at the midbuccal aspect of the alveolar bone in 8 maxillary canines. Removal of bone, PDL and cementum was complete. Experimental sites were filled with collagen gel and covered with collagen membranes; control sites were covered with collagen membranes and the underlying space was spontaneously filled with blood. Mucogingival flaps were repositioned. Histological and histomorphometric observations, 6 weeks post-surgery, indicated that defects covered by collagen membranes presented the most impressive regeneration with almost complete coverage of the denuded root by new cementum (98.4%) and new bone (63.2%). In the experimental defects, 83.5% coverage of new cementum with only 21.9% new bone regeneration was observed. These results suggest that collagen gel, interfered with healing by PDL and bone-derived cells in the submembranous space.

Contiguous autogenous transplant--nineteen years' clinical and radiographic follow-up: a case report

Contiguous autogenous transplant, also known as the bone-swaging procedure, is a technique aimed at regenerating lost periodontium. Clinical healing of bony defects after bone swaging has been satisfactory, but the relationship and mode of attachment between the bone graft and the root surface have not been fully investigated. A 19-year clinical and radiographic follow-up of a bony defect treated with the bone-swaging technique is presented. A significant coronal increase in bone height and a gain in clinical probing depth were achieved postsurgery and remained unchanged during the first 6 years. The long-term clinical and radiographic findings, however, indicated that the attachment developed at the root-bone interface may not have been a true attachment and may have been more vulnerable to pathogenic local agents. These observations may help the clinician to interpret the clinical and radiographic changes that occur in the area of a bony defect following the use of a bone graft.

Gingival hyperplasia induced by calcium channel blockers: mode of action

Gingival hyperplasia is a known side effect in patients treated with diphenylhydantoin, cyclosporin and the calcium channel antagonists. The present study proposes a mechanism by which calcium channel antagonists may induce gingival hyperplasia. The calcium antagonist induces blockage of the aldosterone synthesis in zona glomerulosa of the adrenal cortex since this pathway is calcium-dependent, cyclic nucleotide-independent. This may produce a feedback stimulation of an increase in pituitary secretion of ACTH which affects zona glomerulosa hyperplasia. This hyperplasia is merely related by accumulation of steroid intermediate products (androgens) that are transformed to testosterone because of an increase in 17-alpha-hydroxylase enzyme activity. Elevated levels of testosterone may act on the gingival cells and matrix to produce gingival hyperplasia.

Inhibition of plaque formation by local application of a degradable controlled release system containing cetylpyridinium chloride

The effect of a degradable controlled release system containing cetylpyridinium chloride (CPC) on plaque accumulation and gingivitis was evaluated when applied on the anterior teeth of volunteers (16-17 years) over 4 weeks. At baseline, plaque index (PI) and gingival index (GI) of the Ramfjord teeth were measured in the experimental and placebo groups, including 23 and 21 participants respectively. Following scaling and root planning, the participants were instructed to brush, using one brush stroke, the film-forming solution on the buccal surface of the maxillary and mandibular incisors, 1 x a day before bedtime. The applied active solution contained 9 mg of CPC (approximately 80 mg of 11% CPC solution), while the placebo solution was identical in formation, but without the active agent. After 4 weeks, in the CPC-applied group, the recorded PI scores were 0.52 (+/- 0.56) in the anterior area and 1.31 (+/- 0.80) in the posterior area, whereas the corresponding areas in the placebo group reached 1.25 (+/- 0.74) and 1.51 (+/- 1.00), respectively. The PI = 0 frequency in the buccal anterior surfaces after 4 weeks was 54.6% (+/- 38.7%) in the experimental group as compared with 21.9% (+/- 29.0%) in the placebo group (p = 0.005). In contrast to the anterior teeth, there was no significant difference between groups with respect to the PI scores in the non-applied posterior teeth. It may be postulated that the impressive 58% inhibition of plaque accumulation at the site of application is the result of an increase of the substantivity of the CPC due to its incorporation in the film-forming degradable controlled release system.

