Soft Tissue Integration of Hydroxyapatite-Coated Abutments for Bone Conduction Implants.

PURPOSE: The protocol for bone conduction hearing implant surgery involves reduction of soft tissues around the abutment to minimize the risk of skin-related complications. The present investigation was undertaken to demonstrate that hydroxyapatite-coated abutments provide improved soft tissue integration compared with conventional (pure titanium) abutments and are suitable for use without surgical removal of subepidermal soft tissues. MATERIALS AND METHODS: Forty-eight implants for bone conduction with two different types of abutments (test and control) were inserted in the skull parietal part of eight sheep. Test abutments had a hydroxyapatite-coated surface and a concave shape. Conventional titanium abutments were used as controls. A follow-up time of 4 weeks was used. Histomorphometric analyses of test and control samples were analyzed, and morphometric results were compared using mixed model analysis. RESULTS: Histological assessment showed healthy soft tissues around the abutments with limited or no signs of inflammation. Hydroxyapatite-coated abutments showed intimate dermal adherence, while less close contact was noted for control abutments. Statistically significant differences in mean pocket depth (0.4 vs 1.6 mm, p = .0013) and epidermal downgrowth (0.6 vs 2.0 mm, p = .0003) between test and control abutments were recorded. CONCLUSION: The study confirms that hydroxyapatite-coated abutments resulted in a significant reduction in pocket depth and improved soft tissue integration compared with conventional titanium abutments, possibly by providing tight adherence at the interface. Statistically significant reduced pocket depth formation and epidermal downgrowth were recorded.

Cement-associated signs of inflammation: retrospective analysis of the effect of excess cement on peri-implant tissue.

PURPOSE: Excess cement left in the peri-implant sulcus after the placement of prosthetic restorations risks inflammation in the peri-implant tissue. While many current studies deal with the question of how to avoid undetected excess cement, relatively little is known about the clinical consequences of this complication. This study analyzed the clinical findings associated with excess cement. Further, the influence of the sojourn time of undetected excess cement in the peri-implant pocket on clinical findings was investigated. MATERIALS AND METHODS: Within the scope of a retrospective clinical follow-up, the suprastructures that were originally cemented with a methacrylate cement were revised in 93 patients (171 implants). The patients were split into two groups according to the time between placement of the prosthetic restoration and revision. Group 1 (G1) had treatment revisions within 2 years of restoration placement (71 patients with 126 implants); in group 2 (G2), treatment revisions were conducted at a later time (22 patients with 45 implants). For the purpose of statistical analysis, both groups were further analyzed based on the presence/absence of excess cement at the time of revision. RESULTS: By definition, the average time to revision in G1 was shorter than in G2 (0.71 years versus 4.07 years). There was no significant difference in the frequency of excess cement at revision between G1 (59.5%) and G2 (62.2%). The clinical findings around the implants in G1 were significantly less severe than in G2 (bleeding on probing: G1 without excess cement--17.6%, G1 with excess cement--80%, G2 without excess cement--94.1%, G2 with excess cement--100%; suppuration: G1 without excess--0%, G1 with excess cement--21.3%, G2 without excess cement--23.3%, G2 with excess cement--89.3%). After removing the excess cement, cleaning and disinfecting the implant abutment and restoration, and using a different cement, significantly fewer signs of inflammation were found at further follow-up in both groups. CONCLUSIONS: Within the limitations of this retrospective observational study, excess cement was present in a high number of cement-retained implant restorations. Signs of inflammation were present in a large proportion of implants at short- to medium-term follow-up. At the time of restoration revisions, the clinical observation of previously undetected excess cement was associated with increased prevalence of inflammation. Removal of excess cement significantly reduced the signs of inflammation.

Periodontal Side Effect During Orthopedic Face Mask Therapy.

A 7-year-old patient exhibited gingival recession of tooth #41 and severe plaque accumulation after 3 months of face mask therapy. The recession improved only slightly after appropriate oral hygiene instructions and motivation. Decisive improvement began when the vertical chin pad extension was reduced to avoid pressure on the affected area.

A short-term evaluation of the relationship between plasma ascorbic acid levels and periodontal disease in systemically healthy and type 2 diabetes mellitus subjects.

