The bases for using a particular occlusal design in tooth and implant-borne reconstructions and complete dentures

Clinical performance of and patient satisfaction with conventional complete dentures with different occlusal schemes: A systematic review of systematic reviews

STATEMENT OF PROBLEM

The complete denture occlusal scheme may influence clinical performance and patient satisfaction. However, a consensus on which occlusal scheme should be used for complete denture users is lacking. As a result, many dentists choose the scheme based on their preferences and clinical experience.

PURPOSE

The purpose of this review was to assess the methodological quality and summarize the scientific evidence from secondary studies about the influence of occlusal schemes on the clinical performance of and patient satisfaction with complete dentures.

MATERIAL AND METHODS

Ten sources were surveyed according to the patient, intervention, comparison, outcome (PICO) strategy. Systematic reviews that evaluated the clinical performance and patient satisfaction (O) of rehabilitated edentulous patients with conventional complete dentures (P) under different occlusal schemes (I/C) were included. Methodological quality was assessed by using A MeaSurement Tool to Assess systematic Reviews (AMSTAR) 2 tool by 2 authors independently. The effect of each occlusal scheme in comparison with others was summarized and classified as positive, neutral, negative, or inconclusive based on the conclusions of the systematic review concerning clinical performance and patient satisfaction outcomes.

RESULTS

The search led to the inclusion of 10 systematic reviews. Seven were classified as of critically low, 2 as low, and 1 as moderate methodological quality. The following occlusal designs were included and analyzed: bilateral balanced occlusion, lingualized occlusion, canine guidance, group function, and monoplane occlusion. Bilateral balanced occlusion and canine guidance obtained satisfactory results for both outcomes. Lingualized occlusion showed a trend toward better results than other occlusal schemes for normal and resorbed ridges. Group function presented mainly inconclusive results, and monoplane occlusion did not deliver satisfactory outcomes.

CONCLUSIONS

The present overview concluded that occlusal schemes might interfere with the clinical performance of and patient satisfaction with complete dentures. Lingualized, bilateral balanced, and canine guidance are preferred compared with monoplane occlusion, but lingualized occlusion tends to show better results in some reviews. However, the results should be carefully considered because of the low quality of the systematic reviews included.

The Biomechanical Profile of an Osseo-Integrated Rectangular Block Implant: A Pilot In Vivo Strain Analysis

Aim: To load-test the osseo-integrated rectangular block implant (RBI), measure the generated cortical peri-implant strains, and relate these findings to known human physiological parameters. Materials and methods: Two RBIs were placed into the posterior mandibular saddle in a mature greyhound dog and allowed to osseo-integrate. The half mandible (implants in situ) was mounted in a servohydraulic system. Four triple-stacked rosette gauges were placed cortically (mesial, distal, buccal, and lingual). A modified ISO-14801 protocol was used (1000 N, 300, 2 Hz, 1 h) and the generated principal strains (ep, eq) and their angular orientations (F), were calculated. Results: (1) Bucco-lingual “horizontal” dimension: dominant “horizontal” compressive stresses were on the lingual aspect and “horizontal” tensile stresses on the buccal aspect. The buccal cortex was elastically tensile-stretched, while the lingual cortex was elastically compressed. (2) Bucco-lingual “vertical” dimension: dominant vertical torsional stresses were oriented buccally and apically, with an overall buccally inclined torsional effect. This was also evidenced on the lingual aspect, where there remained high torsional rotation elements (high F and e2). (3) Mesio-distal “horizontal” dimension: dominant torsional stresses oriented as a distal-lingual “counter-clockwise” rotation. Conclusions: The applied off-axial loads generated a heterogeneous pattern of bucco-lingual and mesio-distal cortical strains, both vertically and horizontally. The short dimensioned osseo-integrated RBI design appeared to biomechanically withstand the applied loads and to maintain the strains generated to levels that were within physiological limits. More studies and statistical analyses are needed to confirm these findings.

Occlusal change in posterior implant-supported single crowns and its association with peri-implant bone level: a 5-year prospective study

OBJECTIVES

This study aims to analyze the 5-year occlusal change in posterior implant-supported single crowns and the association between the relative occlusal force (ROF) and peri-implant bone level.