Mucosal considerations for osseointegrated implants

Tissue resistance is determined by the nature of cells and intercellular contacts irrespective of the presence or absence of keratinization, masticatory mucosa, or skin. However, these tissues are more easily maintained and less vulnerable to inflammation when in contact with dental implants. Lack of masticatory mucosa and the presence of alveolar mucosa embracing the implant are often associated with plaque, which can induce inflammation resulting in subsequent peri-implant destruction. To facilitate proper mechanical oral hygiene maintenance, transplantation of autogenous masticatory mucosal grafts at the implant sites was performed in patients without attached gingiva, unfavorable vestibulum with submucosal muscular activity, and uncontrolled peri-implant mucositis. The rationale for having attached mucosa around osseointegrated implants and illustration of possible methods of mucosal management in the different phases of implant rehabilitation are presented.

The use of gingival autografts that contain submucosa in the repair of mucogingival defects in maxillary molars: case reports

Many studies have shown that deep and wide gingival recessions can be predictably covered by free gingival autografts. Most of the autografts in these studies were performed on single-rooted teeth. This article presents a rationale for a new technique that repairs this type of defect in maxillary molar areas by means of thick masticatory mucosa autografts that intentionally include not only the lamina propria, but also portions of the submucosa. In addition, a new suturing approach that allows adequate adaptation of the donor tissue to the recipient site and permits relocation of the graft is proposed. This new approach has been shown to be a significant advantage in the anatomically problematic maxillary molar area.

Polarization microscopy of picrosirius red-stained collagen from oxodipine-induced hyperplastic gingiva of beagle dogs

Using the model of oxodipine-induced gingival hyperplasia in beagle dogs, we investigated the collagen fibres of the hyperplastic gingiva by measuring the polarization colours from Picrosirius-red stained sections. The predominant polarization colours of the thick collagen fibres (1.6-2.4 microns diameter) of male oxodipine-treated dogs were greenish-yellow to yellow, while in controls and in female oxodipine-treated dogs, the same size fibres mostly appeared orange and red. These differences may be indicative of gender variation in the genesis of hyperplastic gingiva in calcium channel blocker treated dogs.

Histologic assessment of a contiguous autogenous transplant in a human intrabony defect. A case report

Increased blood supply, vital bone marrow cells, and minimal mobility may play a significant role in the success of osseous grafts, and are characteristics of the bone swaging grafting technique. As in all autogenous grafts, the risk of disease transmission is minimal. Previous reports of clinical success raise questions as to the type of tissue response to this procedure. This case report examines 8 months radiographic and histologic results of a clinically successful bone swaging graft.

The M20 IL-1 inhibitor prevents onset of adjuvant arthritis

Cytokines, specifically IL-1 and TNF, have been implicated as important mediators of joint destruction in rheumatoid arthritis (RA). Elevated levels of IL-1 in the joint fluid of patients with RA have been reported, as well as the presence of IL-1 inhibitory activity. We have reported the characterization of an inhibitor derived from a myelomonocytic cell line cloned in our laboratory which is specific for IL-1. This IL-1 inhibitor is protein in nature which specifically inhibits activity in vitro and in vivo. Previous studies showed that the inhibitor reduced acute inflammatory reactions associated with IL-1 (fever, leukocytosis, local foot pad swelling, lymph node enlargement and acute phase reactants). Thus it was of interest to study whether the M20 IL-1 inhibitor could modify adjuvant-induced chronic inflammation in rats, which is often used as a model for human RA. Administration of complete Freund's adjuvant (CFA) into Lewis rats, resulted in a severe adjuvant arthritis (AA) which reached peak severity after 14 days. Daily administration of IL-1 inhibitor, beginning after injection of CFA, abolished the appearance of AA. The parameters investigated were: joint swelling (the increase in diameter of joints), peri-articular erythema, limping of the rats and histological examination. The effect of the M20 IL-1 inhibitor was shown to be dose dependent and the IL-1 inhibitor alone had no adverse effects. These results indicate that the M20 IL-1 inhibitor may have a role in the treatment of AA and may be used to reduce pathological processes in joint inflammation.