BACKGROUND: Deficient ascorbic acid levels (AALs) and Type 2 diabetes mellitus (T2DM) are associated with periodontal disease. This study evaluated the relationship between plasma AAL and periodontitis in systemically healthy and T2DM subjects, which to the best of our knowledge is being reported for the first time. METHODS: One hundred twenty subjects were categorized into four groups of 30 each as group 1: without periodontal disease; group 2: chronic gingivitis; group 3: chronic periodontitis, and group 4: chronic periodontitis and freshly diagnosed T2DM. Plaque index (PlI), sulcus bleeding index (SBI), and probing pocket depths (PPDs) were evaluated. Venous blood was evaluated for plasma AAL spectrophotometrically. Randomized subjects were subgrouped within groups 2-4, to receive either scaling and root planing (SRP) with dietary supplementation (450 mg) of ascorbic acid (AA) for two weeks or only SRP. After two weeks, the clinical parameters were reassessed. Tukey's multiple post hoc procedures and paired t test were used with the level of statistical significance adjusted to p ≤ .05. RESULTS: AAL plasma levels were significantly greater in group 1 than in group 2 (p = .0007) and in group 4 (p = .0003). A significant reduction in the SBI was seen in the subgroups that received dietary supplementation of vitamin C within group 2 (p = .0012) and group 4 (p = .036). CONCLUSIONS: Plasma AAL is below the normal range in systemically healthy subjects with gingivitis and diabetics with periodontitis. Dietary AA supplementation with SRP improves the SBI in subjects with gingivitis and diabetics with periodontitis.

Initial expression of the Papillon-Lefevre syndrome in consanguine family.

A rare case of Papillon-Lefevre syndrome is discussed with clinicoradiological presentation. The purpose of the case report is to make the medical community aware of this rare syndrome and its association with consanguinity. Papillon-Lefevre syndrome is an extremely rare genodermatosis of autosomal-recessive inheritance which usually manifests itself between the ages of 6 months to 4 years characterised by diffuse palmoplanter hyperkeratosis (keratoderma), and rapidly progressive and devastating periodontitis, affecting the primary as well as permanent dentition. Papillon-Lefevre syndrome results from a combination of host and bacterial factors, including recessive gene, consanguinity, specific periodontal pathogens and lack of thorough oral hygiene. The present case report describes Papillon-Lefevre syndrome and its association with consanguinity in a 3-year-old girl.

Periodontal healing complications following concussion and subluxation injuries in the permanent dentition: a longitudinal cohort study.

PURPOSE: The purpose of the study was to analyze the risk of periodontal ligament (PDL) healing complications following concussion and subluxation injuries in the permanent dentition. MATERIAL AND METHOD: A total 469 permanent teeth (358 patients) with concussion and 404 permanent teeth with subluxation were included in the study. All teeth were examined according to a standardized protocol including clinical, photographic, and radiographic registration. STATISTICS: The risk of repair-related resorption (surface resorption), infection-related resorption (inflammatory resorption), replacement-related resorption (ankylosis), marginal bone loss, and tooth loss were analyzed with the Kaplan-Meier method. RESULTS: Concussion: In teeth with immature root development, no healing complications were observed. For teeth with mature root development, the risk of repair related resorption after 3 years was 3.2% (95% CI: 0.3-6.0%) and occurred only in cases where several teeth were injured simultaneously (multiple-trauma cases). The risk of marginal bone loss in teeth with mature root development was 0.7% (95% CI: 0-1.6%). Infection-related resorption, replacement resorption, and tooth loss were not observed among teeth with concussion. Subluxation: In teeth with immature root development, the risk of infection-related resorption after 3 years was 1.7% [95% confidence interval (CI): 0-3.8%]. Infection-related resorption occurred significantly more often in teeth with concomitant crown fracture (P = 0.004). For teeth with mature root development, the risk of periodontal healing complications after 3 years was: repair-related resorption, 3.6% (95% CI: 0-7.6%); infection-related resorption, 0.6% (95% CI: 0-1.7%); replacement-related resorption, 0.6% (95% CI: 0-1.7%); and marginal bone loss, 0.6% (95% CI: 0-1.7%). No teeth were lost in the observation period. CONCLUSION: The risk of periodontal healing complications after concussion as well as subluxation injuries in permanent teeth is very low.

A literature review of two-unit cantilevered FPDs.

