Improving oral health in the Middle East - recommendations from the first Middle East Oral Hygiene Advisory Board meeting

Chronic periodontitis may be a sequela of chronic gingivitis, usually because of accumulation of plaque and calculus. Consistent good dental hygiene can help prevent gingivitis and periodontitis. Mechanical removal of plaque through frequent and efficacious brushing and flossing is the principal means of preventing periodontal diseases and diminishing the risk of caries. According to the American Dental Association (ADA), antimicrobial mouth-washes may provide additional oral health benefits, in addition to brushing and flossing, for preventing and reducing gingivitis and plaque. There is a multitude of mouthwashes available for these purposes. The consensus panel of the Middle East Oral Hygiene Advisory Board has recommended that an antiseptic mouthwash should be used as a daily adjunct to mechanical cleaning for prevention of oral disease. Recommending particular mouthwashes should take into consideration the patient's ability to perform good oral hygiene practices (tooth brushing and dental flossing), the condition of the patient's teeth, gingivae and oral mucosa, and the proven efficacy of the mouthwash along with its potential adverse effects. Of the many mouth rinses available, only a few contain chemical agents that have some ability to penetrate biofilm and to kill plaque biofilm bacteria. Currently, only chlorhexidine mouthrinse and Listerine (an essential oil-containing mouth rinse) products, with the claim of plaque and gingivitis reduction, have been accepted for that purpose by the ADA and have a proven record of safety and efficacy. Essential oil-containing mouthrinses have been clinically proven as effective in reducing plaque and gingivitis. Dental care professionals should spend time discussing biofilm control with their patients, and be an information source for the best oral care products. Therefore, it is essential that dental care professionals should continue to monitor published research and work with their colleagues to make evidence-based decisions. In this way, patients will be directed to dental hygiene aids, including antiseptic mouthwashes that can be most effective for improving their oral health.

Occlusal plane discrepancies generated by transverse horizontal axis deviations

STATEMENT OF PROBLEM

Any deviation from the patient's rotational axis of the mandible during closure and the arc of closure on an articulator has been reported to produce occlusal discrepancies. These discrepancies can affect diagnostic planning procedures and the occlusal relationships of restorations.

PURPOSE

This study investigated the magnitude and types of occlusal errors produced by deviations between the patient's transverse horizontal axis and the axle on the articulator.

MATERIAL AND METHODS

A simplified monoplane model was diagrammatically analyzed for deviations from the model's true transverse horizontal axis. Axis deviations of 5 mm were used in 8 different directions from the true transverse horizontal axis of the model. Changes in the orientation of the mandibular plane to the maxillary plane were illustrated diagrammatically. These changes were quantified by geometric and trigonometric assessments.

RESULTS

All axis deviations produced mandibular plane orientation errors with angular plane malalignment to the maxillary plane on complete closure. These axis deviations also produced anterior-posterior shifting of the mandibular plane relative to the maxillary plane.

CONCLUSION

Several different types of planar shifting and angular discrepancies were demonstrated from deviations away from the true transverse horizontal axis.

New abutment for a screw-retained, implant-supported crown

The 1-piece, implant-supported abutment and crown, colloquially described as the UCLA abutment, commonly is used to fabricate single, screw-retained crowns. This abutment was designed to allow attachment of the crown directly to the implant and requires a waxing and casting procedure by a laboratory technician. A new prefabricated abutment has been developed that uses a similar approach but does not require the waxing and casting process. The PDQ abutment is made from a metal-ceramic alloy that is custom contoured by grinding to support a porcelain veneer. Porcelain then is fired to the contoured abutment to develop the 1-piece artificial crown. This article describes the use of the PDQ abutment.

Foundation restorations in fixed prosthodontics: current knowledge and future needs

PURPOSE

The Ad Hoc Committee on Research in Fixed Prosthodontics established by the Academy of Fixed Prosthodontics publishes a yearly comprehensive literature review on a selected topic. The subject for this year is foundation restorations.

METHODS

Literature of various in vitro and in vivo investigations that included technical and clinical articles was reviewed to provide clinical guidelines for the dentist when selecting methods and materials for restoration of structurally compromised teeth. Topics discussed and critically reviewed include: (1) desirable features of foundation restorations, (2) foundations for pulpless teeth, (3) historic perspectives, (4) cast posts and cores, (5) role of the ferrule effect, (6) prefabricated posts, (7) direct cores, (8) foundation restorations for severely compromised teeth, (9) problems and limitations, (10) future needs, and (11) directions for future research.