MATERIALS AND METHODS

Partially edentulous patients who had received implant-supported single crowns in the posterior region were included. Occlusal examinations with a computerized occlusion analysis system were conducted at 0.5, 3, 6, 12, 24, 36, 48, and 60 months after delivery of the implant-supported single crown. The ROFs of implant-supported single crowns, mesial adjacent teeth, and control natural teeth were recorded. Intraoral periapical radiographs were taken at each follow-up time to evaluate marginal bone level (MBL). Ordinary least square regression was used to analyze the association between ROF and MBL.

RESULTS

Thirty-seven posterior implant-supported single crowns in 33 participants (23.9 to 70.0 years) were followed up for 0.5 to 60 months [(42.4 ± 26.0) months]. The ROF of implant-supported single crowns increased from 2 weeks to 3 months (P < 0.01) and increased continuously between all two sequential time points from 6 to 36 months, with significant differences (P < 0.05). Then ROFs of implant-supported single crowns were significantly higher than those of control teeth at 48 and 60 months (P < 0.05). Regression analysis showed that ROF was significantly associated with MBL with a coefficient of 0.008 (P < 0.05).

CONCLUSION

The ROFs of posterior implant-supported single crown have significant change during 5 years' follow-up. The association between ROF and MBL has limited clinical significance.

TRIAL REGISTRATION

Chinese Clinical Trial Registry: ChiCTR-ROC-17012240.

CLINICAL RELEVANCE

The occlusion of implant-supported single crowns should be carefully monitored during follow-up examinations, and occlusal adjustment should be considered to prevent overloading.

Occlusal Schemes for Implant Restorations: Best Evidence Consensus Statement

PURPOSE

Numerous studies have focused on the various complications with implant-retained restorations and a common thread in these publications is the potential for occlusal overload. The purpose of this Best Evidence Consensus Statement on implant occlusal schemes was to review the literature to determine the level of scientific evidence upon which the articles are based.

MATERIALS AND METHODS

Limiting the search to Clinical trials, Randomized Controlled Trials, Systematic Reviews, Meta-analyses, the key words: dental implants, occlusion, found no citations. Expanding the search to Journal articles found 1,483 results, 20 of which pertained to the question. Doing a similar search including Journal Articles, the key words: dental implants and occlusal scheme found 47 citations, 17 of which were pertinent to the question.

RESULTS

After eliminating duplicates and non-relevant articles, 15 were included in the review. Nineteen additional articles were culled by going through the reference lists in the aforementioned articles.

CONCLUSIONS

There is a lack of scientific evidence regarding the occlusal scheme utilized with implant restorations that will minimize or eliminate complications. In light of this lack of scientific evidence, the style of occlusion a practitioner utilizes with tooth or mucosal supported prostheses may be used with implant-supported restorations until compelling evidence dictates otherwise.

What Occlusal Scheme Should Be Used with Removable Partial Dentures?

PURPOSE

Multiple clinical studies have been published comparing different philosophies of complete denture occlusion and different types of denture teeth. However, it is unclear whether comparable data are available for occlusal schemes used with removable partial dentures (RPDs). Therefore, this review investigated the dental literature related to occlusal schemes for RPDs.

MATERIALS AND METHODS

A PubMed search of English language articles was performed using the term "removable partial denture, occlusion" with 765 results. When the term "occlusion in removable partial prosthodontics" was used there were 784 results. Seventy-four articles were identified using the different search term of "RPD, occlusion" while use of the term "occlusal scheme, with removable partial dentures" listed 18 publications. The term "removable partial denture, occlusion, literature reviews" produced 38 potential publications related to the topic. Using the term "removable partial denture occlusion systematic review" resulted in 2 citations. Using the term "RPD occlusion literature review" resulted in one foreign language manuscript whereas using the term "RPD occlusion systematic review" resulted in one article unrelated to dentistry. The term "clinical studies of RPD occlusion" produced 5 results with none related to the topic. There were 23 results using the term "clinical studies of removable partial denture occlusion" with one potentially related to RPD occlusal schemes.

RESULTS

A review of the titles and abstracts revealed 12 articles that appeared to contain specific information about the occlusal scheme used with RPDs. Following a detailed review of those publications, only 4 contained recommendations for RPD occlusion and were included in this review. The available information regarding the recommendations for occlusal schemes in these articles was based on expert opinion. A decision was made to include a hand search of 9 textbooks containing varying amounts of information related to occlusal schemes for RPDs, but no evidence-based references related to RPD occlusal schemes were found in the textbooks. Since this entire review is based on expert opinion, no attempt was made to critique the opinions expressed by these authors but rather to present their perspectives for evaluation by readers.