PURPOSE: This review article evaluated the clinical performance of two-unit cantilevered, single-abutment, single-pontic, resin-bonded fixed partial dentures (FPDs) by comparing them to noncantilevered resin-bonded FPDs with two abutments and a single pontic. MATERIALS AND METHODS: One publication on design principles and 11 clinical research studies were selected by searching two databases. RESULTS: Six of the studies dealt exclusively with two-unit cantilevered resin-bonded FPDs, and five studies compared fixed-fixed design resin-bonded partial dentures with cantilevered resin-bonded FPDs. Two-unit cantilevered resin-bonded FPDs for single-tooth replacement appear to be reliable and predictable restorations, provided their preparations meet the right standards. CONCLUSION: According to the studies reviewed, two-unit cantilevered FPDs show better longevity than resin-bonded fixed-fixed partial dentures in similar situations.

Technique on restoring cervical lesions.

This paper describes a technique of placing a semi-rigid cervical matrix slightly past the cervical border of a lesion that extends below (apical to) the gingival crest and inserting the glass ionomer cement through an opening cut in the matrix above the soft tissue level.

Discrete proteolysis of focal contact and adherens junction components in Porphyromonas gingivalis-infected oral keratinocytes: a strategy for cell adhesion and migration disabling.

Adhesive interactions of cells are critical to tissue integrity. We show that infection with Porphyromonas gingivalis, a major pathogen in the periodontal disease periodontitis, interferes with both cell-matrix and cell-cell adhesion in the oral keratinocyte cell line HOK-16. Thus, infected cells showed reduced adhesion to extracellular matrix, changes in morphology from spread to rounded, and impaired motility on purified matrices in Transwell migration assays and scratch assays. Western blot analysis of P. gingivalis-challenged HOK-16 cells revealed proteolysis of focal contact components (e.g., focal adhesion kinase), adherens junction proteins (e.g., catenins), and adhesion signaling molecules (e.g., the tyrosine kinase SRC). Proteolysis was selective, since important components of adherens junctions (E-cadherin) or signaling molecules (extracellular signal-regulated kinases ERK1/2) were not degraded. The virulence factors gingipains, cysteine proteinases expressed by P. gingivalis, are likely responsible for this proteolytic attack, since they directly digested specific proteins in pull-down experiments, and their proteolytic activity was blocked by the cysteine proteinase inhibitor N-alpha-p-tosyl-L-lysine chloromethyl ketone and also by a caspase inhibitor. Proteolysis was strain dependent, such that ATCC 33277 and 381 had high proteolytic potential, whereas W50 showed almost no proteolytic activity. These findings may help explain the formation of gingival pockets between cementum and periodontal epithelium, a hallmark of periodontitis. Furthermore, they illustrate a new pathogenetic paradigm of infection whereby bacteria may disrupt the integrity of epithelia.

Influence of flap design on periodontal healing of second molars after extraction of impacted mandibular third molars.

OBJECTIVE: The aim of this study was to compare the influence of two mucoperiosteal flaps on periodontal healing of adjacent second molars after extraction of impacted mandibular third molars. STUDY DESIGN: An envelope incision with a releasing incision anterior to the second molar (3-cornered flap) was used on one side and a Szmyd flap on the other side in 14 patients with bilateral impaction of mandibular third molars. The periodontal health of the second molars was evaluated before surgery and at 3 and 6 months postoperatively. A William's periodontal probe was used to measure the pocket depth, clinical attachment level, and bone level of the buccal and mesial surfaces of the second molars. The postoperative measurements were analyzed by using analysis of covariance, with the covariables being the preoperative measurements and variation factors being the type of flap used, the surface measured, and the time since the procedure. RESULTS: No statistically significant differences were found in comparing measurements of probing depth, clinical attachment level, or bone level for the 2 types of flap used or the 2 surfaces measured. However, there was a statistically significant increase in all 3 measurements from the 3-month to the 6-month postoperative time. CONCLUSION: Independent of the design of the mucoperiosteal flap used in extracting an impacted mandibular third molar, the periodontal condition of the adjacent second molar worsened from 3 to 6 months, although it remained within normal values.

Clinical effects of removable acrylic appliance design on gingival tissues: a short-term study.