CONCLUSION

This comprehensive review brings together literature from a variety of in vitro and in vivo studies, along with technique articles and clinical reports to provide meaningful guidelines for the dentist when selecting methods and materials for the restoration of structurally compromised teeth.

Investigation of the effect of three sprue designs on the porosity and the completeness of titanium cast removable partial denture frameworks

STATEMENT OF PROBLEM

Although titanium has been used to cast removable partial denture frameworks, the casting process is arduous and requires specialized equipment.

PURPOSE

This study evaluated the ability of 3 sprue designs (tree, ball, and circular) to produce complete, void-free castings of removable partial denture frameworks made from commercially pure titanium.

METHODS AND MATERIAL

A cast with a Kennedy class III, modification 1, partially edentulous arch was used. The blocked-out cast was modified to facilitate assessment of the completeness of the casting of the clasp arms. Thirty refractory casts were made, and 10 wax patterns for each sprue design were fabricated and invested with ethyl silicate investment. Castings were made with an arc-type automatic casting machine in an argon atmosphere. Castings were examined with radiographic equipment to detect the presence of voids in the castings, and the completeness to each casting was visually verified. Data on porosities were tabulated and statistically analyzed with 1-way ANOVA followed by Student Newman-Keuls test. Chi-square analysis was used to identify statistically significant differences in casting defects among the 3 sprue designs.

RESULTS

No statistically significant differences in the total number of porosities were found between the 3 sprue designs (P =.51). Results of completeness of castings evaluated by using chi-square test revealed a statistically significant deference among the 3 sprue designs (P =.008).

CONCLUSION

The ball-sprue design produced the most complete castings for the removable partial denture titanium frameworks.

An in vitro study of the fracture resistance and the incidence ofvertical root fracture of pulpless teeth restored with six post-and-coresystems

STATEMENT OF PROBLEM

Posts and cores are often required with pulpless teeth to provide retention and resistance form for complete crowns. Nevertheless, conventional posts may increase the potential for root fracture.

PURPOSE

This study compared the resistance to vertical root fracture of extracted teeth treated with post-core systems that were modified with polyethylene woven fibers (Ribbond) with those treated with conventional post-and-core systems.

MATERIAL AND METHODS

Canal instrumentation was performed for 60 maxillary central incisors, and complete crown preparations were made. The coronal portion of each tooth was amputated, and 6 post-and-core systems were studied. Specimens were mounted in acrylic resin blocks with a layer of polyvinyl siloxane covering the roots. Loads were applied at an angle of 130 degrees and measured with a universal testing machine. Results were analyzed statistically with 1-way analysis of variance with Student-Newman-Keuls grouping and chi-square analysis. RESULTS. Cast posts and cores resulted in significantly higher failure thresholds than all others, except for prefabricated, comparably sized, parallel-sided posts with composite cores. All failures in the group with cast posts involved fracture of the teeth, whereas 70% of the teeth with comparably sized parallel-sided posts and composite cores failed as a result of tooth fractures and 30% experienced core fractures. The woven fiber post-core system was significantly lower in strength than all others, and exhibited significantly fewer vertical root fractures.

CONCLUSIONS

Polyethylene woven fiber and composite resin without a prefabricated post resulted in significantly fewer vertical root fractures, but mean failure load was the lowest. Smaller diameter prefabricated posts combined with the polyethylene woven fiber and composite cores improved resistance to failure. Traditional cast posts and cores were the strongest of the 6 post-core systems.

The effect of temperature changes on the dimensional stability of polyvinyl siloxane and polyether impression materials

STATEMENT OF PROBLEM

Dental impressions are commonly mailed to remote dental laboratories and can be subjected to extreme temperature changes; however, the effects of these temperature changes on the accuracy of elastomeric impression materials are unknown.

PURPOSE

This study evaluated the dimensional changes of polyether and polyvinyl siloxane impression materials as a function of storage temperature.

MATERIAL AND METHODS

A total of 144 impressions were made of a stainless steel die similar to ADA Specification No. 19. Half of the impressions were made in perforated custom trays and the other half in solid trays. Measurements of the vertical and horizontal lines on the impressions were made at 10 minutes, 1 hour, 24 hours, and 26 hours, and storage temperatures ranged from 4 degrees C to 40 degrees C.

RESULTS

Changes in storage temperature had a statistically significant effect on the dimensional stability of the horizontal and vertical lines. However, overall dimensional changes were extremely small.