CONCLUSIONS

The occlusion developed with RPDs should be physiologically harmonious, allowing the supporting structures to remain in a good state of health with functional stress distributed among all the occluding teeth. Multiple authors indicate the occlusion in maximum intercuspation/centric occlusion should incorporate bilateral posterior contacts with no deflective occlusal contacts. When most occlusal contacts on natural teeth are missing, it has been proposed that extension base RPDs have their occlusal contacts developed in centric occlusion. Regarding eccentric occlusal relationships, a balanced occlusal scheme has been recommended by multiple authors with one author advocating use of a lingualized balanced. An anterior guided (canine-protected) occlusion has also been recommended when the canines are present and not periodontally compromised. When RPDs oppose a complete denture, several authors indicate a bilateral balanced occlusion should be used to help stabilize the complete denture.

Complete Denture Occlusion: Best Evidence Consensus Statement

PURPOSE

The occlusal scheme required for an edentulous patient is controversial. The purpose of this Best Evidence Consensus Statement was to evaluate the existing complete denture literature related to occlusal schemes.

MATERIALS AND METHODS

A literature search was limited to Meta-analyses, Systematic Reviews (SR), Randomized Controlled Studies (RCT) and Clinical Trials. Key Words were: Complete dentures, occlusion, harm; Complete dentures, occlusion alveolar bone loss; Complete dentures, occlusion, stability; Complete dentures, occlusion. Additional related articles were culled from the authors' library and reference lists in the articles found in the PubMed searches.

RESULTS

Of the 165 articles that met the initial search criteria, 34 related to the focus questions and were evaluated and rated.

CONCLUSIONS

There is strong support that the average denture patient, with good residual ridges and no neuromuscular problems, will function adequately with a properly fabricated complete denture regardless of the occlusal scheme. There is neither strong support for or against bilateral balanced occlusal schemes as it relates to patient satisfaction, preference or chewing ability. There is some support for increased alveolar bone loss with complete dentures that have a non-balanced occlusion. There is a need for bilateral balanced occlusal schemes for patients presenting with loss of stability and retention as a result of their presenting conditions (PDI III and IV).

Association between dental implants in the posterior region and traumatic occlusion in the adjacent premolars: a long-term follow-up clinical and radiographic analysis

Purpose

The aim of this retrospective study was to determine the association between dental implants in the posterior region and traumatic occlusion in the adjacent premolars, using data collected during from 2002 to 2015.

Methods

Traumatic occlusion in the adjacent premolars was assessed by examining clinical parameters (bleeding on probing, probing pocket depth, fremitus, and tooth mobility) and radiographic parameters (loss of supporting bone and widening of the periodontal ligament space) over a mean follow-up of 5 years. Clinical factors (gender, age, implant type, maxillary or mandibular position, opposing teeth, and duration of functional loading) were evaluated statistically in order to characterize the relationship between implants in the posterior region and traumatic occlusion in the adjacent premolars.

Results

The study inclusion criteria were met by 283 patients, who had received 347 implants in the posterior region. The incidence of traumatic occlusion in the adjacent premolars was significantly higher for splinted implants (P=0.004), implants in the maxillary region (P<0.001), and when implants were present in the opposing teeth (P<0.001). The other clinical factors of gender, age, and duration of functional loading were not significantly associated with traumatic occlusion.

Conclusions

This study found that the risk of traumatic occlusion in the adjacent premolars increased when splinted implants were placed in the maxillary molar region and when the teeth opposing an implant also contained implants.

Tardive Dyskinesia, Oral Parafunction, and Implant-Supported Rehabilitation

Oral movement disorders may lead to prosthesis and implant failure due to excessive loading. We report on an edentulous patient suffering from drug-induced tardive dyskinesia (TD) and oral parafunction (OP) rehabilitated with implant-supported screw-retained prostheses. The frequency and intensity of the movements were high, and no pharmacological intervention was possible. Moreover, the patient refused night-time splint therapy. A series of implant and prosthetic failures were experienced. Implant failures were all in the maxilla and stopped when a rigid titanium structure was placed to connect implants. Ad hoc designed studies are desirable to elucidate the mutual influence between oral movement disorders and implant-supported rehabilitation.

