Discussion : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [4]
Contrary to conventional hollow-screw implants (only marginal gap), a problem of the expandable implant is the presence of gaps down to the apical region. Former microbial assessment of different implant-abutment interfaces displayed that none of the marginal connections had the capacity to prevent microbial leakage [63,64,65]. Therefore, an apical microleakage (comparable to distractable implants and endodontically treated teeth) might be a disadvantage of the evolved implant system [66, 67]. However, according to the manufacturer’s information, a microbiological study revealed no microbial leakage through the expanded implants. Over the follow-up period, we equally did not observe any inflammatory signs in the apical region, neither clinically nor radiologically (Figs. 4b and 5c–d). Nevertheless, this aspect should be analysed under mechanical loading in vitro. Based on an earlier animal histologic study [47], as well as a clinical up-to-40-month study [46], which referred to comparable apically expandable implants, authors did not report any periapical inflammatory complications. To eliminate the potential risk of deep intrabony microleakage, it is questionable whether equal biomechanical stability values can be achieved only by the macrothread design avoiding any deep microgaps.
In the present study, the crestal bone changes under loading in the first year exceeded that of the second year. Moreover, the differences between the maxilla and mandible in each year were not statistically significant, which only partially agrees with previous findings in the literature [7, 58]. Besides microbiological conditions, there are several biomechanical aspects which influence maintenance of periimplant crestal bone. Conical and parallel surfaces of the implant-abutment connection (internal hexagon) provide rotational stability and reduce microgaps and micromovement [68]. Another important factor is the thickness of the implant shoulder [69], which might be a weak point in the design of a short implant due to elastic deformity under extra-axial loading. This fact might be the reason for non-inflammatory periimplant crestal bone loss. We addressed this aspect by splitting adjacent implants wherever possible [50, 51]. According to Brenner and co-authors [30] as well as Pommer and co-authors [50], the following prosthodontic factors are to be considered to avoid screw loosening, component fracture, loss of marginal bone or even loss of osseointegration: crown-to-implant ratio (extra-axial loading), cantilever length, status of opposing dentition, splinting of adjacent implants, occlusal surface relief and dimensions.
Serial posts:
- Abstract : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results
- Introduction : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [1]
- Introduction : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [2]
- Material and methods : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [1]
- Material and methods : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [2]
- Material and methods : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [3]
- Results : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [1]
- Results : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [2]
- Discussion : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [1]
- Discussion : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [2]
- Discussion : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [3]
- Discussion : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [4]
- Discussion : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [5]
- Conclusion : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results
- Abbreviations : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results
- References : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [1]
- References : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [2]
- References : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [3]
- References : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [4]
- References : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [5]
- References : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [6]
- References : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [7]
- Acknowledgements : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results
- Author information : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [1]
- Author information : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results [2]
- Ethics declarations : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results
- Additional files : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results
- Rights and permissions : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results
- About this article : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results
- Table 1 Patient recruitment : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results
- Table 2 Surgical treatment protocol : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results
- Table 3 Prosthetic treatment protocol : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results
- Table 4 Clinical characteristics of the study cohort : Novel expandable short dental implants in situations with reduced vertical bone height—technical note and first results
- Fig. 1. a Closed short expandable dental implant (4.1 × 7 mm). The implant-abutment connection is characterised by an internal hexagon for rotation stability, combining the advantages of conical and parallel surfaces to reduce microgaps and micromovement [68]. The microthread concept and platform switching concept are implemented in the implant shoulder to reduce periimplant bone strain [53]. b Manual fixation of the expansion tool. Take note of the distance between both yellow rings. c Completion of the expansion process using the ratchet. Take note of the contact between both yellow rings. d Opened short expandable dental implant (4.1 × 7 mm). The expanded implant provides an increased bone-to-implant interface (pyramid shape) in the apical portion [54]. e Cross-section view of the implant apex. The apical expansion process is characterised by the unfolding of four wings, which are connected by four foils. D1: diameter of the closed implant. D2: diameter of the opened implant. fTop v
- Fig. 2. Cumulative implant survival over the follow-up period. The Kaplan-Meyer diagram visualises the analysis of implant survival in the maxilla and in the mandible (log rank test, p = 0.173) over the follow-up period up to 37 months (Table 4) : Novel expandable short dental implant
- Fig. 3. a Primary implant stability. The histogram visualises the distribution of the implant stability quotients (ISQ) for both jaws measured by resonance frequency analysis (Osstell AB, Göteborg, Sweden). b Secondary implant stability. The histogram shows the distribution of the implant stability quotients (ISQ) of osseointegrated implants. According to the measurement implant stability was classified as low with ISQ values < 60, medium with ISQ values 60–70, and high with values ISQ > 70 [34] : Novel expandable short dental implant
- Fig. 4. a–h Prosthetic restauration—follow-up examination. Intraoral and perioral views of a rehabilitated female patient. (She asked explicitly only for implantological treatment in the mandible.) : Novel expandable short dental implant
- Fig. 5. a Postoperative orthopantomogram. b Follow-up orthopantomogram. c Follow-up standard periapical radiogram (implants i42 and i44). d Follow-up standard periapical radiogram (implants i32 and i34) : Novel expandable short dental implant