CONCLUSIONS

Storing both impression materials at 4 degrees C for 24 hours and then allowing the impressions to reach room temperature resulted in a slightly expanded impression that partially compensated for the contraction that occurred from polymerization shrinkage. Similar results occurred for polyether material only, when stored at 40 degrees C.

Use of aluminum strips to fabricate verification jig for an implant-supported fixed partial denture

Verification of the accuracy of the master cast for an implant-supported fixed partial denture will reduce the chair time and laboratory costs of implant prosthodontic treatment. A wire is usually luted in the mouth to machined components that have been secured to the implants, and the luted assembly is then transferred to the cast to evaluate the positional accuracy of the implant analogs. Unless this wire is dead soft, inaccuracies as a result of elastic memory of the wire can occur. Also, if the wire is not completely rigid, it can be distorted during handling. This article describes a more reliable verification jig for an implant-supported fixed partial denture that can be fabricated with 1.5 mm thick aluminum strips that are luted to the implant components. The use of two aluminum strips creates a metal framework that is rigid and not easily distorted. Also the aluminum pieces do not have elastic memory because they were cut and not bent to shape.

Four uses of a disposable implant mount

The high cost of precision-fitting, machine-milled implant components is a major concern, and the dentist with a busy implant practice must stock numerous components at considerable expense. In this article, the use of a disposable implant mount is described as an adjunct for a positional index during stage-I surgery, immediate provisional restoration at stage-II surgery, verification jig, and implant-supported record base. By reusing the precision-fitting implant mount that is supplied free of charge by the manufacturer, the dentist can reduce the overhead costs required to provide implant prosthodontic treatment.

Programmed tooth preparation for fixed partial dentures

This article describes a method for efficient and precise tooth preparation for fixed partial dentures. Diagnostic procedures are also reviewed.

A procedure for making an interocclusal record without the use of record bases for a combined fixed/removable prosthesis

This article describes a procedure for making an interocclusal record for a remount procedure after tryin of the castings. This method can also be used for the initial mounting by substituting autopolymerizing acrylic resin copings for the metal castings.

Vacuum-formed matrix as a guide for the fabrication of multiple direct patterns for cast posts and cores

Fabrication of multiple posts and cores for severely damaged pulpless teeth is arduous because few landmarks remain. Esthetic requirements, occlusal relations, and long axes of the planned final restorations influence the core design. This article describes a method for directly verifying fabricated post-and-core patterns by combining the procedures for making a thermoformed shell for a preparation template and creating a plastic template for multiple core pattern fabrication.

Effects of chemical disinfectant solutions on the stability and accuracy of the dental impression complex

Currently available impression materials were not designed for disinfection or sterilization, and it is conceivable that disinfectants may adversely affect impressions. This study evaluated the accuracy and dimensional stability of polyether (Permadyne/Impregum) and polyvinyl siloxane (Express) impression materials retained by their adhesives in two different acrylic resin tray designs (perforated and nonperforated) when the materials were immersed for either 30 or 60 minutes in three high-level disinfectants. Distilled water and no solution served as controls. A stainless steel test analog similar to ADA specification No. 19 was used. A total of 400 impressions were made with all combinations of impression materials, tray designs, disinfectant, and soaking times. Samples were evaluated microscopically before and after immersion and 48 hours after soaking. Results indicated that these two impression materials were dimensionally stable. Because the results emphasized the stability and accuracy of the impression complex under various conditions, dentists can perform disinfection procedures similar to the protocol of this study without concern for clinically significant distortion of the impression.

Complete edentulism and denture use for elders in New England

The purpose of this study was to collect information about the oral health of a representative group of elders in the New England states. This study provides the most current descriptive analysis of completely edentulous noninstitutionalized elders to date. In-home examinations and interviews were conducted for a representative sample of elders over 70 years of age. The oral examinations and interviews were conducted by calibrated dentists and trained interviewers, respectively. Of 1156 study participants, 424 (36.7%) were edentulous. Edentulous rates were similar for men and women and were negatively related to levels of education and income. Of the completely edentulous individuals, 89.9% had maxillary and mandibular complete dentures. Most of these dentures (83.2%) were worn during the day. More than one third of the respondents reported wearing one or both of their dentures while sleeping at night. For 77 of the completely edentulous individuals, examination revealed denture irritations, most of which were on the hard palate.