Botulinum Toxin Type A as Preoperative Treatment for Immediately Loaded Dental Implants Placed in Fresh Extraction Sockets for Full-Arch Restoration of Patients With Bruxism

OBJECTIVES

The aim of the present report was to describe the use of Botulinum toxin type A as preoperative treatment for immediately loaded dental implants placed in fresh extraction sockets for full-arch restoration of patients with bruxism.

METHODS

Patients with bruxism who were scheduled to receive immediately loaded full-arch implant supported fixed restorations were included in this retrospective clinical report. To reduce the occlusal forces applied in patients with bruxism, Botulinum toxin type A was introduced prior to the implant placement procedure. Patients were followed and implant survival as well as peri-implant bone level was assessed in each periodic follow-up visit. Adverse effects were also recorded. A control group with no use of Botulinum toxin was evaluated as well.

RESULTS

A total of 26 patients (13 test and 13 control), with bruxism, aged 59.15 ± 11.43 years on average were included in this retrospective report and received immediately loaded dental implants placed in fresh extraction sockets for full-arch restoration. The test group treatment preceded by Botulinum toxin type A injection. Maxillary arches were supported by 8 to 10 implants while the mandibular arch was supported by 6 implants. All surgeries went uneventfully and no adverse effects were observed. The average follow-up time was 32.5 ± 10.4 months (range, 18-51). In the test group, no implant failures were recorded. One patient presented with 1 to 2 mm bone loss around 4 of the implants; the other implants presented with stable bone level. In the control group 1 patient lost 2 implants and another demonstrated 2 mm bone loss around 3 of the implants.

CONCLUSIONS

The preoperative use of Botulinum toxin in patients with bruxism undergoing full-arch rehabilitation using immediately loaded dental implants placed in fresh extraction sockets seems to be a technique that deserves attention. Further long-term, large-scale randomized clinical trials will help to determine the additional benefit of this suggested treatment modality.

Confronting dental uncertainty in old age

OBJECTIVE

To provide an overview of the literature about uncertainty in health care and how it relates to the oral health care of older people.

BACKGROUND

The medical literature describes uncertainty in health care from the initial informed-consent to its impact on a patient's ability to cope with undesirable outcomes.

METHODS

A narrative review of the medical, dental and psychological literature was conducted to identify pertinent information on the theory and implications of uncertainty in healthcare. The findings are infused into a case-report illustrating the recurrence of uncertainty experienced by an older woman who had multiple treatments over several years to restore her dentition damaged severely by dental caries.

RESULTS

Uncertainty originates from inadequate understanding, incomplete information and undifferentiated alternatives leading to unnecessary diagnostic tests and healthcare costs. A conceptual taxonomy clarifies the characteristics of uncertainty in the context of scientific, practical or personal sources and offers management possibilities through effective communications to identify choices and probabilities that help patients to adapt and cope with adverse events.

CONCLUSIONS

Uncertainty pervades healthcare. It can lead patients to self-blame, anger and withdrawal from care unless it is communicated effectively so that they can adapt and cope with the disappointment of adversity and continue with alternative approaches to care.

Motor behavior during the first chewing cycle in subjects with fixed tooth- or implant-supported prostheses

OBJECTIVES

Appropriate sensory information from periodontal mechanoreceptors (PMRs) is important for optimizing the positioning of food and adjustment of force vectors during precision biting. This study was designed to describe motor behavior during the first cycle of a natural chewing task and to evaluate the role of such sensory input in this behavior.

MATERIAL AND METHODS

While 10 subjects with natural dentition, 11 with bimaxillary fixed tooth-supported prostheses (TSP) and 10 with bimaxillary fixed implant-supported prostheses (ISP) (mean age 69 [range 61-83]) chewed a total of five hazelnuts, their vertical and lateral jaw movements were recorded. Data obtained during the first chewing cycle of each hazelnut were analyzed.

RESULTS

The amplitude of vertical and lateral mandibular movement and duration of jaw opening did not differ between the groups, indicating similar behavior during this part of the chewing cycle. However, only 30% of the subjects in the natural dentate group, but 82% of those in the TSP and 70% in the ISP group exhibited slippage of the hazelnut during jaw closure in at least one of five trials. The TSP and ISP groups also exhibited more irregular and narrower patterns of motion (total lateral/vertical movement = 0.15 and 0.19, respectively, compared to 0.27 for the natural group).