Inhibition of plaque formation and gingivitis in beagle dogs by topical use of a degradable controlled-release system containing chlorhexidine

The in vivo efficacy of a newly-developed dental application of a film-forming, chlorhexidine-containing system was examined in beagle dogs. A self-disintegrating film-forming solution was applied three times weekly to the dentitions of 7 out of 13 dogs, which were fed a soft-food diet. Plaque accumulation (Plaque Index) and gingival inflammation (Gingival Index) were recorded at one, two, four, six, and eight weeks. The local delivery of low-dose chlorhexidine to dogs significantly inhibited gingivitis and plaque formation. It is concluded that the dental application of a film-forming system may be a preferable method of periodontal disease prophylaxis, and may enhance supragingival plaque control in areas of isolated periodontal problems associated with obvious local predisposing factors.

Cryosurgical treatment of hemangiomas of the lip

Removal of hemangiomas presents difficult management problems. This article describes the treatment of hemangiomas of the lip by cryosurgery and, in particular, evaluates the effectiveness of freezing in nitrous oxide cryosurgery on these lesions. Four women and two men, ages 40 to 76 years and manifesting angiomatous lesions on the vermillion of the lower or upper lips, were treated. Each site was directly exposed to two consecutive freeze-thaw cycles of 40 seconds freezing time at -30 degrees C to -40 degrees C. No anesthesia was required. Healing was uneventful. Superficial necrotic tissue covered the lesion at 1 week and necrotic slough was separated after 2 to 4 weeks, leaving a fully epithelialized surface. In all cases, there was no scarring and no recurrence was noted during the 2.5 year follow-up.

Healing of experimental wounds in sialadenectomized rat

The present study evaluates the healing of an experimental standardized full thickness excisional wound in the palate of a sialadenectomized rat model. Experimental rats underwent sialadenectomy of the submandibular and sublingual glands and ligation of the parotid ducts. A full thickness circular wound, 3 mm in diameter, was produced in the palate. Wound diameter was measured clinically and the area of inflammation and area of new connective tissue formation were determined histologically at 3, 7, 14, 21 and 28 days post-surgery. Wound diameter was similar in both the experimental and the control groups. The area of inflammation, however, was larger (p less than 0.05) in experimental rats at days 3, 7 and 14. New connective tissue formation was less (p less than 0.05) in sialadenectomized rats at days 14 and 21. The present results indicate that palatal wound healing is altered and delayed in sialadenectomized rats.

Heparan sulfate and fibronectin improve the capacity of collagen barriers to prevent apical migration of the junctional epithelium

The objective of the present study was to assess the effect of bilayered/collagen barriers enriched with fibronectin and heparan sulfate on the prevention of apical migration of the epithelium during the initial stage of periodontal wound healing. Experimental osseous defects were produced on the labial aspect of maxillary canines in dogs. Experimental sites were treated with either bilayered enriched collagen barriers or with non-enriched bilayered collagen barriers, using the guided tissue regeneration technique. Control sites were treated with monolayered collagen barriers that were not enriched with fibronectin and heparan sulfate. Histologic and histomorphometric examinations performed on specimens obtained 20 days post-operative indicate the formation of a short junctional epithelium in the experimental sites treated with enriched collagen barriers. In this group, 95% of the occlusal-apical length of the defects was repopulated by connective tissue cells. In the other 2 groups, a long junctional epithelium developed with only 65% of the occlusal-apical length of the defects being repopulated by connective tissue cells. These findings suggest that the enrichment of collagen barriers with fibronectin and heparan sulfate may be important to enhance the repopulation of exposed root surfaces by connective tissue cells and prevent the apical migration of the epithelium during the initial stages of periodontal wound healing.