The aim of this study was to assess the effects on the gingiva when an experimental palatal acrylic removable appliance, was worn for 3 weeks. Clinical parameters were reassessed after a 3 week recovery period when the appliance was no longer worn. The appliance design featured a base plate on the right side which extended to the gingival margin, but which on the left, was relieved from the gingival margin by 6mm. Plaque index, gingival index, and probing depth were recorded on days 0, 7, and 21, and at day 42. Results indicated that there was increasing gingival inflammation in the right palatal gingiva by day 7, and this became worse by day 21. Statistically significant differences in gingival inflammation were evident when right and left sides were compared at day 7 and 21, although there were no significant differences in plaque accumulation during this period. Probing depth measurements also increased significantly on the right side by day 21. All these gingival changes reversed to baseline levels during the recovery period by day 42. This paper demonstrates the rapid effect of acrylic denture design on gingival tissues.

Site-specific association between supragingival plaque and bleeding upon probing in young adults.

The aim of the present study was to consider supragingival plaque as a risk factor for gingivitis in a group of young adults without destructive periodontal disease. A total of 127 subjects, 17 to 30 years of age, participated. Periodontal probing depth, clinical attachment level as well as bleeding upon probing and supragingival plaque was assessed at 6 sites of every tooth present. The individual odds ratios between plaque and bleeding ranged between 0.237 and 66.6. 23% volunteers had an odds ratio of below 1.2. Only 15% individuals presented with an attributable risk of supragingival plaque for bleeding upon probing of 50% or more. Overall, the odds of bleeding, adjusted for periodontal probing depth, was increased by 67% in the presence of plaque. Large differences were observed at different teeth with the highest odds ratio at mandibular premolars with 2.557 (95% confidence interval 2.033-3.216) and the lowest at maxillary molars with 1.355 (1.161-1.732). It was concluded that there was high interindividual and intraindividual variation of the relative risk for bleeding in the presence of plaque. The observed low overall relative risk has important consequences in educational and health care programmes since the risk of supragingival plaque which is actually attributable for the observed bleeding on probing may be rather small.

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.

Clinical success of class V composite resin restorations without mechanical retention.

The authors describe a study in which they placed 126 Class V composite resin restorations without mechanical retention, divided into three groups of 42, in 23 patients. They followed the performance of the restorations over a three-year period. For all three groups, restorations were placed using All-Bond 2 dental adhesive and Z100 composite resin; A.R.T. Bond and Brilliant Dentin composite; and Prisma Universal Bond 3 and Variglass VLC polyacid-modified composite resin. The authors evaluated retention as well as color stability, wear resistance, sensitivity, sulcular depth, loss of attachment, bleeding on probing and crevicular fluid flow. Based on their results, the authors propose that restoration of Class V lesions without using mechanical retention could be expected to succeed in seven of 10 restorations over a three-year period using these restorative systems.

Posttreatment assessment of surgically exposed and orthodontically aligned impacted maxillary canines.

The records of 96 consecutively treated patients, with a total of 110 exposed maxillary canines, were reviewed after orthodontic alignment of the exposed teeth. In view of the high degree of clinical and patient satisfaction with the results, a random sample of 25 patients, with a total of 30 exposed canines, were critically assessed. The assessment involved scoring for clinical impression, mobility, gingival condition and pocketing, oral hygiene, vitality, and radiographic appearances. The results indicate that the technique of surgical exposure and orthodontic alignment of ectopic maxillary canines provides a satisfactory method of treatment.

A 3-year follow-up study of various types of orthodontic canine-to-canine retainers.

The present study was performed to test the tendency for plaque and calculus build-up along the wire of different types of bonded orthodontic canine-to-canine retainers, whether the presence of such retainers causes any damage to the teeth involved, the failure rate of the retainers, and any changes in incisor alignment during a 3-year period of retention. The four test groups received either retainers made of thick plain wire bonded only to the canines (n = 11); thick spiral wire bonded only to the canines (n = 13); thin, flexible spiral wire bonded to each tooth (n = 11); or removable retainers (n = 14). Accumulation of plaque and calculus along the gingival margin, gingival inflammation and probing attachment level were scored in lingual areas from canine to canine at the time of fixed appliance removal and again 3 years after retainer insertion. Incisor irregularity was measured on plaster models made at the same time periods. Accumulation of plaque and calculus and development of caries along the wire were scored at follow-up. Retainer failures were recorded whenever they occurred. The results revealed no intergroup differences in changes between baseline and follow-up examinations or status along the retainer wire for any of the variables. Gingival inflammation and plaque accumulation were scored less frequently after 3 years in retention than at the time of debonding. No signs of caries were seen adjacent to the wire. Failures were observed of one, four and three of the fixed retainer types, respectively. These patients showed a greater increase in incisor irregularity than the other patients.