CONCLUSIONS

Subjects with fixed tooth- or implant-supported prostheses in both jaws show altered behavior, including inadequate control of the hazelnut, during the first chewing cycle. We propose that these differences are due to impairment or absence of sensory signaling from PMRs in these individuals.

Is buccolingual angulation of maxillary anterior implants associated with the crestal labial soft tissue thickness?

We aimed to examine the relationship between crestal labial soft tissue thickness (CLSTT, measured with a digital calliper at the crestal level of casts) and implant buccolingual angulation (IBLA). The records of 22 females and 10 males treated with two bone-level implants (3.3-4.6mm) between the maxillary canines were evaluated. IBLA was recorded as cingulum, incisal, or labial based on the screw access hole position on provisional restorations. Postoperative implant labial bone thickness (ILBT) at the crestal (2mm from crest) and mid-implant levels were measured on sectional cone beam computed tomography scans. The mean (SD) ridge width at the crestal level was 6.81 (0.98) mm. Mean (SD) CLSTT for implants with cingulum, incisal, and labial angulations were 2.98 (0.84), 2.24 (0.51), and 1.71 (0.72) mm, respectively. Significant differences were detected between CLSTT of implants with cingulum and incisal, as well as cingulum and labial angulations (P<0.01). Of implants with cingulum, incisal, and labial angulations, 3.4%, 20%, and 53.3%, respectively, had a CLSTT<2mm. Overall, 74.2% of CLSTT variance could be predicted by IBLA and ILBT at the crestal and mid-implant levels. A significant association between CLSTT and IBLA was noted when ILBT (crestal level) was <2mm (P<0.01). Implants with labial angulations carry a higher risk of soft tissue complications when the crestal implant labial bone thickness is <2mm.

Occlusion for implant-supported fixed dental prostheses in partially edentulous patients: a literature review and current concepts

Implant treatment has become the treatment of choice to replace missing teeth in partially edentulous areas. Dental implants present different biological and biomechanical characteristics than natural teeth. Occlusion is considered to be one of the most important factors contributing to implant success. Most literature on implant occlusal concepts is based on expert opinion, anecdotal experiences, in vitro and animal studies, and only limited clinical research. Furthermore, scientific literature regarding implant occlusion, particularly in implant-supported fixed dental prostheses remains controversial. In this study, the current status of implant occlusion was reviewed and discussed. Further randomized clinical research to investigate the correlation between implant occlusion, the implant success rate, and its risk factors is warranted to determine best clinical practices.

Dietary guidance for people wearing removable prostheses

BACKGROUND

The authors identified and described dietary strategies appropriate for dental patients who receive dental care that includes the placement and maintenance of dental prostheses.

CONCLUSIONS

Identification of a patient's perception of food choices associated with placement of a dental prosthesis can lead to delivery of patient-focused dietary guidance for the promotion of targeted food choices to improve oral health and systemic health. An interview guide for assessment of patient satisfaction and a guide for suggested dietary choices and modifications are provided.

CLINICAL IMPLICATIONS

Dental professionals can tailor food modification strategies and promote healthful food choices, enhance patient satisfaction and improve health outcomes.

Methodological quality and descriptive characteristics of prosthodontic-related systematic reviews

Ideally, healthcare systematic reviews (SRs) should be beneficial to practicing professionals in making evidence-based clinical decisions. However, the conclusions drawn from SRs are directly related to the quality of the SR and of the included studies. The aim was to investigate the methodological quality and key descriptive characteristics of SRs published in prosthodontics. Methodological quality was analysed using the Assessment of Multiple Reviews (AMSTAR) tool. Several electronic resources (MEDLINE, EMBASE, Web of Science and American Dental Association's Evidence-based Dentistry website) were searched. In total 106 SRs were located. Key descriptive characteristics and methodological quality features were gathered and assessed, and descriptive and inferential statistical testing performed. Most SRs in this sample originated from the European continent followed by North America. Two to five authors conducted most SRs; the majority was affiliated with academic institutions and had prior experience publishing SRs. The majority of SRs were published in specialty dentistry journals, with implant or implant-related topics, the primary topics of interest for most. According to AMSTAR, most quality aspects were adequately fulfilled by less than half of the reviews. Publication bias and grey literature searches were the most poorly adhered components. Overall, the methodological quality of the prosthodontic-related systematic was deemed limited. Future recommendations would include authors to have prior training in conducting SRs and for journals to include a universal checklist that should be adhered to address all key characteristics of an unbiased SR process.