Healing of sites within the dog periodontal ligament after application of cold to the periodontal attachment apparatus

The potential of periodontal ligament-derived tissues to regenerate periodontal attachment after cryosurgical trauma to the PDL in dogs was evaluated. The buccal alveolar plate of each canine tooth was exposed by a semi-lunar excision. A 3 mm thick cryoprobe, cooled to -81 degrees C, was placed on the bone 5 mm apical to the crest for 10 s. This induced cellular devitalization in the bone directly in contact with the probe and the PDL under it. The freezing-thawing cycle was repeated 3 times. Control sites were sham-operated at room temperature. Histologic sections from the center of the lesions were obtained from 1 h, 48 h and 30 d specimens. 1-h control and experimental histologic sections were similar. At 48 h post-surgery, the cellular component of the frozen PDL could not be identified and inflammatory response was minimal. The collagenous framework, however, appeared to form a continuum between the alveolar bone and cementum. Lacunae in the bone at the frozen segment were empty. The injured PDL was surrounded by normal PDL. Control specimens appeared normal. At 30 d, the PDL space in the frozen segments was populated by PDL-like tissue which did not differ significantly from the PDL coronal or apical to it. Collagen fibers appeared to be attached to the cementum on one side and to the alveolar bone on the other. Bone resorption or ankylosis was not observed in the experimental sites. It is suggested that the extracellular matrix in the devitalized area was preserved, supporting regeneration of the cryolesion.

Spontaneous ameloblastic fibro-odontoma in a female mouse

A spontaneous ameloblastic fibro-odontoma is described in a 73-wk-old female mouse. The tumor was located in the molar mandibular region. The diagnosis was made on the basis of the histologic presence of odontogenic epithelial tissue embedded in mesodermal tissue resembling dental papilla, and containing in addition dentin and enamel. The positive reaction for keratin and vimentin confirmed the presence of ectodermal and mesodermal elements respectively in the tumor.

Salivary gland cysts of the oral cavity: clinical observation and surgical management

Mucoceles are common cystic lesions of the oral mucosa. Extravasation mucoceles are mainly found in the lower lip of young patients, whereas retention mucoceles are usually located in the cheek or palate of older patients. The disparate site and age incidences of extravasation and retention mucoceles suggest that these two types are not related and have different pathogenesis. Treatment modalities for mucoceles are reviewed, with special attention to the cryosurgical technique for the treatment of oral ranulas.

A comparison of panoramic radiography with computed tomography in the planning of implant surgery

The accuracy of panoramic radiography and computed tomography (CT) in the evaluation of depth of the mandible at recipient implant sites was compared by measuring the distance between the edentulous bony crest and the superior border of the inferior alveolar canal in a group of ten patients. Distortion was calculated using the metal ball technique for the panoramic radiographs and the computer scale for the CT scans. The precise distance between the bony crest and inferior alveolar canal was determined from postoperative radiographs from the known length of the implants. It was found that although CT scans are more precise, panoramic radiography is sufficiently accurate for routine clinical purposes. CT scans have, however, an additional advantage in presurgical planning, since they reveal the horizontal dimension and shape of the mandible, and the topography and buccolingual location of the inferior alveolar canal.

Estimation of dental plaque levels and gingival inflammation using a simple oral rinse technique

A simple, non-invasive test (the Oratest) has recently been proposed, which provides an estimate of oral microbial levels based on the rate of oxygen depletion in expectorated milk samples. Following 30 seconds of vigorous rinsing with sterilized milk, 3 ml of the expectorate is added to a test tube containing the redox indicator, methylene blue, and the time required for a color change from blue (i.e., aerobic conditions) to white (anaerobic conditions) at the bottom of the test tube is recorded. In the present study, Oratest scores were compared to clinical parameters (Plaque Index [PI] and Gingival Index [GI]) in a group of 49 volunteers. Significant correlations were found between the logarithm of Oratest results and PI (r = -0.58; P = 0.001) as well as GI (r = -0.66; P = 0.001). The data indicate that the Oratest provides a reliable estimate of gingival inflammation, thus extending the previously reported strong correlations between Oratest scores and microbial counts. The data suggest that the Oratest may have potential as a clinical and research tool.

Peripheral giant cell granuloma during orthodontic treatment

Inflammatory and hyperplastic gingival responses during orthodontic treatment are common. These may complicate the actual treatment and may require periodontal therapy. The present report describes the development of an interproximal enlarged peripheral giant cell granuloma during orthodontic treatment, resulting in migration and separation of the neighboring teeth and resorption of the interproximal alveolar septum and molar root. The lesion was excised and the bone was curetted; this led to spontaneous migration of the involved teeth to their natural positions.