A 10-year follow-up study of fixed metal ceramic prosthodontics.

The aim of this retrospective study was to record patients' satisfaction with fixed metal ceramic bridges and crowns made by dental students and to evaluate the functioning and condition of the bridges and crowns clinically and radiologically. Out of the 60 patients treated at the Institute of Dentistry during 1984-85, 30 patients attended the follow-up examination (16 women, mean age 39, range 23-62 years and 14 men, mean age 44, range 26-65 years). The anamnestic data and data regarding treatment procedures were collected from the patient files. The patients had been supplied with 41 crowns and 24 bridges (mean 3.9 units, range 3-6 units), which included 61 abutments and 33 pontics or cantilever extensions (abutment/pontic ratio 1.85: 1). Marginal fidelity was unsatisfactory in 13% of the crowns and bridges and gingival bleeding and pockets of 4-6 mm were noted in 27% and 12% of cases, respectively. None of the subjects had caries in the abutments.

Influence of tooth instrumentation roughness on gingival tissue reactions.

Histological studies have demonstrated a relationship between the amount of subgingival plaque and the magnitude and extension of gingival tissue reactions. The objective of the present study was to evaluate inflammatory reactions in the gingival tissues facing plaque accumulation at a diamond and curet-instrumented root surfaces. Experimental, deep periodontal defects were established at buccal surfaces of mandibular and maxillary canine teeth in 5 beagle dogs. The root surfaces were instrumented by a flame-shaped, fine-grained. rotating diamond point, or by a sharp curet. Next, the dogs were fed a plaque-inducing diet for 70 days. The animals were then sacrificed, and tissue blocks of the experimental sites including teeth, alveolar bone, and gingival tissues were secured. The gingival soft tissue was processed for histomorphometric analyses at 3 levels. Epithelium and connective tissue area measurements showed no differences between the two instrumentations. Junctional epithelium (JE) cell point counts exhibited a higher proportion of inflammatory cells (IC)in specimens facing diamond compared to curet-instrumented defects. A higher proportion of IC was present within the coronal compared to the apical aspect of the JE for both instrumentations (P < 0.05). A significant difference in IC density between instrumentations was detected for non-infiltrated (P < 0.05), as well as for infiltrated (P < 0.01) connective tissue. The infiltrated connective tissue (ICT) inflammatory cell density was significantly (P < 0.01) and positively correlated to the JE inflammatory cell density (r = 0.75), and to area measurements of ICT (r = 0.55). The overall results demonstrate that the character of subgingival root instrumentations significantly affects gingival inflammatory reactions, most likely by influencing subgingival plaque formation.

The influence of titanium abutment surface roughness on plaque accumulation and gingivitis: short-term observations.

The roughness of intraoral hard surfaces plays an important role in bacterial adhesion and colonization. Earlier studies have shown that rough surfaces accumulate up to 25 times more subgingival plaque than do smooth sites. In the present study, the influence of surface smoothing was studied. In six partially edentulous patients waiting for a fixed prosthesis supported by endosseous titanium implants, four titanium abutments with different surface roughness were randomly placed. After 1 month of intraoral exposure, subgingival plaque samples from each abutment were compared within each patient by means of differential phase-contrast microscopy. After 3 months, supragingival and subgingival plaque samples were taken from all abutments for differential phase-contrast microscopy and culturing. Probing depth, recession, and bleeding upon probing were scored at the same visit. Differential phase-contrast microscopy showed that subgingivally, only the two roughest abutments harbored spirochetes after 1 month. After 3 months, subgingivally, the composition of the flora showed little variation on the different abutment types, although spirochetes were only noticed around the roughest abutments. Anaerobic culturing resulted in comparable amounts of colony-forming units for all abutment types, both supragingivally and subgingivally. Subgingivally, the microbiologic composition did not show major interabutment differences. Clinically, small differences in probing depth were observed. The roughest abutment showed some attachment gain (0.2 mm) during 3 months, whereas all other abutments had an attachment loss ranging from 0.8 to greater than 1 mm. The results indicate that a reduction in surface roughness (less than a roughness of 0.2 micron) had no major effect on the microbiologic composition, supragingivally or subgingivally. These observations indicate the existence of a threshold roughness below which no further impact on the bacterial adhesion and/or colonization should be expected. However, clinical evaluation seems to indicate that a certain surface roughness is necessary for increased resistance to clinical probing.