In vitro bone strain analysis of implant following occlusal overload

OBJECTIVES

To enumerate peri-implant bone strain pattern under quantified occlusal load and verify the bone response through comparison with the critical strain thresholds defined by Frost's bone mechanostat theory.

MATERIAL AND METHODS

Mandibular unilateral recipient sites in two greyhound dogs were established with posterior teeth extractions. After 6 weeks, four titanium implants were placed in each dog mandible. Following 12 weeks of healing, successfully osseointegrated implants were placed in supra-occlusal contact via screw-retained non-splinted metal crowns. Plaque control and a dental health enhancing diet were prescribed. A bite force detection device was used to quantify in vivo occlusal load as the dogs functioned with supra-occlusal contact. After 8 weeks, the dogs were sacrificed. In vitro peri-implant bone strain under quantified occlusal load was measured using bonded stacked rosette strain gauges.

RESULTS

The average and peak in vivo occlusal load measured were 434 and 795 newton (N). When individually and simultaneously loaded in vitro (≤476 N), absolute bone strains up to 1133 and 753 microstrains (με) were measured at implant apices, respectively. Bone strain reaching 229 με was recorded at distant sites. For bone strain to reach the pathological overload threshold defined by Frost's bone mechanostat theory (3000 με), an occlusal load of 1344 N (greater than peak measured in vivo) is required based on the simple linear regression model.

CONCLUSION

Under the in vivo and in vitro conditions investigated in this study, peri-implant bone was not found to be under pathological overload following supra-occlusal contact function. Strain dissipation to distant sites appeared to be an effective mechanism by which implant overload was avoided.

Methodological challenges in the study of dental occlusion

This narrative review describes the methodological challenges in the study of dental occlusion. The reigning confusion about the scope of this topic is discussed, and a conceptual framework for understanding dental occlusion research is suggested. The characteristics of clinical studies used in the study of dental occlusion are presented within this proposed framework consisting of a triad comprising the relative positions of the teeth-mandible-maxilla, the oral functions and oral appearance. Challenges in the preparation for a clinical study of dental occlusion are reviewed, which include a discourse on the objectives of a clinical study and appropriateness of different study designs. Guidelines are provided for the conduct of studies with a central focus on dental occlusion and diagnostic tests, prognosis, therapy and aetiology, respectively. Summarising chapters present methodological challenges in designing a clinical study of dental occlusion and threats to the proper conduct of a clinical study.

Prosthodontic considerations designed to optimize outcomes for single-tooth implants. A review of the literature

BACKGROUND

The aim of this study was to review the literature on the restoration of single-tooth implants, and to develop evidence-based conclusions to optimize aesthetic, biologic and patient-related outcomes.

METHODS

An electronic and hand search was conducted using the search terms 'dental implants, single-tooth; dental restoration, temporary; dental impression materials; dental impression technique; dental prosthesis, implant-supported; dental prosthesis design; dental abutments; dental occlusion; maintenance; survival; and survival analysis'. Resultant titles were screened, and full text was obtained where relevant. The authors selected the most appropriate articles, giving preference to systematic reviews and long-term, patient-based outcome data.

RESULTS

Thirty-nine articles were selected and critiqued by the authors.

CONCLUSIONS

There was strong suggestion by several authors that peri-implant soft tissue aesthetics can be sculpted through provisional restoration contour, but there are no clinical outcome studies to define or support this claim. Laboratory studies demonstrate that pick-up type impression copings in conjunction with elastomeric impressions are the most accurate means for transferring implant position to a dental cast. Laboratory and finite-element analysis studies suggest implants with an internal-type connection show improved stress distribution, but supportive clinical data are lacking. The authors of this review favour a screw-retained prosthesis for retrievability. Clinical and histological studies show that gold, titanium and zirconia ceramic abutment materials exhibit excellent biological responses, although there is insufficient data on the clinical service provided by zirconia as an implant-substructure material. The literature does not associate any particular occlusal scheme with superior clinical outcomes. Implant-borne single crowns offer comparable clinical service to tooth-borne fixed dental prostheses. However, single-tooth implant restorations are associated with an increased incidence of biological and technical complications.

Trans-sinus dental implants, bone morphogenetic protein 2, and immediate function for all-on-4 treatment of severe maxillary atrophy

PURPOSE

The aim of this study was to evaluate the clinical outcomes of trans-sinus dental implant placement by use of bone morphogenetic protein 2 (BMP-2) grafting and immediate functional loading by the all-on-4 scheme.