Restoration of pulpless teeth: application of traditional principles in present and future contexts

Posts were recommended more than 100 years ago to retain artificial crowns. Recent studies suggest that posts can weaken teeth; therefore restorative procedures that help preserve pulpal vitality and eliminate the need for posts are desirable. If endodontic therapy is unavoidable, conservation of remaining tooth structure is most important. When a post is required to retain a core for an artificial crown, a custom cast post is the most effective means of conserving tooth structure. The length of the post should not be compromised, although 4 to 5 mm of apical gutta-percha must be maintained. The restorative prognosis is improved if the width of the post does not exceed one half the width of the root, and the cemented artificial crown should extend apical to the core to provide a 1.5 to 2 mm ferrule. Complex procedures have allowed the dentist to restore extensively damaged teeth. However, extraction and replacement with implant-supported prosthodontics may be more prudent with severely compromised teeth.

Repair of posterior base of a maxillary complete denture by use of a cast of stone and resilient material

A method to repair a fractured complete denture and simultaneously augment deficient borders or correct an inadequate posterior palatal seal is described. Corrections were made intraorally with modeling compound and an elastomeric impression material. A resilient impression material was used to block out the undercuts in the denture, and repair was accomplished with visible light-cured resin or an autopolymerizing repair resin. This technique simplifies the laboratory procedures and thereby permits the return of the denture to the patient at the same visit.

Ability of various impression materials to produce duplicate dies from successive impressions

This in vitro study evaluated the ability of five different impression techniques to make duplicate dies of two different types of tooth preparation. One mandibular second premolar Ivorine tooth was prepared for a complete crown and one for an onlay. A master impression was made of each tooth preparation with the use of five impression techniques for a total of 10 master impressions, and a master die was made from each of these impressions. Castings were made on these master dies, and the fit of each casting was verified on the respective Ivorine tooth. Marginal openings of the castings on the master dies were recorded under magnification at four predetermined points. Five successive impressions, with the use of each impression material, were then made of each tooth preparation for a total of 50 test impressions, and 50 test dies were made from these impressions. The fit of the respective casting was evaluated under magnification for each test die at the four predetermined points, and marginal openings were recorded. Differences between the marginal discrepancies of the casting on the master die and on the test die were tabulated and the results were statistically analyzed. Results indicated that none of the impression materials was capable of producing exact replicas. Polysulfide rubber performed significantly better than two materials for the production of duplicate dies with the complete crown preparation; and polyvinyl siloxane used with a putty-light body, single-stage technique produced mean marginal discrepancies that were significantly greater than the other four techniques when used for the onlay preparation.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of ultrasonic scaling and periodontal curettage on surface roughness of porcelain

Changes in the surfaces of glazed porcelain were evaluated with the use of a profilometer and a scanning electron microscope after ultrasonic scaling and periodontal curettage. Thirty samples of glazed porcelain-fused-to-metal were divided into two experimental zones, and the two scaling treatments were performed on each sample. Measurements of surface roughness of porcelain were made before and after instrumentation for both periodontal prophylaxis procedures. The statistical analysis of the differences in surface changes as evaluated on the profilometer indicated that the roughness alterations from both procedures were not statistically significant; however, the qualitative or subjective evaluation of scanning electron micrographs and profile tracings revealed differences between glazed and instrumented porcelain surfaces.

A procedure for making fixed prosthodontic impressions with the use of preformed crown shells

Void-free impressions of tooth preparations for fixed prosthodontics are essential for accurately fitting restorations; however, commonly used impression methods are arduous and time-consuming. A procedure has been developed in which an impression is made in a preformed temporary crown shell for each tooth preparation and then a final over impression is made. The result is an atraumatic and uncomplicated complete-arch impression that incorporates an accurate impression of each prepared tooth.

A nationwide survey of contemporary philosophies and techniques of restoring endodontically treated teeth

Contemporary endodontic therapy has allowed patients to retain severely damaged teeth. The restoration of most endodontically treated teeth involves complex and controversial procedures. There is a diversity of opinion about the need for coronoradicular stabilization, and numerous post systems and techniques have been described. It is not known what materials and techniques are most commonly used. To expand the knowledge of current philosophies and prevailing techniques, a comprehensive nationwide survey of 1525 dentists was conducted. Of the 1066 respondents, 909 (85%) reported restoring more than 30 endodontically treated teeth per year, and this subset became the focus group of the survey. Board-certified prosthodontists comprised 40% of this group, educationally qualified prosthodontists 28%, and general dentists 32%. Responses to questions were statistically analyzed. Statistical analysis revealed that philosophies and techniques varied significantly with the dentist's geographic location, age, specialty status, and dental school faculty status.