PATIENTS AND METHODS

After bone reduction to create the all-on-4 shelf or because of severe maxillary atrophy and prominent sinus anatomy, 10 patients were selected to undergo trans-sinus implant placement and simultaneous BMP-2 sinus floor grafting for immediate provisional loading. Insertion torque was measured upon implant placement. Patients were followed up for at least 1 year after final restoration when either a computed tomography scan or panoramic radiograph was obtained and analyzed for the presence of trans-sinus peri-implant bone. Hounsfield units were recorded mid sinus graft.

RESULTS

Of 19 trans-sinus implants, 18 remained integrated at the 1-year follow-up, for a 5.2% failure rate. All sinus grafts formed bone, with a mean of 460 Hounsfield units. Final fixed prostheses were completed for all 10 patients.

CONCLUSION

Trans-sinus dental implant placement with BMP-2 grafting to gain anterior-posterior spread for immediate function by use of all-on-4 treatment appears to be a viable alternative to the use of zygomatic implants in the presence of severe maxillary atrophy.

TGF-β-activated kinase 1 mediates mechanical stress-induced IL-6 expression in osteoblasts

Mechanical stress plays a key role in bone remodeling. Previous studies showed that loading of mechanical stretch induces a rapid Ca(2+) influx and subsequent activation of stress-activated protein kinase pathways in osteoblasts. However, the activation mechanism and its significance in bone remodeling have not been fully elucidated. Here we show that TAK1 MAPKKK was activated by cyclic stretch loading of MC3T3-E1 cells. Knockdown of TAK1 attenuated the stretch-induced activation of JNK, p38, and NF-κB. Extracellular (EGTA) or intracellular (BAPTA/AM) Ca(2+) chelator prevented the stretch-induced activation of TAK1. Activation of TAK1 and its associated downstream signaling pathways were also suppressed by CaMKII inhibitors (KN-93 and KN-62). Furthermore, TAK1-mediated downstream pathways cooperatively induced the expression of IL-6 mRNA in the stretched MC3T3-E1 cells. We also confirmed that TAK1 mediates cyclic stretch-induced IL-6 protein synthesis in the cells using immunoblotting and ELISA. Finally, stretch loading of murine primary osteoblasts induced the expression of IL-6 mRNA via TAK1. Collectively, these data suggest that stretch-dependent Ca(2+) influx activates TAK1 via CaMKII, leading to the enhanced expression of IL-6 through JNK, p38, and NF-κB pathways in osteoblasts.

Some dogmas related to prosthodontics, temporomandibular disorders and occlusion

It is the aim of this paper to give a few examples of dogmas related to prosthodontics and oral implants and to discuss the controversial role of occlusion in the aetiology of temporomandibular disorders. New knowledge is developing at a rapidly increasing rate in dentistry, as in other areas of society. Our lecturers at university taught us many useful things. But, as time goes by, what is still relevant? Some methods are so well established that they deserve to be called dogmas. It is implied that a dogma is not supported by strong evidence, even though it has existed and been practised for a long time. In the era of evidence-based dentistry it is appropriate to scrutinize such issues. A review of the current literature indicates that conflicting opinions exist concerning a number of common procedures in clinical dentistry, mainly due to a scarcity of good studies with unambiguous results. There is therefore a need for more high-quality clinical research in attempting to reach the goal of evidence-based clinical practice. The dental community should take an active part in this process.

Function. Consensus report of Working Group 3

The method used by the working group was an iterative process based upon a structured review of the relevant literature by the four author groups. Review papers were circulated to the members of the group before the conference and formed the basis for subsequent discussions. Each paper was subject to detailed collective analysis and subsequently modified on the basis of the panel's discussions and referenced to additional relevant literature where appropriate. The group assessed the levels of evidence for the claims and statements made in the supporting documentation. It was recognized that it was often necessary to adopt a compromise between acceptance of the lowest level, resulting in the largest body of material, and the highest level, which in some cases, produced little evidence. While this approach does not represent endorsement of lower evidence levels per se, it was designed to provide conclusions of clinical utility within the existing knowledge base. The papers, following the scrutiny, were amended and approved by the expert group. The consensus report was prepared by the working group after detailed considerations of the five approved papers.