A diagnostic stent for endosseous implants to improve conventional tomographic radiographs

Conventional tomographic radiographs can often provide sufficient information for presurgical evaluation for implant placement with significantly less radiation exposure than computer-assisted tomographic (CT) radiographs. A technique to fabricate a diagnostic stent with a removable indicator for the partially edentulous patient is described. This stent with an indicator guides the radiologist in making conventional tomographic images and can also be used as a template for locating the surgical sites.

Technique to restore unfavorably inclined implants

Unfavorable inclination of implants is a common problem that may compromise esthetics, phonetics, and function of the implant-supported fixed prosthesis. Several methods have been reported to compensate for malaligned implants; however, most techniques are complicated and expensive. A technique that combines a custom abutment from a hexed UCLA-type plastic burn-out pattern and a manually threaded setscrew hole is a relatively inexpensive and uncomplicated approach to eliminate problems caused by unfavorable implant inclination. This article describes the procedures for fabrication of an implant-supported fixed prosthesis with the use of this technique.

A fixed-detachable implant-supported prosthesis retained with precision attachments

The implant-supported, maxillary anterior, fixed-detachable prosthesis is often fabricated with a gingival flange to enhance esthetics and phonetics. However, only the dentist can remove the prosthesis, and the esthetic labial flange invariably impedes patient access for cleaning. A two-piece, fixed-detachable prosthesis that incorporates a substructure retained with conventional set screws and a superstructure retained with precision attachments has been developed. The substructure is contoured to facilitate patient access for oral hygiene because it will be covered by the superstructure and neither esthetics nor phonetics is a concern. The superstructure is easily removed by the patient for routine cleaning and can be designed for favorable esthetics and phonetics. This article reviews and describes the procedures for fabrication of this precision attachment-retained, implant-supported prosthesis.

A new approach to salvaging an existing fixed partial denture

This case report describes the clinical procedures for salvaging a serviceable fixed partial denture (FPD) that deteriorated because of cement dissolution beneath the distal retainer. After removal of the FPD it was noticed that the "core reconstruction" was dislodged (the prefabricated post remained in the canal and required removal). A two-stage casting procedure that differed from reported techniques was customized to fit a cast post and core to the prepared root canal and retainer. The FPD was recemented and has been functioning satisfactorily for over 3 years.

Clinical success of cast metal posts and cores

The topic of posts for endodontically treated teeth has received considerable attention in the literature, but there is sparse in vivo research and certain information from in vitro investigations is contradictory. A retrospective study of 1273 endodontically treated teeth in the practices of nine dentists in general practice indicated an inordinately high failure rate with cast posts and cores compared with alternate systems of coronoradicular stabilization. However, a closer evaluation of the data in this study indicated that almost half of the cast posts were half the desired length or less. The indications for the cast post and core are discussed and the specific causes of failure are reviewed. Additional research is needed to compare the success rate of securely seated cast posts and cores with alternate methods of coronoradicular stabilization.

A dual-purpose stent for the implant-supported prosthesis

Osseointegrated implants are a practical alternative to traditional prosthodontics; however, designing an implant-supported prosthesis with function and esthetics is a challenge. When the available bone or the location of vital structures is questionable, computed tomography (CT) is indispensable for diagnosis and treatment planning. This article describes a stent that implements the information from a CT scan and is then modified to guide the surgical placement of the implants.

The implant-supported, heat-processed provisional fixed partial denture

When fabricating an implant-supported fixed partial denture a provisional prosthesis is commonly required for function and esthetics. A laboratory-fabricated, heat-polymerized provisional restoration will provide excellent fit, function, esthetics, and durability while saving chair time. This article describes the clinical and laboratory procedures for the fabrication of the implant-supported, heat-processed provisional fixed partial denture.

Tissue management with dental impression materials

The coordination of perceptive tissue management, diligent tooth preparation and prudent selection of the impression material for specific clinical conditions ensures the success of cast and ceramic restorations. The introduction of a knitted cord (Ultrapak with Astringedent) has alleviated the arduous aspects of tissue displacement and the new impression materials have displayed exceptional accuracy but healthy tissue is fundamental.

Prevention of self-inflicted trauma: dental intervention to prevent chronic lip chewing by a patient with a diagnosis of progressive bulbar palsy

An appliance is used as a beginning in the prevention of self-mutilative oral behavior. The patient in the case reported here required a quick solution to a severe problem of self-inflicted trauma. The design presented here can be improved on or an altogether new approach may be developed.